Abstract

Summary of present knowledge

Unanswered Questions

REFERENCES

Discussion
Board

In 1978, Woody, Schwartz and Gruen found that pairing acetylcholine with intracellular depolarization produces long-lasting changes in cortical neurons. Since that discovery, numerous studies have examined the ability of iontophoretically applied ACh to produce long-term plasticity in auditory, somatosensory, visual, and olfactory cortex. Others have demonstrated plasticity by replacing the direct application of ACh with electrical stimulation of the basal forebrain, on the supposition that synaptic release of ACh would more accurately reflect physiological conditions. To date, studies have concentrated on determining the conditions that produce this plasticity or on verifying pharmacologically that this effect is due to cholinergic synapses. Questions now need to be raised about the importance of this phenomenon in the intact CNS: Are these long-lasting changes an experimental artifact or do cholinergic neurons serve a similar function in vivo? Do the cholinergic basal forebrain neurons fire in a manner that can produce long-term cortical changes? If so, what controls the firing of cholinergic neurons? Are the outputs of cholinergic basal forebrain neurons sufficiently precise to produce meaningful changes in cortical function? Or do the cholinergic neurons set large portions of the cortex into a modifiable state where the decision for change is totally dependent on the other inputs to a cell?

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Presentation Number SArasmusson0608
Keywords: plasticity, cerebral cortex, cholinergic, basal forebrain