Excitation of slow pyramidal tract cells and their family neurones during phasic and tonic phases of EEG arousal.
1. Intracellular activities of slow pyramidal tract cells and their family neurones were investigated during the EEG arousal of various intensities. 2. By assessing the intensity of midbrain reticular or natural stimuli, the arousal length of EEG and the extent of EEG stage shift, these neurones were identified as the recipient of enduring excitation (E + E) during both the phasic and tonic phases of EEG arousal, and were termed E + E cells. 3. These cells were located in all the cortical laminae. E + E responses took the form of continuous depolarization in most of the deep cortical layer cells, but separated initial and late peaks of depolarization were seen in most of the superficial initial and late peaks of depolarization were seen in most of the superficial layer cells. 4. The E + E response versus stimulus intensity or arousal length relationship consisted of plateau and rising limbs, which would characterize the initial and late E components, respectively. 6. The excitatory tonus was revealed in E + E cells with mean levels of resting membrane potential, being most hyperpolarized during highly synchronized EEG and gradually depolarized according to stage shift towards desynchronization.
D000818:Animals; D001143:Arousal / Q000502:physiology*; D002415:Cats; D004569:Electroencephalography; D009474:Neurons / Q000502:physiology*; D011712:Pyramidal Tracts / Q000166:cytology / Q000502:physiology*; D011930:Reaction Time