id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-104157-rivaoo73	Noreika, Valdas	Alertness fluctuations during task performance modulate cortical evoked responses to transcranial magnetic stimulation	2019-06-28		.txt	text/plain	10469	492	52	We observed rapid, non-linear changes in TMS-evoked neural responses – specifically, motor evoked potentials and TMS-evoked cortical potentials – as EEG activity indicated decreasing levels of alertness, even while participants remained awake and responsive in the behavioural task. Here we combined single-pulse TMS with concurrent EEG recording and a simple behavioural task to quantify changes in motor and cortical reactivity with fluctuating levels of alertness defined objectively on the basis of ongoing brain activity. To assess the instantaneous level of alertness, a two-fold EEG analysis was applied over the time window immediately preceding each TMS pulse: (1) a binary definition of awake and drowsy states following EEG spectral power signatures (θ/α) averaged across all EEG electrodes (Bareham et al., 2014) , and (2) a dynamical definition of alertness levels following a detailed sub-staging system for scoring the transition to N1 sleep (Hori et al., 1994) (Fig. 1C ).	./cache/cord-104157-rivaoo73.txt	./txt/cord-104157-rivaoo73.txt