Wk 3: Cerebral Cortex Organization Models

What is the localization theory?

That there are specific functions that are assigned to regions of the cerebral cortex and that region run independently of each other

What Brodmann's area contains Wernicke's?

Area 22

If someone has a damaged Wernicke's area, what might a symptom be?

Difficulty in language comprehension

What Brodmann's areas are responsible for sound processing?

41 & 42

What Brodmann's areas contain the primary somatosensory cortex?

1, 2, & 3

What Brodmann's areas contain sensory perception?

5 & 7

If someone is having hearing loss in one ear, what Brodmann's areas may be affected and what may be a symptom?

Contralateral 41, 42, & 22 and would have disorders of auditory sensation perception

If someone is having issues with Brodmann's areas 1, 2, & 3; what may be a symptom?

Tactile function disorders

If someone is having issues with Brodmann's areas 5 & 7, what may a symptom be?

Visual or tactical agnosia

What Brodmann areas are affected when someone is suffering from contralateral neglect?

7 & 40 in right hemisphere

What Brodmann areas are affected when someone is suffering from apraxia?

7 & 40 in the left hemisphere

What Brodmann area in the primary somatosensory cortex is closest to the primary motor cortex?

Area 3

What is Brodmann area 3 responsible for?

Receive sensation from muscle spindles, GTOs, and joint receptors that communicate anteriorly with motor neurons in primary motor cortex

What is Brodmann area 1 & 2 responsible for?

Receiving sensation from slowly adapting cutaneous receptors (pain, temp, crude touch)

What Brodmann areas consist of cross modal matching?

39 & 40

What Brodmann's area contains the primary motor cortex?

Area 4

What Brodmann's area contains the pre-motor cortex?

Lateral area 6 & area 8

What Brodmann's area contains the supplementary cortex?

Medial area 6

What is the function of the pre-motor cortex?

Planning and production of complex motor behavior that is visually and/or sensory guided

What is the function of the supplementary motor cortex?

Planning, organization, and execution of complex motor behaviors (especially around proximal and bilateral)

What Brodmann's area contains Broca's?

Area 44

How much sooner is the pre-motor cortex active when compared to the primary motor cortex?

up to a second earlier

What muscles are controlled by the pre-motor cortex?

- Proximal muscles

- Axial muscles

What motor cortex is active during imagined, complex movements?

Supplementary motor cortex

What are the different theories of cortex organization?

- Connectionism theory

- Cellular connection theory

- Cortical lateralization or asymmetry of function theory

- Localization theory

What is the basis of the connectionism theory?

Based on neuroanatomy under the belief that bundles of axons connect different parts of the brain together

What fibers are associated with the connectionism theory?

- Commissural fibers

- Association fibers

- Projection fibers

What are commissural fibers?

Myelinated and unmyelinated axons that cross the midline and interconnect the hemispheres

What is an example of some commissural fibers?

Corpus callosum

What does the corpus callosum connect? What kind of fibers form this structure?

Connects frontal, parietal, temporal, and occipital lobes. Made of commissural fibers

What are association fibers?

Myelinated and unmyelinated axons that interconnect areas of the same cerebral hemisphere

What is an example of a structure made of association fibers?

Arcuate fasciculus

What is the function of arcuate fasciculus? What kind of fibers form this structure?

Connects temporal, parietal, and frontal lobes together within the SAME hemisphere. Involved with the Wernicke-Geschwind model of language. Formed of association fibers

What are projection fibers?

Myelinated and unmyelinated axons that project up and down the neuroaxis

What is an example of a structure made of projection fibers?

The internal capsule

What theories combine to form the cellular connectionism theory?

- Localization theory

- Connectionism theories

What is the cellular connectionism theory?

Belief that hemispheric functions are dependent on discrete, identifiable collections of cells (aka Brodmann areas) that act through integrated, specific connections with other related cell groups within the same hemisphere, across hemispheres, and to other parts of the brain and spinal cord up and down the neuroaxis

What is some evidence supporting the cellular connectionism theory?

- Wernicke-Geschwind model of language

- The 5 cortical areas involved with motor control

What is Wernicke-Geschwind's model of language?

Belief that there's multiple areas in the brain that work together for the whole function of speech

What areas of the brain are part of Wernicke-Geschwind's model of language?

- Visual input (17-19)

- Auditory input (41 & 42)

- Tactile/proprioception input (1-3)

- Left Wernicke's area (22)

- Left angular gyrus (39)

- Left arcuate fasciculus

- Left pre-and post-central gyro (1-4)

- Left broccas area (44)

What Brodman's area contains the primary visual cortex?

17

What Brodman's area(s) contains the association visual cortex?

18 & 19

What Brodman's area(s) contains the primary auditory cortex?

41 & 42

What Brodman's area(s) receives tactile/proprioception input?

1-3

What Brodman's area(s) contains Wernicke's area?

22

What is the function of Wernicke's area?

Changing auditory input into semantic code so that it becomes meaningful units (aka language comprehension)

What Brodman's area(s) contain the left angular gyrus?

39

What is the function of the left angular gyrus?

Combine sensory, visual, and auditory input into "patterns" of letters, words, or even sensory feelings (aka making semantic code)

What is the function of the left arcuate fasciculus?

Joins the posterior brain (receptive areas) with the anterior brain (expressive areas)

What is the function of Broca's area?

Speech production

What is it called when Broca's area ain't working?

Expressive aphasia

What is it called when Wernicke's area ain't working?

Receptive aphasia

What is it called when a right handed individual has damage to their left arcuate fasciculus?

Conduction aphasia

What is conduction aphasia?

When you can still speak fluently, comprehend language, but have a hard time repeating anything that you're told

What is is called when someone has damage to the fascial areas of the pre and post motor cortex?

Dysarthria

What is dysarthria?

Slow, slurred, and labored speech

What is the function of the cortical areas involved in motor control?

Produce visually-oriented, goal-oriented, voluntary movement

What cortex does the majority of the cortical-spinal tract (CST) originate from?

Primary motor cortex

When is the primary motor cortex active?

Right before and during movement

What is the last cortical area to fire prior to movement?

Primary motor cortex

How do you get an individual to have isolated contractions of muscles?

Microstimulation of primary motor cortex

What does the discharge frequency of CST neurons that originate in the primary motor cortex determine?

- Force used to move a limb

- Rate of force production used to move a limb

- Direction of limb movement

Does the discharge frequency of the CST have anything to do with positional changes of a limb?

Nah

What were the different conditions the monkey was put through in Evarts 1968 study?

Condition A: wrist flexion with no load

Condition B: wrist flexion with flexion load

Condition C: Wrist flexion with an extension load

What did Georgopoulos' studies determine about neurons firing rate?

It's proportional to the cosine of the angle between the preferred direction and the actual direction of movement

What are the functions of the posterior parietal lobe?

- Aid in visually guided movements

- Produce spatial relationships between objects and between objects and self

What Brodman's areas form the posterior parietal lobe?

5 & 7

The dorsal pathway from the occipital lobe to the parietal lobe looks over what functions?

- Objects orientations to one another in space

- Objects orientations to self in space

The ventral pathway from the occipital lobe to the anterior, inferior temporal lobe looks over what functions?

- Physical qualities of objects

What is cortical lateralization/asymmetry of function theory?

The belief that the 2 hemispheres split up functions to be more efficient with the space we have. Each hemisphere processes the same info, just differently.

According to the cortical lateralization/asymmetry of function theory, what kind of logic does the right hemisphere deal with in right handed individuals?

Holistic logic

What does holistic logic deal with?

- Spatial organization of sensory info

- Symbolic and tonal communication

According to the cortical lateralization/asymmetery of function theory, what logic does the left hemisphere of the brain deal with in right handed individuals?

Sequential logic

What does sequential logic deal with?

- Using syntactic rules for communication and math calculations

- Organize events in a temporal sequence

What are some specific examples of things processed by the left hemisphere of the brain according to the cortical lateralization/asymmetry of function theory?

- Verbal and written language

- Math

What are some specific examples of things processed by the right hemisphere of the brain according to the cortical lateralization/asymmetry of function theory?

- Drawing

- Music (tone and rhythm)

- Body language

- Drawing

- Spatial perception

What is the equipotentiality theory?

That both hemispheres have equal potential for developing a certain function

What is the parallel-development theory?

Idea that both hemispheres are destined to specialize for a specific function

What did Kolb and Whishaw believe about brain development?

Both hemispheres are functionally specialized at birth but can assume some functions of the other hemisphere if needed

What is the crowding effect?

When a function done by one hemisphere of the brain "goes over" to the other hemisphere and limits that development of the function that was supposed to be in that hemisphere

What were Moscovitch's beliefs about brain development?

One hemisphere inhibits the other from developing similar functions for the sake of space use. Occurs around 5

What is the term for the time that passes between a stimulus and movement initiation?

Reaction time

What is the term for the time that passes between when a movement is initiated and when it is terminated?

Movement time

How many stages are there to cognitive processing?

7

When do the stages of cognitive processing occur?

During the reaction time period

What is the serial processing model of cognitive processing for motor actions?

When each step of the process happens in a linear, specific order

What are the seven stages of cognitive processing for motor actions?

Detect --> ID --> memory search --> decision --> response selection --> response organization --> response execution

What occurs during the detect stage of cognitive processing for motor actions?

Imaged is stored

What are the different image storages?

- Visual image store (VIS)

- Auditory image store (AIS)

What is the visual image store capacity?

17 letters/words/symobls

What is the visual image store code type?

Physical

What is the visual image store decay rate?

200 msec

What is the auditory image store capacity?

5 syllables/sounds/words

What is the auditory image store code type?

Physical

What is the auditory image store decay rate?

1500 msec

What occurs during the identify stage in the cognitive stages for motor processing?

Recognize and/or receive the visual or auditory image

What is the identification capacity?

3 chunks if pure working memory, 7 if using long term memory

What is the identification code type?

- Semantic

- Symbolic

What is the decay rate of identification?

7 seconds

What is encoding?

Putting information into semantic code