Brainscape's Knowledge GenomeTM

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


See full index

Clocks > Lecture 2 Clock circuits in the mammalian brain > Flashcards

Lecture 2 Clock circuits in the mammalian brain Flashcards

1
Q

PVN

A

paraventricular nucleus

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

AHA

A

Anterior hypothalamic area

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

sPVNz

A

subparaventricular zone

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

SCN

A

suprachiasmatic nucleus.

light entrainable circadian pacemaker.

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

OX

A

optic chiasm

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

anatomy of hypothalamus?

A

2x SCN, seperated by the third ventricle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

SCN neurons properties?

A

v small 8-12um.
densely packed.

neurochemically heterogeneous - most contain GABA, but also contain a variety of different neuropeptides, spatially segregated to different subregions of the SCN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

where does SCN recieve monosynaptic input from?

A

retina via the retinohypothalamic tract (RHT).

RHT inputs are primarily to ventral parts of the SCN.

RHT synapses are excitatory (gray type I, therefore the depolarise and activate SCN neurons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the main RHT neurotransmitter?

A

glutamate, augmented by PACAP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is PACAP?

A

pituitary adenylate cyclase activating polypeptide.

located heavily in the ventral SCN (found via immunostaining).

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

How is the GHT formed?

A

Neurons in the intergeniculate leaflet (IGL) of the visual thalamus project to the SCN, forming the geniculohypothalamic tract (GHT)

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

What neurotransmitters does the GHT use?

A

GHT input uses both GABA and Neuropeptide Y (NPY); these are inhibitory; this input hyperpolarises and suppresses SCN neurons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does the MR innervate the SCN?

A

Neurons in the Median Raphe (MR) innervate the SCN; they contain serotonin (5-Hydroxytryptophan or 5-HT); this input suppresses SCN neuronal activity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does the DR innervate the IGL?

A

Neurons in the Dorsal Raphe (DR) innervate the IGL; they contain 5-HT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe non photic inputs to the circadian system

A

IGL - GHT
MR
DR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe photic inputs to the SCN

A

RHT

17
Q

what happens if a glutamate antagonist is given before a light pulse?

A

reduces phase shift, therefore glutamate is the NT.

18
Q

What happens if arousal promoting stimulit is exposed during the day/night?

A

phase advance

night - no change

19
Q

phase response curves for photic and non photic?

A

photic what described before.

non photic - advances during inactive phase, small effect of delay in active phase.

20
Q

neurochemicals of RHT?

A

glutamate and PACAP

21
Q

neurochemicals of GHT?

A

Neuropeptide Y & GABA

22
Q

neurochemicals of brain stem?

A

5-HT

23
Q

neuropeptides made by SCN neurons?

A

intrinsic, following are ventral:
Vasoactive Intestinal Polypeptide (VIP) ,Gastin-releasing peptide (GRP), Substance P (SP)

Ventral/dorsal:
Vasopressin (AVP)

Dorsal:
Somatostatin (SOM)

24
Q

what is the core and shell model?

A

Shell - AVP cells located.
Core - VIP/GRP cells located.

Core recieves input from the RHT.

Core weak clock cells.

Core projects to shell, AVP cells are strong clock cells.

25
Q

Evidence that the SCN contains the main circadian clock?

A

When SCN lesioned arythmic, transplant restores.

26
Q

SCN activity throughout day?

A

high when inactive, low during active, GABA so probably inhibit. Rats.

27
Q

In vitro single unit recordings of cultured SCN neurons?

A

rhythmically express electrical activity -24 hr.

higher at one point of the day.

therefore clock acitivty is a product of individual cells.

28
Q

how are clock genes rhymically expressed in the SCN in vivo.

A

nice rhythms, mPer2, 1

mBmal1, mCry1, AVP

29
Q

Per1 luceferin

A

luceferin comes from firefly - glow.
per1 also makes luceferin.

SCN stays rhythmic for weeks, individual SCN neurons function as autonomous clocks.

30
Q

SCN neuron metabolism?

A

higher during day than night.

31
Q

when does PER gene expression peak?

A

during day.

32
Q

outputs of SCN?

A

Hypothalamus:
aPVN to influence corticotrophin releasing hormone and melatonin frmo pineal gland.

sPVNz
DMH
MPN

Thamalus:
PVT
paratenial nucleus
LGN

33
Q

how does SCN molecule and cellular rhythm change during the day in relation to behavioural activity?

A

SCN molecular and cellular rhythms peak in the day,

behavioural Activity low in day, high at night

34
Q

PK2?

A

Prokineticin 2.
Suppresses locomotor activity.
High during day (for what?)

Clocks (13 decks)

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