Scopul nostru este sprijinirea şi promovarea cercetării ştiinţifice şi facilitarea comunicării între cercetătorii români din întreaga lume.
Autori: Nita DA, Cisse Y, Timofeev I, Steriade M.
Editorial: [Epub ahead of print], J Neurophysiol, 95(2), p.902-13, 2005.
Cortical injury may lead to clinical seizures. We investigated the
changing patterns of the sleep-like slow oscillation and its tendency to develop into
paroxysmal activity consisting of spike-wave (SW) complexes at 2-4 Hz following partial
deafferentation of the suprasylvian gyrus. Experiments were carried out in anesthetized
cats, at different time-intervals (week 1 to week 5, W1-W5) after cortical undercut.
Multi-site field potentials and single or dual intracellular recordings from the whole
extent of the deafferented gyrus were used. The field components of the slow oscillation
increased in amplitudes and were transformed into paroxysmal patterns, expressed by
increased firing rates and tendency to neuronal bursting. The incidence of SW seizures
was higher with transition from semi-acute (W1) to chronic (W2-W5) stages following
cortical undercut. The propagation delay of low-frequency activities decreased from W1
to W5, during both the slow oscillation and seizures. The initiation of seizures took place
in territories contiguous to the relatively intact cortex (area 5 in the anterior part of the
gyrus), as shown by cross-correlations of field potentials from different sites and
simultaneous intracellular recordings from the anterior and posterior parts of the gyrus.
The increased amplitudes of both slow oscillation and SW seizures, and their enhanced
synchrony expressed by shorter time of propagation, are ascribed to increased neuronal
and network excitability following cortical undercut.
Cuvinte cheie: cortical undercut; chronic stages; seizures; multi-site recordings; intracellular