Caffeine enhances frontal relative negativity of slow brain potentials in a task-free experimental setup

Does the P300 reflect conscious perception or its consequences?

“…One of them was left-handed. Subjects were instructed not to drink coffee for 2 h before the experiment in order to standardize the recording conditions and to avoid possible modulatory effects of caffeine on the relative amplitude of slow brain potentials (Murd et al, 2010). All subjects were recruited as volunteers and gave informed consent prior to the beginning of the experiment.…”

Occipital long-interval paired pulse TMS leads to slow wave components in NREM sleep

“…With this research we extend our earlier studies with occipital TMS-EEG where single TMS pulses were used (Murd et al, 2010;Stamm et al, 2011). In one previous study (Stamm et al, 2011) we also contrasted NREM sleep and wakefulness as in the present work.…”

“…TMS-EEG studies of decreased Massimini et al, 2005Massimini et al, , 2010Rosanova et al, 2012;Stamm, Aru, & Bachmann, 2011) or increased (Murd, Aru, Hiio, Luiga, & Bachmann, 2010) states of arousal have provided insights about the mechanisms of sleep and wakefulness. TMS combined with EEG allows one to have a perturbation of the brain functionality together with temporally precise measurement of the effects of this perturbation (Casali et al, 2013;Massimini et al, 2005;Rosanova et al, 2012).…”

Spectral Signatures of the Effects of Caffeine and Occipitally Applied Transcranial Magnetic Stimulation in a Task-Free Experimental Setup

“…Experiments using transcranial magnetic stimulation (TMS) simultaneously with electroencephalography (EEG) recording and in combination with controlled general brain states serve as an example of this strategy. 6,[11][12][13][14] In the majority of cases, the EEG studies of state-dependent processes in response to perturbation by TMS have focused on the effects of sleep/wake states and anesthetic interventions. 6,11,12,15 This is in contrast to a normal arousal state (involving brain processes in their up-states) and a state of decreased arousal (involving brain processes in their downstates).…”

“…Recently, Murd et al 13 combined occipitally applied, neuronavigated TMS, EEG, and caffeine treatment to compare the task-free effects of TMS-evoked perturbations in a higher arousal state (caffeine) with the effects in a control state (placebo). They found that the amplitude of the frontally and parietally recorded event-related potential (ERP/N1) and slow negative potential increased under caffeine, but the latencies of TMS-evoked ERP components did not decrease.…”