Neuroscience

Question 1

Define positive and negative phototaxis

Answer 1

Positive = move towards light, negative = move away from light

Question 2

Define helical phototaxis

Answer 2

Twitching towards or away

Question 3

The role of photoreceptors is to…

Answer 3

Links muscles on same and opposite sides. Causes inhibition of opposite sides

Question 4

Visual neglect causes what problems?

Answer 4

Damage to right parietal cortex. May consistently ignore left half of the world.

Question 5

Name the 3 formal tests used to measure visual neglect

Answer 5

Line bisection task, object comparison task, implicit knowledge task

Question 6

Describe the line bisection task

Answer 6

Normal can do it, but neglect group cut half from the right

Question 7

Describe the object comparison task

Answer 7

If difference is on the left, cannot see it and will say they are both the same

Question 8

The implicit knowledge task consisted of what?

Answer 8

Asked which house they would prefer to live in, pick one without fire but no reason why they did so. Shows their conscious awareness on left side is impaired, but processing isn’t.

Question 9

State the 2 ways that brain activity can be measured

Answer 9

Metabolic activity and electrical activity

Question 10

How can metabolic activity measure brain activity?

Answer 10

Localising measurements tell us where the activity is going on. Fmri measures oxygen levels through magnetic properties of oxygen-rich vs oxygen-poor blood

Question 11

LRP stands for what and what does it show differences between?

Answer 11

Lateralised readiness potential - computed from ERP’s. Shows differences between left and right motor cortex activity during left and right manual responses

Question 12

How can electrical activity measure brain activity?

Answer 12

Large clusters of neurons synchronise electrical activity, combined electrical signal might become strong enough to be measured even at a distance

Question 13

Define ERP

Answer 13

Event-related potential - pattern of activity that remains the same for each occurrence of an event

Question 14

Explain blindsight

Answer 14

Lesions to primary visual cortex causes scotana (blindness in part of visual field), patients report not seeing anything in that area (subjective blindness), patients do not respond to stimuli in that area (objective blindness) so some residual visual processing must be pleasant.

Question 15

Explain results of the finger pointing task

Answer 15

Higher accuracy to pointing in the intact field, but almost as accurate in the blind field - only pointed in blind field when prompted

Question 16

Describe the process of making saccades to a light on the screen

Answer 16

Very short response for light in intact field, no response for light in blind field. Long response time for light in both fields - eyes look towards invisible, then visible

Question 17

What are the results found in the localisation task?

Answer 17

Patients only respond to blind-field stimuli when prompted. They insist that they do not see these stimuli. No spontaneous reaction to stimuli

Question 18

Describe subliminal perception

Answer 18

Did arrow point towards left or right? If stimuli 1 is really invisible, its identity shouldn’t make a difference, it does

Question 19

Explain the 2 hypotheses involved in subliminal free choice priming task

Answer 19

If primes improve target identification (1), then responses to different looking free-choice targets should not be affected. If primes pre-activate a motor response (2), motor responses to free choice targets should be affected.

Question 20

State results found regarding hypothesis 1 of subliminal free-choice priming task

Answer 20

Stimulus 1 primes visual processing of stimulus. The target is easier and faster when stimulus is repeated and harder and slower when stimulus is new

Question 21

What were the results found regarding hypothesis 2 of subliminal free-choice priming task?

Answer 21

Stimulus 1 primes its corresponding motor response. Subliminal arrows only affect choices when want to respond to arrows or in line with our normal response to arrows