Sensorimotor Behaviors

Question 1

Saccades are…

Answer 1

rapid eye movements to direct attention to discrete locations

Question 2

Smooth pursuit enables us____

Answer 2

to lock our gaze on a moving target.

Question 3

Which reflex is activated in response to the movement of the visual field?

Answer 3

Optokinetic Reflex follows the visual field (and Nystagmus brings the eye back)

Question 4

Which of the following areas is not involved in vestibular processing?

Hippocampus, Vestibular nuclei, Thalamus, Cerebellum.

Answer 4

Hippocampus

Question 5

Adaptation of the vestibular-ocular reflex is associated with which brain area?

Answer 5

Cerebellum (primarily LTD in Purkinje cells and Parallel Fibers)

Question 6

What are sensorimotor behaviors? Give a few examples

Answer 6

Sensorimotor behaviors are those with an ongoing relationship between sensory inputs and motor outputs.

When a motor behavior implies the sensory feedback in the loop consisting of the motor environment and the body.

Examples: VOR, Optokinetic reflexes, grasping an object (force on hand specifies tactile feedback)

Question 7

What are saccades?

Answer 7

A saccade is a quick eye motion between points of fixation.

Example: While reading, one performs saccades in between fixating on specific words. We do not move our eyes continuously, but discontinuously.

Question 8

What is the optokinetic reflex (OKR)?

Answer 8

OKR is a reflex that locks your eye with an object in a moving field (a tree passing by the train window).

When you ‘snap back’, this is called a ‘nystagmus’. It is a reflex that can normally be suppressed.

> See this video <

Question 9

What is the function of the semicircular canals and the vestibular system?

Answer 9

They measure the rotational acceleration of the head.

The vestibular system is a sensory system that provides information about motion, head position, and spatial orientation.

The semicircular canals are filled with endolymph. The endolymph flows through the canals and moves the cilia. When the cilia are pushed in one (preferred) direction, the hair cells will be depolarized. If the cilia are pushed in the opposite direction, the hair cells will be hyperpolarized.

Question 10

How can you define sensorimotor integration?

Answer 10

Sensorimotor integration is a process that produces task-specific motor output based on selective and rapid integration of sensory information from multiple sources.

Question 11

The visual system temporarily shuts down during a _____ movement

Answer 11

saccadic

Question 12

What does a tonic neuron do in an eye circuit?

Answer 12

Maintains eye position, the ‘step’ signal.

Question 13

A bursting neuron in an eye circuit most likely encodes____

Answer 13

the ‘pulse’, the signal for saccades.

Question 14

An omnipause neuron in an eye circuit____

Answer 14

stops firing during an eye movement

Question 15

Rotational acceleration of the head is picked up by____

Answer 15

semicircular canals

Question 16

The translational movement of the head is picked up by____

Answer 16

otoliths

Question 17

What is proprioception?

Answer 17

Proprioception is the sense of the position and self-generated movements of our body (muscle contractions and posture). It depends on the relationship between the nervous system and the muscular tissue.

Question 18

Which feature of visual image do the Retinal Ganglion Cells extract?

Answer 18

edges

Question 19

What is the function of the vestibulo-ocular reflex (VOR).

Answer 19

VOR is a reflex that stabilizes the gaze during head movements. The eyes move to the opposite direction of the ‘vestibular world’.

Question 20

What are some of the differences between optokinetic and vestibulo-ocular reflexes?

Answer 20

In the case of OKR, the visual world is moving, and the eyes follow. Something visually or optically drives the eye movement.

In the case of VOR, the vestibular world is moving and the eyes move in the opposite direction in order to stabilize the gaze.

Question 21

What is the name of the reflex that causes our eyes to follow smooth motion of objects?

Answer 21

Smooth pursuit

Question 22

What is the optokinetic reflex (OKR)?

Answer 22

The reflex that locks eyes onto motion of the world.

(such as your eyes as you look outside of a moving train and fixate on the environment. Incidentally, the movement that brings the eyes back when they are at the edge is called “Nystagmus”).

Question 24

What are muscle synergies?

Answer 24

A muscle synergy is a group of muscles and their skeletal constraints that contribute to a particular (stereotypical) movement.

(“Their action is more than the sum of their parts”).

Muscle synergies reduce the dimensionality of muscle control. Single synergies activate multiple muscles.

Question 25

Explain the role of transformations in sensorimotor loops.

Answer 25

Sensorimotor coupling is the loop between the sensory system and the motor system that is closed via the environment.

This integration allows an animal to transform sensory information (e.g. sight) into motor behavior.

Question 28

What are sensorimotor loops?

Answer 28

The idea that motor actions create specific feedbacks to the sensory systems.

Another way to say this is that the embodiment of the brain necessitates certain aspects of the feedback.

Question 29

What is a sensorimotor contingency?

Answer 29

It is a quantifiable and predictable relationship between motor action and its sensory consequence.