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Flashcards in Block 4 Deck (9):
1

Cortical inputs to primary motor cortex

a. Somatosensory cortex
b. Premotor cortex
c. Supplementary motor area
d. Posterior parietal cortex (Areas 5 and 7)

2

Output projections from primary motor cortex

1. Primarily from pyramidal neurons in different Regions
a. Primary motor cortex (Area 4)
b. Premotor and supplementary motor
area (Area 6)
c. Somatosensory (Areas 3, 1 and 2) and
parietal cortex (Areas 5 and 7) d. Frontal eye fields (Area 8)

3

Premotor cortex
Afferent projections

1. Prefrontal cortex
2. Supplementary motor area
3. Posterior parietal (Areas 5 and 7)
4. Cingulate motor area
5. Cerebellum and basal ganglia via
thalamus

4

Supplementary motor area
Afferent projections

1. Area 4
2. Prefrontal cortex/pre-SMA
3. Posterior parietal
4. Basal ganglia
5. Cerebellum

5

Supplementary motor area
Efferent projections

1. Area 4
2. Striatum
3. Brainstem
4. Corticospinal

6

Basic cerebellar circuit

a. Mossy fibers → granule cells → Purkinje cells
b. Climbing fibers → Purkinje cells
c. Purkinje cells → cerebellar nuclei and vestibular nucleus (medial and lateral)
d. Cerebellar nuclei → many targets in CNS

7

Mossy fiber afferents

- Multiple spinal, brainstem sites of
origination
- Synapse on granule cells (excitatory, glutamate) - Produce "simple spikes" in Purkinje cells
- High frequency discharge
- Can encode temporal and intensity information

8

Premotor cortex
Efferent projections

1. Area 4
2. Supplementary motor area 3. Posterior parietal
4. Prefrontal areas
5. Basal ganglia
6. Brainstem, red nucleus
7. Corticospinal

9

Climbing fiber afferents

- Solely from inferior olive
- Monosynaptic to Purkinje cells
- Powerful excitation
- Produce "complex spikes" in Purkinje cells - Low frequency discharge
- May encode "teaching signal"