Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

EXP NEURO > Optogenetics > Flashcards

Optogenetics Flashcards

1
Q

define optogenetics:

A
  • use of light to regulate activity of neurons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

optogenetics: how does it work?

A
  • cells genetically engineered to possess light responsive ion channels= control neuronal activity
  • these ion channels cloned from organisms responsive to light
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

optogenetics: eg. used (2) and ions

A

green algae: channelrhodopsins (+ve ions)

halobacteria: archaerhodopsins (proton pumps- remove +ve ions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

optogenetics: method to inject

A
  • virus carrying specific opsin (channelrhodopsin) and identifier for specific neuron type (promoter) injected into brain area to infect cells of interest
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

optogenetics: how to activate ion channels

A
  • using lasers

- alters activity of infected neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

optogenetics: light wave/ freq and which commonly used?

A
  • electromagnetic radiation many freq, can only see small proportion
  • common colours used: blue, yellow, green
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

optogenetics: to activate use which light and action caused- channelrhodopsin (ChR2)

A
  • blue light
  • lets +ve ions into cell
  • cell stimulated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

optogenetics: to activate use which light and action caused- halorhodopsin (NpHR)

A
  • orange/yellow light
  • lets Cl- ions in
  • cell inhibited
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

optogenetics: to activate use which light and action caused- achaerhodopsin (Arch)

A
  • orange/yellow light
  • pumps +ve ions out
  • inhibits cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

optogenetics: opsins tagged w wat? eg.

A
  • tagged w fluorescent protein so visualise infected neurons under microscope
  • ensures labelled correct cells w channels

eg. green fluorescent protein (GFR) or mCherry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

optogenetics: how to check functioning of channel

A
  • electrophysiology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

optogenetics: why use it?

A
  • electrical stimulation affects all neurons in area, incl fibres of passage
  • neuropharm: all neurons w that type of receptor in area drug is administered
  • optogenetics: specific to neuron/circuit u r targeting (others not affected)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

optogenetics: process of using opsin to find circuitry

A
  • virus injected into B
  • opsin expressed through B (also fibres to A and C)
  • by laser activating B axons on A, corresponding B cell bodies r affected
  • by activating terminals at A only affecting neurons that come from B (where virus was injected)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

optogenetics: process involving locus coeruleus (LC) and amygdala

A
  • virus w photosensitive channels in LC
  • while plant optrode (holds optic fibre in place) in amygdala
    = only neurons from LC to amygdala will be stimulated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

optogenetics: bidirectional control of neurons process

A
  • mixed viral injection of opsins w diff lightwave spctrum into mixed pop of B (activator, inhibitor opsins)
  • opsin expression in B cell bodies to A and C
  • differentiate which opsin activated by using diff coloured lasers, due to photosensitivity of ion channels to diff wavelengths of light
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

optogenetics: use in humans and eg. (4)

A
  • possibly used
  • similar invasive procedure of deep brain stimulation, optic tech to target particular neuron type
  • schizophrenia
  • anxiety
  • depression
  • drug addiction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

anxiety vs fear response features

A
  • universal human emotion, necessary to adapt to env
    fear: defensive behaviours, arousal, -ve emotions
    anxiety: reactions due to anticipation of -ve event
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

fear: subcortical and features- immediate response to a threat

A
  • subcortical
  • visual, auditory stimuli reach thalamus, travel to amygdala
  • amyg alerts other brain structures (hypothalamus- HPA axis and locus coeruleus: LC)
  • surge in cortisol and nAd = sweaty palms, tachycardia, increased BP

fight or flight response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

fear: cortical and features- cognitive processing immediate response to a threat

A
  • cortical
  • info sent from thalamus - cortex and basal ganglia for cognitive processing
  • regions analyse raw data from sensory organs and decide dis/continue fear response
  • if maintained response: amyg remains on alert (helps make further appropriate behavioural responses)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

amygdala: function

A
  • key area in processing fear, anxiety
  • esp basolateral (BLA) and central nuclei
  • alerted when emotional processing, or emotional response required
21
Q

amygdala: name subregions and sig

A
  • BLA: basolateral
  • CeM: central medial amyg believed to drive fear response
  • CeL: central lateral amyg
22
Q

no amygdala=

A

no fear!

23
Q

amygdala: experiment to test how portions connected- activating BLA-CeL? results

A
  • blue light
  • reduced anxiety in elevated + maze
  • reduced anxiety in open field test (rat crossed through box vs. staying towards edges)
  • anxiolytic (reduce anxiety) effect = BLA activates CeL, reducing CeM output
24
Q

amygdala: experiment to test how portions connected- inhibiting BLA-CeL?

A
  • inhibiting w eNpHR3 (halorhodopsin)
  • 👷🏻
  • enhanced anxiety
25
Q

amygdala: experiment to test how portions connected- activation of BLA result, summary

A
  • activating BLA released glutamate in CeL to stimulate GABA cells and inhibit fear response of CeM
  • optogenetic activation of BLA terminals in CeL reduces anxiety stopping output of CeM
26
Q

oxytocin: features (6)

A
  • social neuropeptide
  • social interaction w peers
  • form monogamous pair bonding
  • sexual arousal, orgasm
  • maternal behaviour
  • social memory, anxiety reduction (anxyiolytic)
27
Q

oxytocin: where in brain

A
  • produced in magnocellular neurosecretory cells of hypothalamus
  • magnocellular cells in paraventricular nuclus (PVN) of hypothalamus (lateral/medial section) and supraoptic nucleus of hypothalamus (near optic tracts)
28
Q

oxytocin: where to- from supraoptic nucleus

A
  • volume transmission

- not so much neuron to neuron contact

29
Q

oxytocin: where to- from paraventricular nucleus (PVN)

A
  • classic neuron to neuron contact and vol transmission
  • oxytocin receptors in brain aka OT receptors

neurons to:

  • nucleus accumbens (NAS)
  • bed nucleus stria terminalis
  • amyg (CeA, MeA)
  • dopamine cells of VTA
30
Q

oxy release in central amyg reduce fear response? experiment features general

A
  • link of opsin ChR2 to oxytocin promoter so only oxy cells targeted
31
Q

oxy release in central amyg reduce fear response? result

A
  • yes

- activating ChR2 on oxy terminals of CeL of amyg reduced fear in rats

32
Q

list core brain regions receiving dopamine from VTA: (7)

A
  • subthalamic nucleus
  • striatum
  • orbitofrontal cortex
  • prelimbic cortex
  • nucleus accumbens
  • amygdala
  • hippocampus
33
Q

dopamine received from VTA function: striatum

A

habit

34
Q

dopamine received from VTA function: orbitofrontal cortex

A

impulsivity

35
Q

dopamine received from VTA function: prelimbic cortex

A

decision making

36
Q

dopamine received from VTA function: nucleus accumbens

A

saliency/ motivation

37
Q

dopamine received from VTA function: hippocampus

A

context/ memory of drug use

38
Q

PFC-NAc connection: for dopamine

A
  • prelimbic cortex (PL) of prefrontal cortex. (PFC) has glutamate (+ve) connections back to VTA dopamine cells and nucleus accumbens (NAc)
39
Q

cocaine: method for rats

A
  • intravenous drug self-administration (lever press)
40
Q

cocaine: function at synapses

A
  • DAT = dopamine transporter

- cocaine blocks DAT, modulation of DAT increases dopamine in synaptic cleft

41
Q

reinstatement of cocaine seeking: list 3 tests done

A
  • inject ArchT opsin/virus at PFC, laser via optrode on PFC
  • inject ArchT on NAc, and laser too
  • inject ArchT on PFC, laser on NAc
42
Q

reinstatement of cocaine seeking: inhibition of PL (prelimbic) cortex-

A
  • prevents drug seeking behaviour produced by re-exposure to cocaine
43
Q

function of PFC neurons in rats displaying addiction phenotype: type of cell, features

A
  • pyramidal neuron

- cocaine use resistant to inhibition by -ve consequence

44
Q

function of PFC neurons in rats displaying addiction phenotype: hypoactive neurons result

A
  • willing to keep taking cocaine despite shock (-ve consequence)
45
Q

function of PFC neurons in rats displaying addiction phenotype: activation of PL cortex (somatic method) in shock resistant rats?

A
  • reduced cocaine seeking in shock resistant rats
46
Q

function of PFC neurons in rats displaying addiction phenotype: inhibition of PL cortex (somatic method) in shock sensitive rats?

A
  • increases compulsive cocaine seeking in shock sensitive rats
47
Q

summary: CeL function

A
  • act as modulator of neuronal output of CeM

- CeL stops anxiety output of CeM

48
Q

summary: oxy release in CeL causes

A

reduces fear responses

49
Q

DREADDS: define

A

designer receptors exclusively activated by a designer drug

- targets specific brain cells if virus targets promoter

EXP NEURO (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions