Different Mode of Afferents Determines the Frequency Range of High Frequency Activities in the Human Brain: Direct Electrocorticographic Comparison between Peripheral Nerve and Direct Cortical Stimulation

• Published in: PloS one 2015-06, Vol.10 (6), p.e0130461-e0130461
• Main Authors: Kobayashi, Katsuya, Matsumoto, Riki, Matsuhashi, Masao, Usami, Kiyohide, Shimotake, Akihiro, Kunieda, Takeharu, Kikuchi, Takayuki, Mikuni, Nobuhiro, Miyamoto, Susumu, Fukuyama, Hidenao, Takahashi, Ryosuke, Ikeda, Akio
• Format: Article
• Language: English
• Subjects: Adult; Afferent Pathways - physiology; Afferent Pathways - physiopathology; Analysis; Animal behavior; Auditory evoked potentials; Brain; Brain - physiology; Brain - physiopathology; Brain cancer; Brain Mapping; Brain Neoplasms - physiopathology; Brain research; Broadband; Cerebral Cortex - physiology; Cerebral Cortex - physiopathology; Cortex (somatosensory); Electric Stimulation; Electrical stimuli; Electrocorticography; Electrodes, Implanted; Epilepsy; Epilepsy - physiopathology; Evoked potentials; Evoked Potentials, Somatosensory; Female; High frequencies; Humans; Implantation; Information processing; Magnetic Resonance Imaging; Male; Median nerve; Median Nerve - physiology; Median Nerve - physiopathology; Medicine; Neurology; Neurosurgery; Patients; Peripheral Nerves - physiology; Peripheral Nerves - physiopathology; Physiological effects; Physiology; Propagation modes; Somatosensory evoked potentials; Stimulation; University graduates; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0130461

Physiological high frequency activities (HFA) are related to various brain functions. Factors, however, regulating its frequency have not been well elucidated in humans. To validate the hypothesis that different propagation modes (thalamo-cortical vs. cortico-coritcal projections), or different terminal layers (layer IV vs. layer II/III) affect its frequency, we, in the primary somatosensory cortex (SI), compared HFAs induced by median nerve stimulation with those induced by electrical stimulation of the cortex connecting to SI. We employed 6 patients who underwent chronic subdural electrode implantation for presurgical evaluation. We evaluated the HFA power values in reference to the baseline overriding N20 (earliest cortical response) and N80 (late response) of somatosensory evoked potentials (HFA(SEP(N20)) and HFA(SEP(N80))) and compared those overriding N1 and N2 (first and second responses) of cortico-cortical evoked potentials (HFA(CCEP(N1)) and HFA(CCEP(N2))). HFA(SEP(N20)) showed the power peak in the frequency above 200 Hz, while HFA(CCEP(N1)) had its power peak in the frequency below 200 Hz. Different propagation modes and/or different terminal layers seemed to determine HFA frequency. Since HFA(CCEP(N1)) and HFA induced during various brain functions share a similar broadband profile of the power spectrum, cortico-coritcal horizontal propagation seems to represent common mode of neural transmission for processing these functions.