Fxns Of Single-Source Divergent Networks Flashcards
What is the sole source of histamine in the CNS?
Tubero-mammillary nucleus of the hypothalamus
Where is serotonin created in the CNS?
Raphe nuclei
Where does the Raphe nucleus live?
Several regions
Functions of serotonin
Mediation of attention and arousal Inhibition of impulsive behaviour Modulation of negative emotions Support learning and memory Control of deep sleep (non-REM)
Where is acetylcholine produced?
Principle nuclei are nucleus basalis of Meynert (NB) and the pontopeduncular nucleus (PPN)
Where does the nucleus basalis live?
Basal forebrain
Fxns of acetylcholine system?
Mediation of attention and arousal
Support learning and memory
Control REM sleep (Rapid Eye Mvement)
What are the nuclei that produce dopamine?
Nuclei of the ventral tegmental area (VTA) and the substantia nigra (SN)
Where do axonal projections from dopamine producing and releasing neurons target?
Neurons of the nucleus accumbens (nAc) of the basal forebrain
Fxns of dopamine system
Mediates the brain’s positive reward network + motivation
Modulates positive emotion and mood
Supports learning and memory
Mediates attention and arousal
What is the effect of opiate drugs on dopamine?
Blocking re-uptake of dopamine by binding to and inhibiting Dopamine Transporter (DAT)
What are the results of preventing re-uptake of DA
Activates dopaminergic system by allowing more DA in the synaptic cleft, producing the psychotropic effects characteristic
What are other effects of methamphetamine and amphetamine on dopamine system?
Activates calcium dependent release of DA resulting in the release of a large bonus of dopamine into the synaptic cleft
What are the effects of opium and heroin (other opiates) on the DA system?
Increase the firing of the DA neurons in the VTA by decreasing GABA-ergic inhibitory inter neurons that inhibit VTA neurons
What are the effects of tetrahydrocannabinol on the dopamine system?
It is able to inhibit inter neurons that inhibit the VTA neurons
What is the effect of nicotine on the dopamine system?
It binds to a subtype of glutamate receptor on glutamatergic excitatory neurons that synapse on neurons in the VTA. BinDing of nicotine to nicotinic receptors causes the release of glutamate which bind to VTA neurons activating neurons to release DA
True or False? Increased stimulation of the dopamine system will lead to stronger motivational drive to continue to activate the dopamine system
True
Is histamine excitatory, inhibitory or both?
Excitatory ONLY
Which nucleus is the principle noradrenalin nucleus of the brain?
Locus cerulean (Lc) - paired brain stem nuclei in rostrum pons
Are the actions of norepinephrine inhibitory, excitatory or both?
Both!
Where does the Lc live?
Pons
What are the functions of the norepinephrine system?
Attention and arousal (including the 4Fs) Negative emotion processing Regulating deep sleep (non-REM) Support learning and memory May aid cognitive performance
Where does the tubero-mammillary nucleus live?
Hypothalamus
What are the functions of the histamine system?
Mediation of arousal and attention
Modulation of body energy stores (energy homeostasis)
Control of circadian rhythms
Support learning and memory
Where is the Ascending Reticular Activating System?
Originates in brain stem
Ascends through the intralaminar thalamic nuclei (ILn) and the thalamic reticular nucleus (TRn) of the thalamus
Goes to cerebral cortex
What do all 5 of the single source divergent networks communicate with?
The Thalamic ARAS via axonal projections
What are the 2 main functional nuclear relay regions of the thalamic ARAS?
Intralaminar thalamic nuclei
Thalamic reticular nucleus
True or false: majority of axons within the 5 single source divergent networks are myelinated
False. They’re unmyelinated.
What is Omnidirectional release?
Numerous neurotransmitter molecules can diffuse freely in various directions
What is volume synaptic transmission?
Numerous neurotransmitter molecules can diffuse freely, in response to intracellular calcium
What are the post synaptic physiological ecstatic of non-directed (volume synaptic transmission) synapses?
Large numbers of cells are influenced
Long duration of modulatory effects
Non-directed action
Characteristics unique to the 5 single-source divergent networks
Release only ONE type of signalling molecule that influence numerous other target brain areas
Organized in a hierarchy
Support all cognitive fxns
Exhibit fxnal stability in the face of network damage
Created and altered by synaptic plasticity processes
Consists of many long reaching axonal branches
Categorized by NT utilized
Constantly modulating neural activity!
How can nuclei communicate with each other in cognitive networks?
Serial, parallel or reciprocal neural connections
Which nucleus is responsible for producing norepinephrine/noradrenaline?
Locus coeruleus (Lc)
Coeruleus = blue (CALM colour) and NE calms you down
Where does the pontopeduncular nucleus live?
Midbrain
Where does the VTA live?
Midbrain
Where does the nucleus accumbens live?
Basal forebrain
Where does the substantia nigra live?
Midbrain
What is a Feedback circuit?
Infragranular layers –> thalamus –> layer IV
