Event:

The capability to detect spikes defines a striking contrast between invasive (microscopic) and non-invasive (macroscopic) recordings. While the latter are dominated by summed postsynaptic potentials reflecting neuronal input, invasive sharp micro-electrodes can provide direct access also to the very output of neuronal computation – spikes. This micro/macro gap, however, has been narrowed gradually over the last years by combining special physiological paradigms with neuro-technological advances. The lecture will (i) address the basic neurophysics of near-field and far-field signals distinguishing slow from fast neuronal activities, (ii) elaborate on high-frequency (~600 Hz) somatosensory evoked responses in epidural and scalp EEG reflecting repetitive spiking of area 3b single-units, and (iii) report on recent neuro-technological progress providing a unique opportunity for the non-invasive detection of even single-trial (i.e., unaveraged) high-frequency EEG bursts, opening a perspective to study (patho-)physiological variability in the generation of human cortical population spikes.