Cortical Function

Question 1

Which cerebral hemisphere is dominant in most people

Answer 1

Left

Question 2

Non-dominant hemisphere functions (5)

Answer 2

-Attention to both sides of the world
-Music perception
-Emotional significance to events + language
-Complex visuospatial skills
-Emotion conveyed by tone of voice (prosody)

Question 3

Dominant hemisphere functions (3)

Answer 3

-Attention to the contralateral side of the world (usually the right side)
-Language
-Skilled motor formulation

Question 4

Where is Broca’s area located?

Answer 4

In the frontal lobe of the dominant hemisphere only

Question 5

Where is Wernicke’s area located?

Answer 5

In the temporal lobe of the dominant hemisphere only

Question 6

Premotor cortex vs primary motor cortex

Answer 6

Premotor cortex: projects to the primary motor cortex - plans and organizes how movements will happen (what muscles, what sequence, etc.) and tells the primary motor cortex to initiate them
Ex: architect - draws the blueprint

Primary motor cortex: executes the movements by sending signals to the muscles
Ex: construction worker - follows the blueprint and gets the job done

Question 7

Frontal eye fields (FEF)

Answer 7

Located in the frontal lobe, connected to the brainstem oculomotor nuclei. Initiate voluntary saccadic eye movements (quick jumps of the eyes from one target to another)
Control contralateral gaze:
-Right FEF –> pushes eyes left
-Left FEF –> pushes eyes right

Question 8

Lesion of a frontal eye field

Answer 8

A lesion in a frontal eye fields would result in eye deviation toward the side of the lesion

Question 9

Prefrontal cortex

Answer 9

Important for behaviour - executive function, planning, judgement, problem solving, social behaviour, inhibition of inappropriate behaviour, motivation, etc.
*Also urinary continence

Question 10

Lesion in the prefrontal cortex (4)

Answer 10

-Poor planning, judgment, problem solving
-Disinhibition (inappropriate behaviours)
-Lack of motivation
-Urinary incontinence

Question 11

Function of Broca’s area

Answer 11

Speech production
*Also connects with brain areas responsible for grammar

Question 12

Lesion of Broca’s area

Answer 12

Broca’s aphasia= non-fluent speech (comprehension intact)

Question 13

Function of Wernicke’s area

Answer 13

Speech comprehension

Question 14

Lesion of Wernicke’s area

Answer 14

Wernicke’s aphasia= impaired comprehension (can’t respond to Qs, can’t follow commands)

Question 15

Domains of language (6)

Answer 15

-Spontaneous speech/fluency
-Comprehension
-Naming
-Repetition
-Reading
-Writing

Question 16

Arcuate fasciculus

Answer 16

Connects Broca’s area and Wernicke’s area

Question 17

Global aphasia

Answer 17

Impaired fluency, comprehension, and repetition

Question 18

Conductive aphasia

Answer 18

Impaired repetition but normal fluency and comprehension (due to a lesion of the arcuate fasciculus)

Question 19

Transcortical aphasia:
-What is it?
-Motor vs sensory

Answer 19

A group of aphasias caused by lesions outside the main language areas (Broca’s/Wernicke’s) that disconnect these areas from other parts of the brain –> repetition is spared
-Motor: impaired fluency
-Sensory: imapaired comrpehension

Question 20

Cortexes of the parietal lobe (2)

Answer 20

-Primary somatosensory cortex
-Somatosensory association cortex

Question 21

Functions of the parietal lobe (6)

Answer 21

-Sensation
-Attention
-Spacial awareness
-Calculations
-Writing
-Right-left discrimination

Question 22

Somatosensory association cortex

Answer 22

-Receives projections from the primary somatosensory cortex
-Involved in higher cortical sensory functions

Question 23

What part of the brain pays attention to the sides of the world

Answer 23

Parietal lobe
-Non-dominant side (usually right): pays attention to both sides of the world
-Dominant side (usually left): pays attention to the contralateral side only

Question 24

Praxis

Answer 24

Praxis: the brain’s ability to plan, organize, and carry out purposeful, skilled movements.
How it works:
1. Idea formation - deciding what to do (parietal lobe)
2. Planning - knowing how to do it (premotor cortex)
3. Execution - sending signals to muscles (primary motor cortex –> corticospinal tract –> LMNs)

Question 25

Apraxia:

Answer 25

The inability to perform purposeful movements despite having normal strength, sensation, and understanding

Question 26

Functions / areas of importance in the temporal lobe (4)

Answer 26

-Special senses (all represented bilaterally) -Insular cortex= taste -Olfactory cortex= smell -Auditory cortex= hearing -Wernicke's area -Limbic system -Memory

Question 27

Limbic system - what is it?

Answer 27

The limbic system is the emotional and memory center of the brain

Question 28

Main functions of the limbic system (5)

Answer 28

-Emotion -Memory (especially long-term and emotional memories) -Motivation + reward -Olfaction (strongly linked to memory and emotion) -Autonomic responses

Question 29

Main structures of the limbic system + functions (3)

Answer 29

-**Amyglada:** emotions + motivation -**Hippocampus:** memory -**Hypothalamus:** autonomic control

Question 30

Kluver-Bucy syndrome + features

Answer 30

A behvioural disorder caused by bilateral anterior frontal lobe lesions, involving the amyglada Features: **HHH DOC** -**H - Hyperorality:** excessive preoccupation with oral behaviours -**H - Hypersexuality:** inappropriate/excessive sexual behaviour -**H - Hyperphagia:** overeating, even non-food items -**D - Docility:** loss of fear and aggression, unusual calm -**O - Object agnosia:** Can see objects but can't recognize them -**C - Change in emotional behaviour:** flat affect, lack of normal emotional reactions

Question 31

Circuit of Papez

Answer 31

A neural pathway in the limbic system involved in emotion + memory Hippocampus --> hypothalamus --> thalamus --> cingulate gyrus --> hippocampus

Question 32

Making memories (4)

Answer 32

1. Attention + registration (<1 sec) -Brainstem activating system, frontoparietal networks 2. Working memory (secs - mins) -Frontal lobe (concentration) 3. Consolidation (mins - years) -Medial temporal structures 4. Long term memories -Encoded in multiple cortex areas

Question 33

Dorsal and ventral streams of visual processing

Answer 33

After visual info leaves the primary visual cortex in the occipital lobe, it travels along these two pathways. **Ventral stream:** the *what* pathway -Tells you what you're looking at (object recognition + registration) -Path: occipital lobe --> temporal lobe **Dorsal stream:** the *where* pathway -Tells you where things are (spatial awareness + motion processing) -Path: occipital lobe --> parietal lobe

Question 34

Lesions of the ventral stream of vision cause

Answer 34

-Visual agnosia (can't recognize objects visually) -Achromatopsia (impairment of colour vision) -Prosopagnosia (can't recognize familiar faces) -Pure alexia (can't read)

Question 35

Lesions of the dorsal stream of vision cause

Answer 35

-Akinetopsia (impaired motion sensation) -Simultanagnosia (inability to see more than one object at the same time, to construct a whole from it's parts)