Fig. 2.
Changes in the brain during sleep modulated by acetylcholine (ACh) input.45 Brainstem neurons (localized in the pedunculopontine [PPT] and laterodorsal tegmental [LDT] nuclei of the midbrain) release ACh which prompts the activation of ascending projections to the thalamus. This is accompanied by generalized activation of limbic, parahippocampal, and other thalamic pathways. This cholinergic enhancement is followed by major glutamatergic release to basal ventrolateral preoptic area (VLPO), and it has the simultaneous effect of decreasing the recruitment of prefrontal areas and of the inferior parietal cortex.