Class 2 - Brain systems, networks and disconnection

Question 1

What behaviour exists in spinal cord only organisms?

Answer 1

Reflexes

Question 2

What behaviour exists in low decerebrate (hindbrain) organisms?

Answer 2

Postural support

Question 3

What behaviour exists in high decerebrate (midbrain) organisms?

Answer 3

Spontaneous movement

Question 4

What behaviour exists in diencephalic (hypothalamus, thalamus) organisms?

Answer 4

Motivated behavior

Question 5

What behaviour exists in decorticate (basal ganglia) organisms?

Answer 5

Self-maintenance

Question 6

What are long connections between lobes called?

Answer 6

Tracts

Question 7

What are short connections within lobes called?

Answer 7

Arcuate fibres

Question 8

What are the two main interhemispheric white tracts called?

Answer 8

Corpus callosum and anterior commissure

Question 9

What path does the motor circuit take? What happens when it is damaged?

Answer 9

Motor/sensory cortex > putamen > basal ganglia > thalamus > cortex. Damaged results in akinesia (reduced movement) and bradykinesia (slowness of movement)

Question 10

What path does the occulomotor circuit take? What happens when it is damaged?

Answer 10

Frontal eye fields, posterior parietal cortex > basal ganglia > ventral anterior and mediodorsal thalamic nuclei > frontal eye fields. Problems in voluntary fixational control

Question 11

What path does the dorsolateral circuit take? What happens when it is damaged?

Answer 11

Dorsolateral anterior frontal lobes (BA 9 and 10) > DL caudate nucleus > MD globus pallidus > MD thalamus > cortex. Damage results in executive dysfunction

Question 12

What path does the orbitofrontal circuit take? What happens when it is damaged?

Answer 12

Lateral orbital gyrus (BA 11), inferior frontal gyrus (BA 10 and 47) > VM caudate > M globus pallidus > VA thalamus, MD thalamus > frontal cortex.
Damage results in impulsivity/personality change (no more inhibition)

Question 13

What path does the anterior cingulate circuit take? What happens when it is damaged?

Answer 13

Anterior cingulate gyrus (BA 24) > ventral striatum (nucleus accumbens) > magnocellular MD thalamus > anterior cingulate. Damage results in apathy… no motivational behavior

Question 14

What is the new model of brain networks, up from the Luria model?

Answer 14

Parallel processing. Executive, salience and default mode networks

Question 15

What are small-world brain networks?

Answer 15

Dense local clustering, few long range connections, efficient, supports parallel specialized and distributed processing

Question 16

What is the Connectome?

Answer 16

Circular representation of human cortical networks

Question 17

What is callosal agenesis?

Answer 17

Being born without a corpus callosum

Question 18

What are the three parts of the corpus callosum?

Answer 18

Genu (prefrontal cortex), body (motor and parietal cortex), splenium (temporal and visual cortex)

Question 19

In a split brain patient, a verbal command in the left ear to move a hand would not work for which hand?

Answer 19

Left hand (command cannot cross over to right motor cortex)