Higher Cortical Functions

Question 1

What does the thalamus do?

Answer 1

Thalamus acts as a gatekeeper for things going in and out of the cerebral cortex.

Thalamus also keeps the brain alive because information goes through it to get into the cerebral cortex.

Question 2

What does the mapping effect of the thalamus refer to?

Answer 2

Cortical effects can be mapped onto areas in the thalamus

Question 3

What are intracortical connections?

Answer 3

Connections within the cortex which is the primary way of the brain functioning.

Question 4

How do interhemispheric connections communicate?

Answer 4

Via the corpus collosum

Question 5

How is the brain organised physiologically?

Answer 5

In 6 laminae (6 layers):

I, II, and II are intracortical association fibers

IV is where incoming sensory fibers terminate

V, and VI is where output fibers leave the cortex (V goes to the brain and VI to the thalamus)

Question 6

How do the output fibers in lamina V and VI act?

Answer 6

They are primarily stimulatory and produce mostly glutamate (an excitatory neurotransmitter)

Question 7

What kind of cells are present in lamina V and VI and what neurotransmitter do they produce and what do they do?

Answer 7

Pyramidal cells (in V) and fusiform cells (in VI)

These output fibers are excitatory so they produce glutamate. Some cells produce GABA which is inhibitory but much more rare than glutamate

Question 8

What kind of cells are present in lamina IV?

Answer 8

Incoming sensory fibers. They have short interneurons which produce either glutamate (exc.) or GABA (inh.)

Question 9

How are fibers from I, II, and III lamina different to everywhere else?

Answer 9

They are more branched and interconnective whereas the rest are long and not very connected.

Question 10

What are primary areas of the brain?

Answer 10

First recognition of external stimuli exist here. The rest of the brain makes sense of these areas.

Question 11

What is the premotor area?

Answer 11

Secondary motor area which controls primary area.

Question 12

Where is an image made in the brain?

Answer 12

In a secondary visual area. Primary visual area receives undeciphered visual stimuli

Question 13

What can be said about the size of primary areas of the brain?

Answer 13

They are proportionally very small compared to the total size of the brain

Question 14

What are primary cortical regions?

Answer 14

Point of first contact for Motor and Sensory systems in cortex.

Motor:

Origin of motor tracts which decussate at medulla and descend spinal cord to efferent motor neuron. They have a discrete connection with specific effectors.

Sensory:

Termination of sensory tracts from specific sensory organs. Visual, auditory, somatic

Question 15

How are different regions of the cortex mapped to the function?

Answer 15

Where we have neurons for a specific location the more neurons we have for them in the brain in that particular region of the cortex. (Homunculi)

Question 16

What do secondary cortical regions do?

Answer 16

They are regions of control which are located proximal to primary areas and they begin to make sense out of signals to/from the primary areas.

These areas provide complex patterns of motor activity in motor neurons. They interpret meaning. (Eg. Auditory siren = run, Visual lines continue to form shape recognition)

Question 17

Do we get a full picture from secondary visual areas?

Answer 17

No, only the meaning of primary stimuli. It is the first level of integration of a signal.

Question 18

What are association areas?

Answer 18

Areas in which complex activities take place and higher order functions are done. (Eg. Word formation, Behaviour, emotions, motivation, etc)

Question 19

What area is responsible for word formationa and where is it located?

Answer 19

Broca’s area which is located in the center area directly posterior to the frontal lobe.

Question 20

What area is responsible for behaviour, emotions, and motivation?

Answer 20

Limbic association area

Question 21

Which area is responsible for language comprehension and intelligence?

Answer 21

Wernicke’s area

Question 22

Where do higher order/accessory areas sit?

Answer 22

In between secondary areas

Question 23

What is the prefrontal cortex responsible for?

Answer 23

Planning complex movements and elaboration of thoughts

Question 24

What area is associated with spatial coordinates of body and surrounding?

Answer 24

An accessory area in the parietal lobe that receives input from visual, auditory, and vestibular location of the brain.

Question 25

What do association cortices do?

Answer 25

Produce association between sensory inputs and motor behaviour.

Also has the ability to form memories.

Question 26

What are the 3 major divisions of the association cortex?

Answer 26

Parieto-occipito-temporal AA (involved in polysensory integration and language)

Prefrontal AA (Executive functions, motor planning, attention, working memory)

Limbic AA (memory, emotion, motivation)

Question 27

Where does the Parieto-occipito-temporal Association Area sit?

Answer 27

Sits in a triangle between hearing, somatosensation, and balance location which gives image of the world.

This area allows interpretation of language and gives interpretive meaning.

This area also gives spatial coordinates from visual and somatosensory input and continuous analysis of spatial orientation.

Produces initial processing of visual language.

Naming objects area coordinates names learnt

Language comprehension area (Wernicke’s area)

Question 28

What does prefrontal association area do?

Answer 28

Controls behaviour, in front of primary motor cortex and secondary motor cortex.

Question 29

What does the limbic association area do?

Answer 29

It is located right above limbic system and is responsible for emotional drive, memory, and motivation

Question 30

What happens to movement planning and language processing if the parieto-occipito-temporal association area is damaged?

Answer 30

Failure to plan movements on opposite side of the body

Loss of names

Loss of ability to comprehend language

Question 31

Which part of the parieto-occipito-temporal association area is responsible for language comprehension?

Answer 31

Angular gyrus area

Question 32

What does the prefrontal association area do?

Answer 32

Calling forth information and using it to obtain a goal (motor and non-motor thinking)

Plan/consider consequences of actions performed

Concerted thinking ing a logical sequence

Working memory (analysing thoughts as they occur)

Elaboration of thought (Correlate divergent info, control one’s abilities and ensuring behaviour is culturally appropriate)

Question 33

What happens if the prefrontal cortex is damaged?

Answer 33

Causes an inability to keep track of simultaneous bits of information, and creates easy distraction.

Loss of complex problem-solving, ability to perform sequential tasks, learn parallel tasks, morals/social appropriateness, and purpose.

Question 34

What happens if the limbic association cortex is damaged or obstructed with a lesion?

Answer 34

Difficulties with abstract reasoning, judgement, and mood

Losing ability to integrate behaviour with mood

Question 35

What parts of the brain does communication involve?

Answer 35

Sensory integration (audiovisual)

Formation of thoughts (choice of words)

Motor control of vocalization (vocalization)

Formation of word, thought and choice of words is function of Wernicke’s area (comprehension area).

Broca’s area controls the motor coordination required for speech.

Question 36

What does Wernicke’s area do?

Answer 36

General interpretive area (integrates comprehensive interpretive function, integrates auditory/visual/somatic AAs, complex patterns involving many modalities)

Language-based intellectual functions (Integrates sense to form thoughts (word choice) and feeds directly to Broca’s area)

Everything feeds into Wernicke’s area where it is integrated and then action is achieved by Broca’s area.

Question 37

How does Wernicke’s area feed into Broca’s area?

Answer 37

Directly through arcuate fasciculus

Question 38

`What is the pathway for auditory communication?

Answer 38

Primary auditory area recognition of sound as a word.

Interpretation of the word and the the thought that the word expresses in Wernicke’s area.

Formation of the word that expresses a thought to respond.

Transmission via arcuate fasciculus to Broca’s area.

Activation of motor programs in Broca’s area for control of word formation. (here the complex patterns required to express the though are formed)

Transmission of signals to motor cortex to control speech muscles.

Question 39

What is the pathway for visual communication?

Answer 39

Input from primary visual area

Processing visual information on parietal-temporal-occipital association cortex (angular gyrus region)

Wernicke’s area completely interprets visual input

Broca’s area creates motor formation of the word

Motor cortex creates the necessary movements for the words to be expressed.

Question 40

What is hemispheric dominance?

Answer 40

1 hemisphere is larger than the other.

In some people Wernicke’s area can be as much as 50% larger in the dominant hemisphere.

Question 41

Which hemisphere is commonly more dominant?

Answer 41

95% of population has a dominant left hemisphere.

Question 42

What happens in non-dominant hemisphere of the brain?

Answer 42

Non-dominant side related to other forms of sensory intelligence (music, sensory feelings)

Question 43

Where is language function localized in the brain?

Answer 43

Language function is lateralized as well as other functions of the brain

Question 44

Is hemispheric dominance acquired or congenital?

Answer 44

In neonates Wernicke’s area can be as much as 50% larger in dominant hemisphere

Question 45

What higher functions are lateralized to left side in most people?

Answer 45

Language (and signing)

Reading

Mathematical/analytical

Music (musicians) [For non-musicians its on the right!]

Question 46

What higher functions are lateralized to right side in most people?

Answer 46

Body image

Complex spatial tasks

Non-verbal ideation (

Music (non-musicians)