Procedural Memory System

Question 1

What can procedural memories involving the motor system be broken down into?

Answer 1

Acquisition of habits and skills.

Sensory-to-motor adaptations (involving adaptation of reflexes or Pavlovian conditioning).

Question 2

What are procedural memories?

Answer 2

Habits and skills that become built into our motor system.

Question 3

What is the primary motor cortex critical for?

Answer 3

The control of the force and flow of muscle movements

Question 4

What is the premotor cortex critical for?

Answer 4

Movement preparation and sequencing

Question 5

What are the two major subcortical structures that work with the primary and premotor cortices?

Answer 5

The striatum and the cerebellum

Question 6

What do the striatum and the cerebellum feed into to connect back to the cortex?

Answer 6

The thalamus

Question 7

What may the initial acquisition of procedural memories involve? When may this become consolidated into striatal circuits?

Answer 7

May initially involve a cortical store that during sleep becomes consolidated into striatal circuits

Question 8

Who studied the effects of striatal lesions on the performance of rats in two variations of the radial arm maze?

Answer 8

Cook and Kessner (1988)

Question 9

Who studied monkeys to demonstrate how habits and skills were encoded?

Answer 9

Kermadi and Joseph (1995)

Question 10

Describe Kermadi and Joseph’s study

Answer 10

Trained monkeys to fixate on a central point, and then follow a sequence of three lights appearing to the left, right or above the fixation point.
Monkey then had to repeat this pattern by fixating on each location in the order the sequence was presented.

Question 11

What did Kermadi and Joseph (1995) find about striatal cells in response to learned sequences?

Answer 11

There were cells in the striatum that would respond to one fixation location (e.g. ‘L’), but only when the monkey was going to make that response in a particular sequence (e.g. U, L, R).
The cell wouldn’t fire for L response in any sequence.

Question 12

Where does the striatum receive input from?

Answer 12

The entire cortex

Question 13

Where does the striatum project to, via the thalamus?

Answer 13

Premotor, motor and prefrontal association cortex

Question 14

Where does the striatum have a very small projection to?

Answer 14

The brainstem

Question 15

Where does the striatum not project to?

Answer 15

The spinal cord

Question 16

What does the anatomy of the striatum suggest about its involvement in motor output?

Answer 16

Anatomy suggests that is not directly involved in controlling motor output

Question 17

Why has it been suggested that the striatum might be involved in goal-oriented behaviour?

Answer 17

Because the striatum projects to regions involved in motivation and emotion (e.g. amygdala), and planning (PFC).

Question 18

Where does the cerebellum receive input from?

Answer 18

Descending sensory and motor input from the cortex.
Sensory information direct from the spinal cord.
Major bi-directional connections between brain stem nuclei associated with spinal cord function.

Question 19

Where does the cerebellum project to?

Answer 19

Primary motor and premotor cortices via the thalamus (but smaller projections compared to striatum).

Question 20

How might the cerebellum guide reflex adaptations?

Answer 20

Compares motor plan from the premotor cortex with actual movements being made (from brainstem nuclei and spinal cord inputs) to compute an error signal. Then provides this information back up to the cortex to guide sensory-motor adaptations.

Question 21

What does the anatomy of the cerebellar circuit suggest it may be involved in?

Answer 21

Execution of movements and acquisition of conditioned reflexes

Question 22

Give an example of a well-studied conditioned reflex

Answer 22

The rabbit Pavlovian eye blink

Question 23

Where does the cerebellum receive information about the tone from?

Answer 23

Auditory and pontine nuclei

Question 24

Where does the cerebellum receive information about the air puff from?

Answer 24

The trigeminal system

Question 25

Where does the association between the CS (tone) and US (air puff) occur within the cerebellum?

Answer 25

The interpositus nucleus

Question 26

Where is the output for the CR (eye blink) generated in the cerebellum?

Answer 26

Red nucleus is the output for the interpositus nucleus.

Then via cranial motor nuclei to produce eye blink

Question 27

How is the CR prevented?

Answer 27

By lesioning the interpositus nucleus.
Or protein synthesis block in the interpositus nucleus - thus blocking physical manifestation of the memory representation through LTP

Neither of these affect UR production (eye blink to corneal puff)

Question 28

What happens when the red nucleus is reversibly inactivated, or the pathway between the interpositus and the red nucleus?

Answer 28

Temporary prevention of the CR, but upon recovery of the red nucleus (or pathway) the CR is elicited on every subsequent trial.

Shows that the CS-US association still builds up in the interpositus nucleus, but if the output is ina riveted then can’t produce CR.

Production of CR during training not necessary for conditioning

Question 29

What happens if you reversibly inactivate the cerebellum?

Answer 29

Temporarily block production of the CR, however when activated again the CR is not elicited immediately - there is a gradual increase in the % of CRs elicited (i.e. the animal must learn the association).

Shows that the association is encoded within the cerebellum.