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Cholinergic and Adrenergic

Neurons

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Cholinergic Neurons

Excitotory (N& M1) & Inhibitory M2

Motor neurons

All autonomic preganglionic neurons Postganglionic parasympathetic

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Cholinergic II

Basal forebrain complex: ventral to basal ganglia.Includes medial septal nuclei & bed nucleus ofthe stria terminalis which provide the cholinergicinnervation of the hippocampus, and basalnucleus of myenrt, which provides most of thecholinergic innervation of the neocortex.Collectively, first to die in Alzehmeirs diseas.They play a role In regulating general brain

excitability during arousal and sleep-wake cycles.Play a role in learning and memory formation.Difffuse modulatory system.

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Cholinergic III

Pontomescensphalotegmental complex: pons

& midbrain tegmentum. Act mainly on dorsla

thalamus, where together with noreadrengic

and sertonergic systems, regulate the

excitability of sensory relay nuclei. Also project

to telencephalon providing cholinergic link

between brainstem & basal forebraincomplexes. A diffuse modulatory system.

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Diffuse Modulatory System

Axonal system with highly divergentprojections to multiple areas of the CNSproviding extensive spatial control. Each

system prolongs its actions by using G-proteins coupling receptors. Further coverageby the release of neurotransmitter moleculesinto the extracellular fluid so that they can

diffuse to many neurons rather than beingrestricted to the immediate vicinity of synapticcleft.

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Its parts:

Cholinergic pontomesencephalo-tegmental

system

Noradrengic system (LC) Serotonergic (Raphe Nuclei)

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Noradrenergic Locus Coeruleus

The locus Coeruleus means blue spot because ofthe colour of its pigmentation. There are two ofthem, one on each side in the pons just lateral tothe fourth ventricle. It is a member of diffusemodulatory system. Surprisingly, it is very smallwith about 12, 000 neurons in each nucleus.Axons leave the nucleus, fan out, and branch tomytliple times to supply most regions of the

central nervous system, including all of thecerebral cortex, the amygdala, the hippocampus,basal ganglia, thalamus, hypothalamus, olfactorybulb, midbrain, cerebellum and spinal cord.

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Locus Coeruleus II

It is involved in the regulation of attention,

arousal, sleep-wake cycles, learning &

memory, anxiety, pain, mood, and brain

metabolism. It is a vital link to chronic stress

as it sends sensory input to the amygdala &

hippocampus. Along with the serotonergic

raphe nuclei, it is part of the reticularactivating system.

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Locus

Coeruleus III

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