Voluntary Motion and Cerebellar Control

Question 1

Spasticity is caused by failure to inhibit what

Answer 1

The brainstem inhibitory region

This ultimately leads to overactive gamma motor neurons and hypersensitivity of muscle spindles

Question 2

Dopamine binding to D1 vs D2 receptors vs activation of NMDA receptor on neurons

Answer 2

D1 will excite the neuron
D2 will hyperpolarize the neuron
Binding to NMDA receptor will cause nitrous oxide production

Question 3

Areas of the brain associated with the production of voluntary cortex

Answer 3

Primary motor cortex
Supplementary motor cortex
Pre-motor cortex
Pre-frontal cortex and parietal cortex

Question 4

Premotor cortex function

Answer 4

Receives sensory information required to move
Dorsal area applies the ‘rules’ that determine whether it is appropriate to move
Identifies the intent of the motion and decides what motion to produce

Question 5

Supplementary motor cortex function

Answer 5

Organize motor sequences
Acquire motor skills
Executive control (decision to switch actions/strategies)

Question 6

Layers and functions of primary motor cortex (4/5 only)

Answer 6

Layer 4 receives sensory input

Layer 5 becomes output for corticospinal pathway

Question 7

Sets of neurons in each column and function

Answer 7

Each column has two sets of neurons

One to start the motion, one to maintain it as long as necessary

Question 8

What information from what pathway allows us to complete motor acts based on visual input

Answer 8

The dorsal visual pathway contains axons from the occipital cortex that travel to the parietal/frontal cortex. This gives us the input that enables us to complete the motion based on visual input

Question 9

Visual information and VIP, F4, F2 areas

Answer 9

Information is relayed from the visual cortex to the parietal cortex (V6a, PEc, MIP, VIP)
The ventral intraparietal area (VIP) creates a rough map of the space around you, including the bowl of candy you are reaching for
VIP area sends the map to the premotor cortex (F4), F4 tells you where the bowl of candy is
VIP also sends the map to the F2 region of premotor cortex, which tells you where your arms are in relation to your body and the object

Question 10

Visual information and AIA, PFG and F5 areas

Answer 10

Anterior intraparietal area and PFG (part of inferior parietal cortex) contain neurons that:
A-Respond to see an object that is graspable (visually dominant)
B-Responding once you actually grasp an object (motor dominant)
C-Respond to both
PFG and AIP send information to F5
F5 neurons fire with the GOAL of the action, not the motor act itself (why am I grasping this object)

Question 11

Areas of parietal cortex required for reaching

Answer 11

V6a, PEc, MIP, VIP- visual cortex also involved

Question 12

Areas of parietal cortex needed for grasping

Answer 12

AIP cortex, PFG- visual cortex also involved

Question 13

What areas create map of the space (around object)

Answer 13

VIP= rough map
F4= detailed map

Question 14

What areas create map of body

Answer 14

F2

Question 15

What area is required for awareness of the goal of grasping

Answer 15

F5

Question 16

Spinocerebellum central region vs the sides

Answer 16

Central - postural control of ongoing motions

Sides - force and direction of an ongoing motion, and ballistic motion (swatting a fly)

Question 17

Cerebrocerebellum function

Answer 17

Planning complex motions and sequencing them (i.e. playing piano)

Question 18

Vestibulocerebellum function

Answer 18

Balance/eye movements - particularly those occurring in the future

Question 19

Inputs to spinocerebellum (central area) and outputs of spinocerebellum (central area)

Answer 19

Inputs- vestibular, visual/auditory, efferent copy of what brain sends to muscle
Outputs- Interpositus nucleus (globose and emboliform), fastigial nucleus, then rubrospinal tract (red nucleus)

Question 20

Input/output for the lateral regions of spinocerebellum

Answer 20

Inputs- muscle afferent (how fast muscle is going and what its doing), muscle efferent (what brain expected muscle to do)
Outputs- Interpositis, then to rubrospinal tract

Question 21

Inputs/outputs of cerebrocerebellum

Answer 21

Inputs- all regions of motor cortex (no efferent copy because motion is not in progress)
Outputs- dentate nucleus, back to cortex

Question 22

Pathways that lead to activation of the indirect pathway

Answer 22

EAA released from axons coming from the cortex

Intrastriatal cholinergic pathway releasing Ach on indirect pathway neurons in striatum