Kyle K Morgan1, Evan Hathaway1, Megan Carson1, Mariano Fernandez-Corazza2, Roma Shusterman1, Phan Luu3, Don M Tucker4. 1. Brain Electrophysiology Laboratory Company, Eugene, OR, 97403, USA. 2. Brain Electrophysiology Laboratory Company, Eugene, OR, 97403, USA; LEICI Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales, Universidad Nacional de La Plata, CONICET, Argentina. 3. Brain Electrophysiology Laboratory Company, Eugene, OR, 97403, USA; University of Oregon, Eugene, OR, 97403, USA. 4. Brain Electrophysiology Laboratory Company, Eugene, OR, 97403, USA; University of Oregon, Eugene, OR, 97403, USA. Electronic address: don.tucker@bel.company.
Abstract
BACKGROUND: Initial observations with the human electroencephalogram (EEG) have interpreted slow oscillations (SOs) of the EEG during deep sleep (N3) as reflecting widespread surface-negative traveling waves that originate in frontal regions and propagate across the neocortex. However, mapping SOs with a high-density array shows the simultaneous appearance of posterior positive voltage fields in the EEG at the time of the frontal-negative fields, with the typical inversion point (apparent source) around the temporal lobe. METHODS: Overnight 256-channel EEG recordings were gathered from 10 healthy young adults. Individual head conductivity models were created using each participant's own structural MRI. Source localization of SOs during N3 was then performed. RESULTS: Electrical source localization models confirmed that these large waves were created by focal discharges within the ventral limbic cortex, including medial temporal and caudal orbitofrontal cortex. CONCLUSIONS: Although the functional neurophysiology of deep sleep involves interactions between limbic and neocortical networks, the large EEG deflections of deep sleep are not created by distributed traveling waves in lateral neocortex but instead by relatively focal limbic discharges.
BACKGROUND: Initial observations with the human electroencephalogram (EEG) have interpreted slow oscillations (SOs) of the EEG during deep sleep (N3) as reflecting widespread surface-negative traveling waves that originate in frontal regions and propagate across the neocortex. However, mapping SOs with a high-density array shows the simultaneous appearance of posterior positive voltage fields in the EEG at the time of the frontal-negative fields, with the typical inversion point (apparent source) around the temporal lobe. METHODS: Overnight 256-channel EEG recordings were gathered from 10 healthy young adults. Individual head conductivity models were created using each participant's own structural MRI. Source localization of SOs during N3 was then performed. RESULTS: Electrical source localization models confirmed that these large waves were created by focal discharges within the ventral limbic cortex, including medial temporal and caudal orbitofrontal cortex. CONCLUSIONS: Although the functional neurophysiology of deep sleep involves interactions between limbic and neocortical networks, the large EEG deflections of deep sleep are not created by distributed traveling waves in lateral neocortex but instead by relatively focal limbic discharges.
Authors: Karl Friston; Lee Harrison; Jean Daunizeau; Stefan Kiebel; Christophe Phillips; Nelson Trujillo-Barreto; Richard Henson; Guillaume Flandin; Jérémie Mattout Journal: Neuroimage Date: 2007-10-10 Impact factor: 6.556