Excitation of slow pyramidal tract cells and their family neurones during phasic and tonic phases of EEG arousal.

Abstract

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 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.

Endogenous control of waking brain rhythms induces neuroplasticity in humans

“…Hence, the possibility exists that the motor cortex may have been presynaptically modulated by connections from more distributed cortical or subcortical structures. Direct intracellular recordings of corticospinal tract neurons report increased membrane depolarization during stage shifts towards EEG desynchronization (Ezure & Oshima, 1981). In spite of this we did not observe significant changes in RMT, known to reflect variations in membrane conductance (Ziemann, 2004).…”

The structure of EEG arousal as a dynamic ensemble of neuronal activities in cat motor cortex.

“…We identified these responses as an I+I pattern. Difficulty encountered for this identification was similar to the case of Ed-E responses (EZURE and OSHIMA, 1981c), and the best criterion was often the prolonged length of EEG arousal, as illustrated in Fig. 4B.…”

“…The time course of late responses may provide a good parameter related to the depth profile of cell location (cf. INUBUSHI et al, 1978a;EZURE and OSHIMA, 1981c). The data available from the present analysis were limited in this examination because of difficulties in sampling many cells from different depths in one and the same preparations on EEG arousal with a similar intensity.…”

“…However, the late cellular responses corresponding to tonic EEG arousal were easy to identify in most neurones because of the response dichotomy, as revealed in the case of DF+E pattern. The cases of no apparent dichotomy such as the E+E pattern, the late responses were assured by selecting the EEG arousal ranked as the most intense in terms of the used stimulus intensity or the aroused EEG patterns or both (EZURE and OSHIMA, 1981c). Of the total 164 cells, 132 could be specified in their dominant response during tonic EEG arousal.…”

“…The phasic and tonic phases of EEG arousal have been discriminated by the initial disfacilitation and late excitation (DF+E pattern) in fast pyramidal tract (PT) cells and their family neurones (INUBUSHI et al, 1978b;EZURE et al, 1980;EZURE and OSHIIVIA, 1981b) as well as by the initial and late components of excitation (E+E pattern) in slow PT cells and their family neurones (EZURE and OSHIMA, 1981c). When we are to sample the motor cortical neurones of all types other than the PT cells and their family neurones during phasic and tonic EEG arousal, it is expected that new combinations of dual neuronal activities other than the DF+E and Ed-E patterns will be found.…”