Motor control Flashcards

Question

What are the neurons in the spinal cord called

Answer 1

central pattern generators

Answer 2

they enabled the fast generation of complex movements such as running away.

Answer 3

trained deafferented monkeys to point to a target in a dark room. Deafferented means they had all the somatosensory feedback signals severed (the afferent signals from the nerve receptor back to the brain). An opposing torque was applied to arm to hold it in starting position for a short time. Crucially, because of the deafferentation the monkey didn’t know this force was being applied.

Answer 4

Found that the monkey reached the target even when the opposing force was applied.

Answer 5

require monkeys to move a lever to one of 8 targets, starting from the centre. Neurons preferred a direction. Then he asked them to start from a different position and move the lever in the same direction. The same neurons showed the same selectivity for this movement even though the target location was completely different.

Answer 6

direction of cell’s preferred direction combined with information about strength of firing.

Answer 7

sum of individual neuron vectors

Answer 8

the most accurate estimate of the planned direction of movement

Answer 9

trained rats to press a lever for reward and measured multiple neuron responses in motor cortex.

Answer 10

This led to complex population vector responses such as this one, which shows the output of 40-odd neurons during the different stages of lever pressing.

Answer 11

* Mice eventually stopped pressing the lever as they learnt about the lack of precise correlation between force exerted and reward * Mice continued to produce cortical signals necessary for moving the lever

Answer 12

earning to move in novel environments

Answer 13

transcranial direct current stimulation

Answer 14

the different roles of the cerebellum and the primary motor cortex. tDCS of the cerebellum led to a faster rate of adapation. tDCS of the motor cortex led to increased retention of adaptation (more error for a longer period of time after the end of adaptation). Stimulation of the cerebellum means faster visuo-motor adaptation. Better performance on this task.

Answer 15

The cerebellum stimulation makes little difference to the de-adaptation process. The motor cortex seems to affect it.

Answer 16

for consolidating newly learnt mapping

Answer 17

They got subjects to move their arm to the right and then when a tone occurred to make a movement to a visual target. This task requires a prediction of where your hand will be in the future because there is a delay between hearing the tone and actually initiating the forward movement. If the subject just generated a motor command when they heard the tone they would miss the target because the motor command (trajectory) would be out of date and inaccurate by the time the motor command was actually initiated.

Answer 18

neural activity

Answer 19

There is a complex network of inhibitory and excitatory connections within the basal ganglia and connecting the BG to other structures. Input comes from the substantia nigra into the putamen and travels either via the direct route to the globus pallidus or via the indirect route via the substantia nigra.

Answer 20

activation of the direct pathway leads to excitation (input to thalamus is inhibitory, so if you inhibit that, the net effect is excitation).

Answer 21

Hypokinesia, bradykinesia, tremor

Answer 22

reduction in voluntary movement

Answer 23

slow movement

Answer 24

treatment for parkinsons. | – Crosses the blood-brain barrier, enters the CNS and is converted into dopamine