Rapid recovery (20 ms) of human 600 Hz electroencephalographic wavelets after double stimulation of sensory nerves

• Published in: Neuroscience letters Vol. 286; no. 2; pp. 83 - 86
• Main Authors: Mackert, Bruno-Marcel, Weisenbach, Simon, Nolte, Guido, Curio, Gabriel
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 02.06.2000; Elsevier
• Subjects: Action Potentials - physiology; Biological and medical sciences; Double pulse stimulation; Electric Stimulation; Electroencephalography; Evoked Potentials, Somatosensory - physiology; Fundamental and applied biological sciences. Psychology; High frequency activity (600 Hz); Humans; Median nerve; Median Nerve - physiology; Neural Conduction - physiology; Neural Pathways - cytology; Neural Pathways - physiology; Neurons, Afferent - cytology; Neurons, Afferent - physiology; Peripheral Nerves - cytology; Peripheral Nerves - physiology; Primary somatosensory cortex; Radial nerve; Radial Nerve - physiology; Recovery behavior; Somatosensory Cortex - cytology; Somatosensory Cortex - physiology; Somatosensory evoked potentials; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Time Factors; Vertebrates: nervous system and sense organs; Somatosensory evoked potentials; Radial nerve; Median nerve; Primary somatosensory cortex; Recovery behavior; Double pulse stimulation; High frequency activity (600 Hz); Human; Somatosensory cortex; Stimulus; Electrophysiology; Sensory nerve; Electroencephalography; Somatosensory evoked potential
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(00)01086-7

Non-invasive scalp-recordings of human somatosensory evoked potentials (SEP) contain high-frequency (600 Hz) wavelet bursts, presumably generated by synchronized thalamocortical and/or intracortical population spikes. Here, double pulse stimulation (interval 20 ms) in 12 healthy subjects revealed significantly different burst recovery for mixed vs. sensory-only nerves. For median nerves the second burst response was decreased (11/11 subjects), possibly due to interfering reafferent (e.g. muscle spindle) input. In contrast, for sensory-only superficial radial nerves (containing less fibers than median nerves), weak bursts were detected in 6/11 subjects and were found fully recovered in 4/6 subjects. This potential for rapid burst recovery at 20 ms intervals renders contributions from neurons emitting bursts based on slowly recovering low-threshold calcium spikes unlikely and favors the generation of macroscopic SEP bursts by specialized cell populations, e.g. inhibitory interneurons and/or chattering cells the latter of which are capable to discharge rapidly repeating (50 Hz) high-frequency (600 Hz) bursts of fast sodium spikes.