Acoustically evoked potentials of the basal forebrain and the nucleus cuneiformis of the freely moving rat.
Acoustically evoked potentials (AEP) were recorded and analysed in the basal forebrain (bf, nucleus basalis magnocellularis) and in the mesencephalic parabrachial nucleus cuneiformis (Cnf) of freely moving rats and the modulatory effects of electrical single stimulations within both cholinergic regions on these AEP are described. Bipolar electrodes were implanted in both regions for stimulation and AEP recording. Electrical single impulses with increasing intensities were applied 100 ms before or simultaneously with the clicks. The AEP of the bf as well as the Cnf varied their configuration in dependence on the behavioural state. During grooming, amplitude reductions of certain components of both AEP were found in in comparison to relaxed wakefulness. Electrical stimulation of the bf had no effect on the early component of the Cnf-AEP, which is likely generated within the Cnf. However, a later component of the Cnf-AEP whose generation locus within the mesencephalon is unknown was modulated by bf stimulation. This indicates that the bf is only able to modulate secondary acoustic information processing in the mesencephalon. Cnf stimulation caused reductions of the amplitudes and of the peak times of the bf-AEP. This modulation of the bf-AEP takes place likely within the acoustic pathway.
Bringmann
A
A
Institute for Neurobiology and Brain Research, Academy of Sciences, Magdeburg.
Klingberg
F
F
D000818:Animals; D001921:Brain / Q000502:physiology*; D004558:Electric Stimulation; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D008636:Mesencephalon / Q000502:physiology*; D009068:Movement; D051381:Rats