Amplitude and phase relations of electrocortical waves regulated by transhypothalamic dopaminergic neurones: a test for a linear theory.

We have previously proposed that electrocortical activity (EEG) arises as a manifestation of linear waves generated by resonance among telencephalic neurones, and that this activity is controlled in part by ascending neurones from the brain-stem, which regulate the damping of each resonance. The present experiments focus on a specific class of ascending neurones, the mesotelencephalic dopaminergic cells, because these cells are thought to mediate important psychological effects, and are conveniently subject to selective lesion. A critical test of the theory is undertaken, by performing selective unilateral lesion, assessing the changes in the power spectrum of the EEG attributable to lesion, and determining whether the changes in phase of the EEG correspond to that predicted from the changes in power. Results support the theory, although the model order applicable in these experiments in inadequate. The consequences of these findings for automata theory, linear network theory and their application to mammalian brains are briefly discussed.