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The modulatory Functions of the Brain Stem - Coggle Diagram
The modulatory Functions of the Brain Stem
Ascending monoaminergetic and cholinergic projections from the Brain Stem Mantain Arousal
:
some neurons project to the forebrain control wakefulness and sleep
the monoaminergetic and cholinergetic neurons of the ascending arousal system have widespread projections to almost every part of the NS
a major part of the ascending arousal system cosnsists of monoaminergic and cholinergic neurons
these neurons are found primarily at 4 regions
dorsal and median raphe nuclei
serotonergic and some dopaminergic
pedunculopontine
cholinergic
locus cereleus
norsdrenergic neurons
tubermammillary
histaminergic
monoamines:biochemical compounnds with an aromatic ring synthesized from aromatic aminoacids
Some amonoamines are: epineprhine, norepinephrine, dopamine, serotonine and histamin
Regulation of other brain functions
they regulate cognitive performance during waking and effect a variety of other nervous system functions
the cognitive performance is optimized by Ascending projections from monoaminergic neurons
neurons of the locus cerebelus (
noradrenergic neurons
) release norepinephrine wich plays an important role in attention
monoaminergic imputs from dorsolateral prefrontal cortex (dopaminergetic neurons) can improve working memory
dopamine is alo linked to reward-bases learning
automatic regulation and breathing
neurons in adrenergetic C1 group in the rostral ventrolateral medulla play a key role in maintaining vascular tone as well as adjusting vasomotor necesitated by various behaviors
neurons in noradrenergic A5 group in pons inhibit the sympathetic pregangliar neurons and play a role in depressor reflexes
serotonin regulates automatic funcions like gastrintestinal peristalsi, termoregulation, cardiovascular control and breathing
serotonergic neurons act like CO2 receptors
monoamines modulate pain anti-nonecieptive pathways
noradrenergic inputs to the spinal cord originate from pontine cell groups, incluiding the locus cereleus (noradrenergic neurons)
serotonine
can inhibit dorsal horn neurons response to noxious stimuli
serotonine role in pain procesing is used in trating migraine headaches
monoamines facilitate motor activity
The dopaminergic system is critical for normal motor performace, because a massive projection ascends from the subtantia nigra pars compacta to the stratium
paterns of selective attention
phasic mode: baseline of neurons is low to moderate
tonic mode: baseline activity is elevated and does not change in response to external stimuli
Properties and functions
they fire pontaneous action potentials in a highly regular patern when isolated, their action potential are typically followed by a slow membrane depolarization
monoamine transmission occurs by means of metabotropic synaptic actions through G-protein coupled receptor
sleep- wake cycle
CN neurons fire maximally during waking, decrease firing in slow-wave sleep and increase firing in the REM sleep. motor neurons are the only ones that are totally inactive during sleep and have low frequency during REM
most likely motor neurons (monoaminergetic)
noradrenergic
serotonergic
histaminergic
dopaminergetic neurons within the dorsal raphe region are most active during waking like the motor neuroons
cholinergic neurons in the pedunculopontine and laterodorsal tegmental nulei
increase their activity during REM sleep and decrease durin non-REM
arousal maintaining (thalamus and cortex modulation)
they induce arousal by activating cortical neurons both directly and indirectly
ionic mechanism produce different modes of firing in thalamic neurons during sleep and wakefulness
sleep
fire in burst
wakefulness
fire single spikes