Physio - Cerebral Cortex Structures

Frontal lobes (contain)

Broca’s area

Primary motor cortex

PFC (DL, VL, VM, OFC)

Cerebral cortex

-Outer layer of the brain

-4 lobes (frontal, temporal, parietal, occipital)

-5th lobe = insular cortex

Insular cortex

-one of the 5 lobes in CC

-hidden behind the lateral sulcus (aka Sylvan fissure), horizontal groove that separates the frontal/parietal from temporal lobe

-smallest lobe of CC

-used to be part of limbic system

Location of Broca’s area and Wernicke’s area

-Broca’s area – dominant (L) frontal lobe

-Wernicke’s area – dominant (L) temporal lobe

Broca’s aphasia

-expressive/nonfluent aphasia

-slow, labored speech, primarily nouns/verbs

-comprehension intact

-anomia and impaired repetition

Anomia

Unable to recall words of familiar objects (tip of the tongue)

Present in both Broca’s + Wernicke’s aphasia

Prefrontal cortex (functions beyond EFs)

-prospective memory (memory for future events)

-social judgment

-motivation, ER

-expression of personality

DL PFC (function)

-Cold computer functions, logical planning, most EFs

Damage in DL PFC →

-WM impaired

-Concrete thinking, perseveration

-Apathy, no motivation

VL PFC (function)

(The brakes, motor inhibition)

VM PFC (function)

Moral compass

Damage to VM PFC

-Unfeeling, unethical

-poor empathy, poor facial emotion recognition

-blunted emotional response

-Confabulation

OFC (function)

Social filter, social response inhibition

Damage to OFC →

-Jocularity, improper socializing, lack of filter

-Inappropriateness, impulsive, immature humor

-aggressive, abusive, lack of empathy

Primary motor cortex (function and damage)

-initiating + imagining + watching movement

-damage → weakness or paralysis in muscles on opposite (contralateral) side of body

Temporal lobes (contain)

Wernicke’s area

Auditory cortex

Wernicke’s aphasia

-Receptive, fluent aphasia

-Speech sounds fluent, but is meaningless

-Word salad

-Impaired comprehension of words (both reading/writing, and speaking)

-anomia and impaired repetition

Arcuate fasciculus

-Connects Broca’s and Wernicke’s area

Damage to arcuate fasciculus →

Conduction aphasia

Conduction aphasia

-connection btwn B/W areas are cut

-good comprehension (W) and speech production (B)

-but impaired repetition and anomia

-may say something off, then constantly correct themselves (bc W processes it, and knows it’s wrong)

Parietal lobes (contain)

-Somatosensory cortex

-Integrates bodily awareness, mental map of own body, awareness of oneself

Somatosensory cortex (function)

-Processes sensory info

-Touch, temperature, pain

-Proprioception – body position in space

-O/Agnosia

Without knowledge, unable to identify/recognize

Tactile agnosia

-d/t damage in parietal lobe

-Can’t know what an object it by touching it (inability to recognize an object through touch)

Asomatognosia

-d/t damage in parietal lobe

-Not able to recognize body parts, as your own

Damage to L parietal lobe →

Apraxias – can’t carry out a motor recipe or command

Gerstmann’s Syndrome

Damage to R parietal lobe →

Contralateral neglect

Gerstmann’s Syndrome

FAAL, math-writing-fingers

Finger agnosia – can’t identify/recognize fingers

Agraphia – lost ability to write

Acalculia – lost ability for math

L-R disorientation – can’t tell L side of body from R

Apraxia

Inability to carry out motor sequence

-not d/t motor, sensory, or language impairments

Contralateral neglect

d/t R parietal lobe damage

-ignoring the whole L side of body

e.g., shaving only R side

Ideomotor apraxia

-Can’t carry out motor action when commanded/asked

e.g., “Wave goodbye” → can’t (but will still wave automatically/in social situations)

Ideational apraxia

-lost the idea of a motor sequence

-Inability to carry out motor sequence

e.g., make a sandwich → actions are scrambled

Limb-kinetic apraxia

-Inability to make precise, coordinated movements with limb (finger/hand/arm/leg)

Occipital lobe

Primary visual cortex

Damage to occipital lobe →

-visual agnosia – can’t identify, process meaning of what is being seen

achromatopsia

colorblindness, can’t see color

“The strawberry looks grey”

Color anomia

-can’t name visually-presented colors (know what it is, but can’t say)

“I see the strawberry, but can’t say the word ‘red’”

-language-based (disconnect between language areas + L occipital lobe)

-can match like colors

-can associate colors with objects (e.g., can say that strawberries are red and bananas are yellow)

Color agnosia

-can’t identify/recognize a color

-don’t know the meaning, ‘what color is’

“I see it has a color, but DK it’s red, DK what red means, or that strawberries are red.”

Damage to primary visual cortex → cortical blindness

-Conscious blindness, total loss of conscious vision

-Optic nerve/eyes are intact, but brain doesn’t process visual info

Blindsight

-residual ability in some ppl with cortical blindness

-respond/react appropriately to visual info, despite not being conscious of it

e.g., say they don’t see the object, but guess correctly what they were shown

Damage in occipitotemporal junction → Prosopagnosia

Face blindness, don’t recognize faces (sometimes even own face)

Insula (or insular cortex) functions

-Four distinct regions): SMOG

-Sensorimotor – interoception, somatosensation, pain, and motion

-central olfacto-gustatory region – smell (olfaction) and taste (gustation)

-Social-emotional region – emotion, empathy

-Cognitive region – language, attention, memory

L hemisphere functions

-written and spoken language

-logical, analytical thinking

-positive emotions

R hemisphere functions

Some language functions:

-Emotional prosody – tone, rhythm, rate, volume of speech

-Pragmatics – application of language, and understanding of language within social/situational contexts (e.g., sarcasm, humor, hyperbole)

-Holistic thinking, intuition

-Understanding spatial relationships

-Negative emotions

Sperry’s split-brain research found that people with split-brains who saw a spoon in their R visual field

Could pick it out with R hand, and say they saw a “spoon”

Sperry’s split-brain research found that people with split-brains who saw a spoon in their L visual field

Could pick it out with L hand, but couldn’t say they saw a spoon

Dichotic listening task

-Used in research to understand speech lateralization

-(when presented with two words in L/R ear) Majority will say the word they heard in R ear

Which info is processed contralaterally in the brain?

All sensory and motor info, except smell (L nostril → L brain)