Sensory and Cognitive 40-Hz Event-Related Potentials: Behavioral Correlates, Brain Function, and Clinical Application

Selective visual-spatial attention alters induced gamma band responses in the human EEG

“…Previous studies on animals (Rougeul-Buser and Buser, 1994) and humans (Sheer, 1989) have suggested such an increase of gamma power is due to attentional processes. However, the experimental setup and the results of theses studies do not preclude that a shift of general arousal has caused the effects.…”

Oscillatory gamma activity in humans: a possible role for object representation

“…The inspection of the human EEGrMEG literature since the 1950s reveals numerous reports of gamma oscillatory activities in various sensory Ž modalities and tasks Galambos et al, 1981;Pantev et al, 1991;Pfurtscheller et al, 1994, among many others: Sem-Jacobsen et al, 1956;Sheer, 1989; for review see . At first glance, these observations may appear rather disparate.…”

Event-Related Changes in the 40 Hz Electroencephalogram in Auditory and Visual Reaction Time Tasks

“…The significantly larger pre-stimulus 40 Hz activity in the slow responders might reflect a kind of heightened anticipation or focused preparation to facilitate controlled sensorimotor processing (Sheer, 1989;Crick and Koch, 1990). One might speculate that an increased state of anticipation of the stimulus in slow responders (Fig.…”

“…Electroencephalographic (EEG) studies have reported spontaneous cortical activity in the 40 Hz range during periods of increased alertness and vigilance (Boyer et al, 1987;Steriade et al, 1991), during accurate performance of a conditioned response (Freeman and Dijk, 1987), and during periods of focused arousal during cognitive task performance (Sheer, 1989) including reaction time tasks (Krieger and Dillbeck, 1987). Suppression of 40 Hz activity has been noted during central anaesthesia (Madler and Pöppel, 1987) and delta sleep (Llinas and Ribary, 1993).…”