title: Gamma and beta frequency oscillations in response to novel auditory stimuli: A comparison of human electroencephalogram (EEG) data with in vitro models.
abstract: Investigations using hippocampal slices maintained in vitro have demonstrated that bursts of oscillatory field potentials in the gamma frequency range (30-80 Hz) are followed by a slower oscillation in the beta 1 range (12-20 Hz). In this study, we demonstrate that a comparable gamma-to-beta transition is seen in the human electroencephalogram (EEG) in response to novel auditory stimuli. Correlations between gamma and beta 1 activity revealed a high degree of interdependence of synchronized oscillations in these bands in the human EEG. Evoked (stimulus-locked) gamma oscillations preceded beta 1 oscillations in response to novel stimuli, suggesting that this may be analogous to the gamma-to-beta shift observed in vitro. Beta 1 oscillations were the earliest discriminatory responses to show enhancement to novel stimuli, preceding changes in the broad-band event-related potential (mismatch negativity). Later peaks of induced beta activity over the parietal cortex were always accompanied by an underlying gamma frequency oscillation as seen in vitro. A further analogy between in vitro and human recordings was that both gamma and beta oscillations habituated markedly after the initial novel stimulus presentation.
authors.affiliation: Division of Neuroscience and Psychological Medicine, Imperial College School of Medicine, London W6 8RP, United Kingdom. C.Haenschel@ic.ac.uk
authors.forename: C
authors.initials: C
authors.lastname: Haenschel
authors.forename: T
authors.initials: T
authors.lastname: Baldeweg
authors.forename: R J
authors.initials: RJ
authors.lastname: Croft
authors.forename: M
authors.initials: M
authors.lastname: Whittington
authors.forename: J
authors.initials: J
authors.lastname: Gruzelier
mesh_terms: D000161:Acoustic Stimulation; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques