Naslov
Neurophysiological mechanisms underlying motor evoked potentials in anesthetised humans. Part 1. Recovery time of corticospinal tract direct waves elicited by pairs of transcranial electrical stimuli.

Autori
Deletis, Vedran ; Išgum, Velimir ; Amassian, Vahe E.

Izvornik
Clinical neurophysiology (1388-2457) 112 (2001), 3; 438-444

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Direct wave; Motor evoked potentials; Corticospinal tract

Sažetak
Direct (D) corticospinal tract discharges were recorded epidurally in patients at anesthetic depths suppressing indirect (I) activity and were elicited by two equal transcranial electrical stimuli. The recovery of amplitude of the second D wave (D2) was a function of the interstimulus interval (ISI) and the stimulus duration. For example, with a 100 us pulse, there was no response at an ISI of 1.1 ms, but partial recovery occurred with 500 us pulse. This indicates a relative refractory component at this ISI. Both D2 amplitude and conduction time recovered completely using 4 ms ISI, with evidence of increased amplitude and reduced conduction time (supernormaly) at longer ISIs. These findings are relevant in explaining high frequency D and I discharges and facilitation of motor responses by two transcranial magnetic pulses. Furthermore, this data help to understand why an ISI of 4 ms would be optimal in eliciting limb muscle responses when a short train of transcranial stimuli elicits only D waves in anesthetized patients (Deletis et al., Clin Neurophysiol 112(2001) 445)

Izvorni jezik
Engleski

Znanstvena područja
Kliničke medicinske znanosti

POVEZANOST RADA