Anthro 107 Final
Prefrontal Cortex
rational planning
Dopamine
regulates motor behavior, motivation, pleasure, and emotional arousal
Thalamus
relays messages between subcortical structures and the cerebral cortex
Hippocampus
-critical for the consolidation of episodic memories -not the actual locus of memories, but rather establishes a network of link between memories and puts things in context -major output is the fornix -damage or removal prevents you from making new episodic memories, but doesn't affect already existing ones
Cerebral Cortex Cytoarchitecture
-there are conventionally 6 layers of the cerebral cortex, with each layer having different types of neurons and functions -in sensory-related areas of the cortex there tend to be a well-developed layer 4 and minimal layer 5 -motor-specialized cortex has a minimal layer 4 and expanded layer 5 with large pyramidal cells
Superior Colliculus
-vision -controls automatic orienting of your attention to a sudden sound/movement
Visual Pathway
-visual information enters the eye and down fibers, crossing at the optic chaism, then to the superior colliculus (a secondary target for mammals), and then to the occipital lobe -dorsal stream is the "where" pathway -ventral stream is the "what" pathway
Hoover
-vocal learning is absent in nearly all terrestrial mammals but present in many birds and some aquatic mammals -a seal named Hoover had an unprecedented ability to mimic human vocalizations -suffered from encephalitis as a cub - seems to have mimicked Mr. Sparrow, the man who took care of him when he was young -produced very few normal seal vocalizations -likely caused by encephalitis changing things in his brain (it's what gave Clive anterograde amnesia)
parasympathetic nervous system
a set of nerves that helps the body return to a normal resting state
sympathetic nervous system
a set of nerves that prepares the body for action in challenging or threatening situations
Anterior Commissure
a small bundle of axons that allows a crossover of information between the two hemispheres (including olfactory information)
Insular Cortex/Limbic System
emotion regulation
Homology
common ancestral origin
Myelencephalon
-back of the hindbrain -medulla oblongata
Apoptosis
programmed cell death
Somatic Touch
-includes sensing heat, pressure, texture, position in space, skin stretch and muscle stretch -balance and sound are also forms of touch -pain pathways cross over in the spinal cord, while touch pathways cross over in the brainstem
Herculano-Houzel analysis
-involves dissolving brains into neuron suspensions in order to count cells -humans brains average 87 billion cells -primate brains have greater neuron density than non-primate mammals -birds are the most brain-dense
Fovea
-the central focal point in the retina, around which the eye's cones cluster -nerve fibers bend off to the side -the "highest resolution" is obtained here
Stereoscopic Vision
-the combination of two retinal images to give a three-dimensional perceptual experience -superimposed visual fields (from both eyes being in front of the face) allows for depth perception
Retina
-the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information -an outgrowth of the embryonic neural tube
Cochlea
-a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses -vibrations of its fluid interior are distributed differently by virtue of its resonant chamber -the tactile experience of sound is generated by the shearing movements of two membranes with respect to each other under the influence of vibratory pressure, as this bends sensitive hair cells -most cochlear nucleus neurons project to the contralateral superior olivary nucleus through the trapezoid body, where stereophonic left/right timing differences localize the position of the sound source
Cranial Nerves
-12 pairs of nerves that carry messages to and from the brain (enter and exit from the bottom of the skull/top of the spinal cord)
Visual Cortex
-V1 catalogs input (damage causes blindsight - the ability to respond to visual stimuli without consciously perceiving it) -V2 relays signals -V3 discerns motion and form -V4 discerns color and form -V5 discerns motion
Papez circuit
-a circuit of structures interconnecting the hypothalamus and cortex, proposed to be an emotion system but more likely a memory feedback system -Hippocampus → Fornix → Hypothalamus → Mammillary bodies → Thalamus → Hippocampus -mainly associated with sensory memories -hippocampal inputs from cortex enter in strict "slices", establishing precise correlations between features distributed in different cortical areas involved in the same mental event -Sudden brain damage = memories accumulated a few minutes before the accident don't get consolidated, we can't get back to them bc there was no time for them to cycle and organize themselves
Fornix
-a fiber band that grows towards to the hippocampus -takes information from the hippocampus to the hypothalamus via the amygdala
Spinal Cord Organizaiton
-the sensory tract is ascending and the motor tract is descending -surrounded by myelinated axons with cell bodies in the middle -damage can cause paralysis and loss of feeling -has dorsal horn, lateral horn, and ventral horn
Basal Ganglia
-a set of subcortical structures in the forebrain that control intentional movements, including the amygdala, caudate nucleus, putamen, globus pallidus -plays a complementary role with the cerebellum in terms of execution of motor behavior via loops through motor areas of the cerebral cortex -start/stop movement and emotion -damage causes difficulties in stopping and starting behaviors, inhibition of spontaneous tendencies, or disturbed movements that can't be suppressed
Lateral Geniculate Nucleus (LGN)
-a structure in the thalamus that receives input from the visual system -has altering layers that get input from each of the two eyes then projects back to the cortex to create an interwoven map from the two eyes
Procedural Memory
-a type of implicit memory that involves motor skills and behavioral habits ("muscle memory") -frontal lobe, striatum, cerebellum
Serotonin
-affects mood, hunger, sleep, and arousal -SSRI (selective serotonin reuptake inhibitors) blocks depression effects by blocking Amygdala's uptake of Serotonin
Sylvian Fissure
-also called lateral sulcus -a deep fissure that demarcates the temporal lobe
Middle Temporal Area (MT)
-an area of the brain thought to be important in the visual perception of motion -magnifies the peripheral field -has a reduced representation of the fovea compared to the periphery -sensitive to object motion oriented in different directions
anterograde amnesia
-an inability to form new memories -people are able to learn new skills but won't remember having learned them -H.M. and Clive
Spinal Reflex
-an instantaneous response caused by a stimulus, such as kicking your leg when your knee is tapped -the Babinski response is when infants curl out their feet and toes in response to scraping the bottoms of their feet -can happen in adults too if they have a demyelinating disease like MS
Paul MacLean's Triune Brain Theory
-argued that human brains have three layers: 1. reptilian brain at the center that controls instinct and drive 2. old mammalian brain surrounding reptilian brain 3. new mammalian brain on top -problem: almost all animal brains are laid out in the same general way anatomically -he also identified the limbic system
addition-accretion theory
-as brains got bigger throughout evolution, more areas were added -disproven!
Mosaicism
-assumes independent evolution of parts irrespective of the whole -describes the adaptation of an organismal part as independent of similar adaptation in reasonably related parts -brain structures can evolve separately
Saltationsim and Mutationism
-assumes new functions are produced by radical genetic mutations -evolution is driven by "lucky accidents" -not true because lucky accidents usually happen after they're needed
Essentialism
-assumes that there are unique unprecedented structures in human brains that define our humanness and separates us from all other creatures -overly localized -Descartes believed the pineal gland to hold the soul -Richard Owen thought that only humans have a hippocampus minor, but Thomas Huxley demonstrated that all human brain structures have ape homologies
Homuncularism and Phrenology
-assumes whole brain functions are attributed to brain structures -phrenology is mapping whole brain functions to components by feeling the bumps on heads -certain functions are unique to certain parts of the brains and localization of function but language is produced by the whole brain
Klüver-Bucy syndrome
-caused by bilateral amygdala lesions -failure to register negative emotions -no recognition of danger (physical or social) -lack of disgust responses -indiscriminate hypersexuality -no fight-or-flight response -passivity and placidity -can produce coprophagia (eat their own feces) -only "do-it-again" is left
Sylvian Aqueduct
-central canal that connects the third and fourth ventricles -automatic vocalizations
Balance
-change of posture causes tiny stones in the macula called otoliths to move within the fluid of the inner ear chambers and canals, thereby stimulating hair-cell sensors that send signals to the brain if bent -posture is sensed by hair cells in the utricles and change of movement (acceleration) is sensed by hair cells at the base of the semicircular canals -rotation and angular acceleration is sensed by the way flowing fluid in the semicircular canals bends specialized structures (cupulae) at the base of each semi-circular canal as head is moved in a given direction -there are 3 loops, one for each plane in space
Korbinian Brodmann
-in 1909 he published an extensive map of the cerebral cortex based on distinguishing areas with different cell layer patterns (cyto-architecture), each assigned an arbitrary number from 1 to 52 -allowed us to study differing functionality of each area
Neurotransmission
-chemical communication between cells 1. synaptic spines on the dendrites of the cell body receive signals released by axons of other neurons (only if enough excitatory signals are received within a short time) 2. Action potential is triggered at the axon hillock (place where soma and axon meet) 3. Axon is depolarized allowing ions to rush into the axon, initiating a chain reaction down the length of the axon (signal propagation) 4. The signal reaches the presynaptic ends of the axon, causing neurotransmitter release
Tongue
-complex muscle made of many muscles -glossus referes to tongue as a whole -some extend far back to the styloid process, called the styloglossus -geniohyoid and stylohyoid muscles move the tongue by raising the hyoid bone and larynx -one end of the muscle is connected to bone, but unlike other muscles, the other end is not -intrinsic tongue muscles do not attach to bone, only soft tissue -extrinsic tongue muscles attach to bone at one end and the tongue surface at the other -tongue is like a water balloon that squeezes to allow us to stick our tongue out -longitudinal muscles run alongside the tongue -the hypoglossal nucleus is in the rhombencephalon near the dorsal midline -control is automatic for eating and has visceral function, but also needs conscious control (branchial motor control - both skeletal and visceral)
Afferents
-connections entering a brain structure -typically enter dorsally (from the bottom and move upwards)
Efferents
-connections leaving a brains structure -typically exit ventrally (from the top and move downwards)
concerted evolution
-correlates the adaption of an individual portion with the whole -brain evolves as a whole
Emotion Pathway
-cortex to limbic system, then to midbrain, and then back to cortex (loop) -Cortical activity is assigned +/- valence by limbic structures (a) which activate midbrain-brainstem neuromodulatory systems (b) which alter cortical activity (c); recurrently
Vestibular Nerve
-cranial nerve that conducts impulses related to maintaining balance to the brain -there are 4 vestibular nuclei: superior, lateral, medial, and inferior -the abducens nucleus controls eye movement (in response to body movement)
Golgi Stain
-discovered by Camillo Golgi -allows for visualization of individual neurons
Neurons
-don't divide -have electrically active cell membranes -have specialized input and output branches linked by synapses -release and receive neurotransmitter molecules -propagate sudden ionic potential changes
Hypothalamus
-drives control processes, hunger, and sexuality -the 4 F's (fighting, fleeing, feeding, and f***ing) -regulates visceral muscle systems -has 2 outputs: hormonal and automatic
Telencephalon
-forebrain/cerebrum -includes the cerebral cortex, corpus callosum, caudate nucleus, amygdala, and hippocampus -most vertebrates have a nucleated telencephalon, but mammals are an exception with a sheet-like upper half and nucleated lower half -more prominent in humans and other species with large brains -birds, reptiles, and amphibians lack cerebral cortex, and instead have a nucleated telencephalon
Rosehip neurons
-found in human brains but not in mice brains -inhibitory neurons found in cortical layer 1 -not responsible for human intelligence, they just occur because of our specific evolution -exact purpose is unclear
James Olds
-found that electrical stimulation of the brain evokes emotional responses in animals -stimulation in areas of the basal ganglia was either rewarding and would cause mice to seek it again or punishing and cause them to avoid it
Globus Pallidus
-has a bunch of penetrating white fibers in it
Rhombencephalon
-hindbrain (collective term for metencephalon and myelencephalon)
James-Lange Theory
-the theory that our experience of emotion is our awareness of our physiological responses to emotion-arousing stimuli (interoception) -not true because you can become paralyzed without directly affecting emotion
Vocalization
-limbic projections to the hypoglossal nucleus deal with involuntary innate vocalization (breathing, swallowing, laughing, sobbing) -cortical projections to the hypoglossal nucleus deal with voluntary conscious vocalizations -laughter is the only automatic vocalization that has cortical projections -vocal calls in monkeys are symptoms of corresponding states of emotional arousal -make one's autonomic arousal known to others
Striatum
-made up of the caudate nucleus and putamen
Pyramidal Cells
-major output neurons of the cerebral cortex, with long apical dendrites and soma mostly located in layers 3 and 5 of the cerebral cortex -pyramidal tract involves cell bodies in cerebral cortex with long axons that project all the way down the spinal cord, eventually crossing over at decussation point and goes down to the middle of the back
U-fiber Theory
-maps are mirrored
Mesencephalon
-midbrain -tectum (colliculi) and tegmentum (area of brainstem) -control center for attention involving our heads
Cerebral Peduncle
-midbrain area that is largely fiber tracts that lead cortical outputs to the spinal cord
Substantia Nigra
-midbrain structure where dopamine is produced (and as a result, where melanin is produced) -involved in control of movement
ventral tegmental area (VTA)
-midbrain structure where dopamine is produced: associated with mood, reward, and addiction -connects to the limbic cortex, prefrontal cortex, nucleus accumbens, and amygdala
Limbic System
-neural system located below the cerebral hemispheres; associated with emotions and drives -includes the limbic lobe, amygdala, nucleus accumbens, cingulate cortex, hippocampus, and olfactory cortex -"do it again" responses occur in the front of the limbic cortex and "don't do it again" responses occur in the back
Metencephalon
-part of the hindbrain -pons and cerebellum
Nucleus Accumbens
-plays a role in the reward (dopamine) pathways -leans on the septum -outputs go to hypothalamus, midbrain, and brainstem rather than cortex -creates do-it-again responses -facilitated by dopamine
Amygdala
-plays a significant role in fight-or-flight behavior -disgust and fear -Innate Negatives: things that don't need to be learned because they've been learned by evolution(know to be afraid of snake-like things) -gets both sensory cortical input (conscious) as well as direct thalamic input (unconscious) -outputs go to hypothalamus, midbrain, and brainstem rather than cortex
Periaqueductal Gray (PAG)
-plays roles in emotion and involuntary vocalization due to emotional changes -activated by limbic structures -controls laryngeal muscles via the nucleus ambiguous and breathing via respiratory centers of the medulla oblongata
Motor Control Pathways
-premotor information gets sent to the striatum, then to the thalamus where info from the cerebellum is also being sent, and then back up to the cerebral cortex -a kind of voting system occurs in the striatum to choose a motion
Claustrum
-processes visual information at a subconscious level -keeps track of what is coming from where, spatial awareness and synchronization -stimulation with an electrode made patient lose awareness while still conscious -connection to hippocampus, amygdala and cortex integrates activity and communicates with memory areas(theory of consciousness) -stimulating different areas of the claustrum stops activities in other areas -has reciprocal connections with most cortical areas
Pineal Gland
-produces melatonin -Descartes believed it to be "the seat of the soul"
Recursive Theory of Hippocampus Function
-redundancy of input pattern might be provided by recirculation of associations through the Papez circuit
Eye Movement Pathways
-reflexive, unconscious, automatic eye movements involve the superior colliculus but not the visual cortex -smooth-pursuit, consciously-guided eye movements involve the cerebellum and the visual cortex -vestibular system is also involved because you need to be able to track your own movements and position
Coronal/Frontal/Transverse Section
-separates front and back -rat transverse section ≠ human coronal section
Sagittal/Lateral Section
-separates right and left
Horizontal Section
-separates top and bottom -rat horizontal section ≠ human horizontal section
Inferior Colliculus
-sound
Dermatomes
-tactile bands that project to the same spinal nerve 1. cervical --> head, arms (forelimbs) 2. thoracic --> trunk 3. lumbar --> lowerback, legs 4. sacral --> legs
Diencephalon
-thalamus and hypothalamus -part of the forebrain
Syrinx
-the bird's voice box -sound production in songbirds does not involve the larynx as in mammals, but rather this set of muscles in the chest cavity that can tighten or weaken the air passing through each side -control of sound production shifted from visceral to skeletal -birds have balloon-like air sacs that they can inflate and collapse, driving the air to and from through a tube -in the same tube, air flows one way and blood flows another way (counter-current flow) -this supports a more efficient metabolism for flight and probably aids in high altitude breathing -system requires telencephalon control
Larynx
-voice box -attached to the hyoid bone and suspended from the base of the skull and the tip of the jaw -vocal fold tension is controlled by muscles that move 4 cartilages (thyroid, cricoid, arytenoid, corniculate) with respect to one another 1. inter-arytenoid muscles rotate the paired arytenoid cartilages inward to bring the vocal folds together 2. muscles rock the thyroid cartilage forward on the cricoid cartilage to create vocal fold tension -controlled by the nucleus ambiguous
neuromodulatory systems
-widely broadcast neural systems that correlate with reward, punishment, and alertness -includes dopamine system, norepinephrine system, serotonin system, cholinergic system, and histamine system -the majority of drugs used to treat emotional disorders target one or more of these neurotransmitter systems
Encephalon Order
1. tel- 2. di- 3. mes- 4. met- 5. myel-
Nissl stain
a blue dye that stains cell bodies
Myelin stain
a brown dye that stains white matter with dense axons
retrograde amnesia
an inability to retrieve information from one's past
Differentiation theory
as brains got bigger throughout evolution, functional areas subdivided
Four Humors
blood, phlegm, white bile, black bile
Auditory Input
input goes from the cochlea to the inferior colliculus, then to the MGN of the thalamus, and then to the cortex
Septum Pellucidum
separates the lateral ventricles
Stellate Cells
small local circuit input neurons that have soma in layers 2, 4, and deep layer 3 of the neocortex
Ogliodendrocytes
special glial cells filled with fatty myelin that wrap around axons to propagate signals more rapidly with less susceptibility to disturbance
Organ of Corti
tissue in the cochlea containing the hair cells necessary for hearing
Frontal Lobotomy
type of lesioning that was used to treat mentally ill patients
Pituitary Gland
under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands
