Final exam, chapters 15 & 16
Synesthesia
- Ability to perceive a stimulus of one sense as the sensation of a different sense, such as when sound produces the sensation of color - Estimated incidence is 1 in 23 people - Tends to run in families - Most common form is colored hearing (hearing somthing and seeing a color) - Most pairings are in one direction only-> Example: in colored hearing, seeing a color does not elicit the sound.
The Nature of Thought: Cognition
- Act or process of knowing or coming to know - For behavioral neuroscientists, cognition usually entails - the ability to pay attention to stimuli, to identify stimuli, and to plan meaningful responses to them.
Anomalous speech representation
- Anomalous= abnormal - Condition in which a person's speech zones are in the right hemisphere or in both hemispheres
Intelligence Concept of General Intelligence: Spearman (1920s)
- General intelligence: g factor - Would brains with high or low g have some general difference in brain architecture? - Would cerebral connectivity differ? - Would the ratio of neurons to glia? - Is g related to the activation of specific brain regions, possibly in the frontal lobe?
Neural Bases of Sex differences: Medial frontal cortex, orbitofrontal cortex
- Medial frontal cortex: Neurons in male rats have larger dendritic fields. - Orbitofrontal cortex: Neurons in female rats have larger dendritic fields. - These differences are not seen when the rats have had their gonads or ovaries removed.
Evolution of Sex-Related Cognitive Differences: Why do females have better language skills?
- Perhaps in evolutionary terms females developed good language skills to engage in social interaction. - Females may also have been selected for fine motor skills (e.g., making clothes), which are related to language.
Evolution of Sex-Related Cognitive Differences: Why do males have better spatial skills?
- Perhaps in evolutionary terms males had to tend larger territories than females.
Two neuroeconomic systems
- Reflective system: deliberate, slow, rule-driven, and emotionally neutral( lateral prefrontal, medial temporal, and posterior parietal cortex) - Reflexive system: fast, automatic, emotionally biased(ventromedial prefrontal cortex and ventral striatum (nucleus accumbens)
Temporal, parietal and frontal association cortices..
- Temporal association regions tend to produce cognition related to visual and auditory processing. - The parietal cortex is closely related to somatosensation and movement control, close to somatosensory and motor cortex= controls movement. - The frontal cortex coordinates information coming from the parietal and temporal association regions with information coming from subcortical regions.
Neural Bases of Sex Differences: Kimura (1999)
- investigated people who had sustained cortical strokes in adulthood. - Found that men and women were almost equally likely to be aphasic subsequent to left-hemisphere lesions of some kind. - Men were more likely to be aphasic and apraxic after damage to the left posterior cortex. - Women were far more likely to be aphasic and apraxic after lesions to the left frontal cortex. - Females have more inter-hemispheric connectivity(between hemispheres) - males have more intra-hemispheric connectivity.(in each hemisphere separately) - DTI analysis of brain networks
Divergent thinking
- reaches outward from conventional knowledge and reasoning skills to explore new, more unconventional solutions to problems. - Form of thinking that searches for multiple solutions to a problem (such as, how many ways can a pen be used?) - People with frontal lobe lesions perform poorly on these tests.
Hyperconnectivity
- within a given region-> increased local connections - Increased local connections between two related brain regions.
Prefrontal association cortex
Lateral View - Dorsolateral prefrontal cortex (upper, anterior on outer part of prefrontal cortex) - orbital prefrontal cortex (under dorsolateral prefrontal cortex on outer part of prefrontal cortex) Medial view - dorsomedial prefrontal cortex (dorsal + middle of inner prefrontal cortex) - ventromedial prefrontal cortex (lower under dorsalmedial, also in middle inner prefrontal cortex)
Social Neuroscience: Understanding Others: Theory of Mind
Theory of Mind: - The attribution of mental states to others - We infer the minds of other animals in part by observing their behaviors and, in the case of people, by listening to their words. - Understanding that others may have feelings and beliefs that are different from our own - Empathy is correlated with increased activity in the medial prefrontal cortex. - if watch person who is feeling bad-> see prefrontal cortex activation - sociopaths= different structural activity with pre frontal cortex
Neuropsychological studies using tests of executive (frontal lobe) function show an advantage for
bilingual speakers relative to monolinguals. - Difference hypothesized to reflect bilinguals' consistent need to select language-appropriate words and to inhibit language-inappropriate words.
Phenylketonuria (PKU)
- A behavioral disorder caused by elevated blood levels of the amino acid phenylalanine resulting from a defect in the gene for the enzyme phenylalanine hydroxylase - Major symptoms: intellectual impairments, seizures - PKU can be treated by restricting intake of foods high in protein (beef, fish, cheese) - Unlike PKU, most disorders do not involve a single genetic abnormality, and the underlying causes are largely conjectural (hypothetical)
Cerebral Asymmetry in Thinking Anatomical Asymmetry
- A number of anatomical asymmetries are present - Hemispheric differences - Regional: lateral fissure/ right hemisphere= not so lateral/ tilted/ temporal and parietal on both sides are different - cellular: presence of synapses, tracts, hyperconnections - neurochemical differences - Brain asymmetries are not unique to humans - Human language likely evolved after the brain became asymmetrical - asymmetries allow for specilization
Social Neuroscience: Self Regulation
- Ability to control our emotions and impulses as a means for achieving long-term goals - Prefrontal regions are critical in self-regulation. - Children are often poor at self-regulation, which probably reflects the slow development of prefrontal regions responsible for impulse control - long term goals-> need to regulate to not deviate from plans-> prefrontal cortex - Expectations can alter our feelings: Nobukatsu et al. (2000) - kid falls but not hurt-> screams even tho not hurt-> expectations alter feelings
How do split brain subjects respond to nonverbal responses
- Although split-brain individuals cannot name objects presented to their right hemisphere (left eye), they can make correct nonverbal responses. - Using their left hand, these individuals correctly select the object matching the presented one. - The two hemispheres can act independently. - When each hemisphere is shown a different object, the two hands will select different objects as being the correct one-> they do not agree
Left Parietal Damage causes
- Aphasia: impairment in the use of language - Apraxia: general impairment in making voluntary movements in the absence of paralysis or a muscular disorder - Inability to complete a plan of action accurately - People with left-hemisphere injury, especially in the posterior parietal region, are impaired at copying these movements
Convergent thinking
- Applying knowledge and reasoning skills to narrow the range of possible solutions to a problem, then zeroing in on one correct answer - Form of thinking that searches for a single answer to a question (such as 2 + 2 = ?) - Measured in traditional intelligence tests - People with temporal and parietal lobe lesions perform poorly on these types of tests.
Why would humans need consciousness?
- As the amount of information about an event increases, it becomes advantageous to produce a single complex representation and make it available for a sufficient time to the parts of the brain. This is consciousness.
Einstein's brain
- Average size and weight - Lateral fissure is short; both left and right lateral fissures take a particularly striking upward deflection. - Investigations imply that cerebral connectivity and high glia-to-neuron ratio may play important roles in intelligence. - Example: high glia-to-neuron ratio in inferior parietal cortex contributes to mathematical reasoning. - Certain types of intelligence could be related to differences in cell structure in localized brain regions - KEEP IN MIND: None of the studies of Einstein's brain or any other "elite" brains have been able to conclusively pinpoint the source of intelligence; nature vs. nurture?
Multisensory Integration: Binding problem + one solution
- Binding problem: Philosophical question focused on how the brain ties single and varied sensory and motor events together into a unified perception or behavior. - One solution: regions of the association cortex are multimodal-> These neurons respond to information from more than one sensory modality - ex. dog barks-> noise goes to one place-> image of dog goes to another place - synthesia: hear a tone-> see a color or shiver when music is playing
Mapping the Brain: Brain connectome
- Brain connectome: Map of the complete structural and functional fiber pathways of the human brain in vivo. - wanna map every connection - goal is to provide a reference atlas for those seeking to understand human brain function and dysfunction - Two promising imaging tools for mapping the human brain's connectivity are: - diffusion tensor imaging (DTI), and - functional connectivity magnetic resonance imaging (fcMRI).
Cognition and the Cerebellum
- Cerebellum accounts for 80 percent of the brain's neurons - extensive neocortex-cerebellum interconnections include prefrontal cortex, Broca's area, and neocortical regions that have sensory or perceptual functions. - used to think it was old/primitive and just did old primitive things - sequencing movement-> if wanna make plan-> will help to have connections with brain area that can sequence - Cerebellum appears to be critical in producing fine movements and perception AND be associated with working memory, attention, language, music, and decision-making processes. - Significant area of focus for future research.
Deficits of Attention: Parietal association cortex
- Damage can produce contralateral neglect. - Ignoring a part of the body or world on the side opposite (contralateral to) that of the brain injury - Neglect is particularly severe in RIGHT-hemisphere damage (left= language)
Right vs left hemispheres
Right Hemisphere - Contributes to controlling spatial skills - drawing, assembling puzzles, and navigating in space Left Hemisphere - Contribute to controlling language functions and cognitive tasks related to schoolwork—namely, reading and arithmetic. - Role in controlling voluntary movement sequences differs from the right hemisphere's role
Consciousness Why Are We Conscious? Jeannerod and colleagues (1991) experiment
- Dissociation between motor behavior and conscious awareness - Subjects made movements before they were actually aware of them. - The conscious ventral (lower) stream is needed to discriminate among particular stimuli and respond differentially to them. - Consciousness allows us to select behaviors that correspond to an understanding of the nuances of sensory inputs. Procedure: Participants were required to move their hands and grasp the illuminated rod as quickly as possible-> In the first trial they reach for rod three-> on some trials the light jumps from one rod to another quickly-> the participant must correct his reach-> most found they were grasping the new target before they were aware that it had changed conclusion: It is possible to dissociate behaviors and conscious awareness-> Conscious awareness of the stimulus event occurred only after their movements took place
Compensatory(recompensate) plasticity
- Even the best technology produces uncertain relationships. - Consider multiple sclerosis: brain lesions do not always produce behavioral symptoms and are not always linked to obvious neuropathology. - Meaning: people can change their behavior to adapt to neural change, just as they can display disordered behavior without obvious brain pathology - Big in concussions-> cant always see issue w neuroimaging-> symptoms alleviate-> repeated concussions-> seem like healing, cant see in neuroimaging but might not be fully healed-> very slowly degrading - brains adjusting makes it hard to detect -> lots of disorders cant see what is happening
Causes of Disordered Behavior
- Evidence for brain abnormalities in organic- neurological disorders is straightforward, and the causes are generally known. - Genetic errors (e.g., Huntington disease) - Epigenetic mechanisms - Progressive cell death (e.g., Alzheimer disease) - Rapid cell death (e.g., stroke, traumatic brain injury) - Loss of neural connections (e.g., multiple sclerosis) - Far less is known about the causes of behavioral- psychiatric disorders, but there must be some abnormality in brain structure or activity, complicated because looking for physical evidence, behavioural symptoms overlap ex. depression and schizophrenia, hard b/c both so different as well but both involve dopamine
Dichotic listening
- Experimental procedure for simultaneously presenting a different auditory input to each ear through stereophonic earphones - Right-ear advantage for verbal information - Left-ear advantage for musical information - info desiccates in midbrain
Imitation and Understanding + mirror neurons
- For successful communication, sender and receiver need a common understanding of what counts. Mirror neurons - Cells in the primate premotor cortex that fire when an individual observes a specific action taken by another individual - Rizzolatti: The human capacity to communicate with words may have resulted from evolution of the mirror neuron system. - "monitoring neurons"-> you don't want to just send motor movement and not monitor it
Witelson and Goldsmith (1991)
- Found that the cross-sectional area of the corpus callosum was 11 percent greater in left-handed or ambidextrous (no strong hand preference) individuals - Could be due to a greater number of fibers, thicker fibers, or more myelin
Multiple Intelligences Gardner (1983)
- Gardner (1983) - Neuropsychologist who examined the effects of brain injury on behavior - Proposed seven distinct types of intelligence - Linguistic - Musical - Logical-mathematical - Spatial - Bodily-kinesthetic - Intrapersonal (within the mind) - Interpersonal (between people)
Characteristics of Human Thought
- Human predisposition to sequence movements may have encouraged language development. - A critical characteristic of human motor sequencing is our ability to form novel sequences with ease. - People with frontal lobe damage have difficulty generating novel solutions to problems. - Frontal lobes are critical to organizing not only behavior but also thinking.
The Nature of Thought: Psychological constructs
- Ideas that result from a set of impressions - Mental processes such as thought, language, memory, emotion, and motivation - Difficult to localize constructs in the brain
Deficits of Attention: Extinction
- In neurology, neglect of information on one side of the body when it is presented simultaneously with similar information on the other side of the body - Patients with contralateral neglect exhibit this symptom as they begin to recover. - People who have it fail to pay attention not only to one side of the physical world around them but also to one side of the world represented in their mind. - ex. parietal stroke damage-> as patient gets better develop extinction-> when presented two objects at the same time-> only pay attention to one - somewhere know they have left side but association cortex makes them unaware-> cant integrate (still feel like theres more)
What Is the Neural Basis of Consciousness?
- In some conditions people can process information without being aware of that information ex. Blindsight, form agnosia, visual neglect, amnesia - In some conditions people have conscious awareness of imaginary events ex. Phantom limbs, hallucinations in schizophrenia - The representation of a visual object is likely distributed over many parts of the brain, and part of this neural circuit must produce awareness.
Neuroeconomics
- Interdisciplinary field that seeks to understand how the brain makes decisions - Combines ideas from economics, psychology, and neuroscience, in attempt to explain decision making processes by studying patterns of brain activity as people make decisions
Two types of "personal" intelligence
- Intrapersonal aspect is awareness of one's own feelings - Interpersonal aspect entails recognizing others' feelings and responding appropriately - Both refer to the frontal and temporal lobe operations required for success in a highly social environment
Multidisciplinary Research on Brain and Behavioral Disorders: Behavioral studies
- Investigate the whole organism. - Understanding the whole organism necessitates understanding its parts—its cells, its chemistry, and its genes (macro → molecular).
Modeling simplicity
- Investigating the causes of disorders using animal models - For example rats with specific lesions of the nigrostriatal dopamine system are used to model Parkinson disease. - Meaning: the view of the neurobiology behind behavioral disorders that animal models provide can be oversimplified. - Modeling human disorders is complex. - Critical thinking is important for evaluating studies using animal models that point toward possible cures for human behavioral diseases. - Meaning: objectively identifying any cognitive processes mimicked by a laboratory model is difficult.
Knockout technology
- Is used to build models of human disorders and generate treatments. - can stimulate behaviour seen in humans - Genes related to disordered behavior in fruit flies, fish, and mice are largely the same as those related to similarly disordered behavior in people.
Knowledge about Objects, where in brain
- Knowledge about what objects are is represented in the temporal association cortex, part of the ventral visual stream. - If the temporal association cortex is destroyed, the person will develop visual agnosia. - He or she will lose all visual knowledge about objects (e.g., what they are, and what they are used for). - knowledge of "what" things are= temporal - knowledge of "how" to grasp the object= parietal
Characteristics of Human Thought: Language + what is syntax
- Language gives humans an edge in thinking. - Language provides the brain with a way to categorize information - Language provides a means of organizing time (e.g., Monday at 3:00 P.M.). - Language has syntax. - Sets of rules for putting words together to form meaningful utterances - Proposed to be a unique characteristic of human language - Allows humans to have a language that moves beyond the concrete world of here and now, can make plans or think about future
Consciousness
- Level of responsiveness of the mind to impressions made by the senses - Consciousness may provide an adaptive advantage
Mirror Neurons
- Many "movement" neurons located in the inferior frontal and posterior parietal cortex discharge when a monkey sees other monkeys make the same movements - also discharge when the monkey sees the experimenter make the movements - Mirror neurons could provide the link between the sender and the receiver of a communication - used both for imitating others' actions and for understanding their meanings - Previously thought critical in the basis of understanding actions. Now more understood as a action monitor (which improves speed and accuracy of movements). - "monitoring neurons"-> you don't want to just send motor movement and not monitor it
Causes of Disordered Behavior: Microscopic, Intermediate, Macro level
- Microscopic: genetic error: Tay-sachs disease(neurons destroyed in brain + spinal chord) and huntingtons disease (involuntary movements) - Intermediate: One time events: Infections, injuries toxins (encephalitis) - Macro level: Nutrition, stress: Korsakoff syndrome - Factors may interact
Handedness and Cognitive Organization
- Most right-handed people have language localized in their left hemisphere. - The opposite is not true of left-handed people. - About 70% also have language localized in their left hemisphere. - About 15% have language localized in their right hemisphere. - About 15% have bilateral representation of language.
Systemic complexity
- Multiple receptor systems serve widely varied functions. - For example, when people ingest a GABA agonist, such as a benzodiazepine, multiple effects on behavior become apparent. - Meaning: most drug treatments may improve a target behavior but at the same time produce varied side effects, some people exhibit a greater firing effect-> others lesser
Organizational complexity
- Nervous system far outstrips other body systems in complexity. - Brain has a wider variety of cell types than does any other body organ. - Nervous system cells and their connections are plastic: they change with experience. - Features add a whole new dimension to understanding healthy and disordered functioning
Selective Attention: Moran and Desimone (1985)
- Neurons in areas V4 could be trained to respond selectively to information in their receptive field. - Each animal was trained to attend to stimuli presented in one particular area of the visual field and to ignore stimuli in any other area. - In this way, the same visual stimulus could be presented to different regions of a neuron's receptive field to test whether the cell's response varied with stimulus location. - Attending to specific parts of the sensory world is a property of single neurons: more evidence that the neuron is the computational unit of cognition - monkey-> looked at fixation-> flash stimuli on both sides-> monitoring v4(color form) neurons-> If to one side certain neuron fires (vice versa)-> get monkey to focus attention to the right-> still fixating-> but right side has more attention-> the unrewarded side (left) is not firing now it shows selective attention-> its only letting one side of the brain focus
Variations in Cognitive Organization Sex Differences in Cognitive Organization
- On average, females are better than males at short term memory tasks and verbal fluency tasks (ex. fill empty boxes w the appropriate symbols from the top row, fill in each blank w words). - On average, males are better than females at spatial relation tasks and mental rotation tasks. (ex. water in cup task-> draw a line do indiacate waterline in tipped glass, choose which box could be made from the plan)
Social Neuroscience: Living in a Social World
- Our understanding of our "self " and our social interactions link together as a single mental action. - When we express attitudes (including prejudices) toward ideas or human groups, brain imaging shows activation in prefrontal, anterior cingulate, and lateral parietal regions. - cultural information biases brain systems, which in turn biases attitudes. - parkinsons, idea of self, sleep, alzheimers, schizophrenia= all dopamine/ tied to reward/ religious experience/ religious experience-> people with lack of DA might have lower religious aspects-> what is religion? Idea beyond self - people who arent religious= belive their in charge-> hemisphereic differences - Social cognitions running the gamut(range) from understanding ourselves to understanding others clearly are associated with activation of specific brain regions, especially prefrontal regions. - The obvious conclusion is that prefrontal activity produces our social cognitions, just as activity in visual regions produces our visual perceptions. - McLure et al. (2004) attitudes towards cola-flavored sodas experiment: - experiment= coke vs pepsi-> blind test-> people say they can tell difference-> but when do test find they cant-> when dont know what drinking brain looks the same-> when know what drinking have prejudice/ anterior cingulate cortex activity= altered
Challenges to Diagnosis
- People are seldom objective observers of their own behavior or that of a loved one. - The patient and loved ones may be selective in what they notice. - People are seldom specific in identifying symptoms. - Evaluators have their own conceptual biases, which may influence the questions they ask and the information they gather. - Behavioral information may be interpreted differently by general physicians, psychiatrists, neurologists, psychologists, social workers, and others. - people are terrible at telling you -> especially after brain injury-> sometimes family member is also biased ex. to memory problems or language but not visual
Deficits of Attention: Frontal association cortex
- People with frontal lobe injuries tend to be overly focused on environmental stimuli. - They seem to selectively direct attention to an excessive degree or to have difficulty shifting attention
Freudian Views of the Mind
- Primitive functions, including "instinctual drives" of sex and aggression, arise in the id (unconscious). - Rational part of the mind is the ego: Believed to be unconscious, although experience (to Freud, our perceptions of the world) is conscious - The superego acts to repress the id and to mediate (intervene) ongoing interactions between the ego and the id -Id= limbic system and brainstem, regulate instincts and drives - Ego= posterior cortex, generates sensory representations of the world, intervenes between the unrealistic id and the external real world. It is the decision-making component of personality. Ideally, the ego works by reason, whereas the id is chaotic and unreasonable - Superego= Dorsal frontal cortex is locus of self conscious thought-> intervenes interactions between ego and Id, incorporates the values and morals of society which are learned from one's parents and others, control the id's impulses, especially those which society forbids, such as sex and aggression. It also has the function of persuading the ego to turn to moralistic goals rather than simply realistic ones and to strive for perfection, behavior which falls short of the ideal self may be punished by the superego through guilt. The super-ego can also reward us through the ideal self when we behave 'properly' by making us feel proud - Repressed information= Ventral frontal cortex regulates inhibitions
Spatial Cognition
- Refers to a range of mental functions, from the ability to navigate from point A to point B to the representation of complex visual arrays - The ability to mentally manipulate things likely evolved in parallel with our ability to navigate in space. - The dorsal visual stream in the parietal lobes is important in spatial cognition. - helps us navigate/ internal mental maps - as we move and interact we need neural system to help manage that - use other previous information to help you navigate - dorsal stream= how we move and interact with our environment - test spatial cognition by giving subjects pairs of stimuli like this and asking if the shapes are the same or different.
Technological resolution
- Resolution of a tool may not show sufficient detail to detect subtle neuronal change. - Consider behavioral problems after a brain trauma in a patient showing no obvious signs of brain damage on an MRI. - Meaning: given the current diagnostic methods for both behavioral disorders and neuropathology, identifying disorders and their causes is seldom easy.
Cerebral Asymmetry in Thinking
- Returning to and extending Broca and Wernicke's research - Different ways to examine cerebral asymmetry - Anatomical asymmetry - Function asymmetry in neurological patients - Functional asymmetry in the healthy brain - Functional asymmetry in the split brain
Visual system
- Right visual field has an advantage for language related information. - Left visual field has an advantage for nonverbal spatial information. - word in right visual felid goes to left hemisphere has advantage - pic of face in left goes to right has advantage
Attention
- Selective narrowing or focusing of awareness to part of the sensory environment or to a class of stimuli - Can be directed inward or outward - William James (1890): "[Attention] is the taking possession by the mind in clear and vivid form of one out of what seem several simultaneous objects or trains of thought." - narrow awareness of a particular part of the environment or sensation - can be inward ex. focus on heartbeat - "selectively focus"= focus only on white shirts
Cognitive neuroscience
- Study of the neural basis of cognition (acquiring knowledge) - Broad definition includes neuropsychological testing. - Compares the effects of injuries to different brain regions on particular psychological tasks
Split brain
- Surgical disconnection of the two hemispheres in which the corpus callosum is cut - electrical storm-> motor cortex is over firing leading to motor movements of a seizure - After the corpus callosum is cut, the hemispheres have no way of communicating with one another. - Information in the left visual field goes to the right hemisphere, and information in the right field goes to the left hemisphere. - With the corpus callosum cut, information presented to one side of the brain has no way of traveling to the other side. - The right hemisphere, which receives the visual input, does not talk, so it cannot respond verbally. - The left hemisphere does talk, but it does not see the object, so it answers that nothing was presented. ex. patient fixates on the dot in the center of the screen while an image is projected to the left or right visual field-> he is then asked to identify verbally what he sees Results: - If the spoon is presented to the right visual felid (goes to left language hemi) the subject says "spoon" - If the spoon is presented to the left visual field (goes to right non language area) the subject says " I see nothing"
Mental manipulation
- The ability to manipulate an object in the mind's eye probably flows from the ability to manipulate tangible objects with the hands.
Neuropyschoanalysis
- The brain as the ultimate source of behavior
Why is the left hemisphere specialized for language?
- The left hemisphere helps to control fine movements, and fine movements are necessary for the production of language.
Neuronal plasticity
- The nervous system can adapt to extreme stress or injury. - For example, only when the loss of dopamine neurons exceeds about 60 percent to 80 percent do investigators see clinical signs of Parkinson disease. - Meaning: the brain's compensatory plasticity is considerable; the brain has a remarkable capacity for adapting.
Planning
- To plan, you need to recognize objects (an occipital and temporal lobe function) and to make appropriate movements with respect to them (a parietal lobe function). - In this case, the frontal lobes as acting like an orchestra conductor. - The frontal lobes make and read a motor plan to organize behavior in space and time—a kind of score, analogous to the musical score a conductor uses. - People with frontal lobe injuries are simply unable to organize their behavior - frontal lobes are like the boss-> tell everything else what to do with their information
Tractography Using Diffusion Tensor Imaging
- Tractography measures actual neuroanatomical pathways that can be related to specific traits. - Can be done quickly on many living brains, and measurements can be made simultaneously in the entire brain - a 3D modeling technique used to visually represent neural tracts using data collected by diffusion-weighted images (DWI). It uses special techniques of magnetic resonance imaging (MRI) and computer-based image analysis.
Left Hemisphere, Language, and Thought: Gazzaniga (1992)
- Unlike in other animals, the speaking left hemisphere in humans acts as an interpreter: it is able to infer relationships among stimuli. - The language capability of the left hemisphere gives it a capacity for interpretation that the right hemisphere lacks. - Language may label and express the products of other cognitive systems. - Humans are a believing species: we make inferences and have beliefs about sensory events.
Using fcMRI in Brain Mapping
- Uses resting-state fMRI (rs-fMRI) to measure functional correlations between brain regions - Identifies consistent patterns of connectivity, or nerve tracts, in the brain - Does not measure static anatomical connectivity but rather uses temporal (time- based) correlations between neurophysiological activity in different regions to infer functional connectivity
Synaptic organization is partly directed by a person's genes, but it is also epigenetic
- Variations in experiences, coupled with variations in genetic patterns, contribute to observed individual differences in both quantitative and qualitative intelligence.
Considerations
- We do not yet understand all of the brain's parts and their functions, nor is it clear how the brain produces mind, a sense of well-being, and a sense of self. - Significant advances have led to the realization that while in some circumstances the brain copes competently with life's challenges, in other circumstances, it is not up to the job.
Neural Unit of Thought + Alex the parrot
- What is thinking? Is it exclusively human? - Consider Alex the parrot - Birds do not possess a neocortex (instead, they evolved specific brain nuclei that function much as the layers of the human cortex do) - Alex displays complex thinking that includes vocabulary with meaning, abstract ideas (color, shape, material relative size), integration of concepts, and comprehension. - Thinking must be an activity of complex neural circuits, not of some particular brain region.
Testing for extinction
- When shown two identical objects: Patient sees only the object in his right visual field-> When shown two different objects: then patient sees the object in BOTH visual fields-> When shown two kinds of the same object ex. big fork and small one the patient sees only the objects in his right visual field - A stroke patient who shows neglect for information presented to his left responds differently depending on whether objects in the left and right visual fields are similar or different
Sex Differences in Brain Volume
- Women have a larger volume of dorsal (lower) prefrontal and associated paralimbic regions. - Men have a larger volume of more ventral (upper) prefrontal regions.
Neural Bases of Sex Differences
- Women have relatively high cortical gray matter concentration in many regions of the cerebral cortex. - Men's gray matter concentration is more uniform across the cortex. - Women show increased gray matter concentration in the cortical regions shown in color. Gray shaded regions are not different in males and females.
Neural Bases of Sex differences: Gonadal hormones
- influence the structure of neurons on the rat prefrontal cortex
Hypotheses regarding the neural basis of synesthesia
1. Extraordinary neural connections between sensory regions 2. Increased activity in multimodal areas of the frontal lobes that receive input from more than one sensory area 3. Particular sensory inputs eliciting unusual patterns of cerebral activation
Wisconsin Card Sorting Test:
1. The task is to place each card in the pile under the appropriate card in the row, sorting by one of three possible categories. 2. Subjects are never explicitly told what the correct sorting category is—color, number, or form; they are told only whether their responses are correct or incorrect. 3. After subjects have begun sorting by one category, the tester unexpectedly changes to another category (people w frontal lobe damage and a extinction symptom will not stop even if they know its wrong)
A poor or underresourced environment can hinder the development of intelligence ___ in people with higher than average intelligence ___.
A poor or underresourced environment can hinder the development of intelligence B in people with higher than average intelligence A. - dont get to use their genetic intelligence to full potential
Cognition and the Association Cortex
Association cortex - Neocortex outside of the primary sensory and motor cortices; produces cognition (Association cortex= 2/3, primary cortex= 1/3) - One of the key differences between association cortex and the primary sensory and motor cortices is the pattern of connections. - The association cortex receives information that is more highly processed than information received by the primary cortices. - the information thats coming into the association cortex is the fundamental difference between that of the primary cortex as it receives raw info from sensory input but the association cortex receives highly processed information - Contains knowledge either about our external or internal world or about movements - any areas that aren't referred to at the primary cortices is the association cortex which functions in thinking
Appropriate postnatal experiences can enhance development of intelligence _____ in people with lower than average intelligence _____.
B in people with lower than average intelligence A.
Association cortex route
Brainstem-> thalamus (relay center)-> Primary cortices-> Association cortex-> back to thalamus - raw info goes to the primary cortex ie. primary motor, sensory, visual, auditory, olfactory + taste - manufactures in brain-> contains association knowledge of both internal and external
Planning and the frontal lobes/ wisconsin card sorting tasks
Frontal lobes - Performance on the Wisconsin Card Sorting Test exemplifies the deficits frontal lobe injury causes. Wisconsin Card Sorting Test: - Neuropsychological measure of planning and abstract reasoning - Shifting the response strategy is particularly difficult for people with frontal lobe lesions. - Pattern of behavior known as perseveration is the tendency to repeat the same verbal or motor response to varied stimuli.
Cell assembly
Hebb, 1949 (neurons that fire together wire together) - Hypothetical group (network) of neurons that become functionally connected via common sensory inputs - Proposed by Hebb as the basis of perception, memory, and thought - Connections among neurons are not random but rather are organized into systems and subsystems. - Thinking must result from the activity of these complex neural circuits. - Cell assemblies provide the basis for cognition. - Different ensembles come together, much like words in language, to produce coherent thoughts. - Cell assemblies may be distributed over fairly large regions of the brain or confined to smaller areas, such as cortical columns - Neurons are the only elements in the brain that combine evidence and make decisions. - Foundation of cognitive processes and of thought - The combination of individual neurons into novel neural networks produces complex mental representations
what part of the brain showed an increase in bilingual speakers before age 6
Increased gray matter volume in the frontal lobe of adults who learned two languages before age 6 reflects this behavioral advantage.
Intelligence A and B
Intelligence A: Hebb's term for innate intellectual potential, which is highly heritable and cannot be measured directly Intelligence B: Hebb's term for observed intelligence, which is influenced by experience as well as other factors in the course of development and is measured by intelligence tests - Experience may influence intelligence by increasing the number of synapses and the number of glial cells.
Investigating the Neurobiology of Behavioral Disorders
It is difficult to predict a specific biochemical abnormality from information at the neurological, behavioral, or social level, if measure someones behavioural level then see how they do on a executive function task and give you a MRI-> results often dont correlate
Functional Asymmetry in Neurological Patients: R v. L Parietal Damage
Patient G.H: Injury to this area of the right hemisphere cause difficulties in copying drawings, assembling puzzles and finding the way around a familiar city whereas Patient M.M: has injury to the same area but on the left hemisphere causing difficulties in language, copying movements, reading and generating names of objects or animals
Why is the right hemisphere specialized for spatial abilities?
The right hemisphere plays a role in the control of actual movements in space and in mental images of such movements (elaboration of the functions of the dorsal stream).
Dorsal stream in the parietal lobes is central in..
controlling vision for action - Evolutionary development provided a neural basis for such spatial cognitive skills as mentally rotating objects. - People with damaged parietal association regions, especially in the RIGHT hemisphere, have deficits in processing complex spatial information, both in the real world and in their imagination - if we can interact with our environment then its a small leap to imagine moving it in our mind
Consciousness is likely a product of all
cortical areas, their connections, and their cognitive operations
The greater the complexity in neural circuitry, the greater the...
degree of consciousness
Performance on IQ tests and what are correlated
memory are highly correlated
Consciousness is presumably a process that emerges from..
neural circuits rather than from individual neurons
Gray matter volume in the right dorsolateral prefrontal region correlated with
the participant's accuracy in working memory tasks.
Performance speed correlated with increased activation in ___________________ and with an increase in the interaction between the _______________________
the right dorsolateral prefrontal cortex, prefrontal cortex and right posterior parietal cortex.