Nucleus Basalis Of Meynert And Nucleus Of The Diagonal Band Of Broca

These nuclei consist of scattered groups of large cells in the basal part of the cerebral hemisphere, just ventral to the anterior commissure and the globus pallidus. The nucleus basalis (Figs. 2 and 3) is most prominent at the level of the anterior commissure, but some of its cell clusters extend caudolaterally toward the amygdala and dorsally around the edges of the globus pallidus. The diagonal band nuclei extend medially and dorsally (diagonally) into the septum. Because many of the cells utilize acetylcholine as their transmitter, the nuclei stain very darkly for acetylcholinesterase. Other cells in the complex use GABA as transmitter. As a group, they project axons widely to all parts of the cerebral cortex (and the olfactory bulb and amygdala), although individual neurons within the group appear to have very restricted projections.

The principal action of acetylcholine on cortical cells is to enhance the action of other synaptic inputs. The nuclei are situated along fiber pathways that connect limbic structures such as the orbital and medial prefrontal cortex and the amygdala with the hypothalamus and brain stem, and they receive major input from all of these. The magnocellular basal forebrain nuclei are therefore well situated to modulate cortical activity in relation to limbic activity. They have been implicated in the activation (desynchronization) of the cortex that is characteristic of the waking state, and they are presumably involved in many other functions as well.

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Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

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