Corrections of Faulty Neural Circuits

Question 1

function of channelrhodopsin channel

Answer 1

blue light (mainly) → causes channelrhodopsin channels to open -> membrane depolarisation

Question 2

function of halorhodopsin channels

Answer 2

calcium channels opened by yellow light -> depolarisation

Question 3

how can small molecules be used to alter neurone function

Answer 3

• can use small organic compounds to insert channelrhodopsin and halorhodopsin into membranes
  e.g photocontrol of gaba receptors
  light → changes function/conformation of GABA receptors

Question 4

what does a double bond mean for molecule structure

Answer 4

double bonds = allows molecules to have 2 possible conformations

Question 5

what is retina pigmentosa disease

Answer 5

• progressive decrease in number of photoreceptors
• bipolar cells eventually degenerate due to lack of input from photoreceptors
• stimulate visual system → restores vision

Question 6

why must you act quickly with retina pigmentosa

Answer 6

• Retina performs complex computations
• Different ganglion cells have different functions and project to different brain areas
• Stimulation of RGC with simple stimuli is useless (e.g. motion sensitive RGC is active only when there is motion)

Question 7

how could you activate the retina with RP

Answer 7

• electrical stimulation
• channelrhodopsin and halorhodopsin stimulation

Question 8

how do artificial retinas aid RP and what are the issues

Answer 8

• activated by light → generates current
• stimulates ganglion cells not phororeceptors or bipolar cells due to location

Question 9

treatment for retina pigmentosa

Answer 9

• use light to stimulate deeper layers (bipolar/photoreceptors)
• increase halorhodopsin expression

Question 10

organisation of photoreceptors

Answer 10

centre surround and direction selective