Limbic System and Hypothalamus

Question 1

Hippocampal formation

Answer 1

1. Subiculum
2. Hippocampal gyrus (molecular, pyramidal, polymorphic layer)
3. Dentate gyrus (molecular, granular, polymorphic layer)

Question 2

Amygdala Nuclei

Answer 2

• corticomedial (olfactory input)
• basolateral nuclei (receives and processes all other input, then sends to central nucleus)
• central nucleus (main output)

Question 3

Function of amygdala

Answer 3

• controls expression and experience of emotion responses
• involved in emotional learning

Question 4

Hippocampus Functions

Answer 4

Consolidation of declarative memory.
Lesion causes anterograde amnesia (can’t make new memories).

Question 5

Motor loop

Answer 5

1. Motor cortex -> putamen (+)
   2a. Putamen -> GPi/SNr (-)
   2b. Putamen -> GPe (-) -> STN (-) -> GPi/SN (+)
2. GPi/SNr -> thalamus (-)
3. Thalamus -> cortex (+)

GPi inhibits thalamus, putamen disinhibits thalamus by inhibiting GPi.

Question 6

Parkinson’s Disease

Answer 6

• bradykinesia, akinesia, rigidity, resting tremor
• due to degeneration of SNc (provides dopamine to striatum) and Lewy body formation
• hypokinetic (dopamine promotes direct pathway, no dopamine)

Question 6

Parkinson’s Disease

Answer 6

• bradykinesia, akinesia, rigidity, resting tremor
• due to degeneration of SNc (provides dopamine to striatum) and Lewy body formation
• hypokinetic (dopamine promotes direct pathway, no dopamine)

Question 7

Hemiballismus

Answer 7

• uncontrollable ballistic movements of contralateral arm and leg
• due to damage to STN (-> no more stimulation of GPi, which inhibits thalamus, so promotes direct pathway)

Question 8

Chorea

Answer 8

• involuntary, irregular, purposeless movements
• athetosis: flowing, writhing movements
• due to loss of striatal neurons projecting to GPe, so promotion of direct pathway

Question 9

Deep cerebellar nuclei

Answer 9

• fastigial nuclei (input from vermis and flocculonodular lobe)
• interposed nuclei (input from paravermal zone)
• dentate nuclei (input from lateral hemisphere)

Question 10

Cerebellar Divions

Answer 10

• vestibulocerebellum (archicerebellum, maintains balance, driven by vestibular input, flocculonodular lobe)
• spinocerebellum (paleocerebellum, adjusts movement during execution, driving by proprioceptive input, vermis + paravermis)
• cerebrocerebellum (neocerebellum, driven by cortical input via pontine nuclei, plans movement before execution, lateral hemisphere)

Question 11

Cerebellar syndromes

Answer 11

• cerebellar ataxia: lack of coordination
• flocculonodular syndrome: wide gait, abnormal nystagmus, problem with balance
• neocerebellar syndrome: hypotonia, hyporeflexia, dysmetria (misjudging distance), intention tremor, dysdiadochokinesia, ipsilateral ataxia