Brain bee chapter 5

First 2 filters for the world and its many stimuli.

Perception through senses

Interpreting perception - comparing perceptions to memories of past experiences/observations

How does the brain deal with variable perceptions? What are variable perceptions?

Differences in how sensory inputs, physical states, or environmental conditions are interpreted and processed by the mind

Ability to store information in the short-term is limited, so it build simple representations of people, places, events, and objects as references. To make sense of moment-to-moment perceptions, brain relies on network of associations assembled from prior experiences. Connections enable your brain to deal with variable perceptions.

Connecting representations relies on __ ___

Semantic memory - Knowledge about facts

nature of semantic memory and what brain processing revealed

scientists are just beginning to understand the organization of cortical areas involved in semantic memory. But specific cortical networks are specialized for processing certain types of information. Studies involving functional brain processing revealed regions of the cortex that selectively process different categories of information such as animals, tools, etc

“concept cells” what they are, what they form, where they are located, and how they are identified.

Specific single cells that fire when interpreting specific objects but are silent when viewing others. They work together and are inter-connected (needle-sew-thread). These cells and their connections form the basis of our semantic memory.

Identified through recording of the electrical activity of individual brain cells.

located in temporal lobe.

Who do we study for our understanding of thinking and language? DBO…?

People with unique deficits caused by particular patterns of brain damage

DBO a 72 year old man who suffered multiple strokes. Could only identify 1/20 common objects on sight. BUT he could identify based on touch and sound. CONClUSION: strokes damaged brain in a way that prevented visual input from being conveyed to anterior temporal regions where semantic processing occurs. Blocked access to names of objects he could see.

Anterior temporal lobe

Front most part of temporal lobe, crucial for semantic memory, social knowledge, and language comprehension. Has relations to epileptic seizures, strokes in this region can result in associative agnosia, prosopagnosia, and semantic dementia.

Agnosia

Problems recognizing and identifying visual stimuli

Damage to certain areas of the temporal lobe warrants this

Several forms depending on place of damage.

Prosopagnosia

“face blindness”

Underside of temporal lobe called the fusiform face area (FFA) crucial for recognizing faces

Bilateral damage (damage to both sides of brain) leads to prosopagnosia

topographical disorientation or the subtype of Topographical agnosia

Damage to parahippocampal place area (PPA) causes place blindness. Responds to specific locations.

How is information organized within these brain areas?

Organized into hierarchies as complex skills and representations are built up by integrating info from simpler inputs.

Ex: Words

Semantic system

A constellation that responds kore strongly to words than sounds and more strongly to natural speech than artificially garbled speech.

Posterior parietal cortex, parts of temporal lobe, and regions in the PFC.

Occupies big portion of human brain, especially when compared to other brines, Shows why humans have a better capacity for speech.

How are words separated by areas and hemispheres?

Words related to each other activate the same areas while unrelated words do not.

functional magnetic resonance imaging (fMRI) have found that words tend to activate left-hemisphere the most. BUT words presented in narrative or other context activate both sides.

Written language involves additional brain areas such as

visual word form area (VWFa) is the fusiform gyrus recognizes written letters and words (across languages).

Connections between VFMA and areas that process visual info, bridges help the brain link meaning to written language.

Regions that represent numbers

Parietal cortex with input from occipitotemporal cortex (visual recognition and reading)

work together to identify the shape of a written symbol and connect it to its concept, which may be broad (trio-3-rhythm)

How did Louis Victor Leborgne (patient Tan) aid the neuroscience world?

When he met Pierre Paul Broca, he could only say the world tan. He could comprehend speech and was trying to respond the the best of his abilities. After death, autopsy proved a large damage area (lesion) in the frontal lobe. SO - damage to specific parts of left-hemisphere results in aphasia -language disorders

Broca’s area and Broca’s aphasia

Broca’s area- frontal lobe, crucial for speech production

Broca’s aphasia - “non-fluent” aphasia, speech production impaired but comprehension intact. LEFT frontal lobe can produce varying degrees of non-fluent aphasia

How was 59 year old S.A. crucial to neuro discovery?

Lost her ability to understand speech, she could speak but her sentences made no sense. After death, WERNICKE found she had damage to her left temporal lobe causing the deficit “Wernicke’s aphasia” or “fluent aphasia'“. Might understand short individual words and their tone and speed can sound good.

“pure word deafness”

Damage to the superior temporal lobe in BOTH hemispheres

Unable to comprehend herd speech on any level. But they aren’t deaf (can identify rhythm, gender, tone of voice) and can understand written word.

Producing complex speech is dependent on…

Strongly dependent on left hemisphere (less than originally thought) including frontal lobe and posterior regions in temporal lobe. - assessing appropriate word and speech sounds.

Reading and writing involves c=what categories of brain regions?

Regions needed for speech comprehension AND those controlling vision and movement. Words - connections between brains language areas and the areas that process visual perceptions.

FOXP2

One language associated gene that codes for a special type of protein that switches other genes on and off in particular parts of the brain.

Mutations in FOXP2 result in…

RARE - difficulty making mouth and jaw movements in the sequences required for speech. Accompanied by difficulty with spoken and written language.

Many insights into human speech have come from studies of…? Why? And how are __ similar to humans?

Birds! Possible to induce genetic mutations and study their effects on singing.

Like humans - baby birds learn songs by imitating model bird during an early critical period. Depends on auditory feedback (hear their own attempts at imitations).

FOXP2 mutations can disrupt song development in young birds, like human kids.

Disruptions of FOXP2 can severely affect… Leads to?

Signaling in the dorsal striatum (part of the basal ganglia).

Specialized neurons in dorsal striatum express high levels of the product of FOXP2 Mutations in FOXP2 interrupt flow of information through the striatum, speech deficits. Show the genes importance in regulating signaling between motor and speech regions of brain.

Changes in the _ _ of FOXP2 might have influenced…?

Changes in the nucleotide sequence of FOXP2 might have influenced the development of spoken language in humans and explain why humans speak while others don't.

Functional imaging studies identified brain structures not previously known to be involved in language. LIKE (3 regions)?

Portions of middle and inferior temporal lobe - assessing meaning of words

Anterior temporal lobe - MIGHT sentence-level comprehension

Left posterior temporal lobe — sensory motor circuit for speech - communication between systems for speech recognition and speech production. Circuit is involved in speech development and likely to aid verbal short term memory.

Executive function

The processing that takes place in the prefrontal cortex (outer layer of brain above forehead).

Supervises all brain actions, taking in sensory and emotional info to plan and execute decisions and actions

Inhibition, working memory, and shifting

Why does the PFC interact with a large network of posterior cortical areas?

Specific regions of PFC support functions such as selecting, rehearsing, and monitoring information being retrieved from long-term memory. SO it interacts with posterior cortical areas that encode specific information (visual information, sounds, words, spatial location)

How does “working-memory” translate over to other animals?

Nonhuman primates show that neurons in PFC keep information “acitve’ or “in-mind” while the animal is carrying out a task that depends on it.

Inhibition (executive function definition) and how it matures from toddlers to grown

Suppress an inappropriate behavior or action

Even toddlers display hints at developing a inhibition ability. Lucias hand game where toddlers are shown a finger but told to make a fist and vice-versa. Hard for 3 year olds to inhibit automatic initiation of adults, easier for 4 year olds.

working memory (executive function definition). Location.

Ability to hold a rule in mind while you decide how to act.

New experiences, information initially enters working memory - transient form of declarative/ conscious memory

PFC and parietal lobe

Shifting. Definition, location, maturity.

mental flexibility, allows you to adjust ongoing behavior when conditions require it.

Damage to PFC means difficulty in doing this.

Ability to shift appears weakly in pre-schoolers. Monitor one’s errors in evident in adolescence. Mid-adolescence = adult levels.

Likely involves MANY regions of the PFC.

Changes in executive functioning are

gradual though more apparent in kids. Use inputs from all over brain. Activity level associated with executive functioning decreases with age because circuits become fine-tuned and afferent and the neuron networks mature.

Decision making

3 fundamental executive functions provide the basis for this

requires a person to weigh values, understand rules, plan, and make predictions about the outcomes of choices

Many different types of decisions

2 main types of decision making

Logical reasoning (determining which route is faster)

Emotional consequence atstake.

Affective decision making:emotional processes and rational reasoning interact to guide decisions under risk and uncertainty

Areas involved in decision making. 3 cerebral areas.

PFC: overriding emotional responses in decision-making. Because it has strong connections with regions related to motivation and emotions like amygdala and nucleus accumbens,

Lateral PFC is most active when declining small reward for a big reward in the future. Area develops late (early 20s) which relates to teenage impulsiveness.

Orbitofrontal cortex: region of PFC behind eyes. Important in affective decision making especially in situations with punishment and reward. Addiction and social behavior.

Social neuroscience

Study of neural functions that underlie interpersonal behavior

Humans are highly sociable (like other animals) and large parts of brain are decimated to processing information about others

Mentalizing and other neural function apart of interpersonal behavior

Making sense of your own thought processes and those of others

Understanding social rules, reading social cues, and coding appropriate responses.

Medial and lateral PFC are highly involved in these skills