three

Question 1

LGN

Answer 1

-90% of fibres operating in the retina and travelling in the optic nerve terminate in the LGN
-most info come in and synapses in the LGN before projected into the cortex

Question 2

optic chiasm is where

Answer 2

the fibres from each eye cross over

Question 3

cells in the LGN

Answer 3

-on centre and off surrounds of the LGN cell
-the cell will respond when the area it responds to is fully stimulated no just partially stimulated

Question 4

LGN retinotopic map

Answer 4

-visual world maps on the the retina then on to the LGN
-spatial relationships are maintained in the nervous system
-fibres from LGN project to primary visual cortex/V1

Question 5

simple cells response in V1

Answer 5

-responds best to elongated bars
-orientation selective
-seperate on and off subregions
-can be monocular or binocular

Question 6

complex cells in V1

Answer 6

-are orientation selective
-spatially homogenous receptive fields (no seperate on/off subregions)
-nearly all binocular

Question 7

columnar arcitechture of V1
-perpendicualr

Answer 7

-when an electrode is moved perpendicular to the cortical surface, receptive feels and orientation preference cells are maintained

Question 8

columnar arcitechture of V1
-paralell

Answer 8

-when an electrode is moved parallel to the cortical surface receptive fields and orientation preference cells shift

Question 9

topographic organisation

Answer 9

-each point of the visual field maps on to a local group of Neurons in v1
-foveal region uses more of v1 therefor a greater magnification

Question 10

why topographic?

Answer 10

-reduces volume of the Brian
-reduces axon volumes
-reducing axon length provide more space for neuron
-faciliates processing e.g. lateral inhibition

Question 11

sound

Answer 11

-pressure pulses
-travel 340m/s
-frequency cycles /s Hz

Question 12

pathway to the auditory cortex

Answer 12

-cochlea
-brainstem
-midbrain-intercollic
-medial geniculate nucleus of thalamus (forebrain)
-auditory cortex

Question 13

how we hear

Answer 13

-pressure impulses come in and impact on the eardrum and cause to vibrate
-transferred through three bones in the inner ear
-melleus
-stapes
-cochlea

Question 14

what does the cochlea do

Answer 14

-has a membrane that runs down the side of the cochlea
-the vibrations cause pressure pules which causes the membrane
- move hairs and convert energy into electrical through ions moving across channels

Question 15

top down processing in hearing

Answer 15

-allows for integration of sensory input
-allows for context and procedural demands for bias perceptions
-greater predictive capacity