Are high-frequency (600 Hz) oscillations in human somatosensory evoked potentials due to phase-resetting phenomena?

作者：Waterstraat Gunnar^*; Telenczuk Bartosz; Burghoff Martin; Fedele Tommaso; Scheer Hans J; Curio Gabriel

来源：Clinical Neurophysiology, 2012, 123(10): 2064-2073.

DOI：10.1016/j.clinph.2012.03.013

• Evoked potentials
• High-frequency oscillations
• Single-trial analysis
• Phase-reset
• Added-activity
• Detectability analysis

Objective: Median nerve somatosensory evoked potentials (SEP) contain a brief oscillatory wavelet burst at about 600 Hz (r-burst) superimposed on the initial cortical component (N20). While invasive single-cell recordings suggested that this burst is generated by increased neuronal spiking activity in area 3b, recent non-invasive scalp recordings could not reveal concomitant single-trial added-activity, suggesting that the SEP burst might instead be generated by phase-reset of ongoing high-frequency EEG. Here, a statistical model and exemplary data are presented reconciling these seemingly contradictory results. %26lt;br%26gt;Methods: A statistical model defined the conditions required to detect added-activity in a set of single-trial SEP. Its predictions were tested by analyzing human single-trial scalp SEP recorded with custom-made low-noise amplifiers. %26lt;br%26gt;Results: The noise level in previous studies did not allow to detect single-trial added-activity in the period concomitant with the trial-averaged r-burst. In contrast, optimized low-noise recordings do reveal added-activity in a set of single-trials. %26lt;br%26gt;Conclusions: The experimental noise level is the decisive factor determining the detectability of added-activity in single-trials. A low-noise experiment provided direct evidence that the SEP r-burst is at least partly generated by added-activity matching earlier invasive single-cell recordings. %26lt;br%26gt;Significance: Quantitative criteria are provided for the feasibility of single-trial detectability of band-limited added-activity.

• 出版日期2012-10