Clinical Neuroscience Midterm 1

hemmorage aphasia

- 67 yo right handed woman o High blood pressure uncontrolled o Sudden onset of headache, neck pain, nausea, vomiting (hemorrhage symptoms) o Speaking fluently & following commands o Can write sentence and read o Cannot repeat phrases o CAT scan in order to look for hemorrhages o Left hemisphere o Blood vessel bursts and blood leaks into brain tissue o Conduction aphasia § The root or the white matter arcuate fasciculus gets destroyed (what connects broca and Wernicke) o Large number of aphasia is from strokes

damage to MTL episodic memory semantic memory

- Children with damage to MTL can still form new semantic memories even w/ episodic memory deficit o HM can form some semantic memories, but deficits in forming new semantic memories § Temporal gradient - the more remote the memory the better they remember it o Semantic dementia - opposite pattern; remote info is lost and better with recent things § Motor memory o Bilateral medial temporal & Diencephalic § Need to have damage to medial and lateral to develop dense amnesia seen in o HM - no new memories are formed anterograde amnesia § The more recent the memory the worse it is encoded in memory Damage also seen in alzheimer's patients o Cortical system is affected § Lateral temporal o Ok in episodic memory

The President's Speech

- Global aphasia: cannot understand words o They can understand intonation and can "read the room" in order to understand words and phrases o Would need to remove all inflection in words and speak in a robotic voice in order to make them aware of their aphasia - Speech consists of utterance (an uttering-forth of one's whole meaning with one's whole being) - One cannot lie to an aphasiac bc he cannot grasp your words, he can grasp the expression that goes with the words o Understanding without words - Tonal agnosia: lost their tone and character, but can still understand words o Associated with disorders of the left temporal lobe - Paradox of President's speech: normal people were fooled by the president's speech (populus vult decipi, ergo decipiatur) only the brain damaged could be undeceived

History of Neuroscience

- Skull was found in Polynesia and the way it healed, people could tell that the person had survived the event - In ancient Egypt o Brain damage and behavior (hieroglyphics) - Hippocrates o The 4 humors § Chemical imbalance that could cause mental or behavioral problems - Galen o Invented psychotherapy (talk therapy) - Lunacy trials o Figure out what to do with people whose brains were too damaged to function o Would end up in a warehouse which became sort of a human zoo for rich people - Charcot o Treated with hypnosis o Worked with Babinski o By hypnotizing, they found that some problems were due to neurosis, not physiological - Freud o Psychodynamic thinking § Based on Ann O - Phineas Gage o Got a tamping iron go through his head (open head injury) o His personality changed § Abt 20% of people that go through this survive it § When brain is hit, it swells - when people get a hole in their skull the brain is able to release some of that pressure o Observed by Harlow

-Brain Stem and Spinal cord - ventricles

- automatic nervous system o Fluid filled cavities in the brain § Cerebral spinal fluid · Covers the whole brain · Serves as kind of another protective layer · Made by choroid plexus that filters blood · Gets absorbed by arachnoid granulations · Important because you can sample it (lumbar spine) Its like a sample of the brain

Affective States

- mediated by local specialized systems in the brain o trouble with the affective aspects of language, such as intonation (prosody). § Represented in the right hemisphere o Damage to the right temporal area corresponding to Wernicke's area in the left temporal region leads to disturbances in comprehending emotional aspects of speech, for example the ability to appreciate from a person's tone of voice o damage to the right frontal area corresponding to Broca's area leads to difficulty in expressing emotional aspects of speech § meaning that some neurons needed for language also exist in the right hemisphere (such as irony, metaphor, and wit, as well as the emotional content of speech. There is also preliminary evidence that the ability to enjoy and perform music involves systems in the right hemisphere) § Aprosodias, disorders of affective aspects of language that are localized to the right hemisphere, are classified as sensory, motor, or conductive, following the classification used for aphasias. o Ictal phenomena: characteristic emotional changes that occur fleetingly during a seizure § Feelings of unreality, déjà vu, hallucinations, etc o Interictal phenomena: enduring emotional changes when patients are not having seizures § Resemble a coherent psychiatric syndrome § lose all interest in sex, and the decline in sexual interest is often paralleled by an increase in social aggressiveness o patients with epileptic foci outside the temporal lobe typically show no abnormal emotion and behavior o high frequency electrical stimulation of the subthalamic nucleus (part of the motor system) can improve the tremor characteristic of Parkinson disease § stimulation of this region also induces unusual emotional states including euphoria, increased libido, feelings of merriment o amygdala § lies within the cerebral hemispheres § lesions are the opposite of the ones resulting from a stroke or injury · destructive lesions bring about loss of function, often through the disconnection of related functional systems, the electrical activity brought about by epilepsy can increase activity in the regions in which the epileptic seizure occurs. In the case of amygdala seizures the increased activity leads to excessive expression of emotion.

language Broca Wernicke

- medium of thought o Helps create interpersonal space that we all share o Vital to being a social being - discovered that people with damage to left hemisphere had problems producing language o Anthropologist, early localizationist o Most language problems come from stroke patients o Broca's patients had problems with expressive language o Close to primary motor cortex (face and mouth area is close by) o Formulates expressive language o Focused on receptive language o Deficits in language comprehension Core comprehension translating speech sounds into meaning - Brocas area is further forward (frontal lobe) [above fissure] than wernicke's area (temporal-parietal) o Broadman's areas (system of numbering of the cortex) o Neighboring lesions around the areas could cause similar problems o They're along the sylvian fissure § Lateral sulcus o Soundwaves -> ear drum -> cochlea filled with fluid -> translates frequency of soundwaves through patterns of neurons

hippocampus 2 memory circuits alzheimer's

- sends fibers through fornix -> mammillary bodies -> thalamus o Amygdala fugal pathway connected to thalamus o Medial temporal cortex receives info from almost every other part of the brain in terms of senses (entorhinal cortex) § Loop of connections o Why it took a while to make these discoveries o Need to have damage in both circuits in order to have the dense anterograde amnesia o Lateral memory system § Medial temporal cortex § Amygdala § Ventral amygdalofugal pathway § Dorsomedial thalamus (korsokoff) o Medial system § Medial temporal cortex § Hippocampus § Fornix -> mammillary bodies (korsokoff) § Mammillothalamic tract -> anterior thalamus - attacks the whole cortex o Damage is due to molecular changes o Neurodegenerative disease (due to build up of protein)

- Mental processes

- the end product of the interactions between elementary processing units in the brain o Phrenologists introduced the idea of localization in an exaggerated form and without adequate evidence § imagined each region of the cerebral cortex as an independent mental organ dedicated to a complete and distinct aspect of personality § Specific brain regions are not responsible for specific mental faculties but instead are elementary processing units · Perception, movement, language, thought, and memory are all made possible by the interlinkage of serial and parallel processing in discrete brain regions, each with specific functions. As a result, damage to a single area need not result in the complete loss of a cognitive function (or faculty) · a process consisting of several parallel pathways in a communications network that can interact and ultimately converge upon a common set of target cells o the sum of what we mean when we say "I"—is achieved through the connection of independent circuits in our two cerebral hemispheres, each mediating its own sense of awareness o corpus callosum was severed - found that each hemisphere had a consciousness that was able to function independently of the other

The Lost Mariner

- was able to recall his past in vivid detail - changed his sense of tense when speaking about the navy as if it was currently happening - Dr showed him himself in a mirror bc Jimmy believed that he was still 19 - He couldn't remember things that had just happened o He actually could remember that things had recently happened, but he remembered them as if they had happened long ago - At first believed that it was Koraskov's syndrome - Luria had cases that were similar to Koraskov's but which later spread and became fatal - Found no evidence of massive brain damage, however atrophy of mammillary bodies would not show up on EEG tests - Contacted his brother who let them know that jimmy was a heavy drinker - Tried to hypnotize Jimmie to see if he was repressing anything, because there seemed to be a gap in his memory o He could not be hypnotized because he would lose track of what the hypnotist was saying - Jimmy would randomly remember things from the 60's but did not remember that it was from any time after 1945; he would make offhanded remarks about some events that had happened o Over time he would recognize people working in the home but would often confuse them with people he had known in his past - He would not remember his diary entries from the day before but recognized his handwriting - Referred to Jimmy as Humean - He wanted something to do, he was becoming apathetic and depressed - Jimmy was able to focus and function in church - He liked to garden, art, spirituality, music - It seems as though the human spirit can be preserved despite mental disorder - Postscript o Retrograde amnesia is extremely common in Koraskov o However, Koraskov's syndrome is extremely rare in its own, without other pathologies such as tumors - "final" amnesia may occur in terminal dementia but may not happen suddenly in consequences of a stroke - Total koraskov confined to visuality: complete loss of sight, visual memories, any sense of having been a visual being in the past o Sudden thrombosis of the posterior circulation of the brain

molecular and cellular physiology

-ipsilateral = same side o August D: had dementia § Her doctor was Alzheimer § Ppl with dementia with be unaware of their deficits (anosognosia) § After she died, Alzheimer removed her brain so he could examine it § Her brain looked different, it was more spaced out (larger sulci) · Gyri were thinner · Brian atrophy: shrinkage (particularly of the cerebral cortex) · Cerebellum stays pretty much the same § Took sections of the brain and stained them · He found that there were inclusions in the cells (tangles of the fibers) · Eventually led to ghost tangles (neural tangles but no more neuron) · Primary motor and sensory (and visual) had no damage § What seems to happen is that brain becomes disconnected from itself · Nodes that send out projection fibers have been destroyed or severely damaged § Amyloid plaque (senile plaque) · Outside of the cells (protein called amyloid) and tangles were inside the cell (tao) o Early onset familial Alzheimer's disease § Autosomal dominant pattern · Not a sex chromosome · You only need one copy of the gene in order to get it § 100% of Down syndrome develop Alzheimer's · Early onset · Evidence that Alzheimer's gene is on chromosome 21 o Histones have DNA strands wrapped around them (histones are in chromatids) o Polymorphisms (mutations/variations in a gene) § Gene that codes amyloid precursor protein · Some people had too much amyloid · Cleaved at multiple sites to make amyloid found in Alzheimer's brain · All mutations led to formation of amyloid that led to mutations in the brain · Get a lot of b secretase cleavage § More than 90% of Alzheimer's disease cases are not due to a known genetic abnormality or familial cause · Doesn't have to run in your family § Exon: codes for amino acids § Intron: just there § RNA: need to get rid of introns to make the protein (exons get spliced together) · One RNA molecule can make different proteins depending on how its spliced · If histone is tightly bound, gene will not get expressed o Found that certain genes can be expressed as a result of the environment

Broca's Aphasia Wernicke's Aphasia

74 yo right handed woman o History of heart disease o Language is all about the blood vessels in the brain (stroke is key) o Suddenly stopped speaking o Weak on right side of the body o Speaking in single words/ short phrases o Able to follow commands § Best way to test understanding o Could not repeat words o Couldn't read § Important bc you need to see if there's an issue with language or the ability to form words o Couldn't write full sentences o Seems to be expressed language bc she cant understand o Lesion in the left frontal lobe o Radiology scans are flipped (they switch sides) o Lesion in Broca's area (stroke) o Ischemic stroke: no treatment due to late arrival § Cardiovascular disease -> blood clots -> strokes § Clot blocked the vessel so now the brain is no longer getting blood flow § Cells will die in the brain without blood flow · Infarction o If you get there on time, they put a line through femoral artery in leg to break up the clot o 2 months later she could speak sentences § Very mild pauses and naming problems (dysnomia) § Most ppl with aphasia have word finding problems o Localizationalist an equipotentiality supporters were right and wrong § L: right bc they discovered Broca's area · Wrong bc after a few months memory improves o E: lashley's idea that other neurons pick up the slack o Non-fluent aphasia (Broca's aphasia) § Problems with repetition § Might be bc you destroy the connection with wernicke's area o Frustrated because she could not express herself - 81 yo right handed woman o History of heart disease o Suddenly cant communicate properly o Speaking words that don't make sense o Person can speak fluently but doesn't make sense o Cant follow commands (might be bc she cant comprehend language o Double dissociation from Broca's § Deficits and preserved functions are opposite of Broca's aphasia o Grammar, syntax, and fluency is intact o Pleasant and unconcerned disposition § She's unaware that she has a problem · Anosognosia o Comprehensive language has been deleted from their language o Posterior left hemisphere § Infarct Cant get repetition bc connection to Broca's has been severed

normal orientation in the brain midbrain orienting in 3D

Dorsal Rostral + caudal ventral rotates 90 degrees (orientation is more like a lizard) bc midbrain turns along the spine rostral ventral + Dorsal caudal - Medial: towards the middle/ lateral towards the outside - Orienting in 3D o Coronal plane (vertically) think of the crown § Can see the ventricles and both hemispheres o Horizontal plane § Can see the ventricles and chambers o Sagittal (bow & arrow) § Frontal temporal parietal and occipital lobe § Cut down the middle (splits forehead in half)

cellular and molecular basis of memory

o Aplysia § Slug boi; can learn simple behaviors § Habituation § Long term sensitization · Repeated tail shock - gill retraction will be more vigorously and it stays that way · Facilitating interneuron can cause change in the motor neuron of the gill that forms the memory o The shock -> facilitating interneuron -> motor neuron -> retracts gill o Shock sends serotonin which causes calcium to enter the cell, which causes more neurotransmitters to go to the motor neuron o Growth of synapse bc new connections are forming · Serotonin from facilitating neuron o Increases transmitter release o Triggers gene expression of growth proteins leading to synapse growth · More vigorous gill withdrawal o Nonconscious memory in basal ganglia can create memory (non-associative forms of learning) o Classical conditioning § Bell has to come first then the food § In order for this to work · Coincidence detector o Just touching the skin will cause excitatory neuron to fire bc new synaptic connection has been established § Impaired in Huntington's disease (not in HM's case) o Basal ganglia is necessary for motor learning and procedural memory and classical conditioning Double dissociation from medial temporal injury and semantic dementia

HM

o Bilateral medial temporal lobes (hippocampus was resected in an attempt to control his medically refractory epileptic seizures) o Unable to recall new facts or experiences o Led to intensive investigations of the medial temporal lobes' role in human memory § Patients today with the same problem (medically refractory temporal lob epilepsy) can be cured with unilateral medial temporal lobe resection · Bilateral mtlr is no longer performed bc of what happened with HM o What was learned § Declarative (explicit) memory: conscious recollection of facts or experiences · HM suffered loss in this area · Amnesia: usually used to describe declarative memory loss o Typical of bilateral medial temporal lobe or bilateral medial diencephalic lesions § Unilateral lesions don't typically produce severe memory loss · Unilateral lesions of the dominant (usually L) medial temporal or diencephalic structures can cause some deficits in verbal memory · Lesions on the nondominant (usually right) hemisphere can cause deficits in visual-spatial memory § Nondeclarative (implicit) memory: nonconscious learning of skills, habits, and other acquired behaviors · Specific lesions don't usually result in clinically significant selective loss · Learning of skills and habits likely involves plasticity in areas including basal ganglia, cerebellum, and motor cortex · Caudate nucleus: habit learning (may be linked to OCD) § Priming (several cortical areas); classical conditioning, habituation and sensitization ( cerebellum [CC], amygdala [conditioned fear], cerebral cortex, brainstem nuclei, and spinal cord) o Temporal aspects of memory and memory loss § Immediate recall, attention, and working memory are tested when examining memory · Do not depend on the medial temporal or medial diencephalic memory system · Alertness and attention are mediated by an interaction of the brainstem—diencephalic and frontoparietal networks · Working memory: holding a particular concept briefly in awareness while a mental operation is performed o Involves participation of the dorsolateral prefronal association cortex § First working ( attention) memory should be tested, in order to see that they can register new information, followed by recent memory test ( bilateral medial temporal or medial diencephalic regions) § Remote memory tested by asking about personal info (medial temporal or medial diencephalic · Seem to mediate a process in which declarative memories are consolidated in neocortex o Anterograde amnesia: deficit in forming new memories o Retrograde amnesia: loss of memories from a period of time before the brain injury · Suggests that recent memories are dependent on the normal functioning of medial temporal and diencephalic structures (more remote memories are not) § Lesions in medial temporal lobe or medial diencephalic memory systems: combo of retrograde and anterograde amnesia for declarative memories o *** memory storage and anatomical structures *** o Patients with reversible causes of amnesia: retrograde amnesia shrink s forward (older memories recovered before more recent ones) § Short time period (hours) of permanently lost memories from before the injury and a period of lost memories from injury until the time they recover from the anterograde amnesia o Why are short term and long term not ideal terms? § Bc long-term memory includes recent memories that are disrupted by bilateral medial temporal or diencephalic disorders o *** causes of memory loss chart*** o Differential diagnosis of memory loss § Cerebral contusions: caused by head trauma - anteromedial temporal lobes/ basal orbitofrontal cortex—permanent deficits in memory § Concussion: memory loss that is usually reversible § Infarcts/ ischemia: memory deficits - when bilateral medial temporal or medial diencephalic structures are affected - lesions at the top of basilar artery are positioned to cause bilateral mt or medial dp infarcts § Global cerebral anoxia: cardiac arrest - memory loss is prominent - vulnerability of the hippocampus to anoxic injury § Anterior communicating artery aneurysm: damage basal forebrain - cause memory loss together with other deficits seen in frontal lobe lesions § Wernicke-koraskoff syndrome: thiamine deficiency - bilateral necrosis of the mammillary bodies and a variety of medial diencephalic and other periventricular nuclei · Thiamine deficiency - eye movement abnormalities and a confusional state · Severe cases can result in coma or death · People who survive acute stages are left with both types of amnesia thought to be caused by bilateral diencephalic lesions · Usually have other dysfunctions that suggest frontal lobe damage · Tend to guess instead of saying they don't remember § Seizures: memory loss during and right after - memory in general may be normal unless caused by lesions of mtl such as hippocampal sclerosis · Ect is effective for refractory depression § Transient global amnesia: develop both types of amnesia out of nowhere - occur under stress - lasts 4-12 hrs § Alzheimer's: affect bilateral hippocampal, temporal, and basal forebrain structures § Psychogenic amnesia: don't have a pattern of either amnesia affecting mainly recent memories - have memory loss for events of emotional significance § Infantile amnesia: 1-3 yrs of life § Benign senescent forgetfulness: normal mild decline in memory over years

- Central Nervous System

o Brain and Spinal Cord § During development forms from a neural tube - form ventricles filled with cerebrospinal fluid (CSF) § Brain · Forebrain (prosencephalon), midbrain (mesencephalon), hindbrain (rhombencephalon) o Forebrain is the largest part of the nervous system in humans (subdivisions: telencephalon and diencephalon) § T: (end brain) made up of cerebral hemispheres § D: thalamus, hypothalamus, associated structures § Sits on top of the midbrain, pons and medulla (brainstem) · Most ancient part of the human brain [resembles the brains of fish and reptiles] o controls most basic bodily functions (respiration, blood, pressure and heart rate) o Midbrain: connects forebrain and hindbrain § H: pons and cerebellum together with the medulla § Midbrain, Pons, and Medulla connect the forebrain and the spinal cord · Cerebrospinal fluid formed by lying within the ventricles called choroid plexus o Lateral ventricles -> third ventricle -> 4th ventricle § Covered by meninges: from inside to out: pia, arachnoid, and dura) PAD · CSF travels between arachnoid and pia after leaving the venous system § Orientations · Ventral (bottom); dorsal (top); rostral (front); caudal (back) aka inferior, superior, anterior, posterior o Turns 90 degrees around the forebrain and spinal cord (in the region of the midbrain · Imaging: horizontal sections (axial or transverse) horizontal to the floor o Coronal - vertical o Sagittal: down the middle from forehead to back of head § When down the midline: midsagittal; just off the midline: parasagittal · When a plane lies somewhere between the 3 planes its called oblique § Gray matter (cell bodies) and White matter (myelinated axons) · Most of the synaptic communication between neurons occurs in gray matter; axons in the white matter transmit signals over greater distances · Cerebral cortex = gray matter o Pic of cerebral hemisphere, brainstem, spinal cord o Cerebral hemisperes: the gray matter outside while white matter inside o Spinal cord: white matter outside and gray matter inside o Brainstem: gray and white are found on inside and out but most of the outside is white matter · Basal ganglia, thalamus, cranial nerve nuclei are in cerebral hemisphere and brain stem § White matter in CNS: tract, fascicle, lemniscus, bundle · Pathway that connects structures on the right and left sides of the CNS is called commissure

mass actoin

o Brain is so interconnected that you can't separate one camp from another § More of a question on how big the damage is · Equipotentiality: each brain area can do what the other areas can do · Carl Lashley: cut the rats brains to see if he could find which part of the brain stored memory o Experiments were flawed bc didn't take into account the other sense · Plasticity o Wilder penfeld § Figured out that currents through the brain makes you twitch, so he thought that maybe certain areas of the brain control certain parts of the brain § Discovered primary motor cortex § Was able to do experiments on patients awake bc brain doesn't have nerves · This was ground breaking bc the person is able to talk and tell the surgeon what's going on § They would stimulate an area and would figure out what part of the brain moved what · Mapped out the body senses and body movement areas of the brain · Precentral gyrus: before the central sulcus · Post central gyrus: body sensations · Figured out that hemispheres control the opposite sides of the bodies § Somatotopic maps (body maps of the brain) · Aka (little person) homunculi

-Neural structure & supporting structure -grey v white matter -limbic cortex underneath the cerebral cortex

o Dendrites -> Cell body -> axon -> oligodendrocyte (glial cell) [protects the axon; includes nodes of ranvier] o Communicate chemically, operate electrically o G: the tissue mostly made up of cell bodies o W: mainly axons (corpus callosum) o Older cortex o Phylogenetic = evolutionary development o Ontogenetic = development of an individual (aka baby to adult)

- Vascular territories of different arteries

o Determine brain injury by stroke o Medial cerebral artery § Superior division (b) § Inferior division (w) § Watershed zone · Between middle cerebral territory and the other ones (surrounds both divisions) · Damage to areas in this zone = mild versions of aphasia o Transcortical motor aphasia § Broca's aphasia but repetition intact o Transcortical sensory § Wernicke with intact repetition o Transcortical mixed aphasia § Global with intact repetition § 4 vessels feed the brain · Carotid artories and vertebrals arteries (thru vertebrae) o R & L o Where all the blood flow to the brain comes from o Vertebrals come from the brain stem emerge in basilar artery § Connects to carotids o Carotids come in to form vessels in middle cerebral artery § Takes over area of language § Shares watershed region with anterior and posterior o Posterior communication arteries Anterior cerebral artery connected by interior communicating artery · All connected in circle of willis (protects us from brain damage due to brain vessels being blocked) o All vessels are connected in case one of the arteries get cut off o Anomic aphasia: when people improve and end up with naming problem o For most people the left is dominant o Right hemisphere is mute and does the bidding for the left hemisphere § Can help in terms of brain injury to take over the injured parts

episodic v semantic memory

o Double Dissociation § What abilities are truly dissociable? § Episodic memory (what's happened to you) v semantic memory (general knowledge) § Multiple trace view - there are two completely different memory stores in the brain, they do not blend o 68 yo woman who was an engineer § Difficulty remembering names (aware of deficit) § Progressive loss of semantic knowledge · Losing knowledge of meaning of words § Autobiographical and episodic memory was intact § The left temporal lobe showing atrophy; hippocampus is intact · Sulci are expanding and gyri are shrinking o Suggests that semantic memory is stored in different areas of temporal cortex § Breakdown in semantic networks § Semantic dementia caused by TDP-43 · Plays a role in transmission of proteins and splicing § Eventually progresses to worse memory loss § Both medial and lateral circuits need to be damaged in order to have damage to episodic memory § Damage to cortex of temporal lobe - loss of word meaning and knowledge about the world

working memory (attention span)

o Ebbinghaus § Learning curve forgetting curve § Quizzed himself to see what he could remember and at what point he would forget · Saw that there was some amount that he kept § HM: had poor immediate attention span § Rate of forgetting with study/ repetition · Every 20 minutes you lose memory, but if you practice over and over again the loss of memory is slower and slower · You can train yourself to retain as close to 100% as possible o Initial attention span vs working memory § Temporary storage that HM was able to retain § We can store 5-9 bits of info in short attention span (this was intact in HM ) § Working memory · You can manipulate the memory § Phonological loop · You can loop info and keep it there indefinitely · Saying something over and over again o HM could do this but if you distract him he would forget § Nonverbal information (visual sketchpad) · Call up imagery and mentally manipulate it o HM can do this too § All these functions are performed by the frontal lobe · Mental manipulation information o 78 yo widowed man § Cardiovascular disease history § Lives alone § One day they came and the house was a mess, wasn't taking care of himself § Did an episodic memory for a word list · Impaired free recall § But recognition memory was intact · he could remember everything on the list when asked about it · this is different bc its recognition, not forced choice § damage to white matter that connects frontal lobe to the rest of brain § ppl with vascular disease sometimes spreads to brain · have problems with attention and working memory § he was forming new memory but he couldnt retrieve them bc frontal lobe wasn't working o frontal lobe Medial Temporal & Diencephalic Regions Cerebral Cortex o working memory & retrieval -> encoding and consolidation -> long term storage o in first cases, middle section wasn't working o semantic dementia, last section wasn't working o vascular dementia, front section wasn't working, poor attention o basal ganglia cerebral cortex o procedural memory & classical conditioning priming & sensory memory o huntingtons: basal ganglia issues

karl lashley HM

o Engram (parts of the brain responsible for memory) o Cut cerebral cortex of rats § He missed the memory areas (they are below the cortex) - o Show us that there are different kinds of memory which are stored in different areas of the brain o Had epilepsy (neurons become hyperexcited) § Grand mal seizure - whole body seizes § Kindeling effect: each seizure causes more damage, so every time you have one you're more likely to have another one o Neurosurgery: record different areas of the brain to try to figure out where it's coming from § Locusts: where abnormal tissue is o Cut the bilateral medial temporal cortex § Removed amygdala, hippocampus, cortex o Normal intelligence, normal personality, normal attention span o Forget any info after a period of seconds-minutes § Couldn't remember any new information (anterograde amnesia) ; couldn't remember things for a few years prior to surgery (retrograde amnesia) o Still had remote memory, immediate memory span o Still had semantic memory (knowledge of facts) o Autobiographical memory was deficient after brain injury o Motor learning § Could learn new motor tasks (drew a star in a mirror) o Declarative memory (explicit): you're making a conscious effort to remember something § *damage to medial temporal lobe - where HM was deficient* § Facts § Events (HM deficient) o Nondeclarative (implicit): unconscious memory - riding a bike

HM and new semantic memories

o Even though he cant for new episodic memories o He loved crossword puzzles § Gave him a new one developed after his injury § Reference new pop culture that he could not know because we're assuming that he can't form new semantic memories · He was not conscious that he knew this info, but he did pretty well on the crossword - HM would not have been able to do the memory exercise we did - We are better at forced choice - out of a list of words which were on the OG list? o Patients like HM get more correct than you would think § He may have learned some new semantic memory even if not conscious of it

NA

o Foil went into right nostril and broke nose bone (separates nasal cavity from brain) § Area of the thalamus was stabbed & crossed over in left thalamus (left hemisphere) o Eye movement abnormalities, weakness in right side o Normal intelligence, normal personality, normal attention span, normal remote memory (could remember things about his childhood), normal motor learning, normal knowledge of facts, rapid forgetting of verbal information § If you told him a story and then asked him about it 30 minutes later he wouldn't remember § But if you asked him to copy a design 30 mins later he could § May be bc language section is in the left hemisphere o Mammillary bodies taken apart in accident § Connected to thalamus through a tract § Alcoholic Korsakoff Syndrome · Bilateral - affects both hemispheres · Wernicke Encephalopathy o Get into a confused state § Can come back from this · Wernicke-Korsakoff o Dense amnesia o Damage to mammillary bodies and thalamus · Vitamin B deficiency · Lost mariner** · Rapid forgetting - anterograde amnesia · Lose taste for alcohol § Can also get it bc of anorexia o Mammillary bodies begin to atrophy § Ventricles expand and spinal fluid fills - Damage to right hemisphere have problems with nonverbal memory

Lesions usually affect neighboring regions as well - critical in localizing neuroanatomical lesions --comparing the CNS and the PNS

o Glial cells in CNS: oligodendrocytes o Glial cells in PNS: shwann cells o CNS: excitatory NT: glutamate; inhibitory NT: GABA o PNS: acetylcholine = main transmitter at neuromuscular junctions; both acetylcholine and norepinephrine are important in the automatic nervous system o Pathways carrying signals toward a structure are afferent, carrying away are efferent § PNS have afferent sensory info to send to CNS and carry efferent signals for motor activity from CNS to periphery

-Hebb -limits to semantic memory

o LTP § Gives a sense of the strength of connections between neurons § If there's a lot of activity between cells, increases level of efficiency to communicate with each other o Loop: all senses & motor -> MT circuit -> cortex § Coincidence detectors · Can form an associative memory o Info is conveyed back to the cortex · MT is storing some of these memories through coincidence detectors and causing a change back in the cortex · This is how hippocampus is forming new memories and storing as new associations o Working memory 5-9 units of info (frontal lobe) lasts seconds to minutes o Long term storage has exponential forgetting curve and limit § Medial temporal lobe; minutes, hours days months years o Semantic memory has no known limits § Stored in the cortex; years, decades; physiological limits: 100 trillion synapses · We can store hella information in our cortex

Motor systems

o Main motor pathways § most important motor pathway in humans is the corticospinal tract. The corticospinal tract begins mainly in the primary motor cortex, where neuron cell bodies project via axons down through the cerebral white matter and brainstem to reach the spinal cord § sometimes called the pyramidal tract because of its triangular shape in the medulla § The majority of fibers in the corticospinal tract (about 85%) cross over to control movement of the opposite side of the body. This crossing over, known as the pyramidal decussation, occurs at the junction between the medulla and the spinal cord. Thus, lesions occurring above the pyramidal decussation produce contralateral(opposite-sided) weakness with respect to the lesion, while lesions below the pyramidal decussation will produce ipsilateral (same-sided) weakness. o Cerebellum and basal ganglia § do not themselves project directly to the LMNs. Instead, the cerebellum and basal ganglia act by modulating the output of the corticospinal and other descending motor systems. The cerebellum and basal ganglia both receive major inputs from the motor cortex. The cerebellum also receives significant inputs from the brainstem and spinal cord § The cerebellum and basal ganglia, in turn, project back to the motor cortex via the thalamus § Lesions in the cerebellum lead to disorders in coordination and balance, often referred to as ataxia. Lesions in the basal ganglia cause hypokinetic movement disorders, such as Parkinsonism, in which movements are infrequent, slow, and rigid, and hyperkinetic movement disorders, such as Huntington's disease, which is characterized by dancelike, involuntary movements.

Brainstem and Cranial Nerves

o Most cranial nerves arise from the brainstem § both sensory and motor functions. However, they also carry out more specialized functions relating to the organs of the head o the brainstem contains nuclei that play important roles in the motor system; nuclei that produce nausea and vomiting in response to certain chemicals; modulatory nuclei containing the neurotransmitters norepinephrine, serotonin, dopamine, and acetylcholine § nuclear areas involved in pain modulation; and nuclei controlling heart rate, blood pressure, and respiration, among other functions. § contains many of these nuclei is the reticular formation. Named for the network-like appearance of its fibers in histological sections, the reticular formation extends throughout the central portions of the brainstem from the medulla to the midbrain. The more caudal portions of the reticular formation in the medulla and lower pons tend to be involved mainly in motor and autonomic functions. The rostral reticular formation in the upper pons and midbrain plays an important role in regulating the level of consciousness, influencing higher areas through modulation of thalamic and cortical activity · lesions that affect the pontomesencephalic reticular formation can cause lethargy and coma. · the level of consciousness can also be impaired in bilateral lesions of the thalami or in bilateral (or large unilateral) lesions of the cerebral hemispheres · mass lesions above the brainstem often cause impaired consciousness indirectly when they exert pressure on the brainstem through mass effect, thus distorting or compressing the reticular formation and thalamus. o Limbic system § includes deeper structures, such as the hippocampal formation and the amygdala, located within the medial temporal lobes § interconnected by a variety of pathways, including the fornix—a paired, arch-shaped white matter structure that connects the hippocampal formation to the hypothalamus and septal nuclei § Lesions in the limbic system can cause deficits in the consolidation of immediate recall into longer-term memories. Thus, patients with lesions in these areas may have no trouble recalling remote events but have difficulty forming new memories § epileptic seizures most commonly arise from the limbic structures of the medial temporal lobe, resulting in seizures that may begin with emotions such as fear, memory distortions such as déjà vu, or olfactory hallucinations o association cortex § carries out higher-order information processing § unimodal association cortex, higher-order processing takes place mostly for a single sensory or motor modality. Unimodal association cortex is usually located adjacent to a primary motor or sensory area § Heteromodal association cortex is involved in integrating functions from multiple sensory and/or motor modalities. o Language is usually perceived first by the primary auditory cortex in the superior temporal lobe when we are listening to speech or by the primary visual cortex in the occipital lobes when we are reading. o Wernicke's area: in L hemisphere § Lesions cause deficits in language comprehension (receptive or sensory aphasia/ wernicke's aphasia) o Broca's area: located in frontal lobe, left hemisphere adjacent to the areas of primary motor cortex involved in moving the lips, tongue, face, larynx § Lesions cause deficits in the production of language with relative sparing of language comprehension (expressive or motor aphasia/ Broca's aphasia) o Lesions in the inferior parietal lobule in the left hemisphere can produce an interesting constellation of abnormalities, including difficulty with calculations, right-left confusion, inability to identify fingers by name (finger agnosia), and difficulties with written language. This group of abnormalities is called Gerstmann's syndrome o diffuse lesions of the cortex, or sometimes more focal lesions affecting the frontal or left parietal lobe, can produce abnormalities in motor conceptualization, planning, and execution called apraxia. o lesions in the parietal lobe, especially in the nondominant (usually right) hemisphere, often cause a distortion of perceived space and neglect of the contralateral side o right parietal lesions can cause left hemineglect. With this syndrome, patients will often ignore objects in their left visual field o Unawareness of a deficit is called anosognosia o extinction, in which a tactile or visual stimulus is perceived normally when it is presented to one side only, but when it is presented on the side opposite the lesion simultaneously with an identical stimulus on the normal side, the patient neglects the stimulus on the side opposite the lesion o * primal reflexes* o Lesions in the visual association cortex in the parieto-occipital and inferior temporal lobes can produce a variety of interesting phenomena, including prosopagnosia (inability to recognize faces), achromatopsia (inability to recognize colors), palinopsia (persistence or reappearance of an object viewed earlier), and other phenomena. Seizures in the visual association cortex can cause elaborate visual hallucinations.

localized function

o Paul Brocca: people with damage in the left frontal lobe had a hard time speaking fluently o Werkicke: found lesions on the left posterior part of the brain and people had a hard time comprehending language o Phrenology § Map of the brain § Became pseudoscience

- Overall view of brain information flow

o Primary sensory cortex § 1st part that becomes activated and begins to process information § Multiple loads of sensory information o Gets passed to association areas (unimodal association cortex) o Sensory multimodal association (heteralmodal) § Higher level of processing, combining all the senses § Gets conveyed to the frontal lobe o Motor multimodal association § Motor association cortex § Primary motor cortex (body movements) o Limbic cortex concerned with memory and emotion o Language is in the frontal lobe o Wernicke's area is next to auditory cortex

- Cortical nondeclarative implicit learning -nondeclarative learning

o Sensory imprint § Neural representation after the sensory input is gone § Occurs in cortex (visual centers in brain) o Priming § Not MTL system § Implicit info happens in the cortex o Sensory learning in cortex § Monkeys were given a very delicate task to do which involved sensation in fingertips · Somatosensory cortex grew · Plasticity in cerebral cortex · Implicit memory o HM lost episodic memory (MTL injury) o Semantic dementia lost facts (lateral temporal injury) o Motor learning o SH § No medical problems up to this point § Experiencing depression and abnormal face and arm movements · Sticking tongue out & writhing arm movements § Normal memory § Couldn't learn new motor tasks (couldn't do mirror tracing task) § Double dissociation (opposite of HM) § Large sulci ( spinal fluid in brain) § Atrophy in the striatum surrounding the basal ganglia caudate & putamen shrunken § 50 copies of the CAG repeat in Huntington gene · If you have more than 36 repeats of the CAG you have huntington's § Huntington's Disease · Genetic disorder HTT gene (4p16.3) · Autosomal dominant pattern of inheritance like in Alzheimers · Polyglutamine cant be processed in the brain so it builds up in the basal ganglia · Coria: hypokinetic movement · Basal ganglia is important in regulating automatic movements o Cant learn new movements without bg o Basal ganglia injury: messes with nondeclarative memory § Skills and habits, simple classical conditioning impairment

-golgi -somatosensory pathways

o Silverstain technique § You can stain neurons to map them out § Doesn't stain every cell o Thalamus -> medulla § Decussation (signal crosses over to medulla) · This is why each hemisphere controls the opposite side o Proprioception "limbic position sense" § You can sense the position of the limbs · Some people can lose the feeling of being in your body/ can't sense your limbs o Fine touch § Pain, temperature, crude touch include different pathways and different types of sensors o Motor pathways § Precentral gyrus § Pyramidal system · Bc it decussates in a pyramid shape in the medulla · Exists through peripheral nerve o Extrapyramidal system controls involuntary movement § Series of loops between the cortex, basal ganglia, thalamus, pons, cerebellum § Basal ganglia · Straitum o Caudate o Putamen · Globus pallidus o Lateral o Medial · Thalamus o Relay station that does a lot of processing and passes communication along o Sensory cortex § Has a thicc 4th layer bc that's where all the sensory info is coming in (afference) [efference is going out] o Motor cortex has a thick layer 5 · Cerebellum

Somatosensory Systems

o Somatic sensation: conscious perceptions of touch, pain, temperature, vibration, and proprioception (limb or joint position sense) § 2 main pathways for somatic sensation · 1. The posterior column pathways convey proprioception, vibration sense, and fine, discriminative touch. · 2. The anterolateral pathways convey pain, temperature sense, and crude touch. § primary sensory neuron cell bodies are located outside the CNS in the dorsal root ganglia and that they have bifurcating axons, with one long process extending to the periphery and one into the spinal cord o posterior column pathway: Primary sensory neuron axons carrying information about proprioception, vibration sense, and fine touch enter first the spinal cord via the dorsal roots and then the ipsilateral white matter dorsal (posterior) columns to ascend all the way to the dorsal column nuclei in the medulla § make synapses onto the secondary sensory neurons, which send out axons that cross over to the other side of the medulla. These axons continue to ascend, now on the contralateral side, and synapse in the thalamus, and from there neurons project to the primary somatosensory cortex in the postcentral gyrus. o Anterolateral pathway: Axons from the secondary sensory neurons cross over to the other side of the spinal cord and ascend in the anterolateral white matter, forming the spinothalamic tract. After synapsing in the thalamus, the pathway again continues to the primary somatosensory cortex. § Thalamus: nearly all pathways that project to the cerebral cortex do so after synapsing in the thalamus · consists of multiple nuclei. Each sensory modality, including vision, hearing, taste, and somatic sensation, has a different nuclear area where synapses occur before the information is relayed to the cortex (olfactory inputs are an exception and do not pass directly through the thalamus) · virtually all cortical regions project strongly via layer VI back to the thalamic areas from which their major inputs arise. o Stretch reflex § The monosynaptic stretch reflex is a well-studied reflex arc that provides rapid local feedback for motor control. The reflex arc begins with specialized receptors called muscle spindles, which detect the amount and rate of stretch in muscles § In the spinal gray matter the sensory neurons form multiple synapses, including some direct synapses onto LMNs in the anterior horn. The LMNs project via the ventral roots back out to the muscle, causing it to contract. Damage anywhere in this pathway can cause the reflex to be diminished or absent. § if these higher centers or their descending pathways are damaged, the stretch reflex may become hyperactive or hypoactive. Thus, by testing the stretch reflex on neurologic exam, one obtains information about multiple pathways, including sensory neurons and motor neurons in the PNS and descending modulatory pathways in the CNS. Often known as the deep tendon reflex bc you test it by tapping a tendon

primary auditory cortex

o Sound gets conveyed first in the brain stem then goes up to the cortex o Auditory info goes straight to both hemispheres instead of going to L or R § Different compared to somatosensory § If you get brain damage on one side, you would still be able to hear out of both ears o If damage to primary somatosensory cortex on the right, you will not feel anything on your left side o Heschel's gyrus/ transverse temporal gyri § Laying flat inside the brain § Not a language area § Only processes sounds *initial place where sound is processed*

CNS

o Spinal Cord: receives and processes sensory info § Continues as the brain stem (receives sensory information from the skin and muscles of the head as well as provides motor control for head) o Also conveys info from spinal cord to the brain and vice versa o Regulates levels of arousal and awareness through reticular formation · Medulla oblongata : includes centers responsible for vital autonomic functions (digestion, breathing, control of heart rate) · Pons : info about movement from the cerebral hemispheres to the cerebellum · Midbrain: controls many sensory and motor functions (eye movement and the coordination of visual and auditory reflexes · Cerebellum: modulates the force and range of movement & involved in learning motor skills · Diencephalon: contains thalamus (processes info reaching the cerebral cortex from the rest of the nervous system) o Hypothalamus (regulates autonomic, endocrine, and visceral functions) · Cerebrum: consists of both hemispheres (made up of cerebral cortex) and 3 deep lying structures (the basal ganglia, the hippocampus, and the amygdaloid nuclei) o Basal ganglia: regulate motor performance o Hippocampus: memory storage o Amygdaloid nuclei coordinate the autonomic and endocrine responses of emotional states § Tying it all together: hindbrain (medulla oblongata, pons, and cerebellum), midbrain, and forebrain (diencephalon and cerebrum). · The hindbrain (excluding the cerebellum) and midbrain together include the same structures as the brain stem

-basal ganglia -lower structures -spinal cord -brain stem spinal

o Striatum § Caudate § Putamen o Thalamus (2 of them) § Connected to cortex and connects upper and lower structures o Midbrain o Brainstem o Part of the central nervous system o Peripheral nervous system (once nerves exit the spinal cord) Voluntary movement

Evidence for localization of cognitive abilities

o Studies of language disorders § Aphasia: occurs when certain areas of brain tissue are destroyed § Broca was the first to ID areas of the brain concerned with language · Broca's area: posterior region of the frontal lobe § the right hand, the one most used for writing and skilled movements, is controlled by the left hemisphere, the same hemisphere that controls speech. In most people, therefore, the left hemisphere is regarded as dominant. · Grammar § Wernicke: the lesion occurred in the posterior part of the cortex where the temporal lobe meets the parietal and occipital lobes · Conduction aphasia (paraphasia): incorrect use of words o Aware of their own errors · Cytoarchitectonic method: distinguished 52 anatomically and functionally distinct areas in the human cerebral cortex o Lashley critical of this § Rats and maze study; the severity of a learning defect depended on the size of the lesion, not on its precise location · Later discredited bc so many senses are involved and this was not accounted for · After this many other psychologists concluded that learning and other higher mental functions have no special locus in the brain and cannot eb attributed to specific collections of neurons § Aggregate-field view of the brain dominated experimental thinking § Mass action: full mass of the brain is critical to function · This was applied to aphasia, in which language disorders can result from injury to almost any cortical area § Localization of function · Touching different parts of a cat's body elicits electrical activity in distinct regions of the cerebral cortex · functionally distinct areas of cortex can be defined unambiguously according to anatomical criteria such as cell type and cell layering, connections of cells, and—most importantly—behavioral function. · functional specialization is a key organizing principle in the cerebral cortex, extending even to individual columns of cells within a functional area § Penfield & Ojemann · Asked to interact during brain surgery for epilepsy · Insula was discovered § PET & fMRI = anatomical analysis § Hirsch: If the second language is acquired in adulthood, it is represented in a region separate from that which represents the native language. If the second language is acquired early, however, both the native language and the second language are represented in a common region in Broca's area. · indicate that the age at which a language is acquired is a significant factor in determining the functional organization of Broca's area § language instinct (Musso and Morro) · Darwin suggested that the acquisition of language is an inborn instinct · Chomsky: believed that humans have the ability of generalizing to a complete and coherent language o Universal grammar: implies that there is an innate system in the human brain that evolved to mediate this grammatical design of language · the region of Broca's area concerned with second language becomes established and increases in activity only when an individual learns a second language that is "natural," that is, one that shares the universal grammar. If the second language is an artificial language, a language that violates the rules of universal grammar, activity in Broca's area does not increase. o Broca's area must contain some kind of constraints that determine the structure of all natural languages. · Deaf people can lose their ability to sign if they get damage to certain areas of the brain o Signing is also localized to the left hemisphere (deaf people can become aphasic for sign language) o 3 points of this finding § the cognitive processing for language occurs in the left hemisphere and is independent of pathways that process the sensory and motor modalities used in language. § fully functional auditory and motor systems are not necessary conditions for the emergence and operation of language capabilities § spoken language represents only one of a family of language skills mediated by the left hemisphere · Similar conclusions that the brain has distinct cognitive systems have been reached from investigations of behaviors other than language · visual system, a dorsal cortical pathway is concerned with where an object is located in the external world while a ventral pathway is concerned with what that object is.

The Brain and Behavior

o The current challenge in the unification within biology , is the unification of the study of behavior—the science of the mind—and neural science—the science of the brain. § Mind and body are not viewed as separate entities - all behavior is the result of brain function o Mind = set of operations carried out by the brain

Blood supply to the brain and spinal cord

o The internal carotid arteries form the anterior blood supply, and the vertebral arteries, which join together in a single basilar artery, form the posterior blood supply o e anterior and posterior blood supplies from the carotid and vertebrobasilar systems, respectively, join together in an anastomotic ring at the base of the brain called the circle of Willis o the anterior and middle cerebral arteries derive their main blood supply from the internal carotid arteries (anterior circulation), while the posterior cerebral arteries derive their main supply from the vertebrobasilar system (posterior circulation). The main arteries supplying the brainstem and cerebellum also arise from the vertebral and basilar arteries. These include the superior, anterior inferior, and posterior inferior cerebellar arteries. Venous drainage for the brain is provided almost entirely by the internal jugular veins. The spinal cord receives its blood supply from the anterior spinal artery, which runs along the ventral surface of the cord in the midline and from the paired posterior spinal arteries, which run along the right and left dorsal surfaces of the cord. The anterior and posterior spinal arteries are supplied in the cervical region mainly by branches arising from the vertebral arteries. In the thoracic and lumbar regions, the spinal arteries are supplied by radicular arteries arising from the aorta.

cerebral cortex

o The outer part (aka cortical surface) o Newest part of the brain o Bigger compared to other animals o Bunched up sheet of cellular tissue § Gyri - bulges between folds (hills) § Sulci - folds (valleys) o Two symmetrical hemispheres o Wraps around lower and older brain structures o Parenchyma § Glial cells send out projections that form a barrier that protects brain from the blood (blood-brain barrier) o 6 layers in the cortex (different levels of processing) - basic organization and primary sensory and motor areas o lobes of the cerebral hemispheres § frontal lobes are, appropriately, in the front of the brain and extend back to the central sulcus of Rolando. The frontal lobes are separated inferiorly and laterally from the temporal lobes by an especially deep sulcus called the Sylvian fissure, or lateral fissure. (The term fissure is sometimes used to refer to deep sulci.) The parietal lobes are bounded anteriorly by the central sulcus but have no sharp demarcation from the temporal lobes or the occipital lobes when viewed from the lateral side of the brain § medial aspect, the parieto-occipital sulcus can be seen more easily, separating the parietal from the occipital lobes § an additional region of cerebral cortex called the insular cortex lies buried within the depths of the Sylvian fissure. The insula is covered by a lip of frontal cortex anteriorly and parietal cortex posteriorly, called the frontal operculum and parietal operculum § The two cerebral hemispheres are separated in the midline by the interhemispheric fissure, also known as the sagittal or longitudinal fissure § C-shaped band of white matter called the corpus callosum (meaning "hard body") connects both homologous and heterologous areas in the two hemispheres § ** surface anatomy of cerebral hemispheres in detail pictures** · Lateral; Medial; Inferior; superior o Primary sensory and motor areas § **pic of brain** § Sensory and motor pathways are usually topographically organized. This means that adjacent areas on the receptive (or motor) surface are mapped to adjacent fibers in white matter pathways and to adjacent regions of cortex. § somatotopic maps on the cortex are sometimes called the motor or sensory homunculus ("little man"). Similarly, adjacent retinal areas are mapped in a retinotopic fashion onto the primary visual cortex, and adjacent regions of the cochlea, sensing different frequencies, have a tonotopic representation on the primary auditory cortex. § Interestingly, the primary somatosensory cortex and primary motor cortex represent sensation and movement, respectively, for the opposite side of the body. o Cell layers and regional classification of the cerebral cortex *** chart § Layer I contains mainly dendrites of neurons from deeper layers as well as axons. § Layers II and III contain neurons that project mainly to other areas of cortex. § Layer IV receives the majority of inputs from the thalamus. § Layer V projects mostly to subcortical structures other than the thalamus, such as the brainstem, spinal cord, and basal ganglia. § Layer VI projects primarily to the thalamus § The relative thickness of the cell layers varies according to the main function of that area of cortex § Brodmann's cytoarchitectonic areas **chart**

standard consolidation model multiple trace theory

o You can keep info in a temporary storage space o Medial temporal memory systems form new memories but these shift over time to cortical storage independent of medial temporal lobe § Working on memories you've acquired over the last few years § HM could still retrieve old memories, while semantic dementia patients can form new episodic memories § Need MTL and thalamus to move memories to long term o Tries to account for MTL moving into long term storage and consolidates it over time § Tries to account for info abt HM case o Both MTL and cortex are regions where memory is stored § This is why when MTL is destroyed, you lose new memories · Bc it plays a role in storing new memory

- Functional regions of the brain

o operations responsible for our cognitive abilities occur primarily in the cerebral cortex, the furrowed gray matter covering the two cerebral hemispheres § frontal lobe: short-term memory and planning future actions and with control of movement § parietal lobe: somatic sensation, with forming a body image and relating it to extrapersonal space § occipital lobe: vision § temporal lobe: hearing and—through its deep structures, the hippocampus and amygdaloid nuclei—with learning, memory, and emotion o organization of the cerebral cortex: § each hemisphere is concerned primarily with sensory and motor processes on the contralateral (opposite) side of the body. · sensory information that reaches the spinal cord from the left side of the body crosses to the right side of the nervous system on its way to the cerebral cortex. Similarly, the motor areas in the right hemisphere exert control over the movements of the left half of the body. § that the hemispheres, although similar in appearance, are neither completely symmetrical in structure nor equivalent in function.

Views about the relationship between brain and behavior

o views about nerve cells, the brain, and behavior emerged during the 20th century from a synthesis of five experimental traditions: anatomy, embryology, physiology, pharmacology, and psychology o Anatomy: Galen: nerves convey fluid secreted by the brain and spinal cord to the body's periphery § microscope revealed the true structure of the cells in nervous tissue o Golgi developed a method of staining neurons with silver salts that revealed their entire cell structure under the microscope. § Ramón y Cajal discovered that nervous tissue is not a syncytium, a continuous web of elements, but a network of discrete cells · Developed some of the key concepts and early evidence for the neuron doctrine (individual neurons are the elementary building blocks and signaling elements of the nervous system) o Definite proof of the neuron doctrine: electron microscopy § Sanford palay: existence of synapses, specialized regions that permit chemical or electrical signaling between neurons · Cellular connectionism: neurons are the signaling unit sof the brain - connect to one another in a precise fashion o Believed that cortex was a mosaic of functionally specific areas · Embryology: Ross Harrison: dendrites and the axon grow from the cell body o growth cone, which leads the developing axon to its target, either to other nerve cells or muscles o Physiology: Luigi Galvani discovered that muscle and nerve cells produce electricity § 3 german scientists: Electrical activity of one nerve cell affects the activity of an adjacent cell in predictable ways o Pharmacology: drugs do not act just anywhere on a cell but bind discrete receptors typically located in the surface membrane of the cell § Means that nerve cells can Communicate with each other by chemical means o Psychological thinking: Descartes: distinguishing the body and mind § Dualism § Mind: the higher mental functions and conscious experience is not represented in the brain but in the soul · He believed that this was found in the pineal gland o 18th century: ideas split § Empiricism: believed that the brain is initially a blank slate (tabula rasa) § Idealism: Immanuel kant · Believed that our perception of the world is determined by inherent features of mind or brain o Darwin § Modern understanding of the brain · Gave rise to ethology (investigation of the behavior of animals in their natural setting, and later to experimental psychology, the study of human and animal behavior under controlled conditions) o Freud § Psychoanalysis: the first systematic cognitive psychology o Joseph Gall (localization) § Phrenology: determining the personality and character based on the shape of the skull § brain is the organ of the mind and that all mental functions emanate from the brain (rejected the dualistic approach) § argued that the cerebral cortex did not function as a single organ but contained within it many organs, and that particular regions of the cerebral cortex control specific functions · assigned intellectual processes, such as the ability to evaluate causality, to calculate, and to sense order, to the front of the brain. Instinctive characteristics such as romantic love (amativeness) and combativeness were assigned to the back of the brain. § believed that the bumps and ridges on the skulls of people well endowed with specific faculties identified the centers for those faculties in the brain. He assumed that the size of an area of brain was related to the mental faculty represented in that area o Holistic view § Based partly on Flouren's work in that any part of the hemisphere is able to perform all the hemisphere's functions § Broca and Wernicke challenged this view · First important evidence for localization emerged from the studies of how the brain produces language § Believed that every mental function involved the entire cerebral cortex

Peripheral Nervous System

§ Axons in PNS form bundles called peripheral nerves · Clusters of cell bodies are called ganglia § Nervous Composed of neurons and glial cells (glia) · Neurons: basic units of signaling in the nervous system o Most mammalian neurons are multipolar (several dendrites and axons o Some neurons are bipolar: single dendrite and single axon § Sensory neurons such as those involved in vision o Unipolar: both axons and dendrites arise from a single process coming of the cell body (occurs mainly in invertebrates) o Electrically and chemically active § Action potential travel throughout the length of the neuron; communicate chemically with other neurons through neurotransmitters · Segments in axon = nodes of ranvier - action potentials jump from node to node thru saltatory conduction · Fast EPSPs and IPSPs occur on the timescale of tens of milliseconds and rapidly move the membrane voltage of the postsynaptic neuron between states more or less likely to fire an action potential. The postsynaptic neuron summates EPSPs and IPSPs arising from many presynaptic inputs. The second function of chemical neurotransmitters is neuromodulation, generally occurring over slower time scales. Neuromodulation includes signaling cascades that regulate synaptic transmission, neuronal growth, and other functions. Neuromodulation can either facilitate or inhibit the subsequent signaling properties of the neuron. § Throughout the nervous system, motor systems tend to be more ventral, or anterior, and sensory systems more dorsal, or posterior. · dorsal nerve roots convey mainly afferent sensory information into the dorsal spinal cord, while ventral nerve roots carry mainly efferent motor signals from the ventral spinal cord to the periphery o cervical, thoracic, lumbar, and sacral nerve root § spinal cord ends at the level of the first or second lumbar vertebral bones; Below this the spinal canal contains a collection of nerve roots known as the cauda equina continue down to their exit points · The sensory and motor nerve roots join together a short distance outside the spinal cord and form a mixed sensory and motor spinal nerve § Control of the arms and legs requires much more signal flow than does control of the chest and abdomen. Thus, the nerves controlling the extremities give rise to elaborate meshworks referred to as the brachial plexus for the arms and the lumbosacral plexus for the legs (see Figure 2.8A). In addition, the spinal cord contains a relatively increased amount of gray matter in these segments, causing the overall thickness of the cord to be greater. These regions of the cord are called the cervical enlargement and the lumbosacral enlargement, respectively. § Automatic Nervous System Is made up of Sympathetic and Parasympathetic divisions · S: fight or flight o arises from thoracic and lumbar spinal levels T1 to L3 (the thoracolumbar division) o releases norepinephrine · P: rest or digest o arises from the cranial nerves and from sacral spinal levels S2 to S4 (the craniosacral division) o releases acetylcholine

Skull (cranial vault) -Meninges

§ Cover the CNS § Arteries are red/ veins are blue § Deoxygenated blood is drained away by veins § Sinus is thick vein that goes along brain · Embedded within the dura matter · If vein tears and begins to bleed under the dura matter, there will be pressure in the brain § Dura matter (1st of 3 layers called meninges) · Dura gets pulled back to look for bleeding within o CT scan to check for bleeding § Subarachnoid space (2nd) · Cerebral cortex arteries and veins § Pia matter (final layer) · Covers brain parenchymal o Surface and ensheaths penetrating veins and arteries o Protects vessels that are actually going into the brain Intraparenchymal bleed (bleeding into the brain)