Stimulus localisation and processing of motion

Question 1

What is the orientation reflex?

Answer 1

Turning head and eyes to face stimulus

Question 2

What effect would the abolition of the optic tectum have on this?

Answer 2

Loss of the orientation reflex

Question 3

What are the most important areas involved in stimulus localisation and processing?

Answer 3

Dorsal stream of the cortex
Superior and inferior colliculus
Retina

Question 4

What is the main function of the superior colliculus?

Answer 4

Integration of different sensory modalities and regulation of saccadic movements (simultaneous movement of both eyes)

Question 5

What would a lesion here lead to? (superior colliculus)

Answer 5

Disappearance of the orienting reflex

Question 6

What is the foveation hypothesis?

Answer 6

2 retinotopic maps
1 has a population of sensory neurons that respond to light
1 has a population of motor neurons
These maps overlap
Activation of specific sensory neuron leads to movement

Question 7

Where do the 2 retinotopic maps overlap?

Answer 7

superior colliculate nucleus

Question 8

In which stream does most of the processing of motion happen?

Answer 8

Dorsal stream

Question 9

What do bipolar cells do when there is a light bar in preferred direction?

Answer 9

Less inhibtion