Brain

Question 1

List the 3 parts of the brain

Answer 1

1. Cerebrum + basal ganglia
2. Cerebellum
3. Brainstem

Question 2

List the lobes of the brain (5)

Answer 2

frontal, parietal, occipital, temporal, limbic

Question 3

List the functional areas of the frontal lobe.

Describe the areas of the frontal lobe in relation to each other.

Answer 3

Primary motor cortex (anterior to central sulcus): voluntary movement and muscle activity coordination

Premotor motor cortex (anterior to the primary motor cortex): planning/ coordination of movement

Prefrontal cortex (most anterior part of the frontal lobe): executive functions, behaviour, personality

Broca’s Area: most ventral portion - muscles of speech and production of speech

Question 4

List the functional areas of the parietal lobe.

Describe the areas of the parietal lobe in relation to each other.

Answer 4

overall: sensory perception and integration

Primary somatosensory cortex (closest to central sulcus. anterior to it): receives somatosensory information

Somatosensory association cortex (posterior to primary somatosensory cortex): processing/analyzing/recognizing somatic sensations; memory of sensation

Posterior association cortex (most posterior portion of the parietal lobe): visual, auditory, spatial awareness of body

• Deficits can affect attention, perception of time, mathematical reasoning
• Difficulty with spatial awareness, body image, proprioception. Can affect coordination and balance
• Hemispatial neglect, reduced awareness of stimuli on one side
• Difficulty with tactile perception - recognizing objects by touch

Question 5

List the functional areas of the occipital lobe.

Describe the areas of the occipital lobe in relation to each other.

Answer 5

Overall function: vision

Primary visual cortex: Straddles the calcarine sulcus

visual association cortex: above the calcarine sulcus; object recognition, spatial perception, formation of mental images

Deficits result in: partial or complete loss of vision; visual hallucinations, disturbances in visual perception, altered color perception, motion blindness; difficulties perceiving and recognizing objects or faces (visual agnosia)

Question 6

List the functional areas of the temporal lobe.

Describe the areas of the temporal lobe in relation to each other.

Answer 6

Primary auditory cortex (ventral transverse slice): awareness of auditory stimuli

Auditory association cortex (lateral slice that is dorsal to primary auditory cortex) : process, analyze, understand, recognize, memory of sounds

Wernicke’s area: speech comprehension

Primary olfactory cortex

Deficits: fluent aphasia; difficulty understanding speech

Question 7

Limbic lobe function and components

Answer 7

Emotional processing, memory formation, regulation of basic instinct and drives such as hunger, thirst, sexual behaviour

Includes hippocampus, cingulate gyrus, amygdala, parts of hypothalamus and thalamus

Question 8

Longitudinal cerebral fissure

Answer 8

separate the hemispheres

Question 9

Central sulcus

Answer 9

prominent sulcus that runs down the middle of the lateral surface of the brain, separating the frontal lobe from the parietal lobe. Separates the primary motor cortex and the primary somatosensory cortex

Question 10

Lateral sulcus

Answer 10

separates the temporal lobe from the frontal and parietal lobes

Question 11

Parieto-occipital sulcus

Answer 11

separates the occipital lobe from the parietal and temporal lobes

Question 12

Basal ganglia
- function
- components
- what diseases arise from issues with the basal ganglia?

Answer 12

selection and sequencing of motor movement; suppresses unwanted movement.

Caudate and lentiform nuclei (lentiform is further divided into putamen and globus pallidus)

• Parkinson’s disease; Huntington’s disease; OCD

Question 13

Internal capsule

Answer 13

partition between caudate and lentiform. White matter structure that couples the cerebral cortex to deeper structures of the brain.

where the corona radiata converge; key conduit for communication between the cortex and other parts of the CNS

Corona radiata is the fanlike structure of myelinated nerve fibers including both motor and sensory pathways

Question 14

Thalamus
- function
- what can deficits to this area result in?

Answer 14

relay station for sensory information

damage causes loss of sensation, altered sensation, movement disorders

Question 15

Amygdala
- function
- where can you find this?
- what can deficits to this area result in?

Answer 15

• processing and regulation of emotions and memories; response to fear and threat
• temporal lobe; component of limbic system
• Deficits can affect: recognition or response to emotion; increased propensity for fear, anxiety, or aggression
• Deficits can contribute to depression or anxiety disorders

Question 16

Hippocampus
- function
- deficits can result in what?
- associated with what disease

Answer 16

memory formation, learning, spatial navigation

Deficits results in difficulties forming new memories (anterograde amnesia), difficulties with recalling past events or information (retrograde amnesia)

Associated with Alzheimer’s

Question 17

Hypothalamus
- function
- deficits can result in what?

Answer 17

Governs autonomic nervous system, endocrine system, and various motivated behaviors

Dysfunction can result in disturbances to appetite, body weight, sleep disorders, hormonal imbalance, disruption to emotional and behavioural regulation

Question 18

Cerebellum
- function

Answer 18

responsible for balance, coordination, and integration of movement

Question 19

What are the components of the brainstem and their functions

Answer 19

midbrain: associated with CN III and CN IV; plays an important role in motor eye movement
- Also plays a role in arousal and wakefulness

pons: Sleep regulation, respiration, micturition; Relays information between cerebral cortex and cerebellum; contributing to coordination and modulation of motor movements

medulla: essential autonomic functions
- Essential autonomic functions, cardiovascular regulation, respiration, swallowing, coughing

Question 20

Draw the somatosensory and motor homunculus

Answer 20

see photo album

Question 21

List and describe the 3 categories of white matter tracts

Answer 21

1. Commissural fibres
   - cross midline transversely
   - corpus callosum: bridge left and right cerebral hemispheres
2. Association fibres
   - Link different regions of the same cerebral hemispheres. Don’t cross the midline.
   - Example: Connects lateral geniculate nucleus of the thalamus (where visual information arrives) to primary visual cortex in the occipital lobe
3. Projection fibres
   - Travel long distances, mostly superiorly and inferiorly
   - Example: corticospinal tract (voluntary motor function)
   - Example: corona radiata

Question 22

Corticospinal tract
- function
- pathway

Answer 22

Function: control of the musculature of the body

Upper motor neurons coalesce in the internal capsule, descend ipsilaterally through brainstem until it decussates at the medullary pyramids (and becomes the lateral corticospinal tract)

Innervates lower motor neurons in the ventral horn of the spinal cord; these neurons extend axons via the ventral root and then innervate skeletal muscles

however: some axons peel out of this tract early. At the brainstem is where cranial nerves emerge from.

important notes:
- Motor control from the primary motor cortex is contralateral
- medial portions of the primary motor cortex govern the opposite lower limb
- Lateral portions of the primary cortex govern the opposite upper limb
- anterior tract: axial limb
- lateral tract: distal limb

Corticobulbar tract: governs volitional motor control of the head

Originates in primary motor cortex (precentral gyrus)

Pathway: primary motor cortex (precentral gyrus) → internal capsule → brain stem via the cerebral peduncles → synapses onto cranial nerve nuclei in the brainstem

Question 23

What would damage to the primary motor cortex be called?
What about damage to the cranial nerve?

Answer 23

upper motor neuron lesion

lower motor neuron lesion

Question 24

list the two somatosensory tracts

Answer 24

the dorsal column-medial lemniscus pathway and the spinothalamic pathway

Question 25

Describe the function and pathway of the dorsal column medial lemniscal tract

Answer 25

Fine touch, two point discrimination, conscious proprioception, vibration

Information ascends, then decussates at the medullary pyramids to synapse on the contralateral thalamus and then synapse on the contralateral primary somatosensory cortex

If its information about fine touch and proprioception from the face, it joins at the medial lemniscus, synapses onto the contralateral thalamus, then travels to the contralateral primary somatosensory cortex

Question 26

Describe the function and pathway of the spinothalamic tract

Answer 26

pain/ noxious stimuli, temperature, deep touch

Information immediately commissures at the spinal cord level once entering the dorsal horn. Then ascends upwards to synapse on the contralateral thalamus and contralateral primary somatosensory cortex

If it’s information about pain and temperature from the face, it crosses the midline at the brainstem, travels to contralateral thalamus and contralateral sensory cortex