ELECTRICAL-ACTIVITY OF THE ACUTELY ISOLATED PONS IN CATS

The cat's pens was isolated by two brainstem transections, at the junc tion of medulla and pens and at the junction of pens and midbrain. In the deafferented pens the EEG activity was virtually absent, whereas t he spatial density of active units and the rate of their spontaneous s pike activity were at a high level. In the pens of control preparation s with brainstem transected only at the ponto-midbrain junction the EE G activity was present, while the single-unit activity was such as in the isolated pens. The electrical activity of the isolated pens was si milar to that previously described in the cat's isolated midbrain. The discrepancy between EEG and single-unit activity suggests that in the deafferented pens or midbrain many neurones are asynchronously autoac tive. Also, these results show that a flat EEG record is not necessari ly a sign of absence of the neural activity and neural death.