brain stem: chemically identified circuits (CIC) Flashcards
1
Q
- wide spread, medulla/pons/midbrain
- far reaching to most areas of the brain
- some circuits have names, some have number
A
CICs
2
Q
- chemical messenger
- transmitters are dopamine, serotonin, and norepinephrine
A
monomines
3
Q
how were the transmitters found?
A
formaldehyde vapors
4
Q
- both ascending and descending portions
- one axon splits and goes both directions
- some didnt stop at the thalamus
A
CICs
5
Q
- original # A1-A10
- circuits contain large nerve endings
- do not react to external stimuli
- more restrictive: two paths
A
dopamine
6
Q
parkinson’s
from reticular formation to the basal ganglion
pars compacta of the substantia nigra
A
dopamine path 1
7
Q
A10
reticular formation to the limbic system
ventral tegmental area (VTA)
- sensitive to antipsycotropic
A
dopamine path 2
8
Q
- found in the locus ceruleus which is a true nucleus
- an extreme amount of arborization is seen and this expansion extends everywhere within the brain
- this system seems to be a type of arousal system or in the least, excitatory
- cocaine and amphetamines work here
- this part may be the original “ activating system” that has been assigned to the reticular formation
A
norepinephrine
9
Q
- ventral noradrenergic bundle
starts in locus ceruleus
goes through reticular formation
ends in the limbic system - dorsal noradrenergic bundle
starts in the spinal cord
goes through locus ceruleus
then to the limbic system and basal ganglion
A
norepinephrine pathway
10
Q
- originally B1-B9
- not in the original experiment
- comes from raphe nucleus which lies close to the midline in the brain stem
- raphe means seam
- system that goes everywhere but starts from just one spot in the brain stem
A
serotonin
11
Q
- pain control and usually inhibitory
- depression drugs act on the serotonin system but no one is sure how —– one of two ways
- hallucinogens and antagnostics also work on this system and end to shut it down
A
role of serotonin
12
Q
- causes more serotonin to be released making it more available
- affects the post synaptic endings allowing more of the chemical to be accessed by the dendrites
- termed as the “uptake” pharmaceuticals
A
two ways that depression drugs could act on the serotonin system
13
Q
- fibers are not myelinated
- no 1 on 1 correspondence to body parts
- they dont just synapse on axons also release neurotransmitters into the ventricles (hormone-like)
- functions are not involved with information transfer but are concerned with regulation
- the outputs are not well defined and course through the entire brain
A
general CIC system points
14
Q
- showed the brain works differently than what was generally expected
- papers were contraversal because it was thought that info had to go through thalamus
- seems to be self regulatory
- modifying info coming to and from spinal cord
- have the ability to shut off systems, neuromodulator
A
points from Dahlstrom and Fuxe
