week 9 the cerebellum

Question 1

LABEL

Answer 1

CEREBELLUM

Question 2

Organization and subdivisions of the cerebellum

Answer 2

Question 3

peducle is

Answer 3

a major fiber bundle or tract

Question 4

all input and outputs to cerebellum go through these three synaptic relay stations

Answer 4

1. fastigial nucleus
2. interposed nuclei
3. dentate nucleus

Question 5

how did the cerebellum likely evolve?

Answer 5

as a massive expansion of the brainstem vestibular nucleus, which in all vertebrates integrate vestibular information into core motor control to reflexively maintain balance

Question 6

outputs of the cerebellum

Answer 6

1. motor and premotor cortices (motor planning)
2. lateral descending systems (motor execution)
3. medial descending systems (motor execution)
4. vestibular nuclei ( balance and eye movement)

Question 7

Cerebellar cortex is organized by somatotopic map(s) but differs from cerebral cortex in that it maps the _________ side rather than the ___________ side of the body.

Answer 7

ipsilateral ; contralateral

Question 8

_____________ is another example of collateral projections (copies of commands) from the motor pathways.

Answer 8

Cerebellum

Question 9

Copies of _________ ________ _________ are sent into cerebellum also ___________ __________ __________ from the spinal cord are also sent into the cerebellum.

Answer 9

descending motor commands ; ascending proprioceptive feedback

Question 10

Cerebellar outputs from Deep Cerebellar Nuclei (DCN) project onto motor pathways at multiple places, including …

Answer 10

• Motor cortex
• Midbrain (e.g. superior colliculus)
• Descending motor pathways
  (these outputs modulate ongoing motor activity)

Question 11

The cerebellum has ____ main inputs and ____ output.

Answer 11

two ; one

Question 12

It is hypothesized that the cerebellum’s main function is ….

Answer 12

to compare intended movements (motor commands) to actual movements (proprioceptive feedback) and generate a corrective modulatory output. In this way the cerebellum helps to produce smooth & precise movements.

Question 13

what is the equation for how the cerebellum calculates correction? where does this take place?

Answer 13

Intended - Actual = Correction
(input 1) - (input 2) = (output 1)

this takes place in cerebellar cortex

In this context, it is possible to interpret the functional organization of the cerebellar neural circuits.

Question 14

Purkinje cell dendrites compare inputs from _________ ________ and _________ _______and sends an output to deep cerebellar nuclei.

Answer 14

climbing fibers ; mossy fibers (granule cells)

Question 15

Purkinje cell dendrites receive and integrate the _____ types of inputs.

Answer 15

two

Question 16

Purkinje cell output represents the _________ _________ _______

Answer 16

calculated corrective action

Question 17

Mossy fibers deliver sensory feedback through _________ ________, which send ________ _______ (axons) across many Purkinje cell dendrites.

Answer 17

granule cells ; parallel fibers

Question 18

__________ _________deliver motor commands directly to Purkinje cell dendrites.

Answer 18

Climbing fibers

Question 19

Purkinje cell output is always

Answer 19

GABAergic

Question 20

Purkinje cell output is delivered….

Answer 20

to deep cerebellar nuclei from which it is sent into descending motor pathways.

Question 21

Purkinje cells are organized in a __________ manner along the surface of the cerebellar cortex, so that neighboring groups of motor fields can be smoothly coordinated.

Answer 21

somatotopic

Question 22

________ _____ and _______ _____ are local interneurons that participate in the comparison of ongoing movement and sensory feedback in complicated ways.

Answer 22

Basket cells ; Stellate cells

Question 23

THE ONLY OUTPUT FROM CEREBELLAR CORTEX IS

Answer 23

INHIBITORY GABA SYNAPSE

Question 24

Output from DCN is excitatory to ____, but normally inhibited by ________ _______

Answer 24

M1 ; PURKINJE CELLS

Question 25

LABEL

Answer 25

“complex spike” evoked in Purkinje cell by climbing fiber

Question 26

how do climbing fibers lead to excitation of the motor cortex.

Answer 26

Climbing Fiber inputs temporarily suppress tonic Purkinje Cell output, which “disinhibits” (allows) output from deep cerebellar nuclei, sending excitation to motor cortex

Question 27

When the cerebellum is damaged (or removed) movement can still happen, but

Answer 27

they are unsteady and inaccurate.