Lecture #20 - Integrating and coordinating roles of the nervous system (not full)

Question 1

What’s the difference between sulcus and fissure?

Answer 1

Sulcus is a a furrow and fissure is a deep sulcus

Question 2

Name the major sulci (3), gyri (2) and fissures (1)

Answer 2

Central sulcus (between frontal and parietal)
Parieto-occipital sulcus (between parietal and occipital)
Lateral sulcus (between frontal and temporal)

Pre-central gyrus
Post-central gyrus

Transverse fissure (temporal lobe and cerebellum)

Question 3

What’s the main function of

1. Frontal lobe?
2. Parietal lobe?
3. Occipital lobe?
4. Temporal lobe?

Answer 3

1. Frontal - Motor and pre-frontal cortex
2. Parietal - Sensory
3. Occipital - Vision
4. Temporal - Memory and hearing

Question 4

Motor Cortex in Frontal lobe

1. Control of voluntary/involuntary movement?
2. Two types

Answer 4

1. Control of VOLUNTARY MOVEMENT
2. Pre-motor cortex and Pre-central gyrus

Pre-motor - PLANNING of movement
Pre-central gyrus - EXECUTION of movement

Question 5

Pre-frontal cortex of frontal lobe

1. Three functions
2. Damage and development….
3. Involved in…..

Answer 5

1. DECISION making, ANTICIPATING consequences of actions and emotion
2. Damage to this can change “who we are” and development may be altered by ALCOHOL
3. Involved in MENTAL ILLNESSES that change who we are e.g. schizophrenia
   - one of the last places to get full myelination (mid-20s)

Question 6

Major division of the brain

Three things with 2, 2, and 3 parts

Answer 6

1. CEREBRUM
   - cerebral cortex
   - corpus callosum (white matter)
2. DIENCEPHALON
   - thalamus
   - hypotalamus
3. BRAINSTEM
   - mid-brain
   - pons
   - medulla oblongata (spinal cord starts here

Question 7

What’s the forebrain and hindbrain?

Answer 7

Thalamus - forebrain (not part of brainstem)

Pons and medulla oblongata - hindbrain

Question 8

Three types of white matter - explain em (with examples)

Answer 8

1. COMMISSURAL TRACTS - axons go from side to side (go both ways) e.g. corpus callosum (so one side can communicate with other)
2. PROJECTION TRACTS - between cortex and other CNS areas e.g. corticospinal tract
3. ASSOCIATION TRACTS - axons on same side within cerebral cortex; communication between brain areas e.g. communication between motor cortex and somatosensory cortex (“association”)

Question 9

Primary motor cortex organisation (pre-central gyrus)

Answer 9

Specific regions of the motor cortex CONTROL specific regions of the body (stroke if something goes wrong)

Question 10

Primary somatosensory cortex (post-central gyrus)

Answer 10

Specific regions of the somatosensory cortex receive SENSORY information from specific regions of the body

Question 11

The corticospinal tract: a descending somatic motor tract

Answer 11

1. Cell bodies (efferent) in primary motor cortex
2. Most fibres cross to opposite side in medulla (right side of brain will have axon in left side of spinal cord)
3. Axons descend until spinal
4. Synapse in spinal cord

Question 12

Functional anatomy: parietal lobe (three points)

Answer 12

1. Somatosensory (post-central gyrus)
2. Integration of multiple type of sensory info
3. Association

Question 13

Simple somatic sensory (afferent) pathway (up and across)

Answer 13

1. Sensory information - ascends in dorsal white columns
2. Ascends to medulla - crosses side to opposite side (synapse)
3. Ascends to thalamus - synapse here too and then to somatosensory cortex (post-cental gyrus)

Question 14

Integration between motor and sensory systems: role for cerebellum (5 steps)

Answer 14

1. Motor cortex initiates MOVEMENT (pre-central gyrus)
2. Copy of INSTRUCTIONS sent to cerebellum
3. Some SENSORY information goes to the cerebellum = information about actual movement
4. Cerebellum COMPARES this info with copy of motor output
5. “Adjusts” motor output for COORDINATION
   - The cerebellum co-ordinates movement, guided by sensory feedback

Question 15

Integration between motor and sensory systems: role for basal/deep nuclei (3 steps)

What happens if it goes wrong?

Answer 15

The basal nuclei aka basal ganglia (we’re stuck with the name even though ganglia is for collection of bodies in PNS - not CNS)

1. Select and appropriate movement for a given situation
2. Initiate movement
3. Terminate movement

If wrong - Parkinson’s

• Loss of neurotransmitter dopamine
• Normally dopamine regulates the basal ganglia
• Inability to initiate movement -> rigidity, tilted posture, shuffling gait
• Inability to terminate movement -> tremors