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Biomedical subjects

J C Hirsch

Publications and source records attributed to J C Hirsch.

54 records · Page 3Linked to original sources
PubMed1980

Synaptic potentials in cat's lateral geniculate neurons during natural sleep with special reference to paradoxical sleep.

Juxtacellular DC recordings from lateral geniculate body (LGB) relay cells were performed in completely undrugged cats during natural sleep. Paradoxical sleep (P) was characterized by a decrease in synaptic (S) potentials and an increase in spike discharge as compared to slow wave sleep. During the P grouped discharges simultaneous with eye movements and cortical waves, a further decrease in S potentials accompanied by an increased cell excitability as indicated by the higher probability to elicit an antidromic spike occurred. The results suggest that the decrease of S potentials in P is not the result of presynaptic inhibition but that most of them reach firing level during the P grouped discharges.

Action Potentials↗
PubMed1978

[Study of the relationship between intracrânial pressure and paradoxal sleep in the cat (author's transl].

The present study reports on the modification of the intracranial pressure (ICP) during rapid eye movements (REM) sleep in seven chronic cats. 1. REM sleep episodes were characterized by a succession of short lasting (9 +/- 4 seconds) oscillations of the ICP. Peaks amplitude represented a hundred percent increase of the pressure as compared to its resting level. 2. These oscillations either arose from an ICP level similar to that recorded during the preceding slow wave sleep period or were seen to overide a wave of raised ICP that lasted throughout the REM period. 3. Eighty eight percent of the phasic oscillation coincided with a burt of eye movement characteristic of REM sleep. 4. Cerebral pulse wave amplitude can vary for identical ICP mean value in the course of a same REM period.

Animals↗
PubMed1976

Temporo-spatial propagation of epileptoform after-discharges in the isolated cat suprasylvian gyrus.

1. Epileptiform after-discharges (EADSs) induced by electrical stimulation of the isolated suprasylvian gyrus were studied in cats with chronically implanted electrodes. 2. In a given region and at a certain time after stimulation, the following events took place: (a) a slow radial spread of the zone of maximal depolarization, from the cortical surface downward, as evidenced by a laminar study; (b) a massive cellular discharge preceded by a period during which few unit activities were detected, followed by bursts of spike activity timed with the surface-positive waves of the ECoG; (c) a surface-negative DC shift with maximal amplitude around 1000 mum below the surface; (d) the occurrence of a synchronizing focus from which the paraoxysmal waves propagated to the whole gyrus. 3. All these phenomena spread across the surface of the gyrus with a velocity (7-20 mm/min) similar to that of focal seizures in man.

Action Potentials↗