Rhythmic oscillations shape cortical dynamics during active behavior, sleep, and general anesthesia. Cross-frequency phase-amplitude coupling is a prominent feature of cortical oscillations, but its role in organizing conscious and unconscious brain states is poorly understood. Using high-density EEG and intracranial electrocorticography during gradual induction of propofol general anesthesia i...

Philosophical (p-) zombies are constructs that possess all of the behavioral features and responses of a sentient human being, yet are not conscious. P-zombies are intimately linked to the hard problem of consciousness and have been invoked as arguments against physicalist approaches. But what if we were to invert the characteristics of p-zombies? Such an inverse (i-) zombie would possess all o...

Sir,—In commenting on our paper [1], Kardos, Rudas and Simon described their own use of the analysis of short-term heart rate variability to assess the effect of varying posture on cardiac autonomic control. Essentially they have confirmed that head-up tilt causes sympathetic activation (as evidenced by an increase in the low frequency variability) in comparison with supine and head-down positi...

The perturbational complexity index (PCI) measures the spatiotemporal dynamics of transcranial magnetic stimulation (TMS)-evoked electroencephalography (EEG) potentials (TEPs) [1]. High PCI values reflect joint presence integration and differentiation in thalamocortical networks conscious brains Low have been reported during natural non-rapid eye movement sleep, disorders consciousness, unrespo...

There are more than 140 references in the Quarterly Cumulative Index Medicus to papers on fusion of cervical vertebrae, including the KlippelFeil syndrome. A particularly useful review of the Klippel-Feil syndrome is that by Erskine (1946). He wrote that 'Essential features of the cervical deformity are synostosis of two or more cervical vertebrae and flattening and widening of the vertebrae bo...

OBJECTIVE Using evoked potentials, this study investigated effects of deep propofol sedation, and effects of recovery from unconsciousness, on the processing of auditory information with stimuli suited to elicit a physical MMN, and a (music-syntactic) ERAN. METHODS Levels of sedation were assessed using the Bispectral Index (BIS) and the Modified Observer's Assessment of Alertness and Sedatio...

Objective—An emerging paradigm for understanding how anesthetics induce altered arousal is relating receptor targeting in specific neural circuits to electroencephalogram (EEG) activity. We have previously found that enhanced gamma amino-butyric acid A (GABAA) inhibitory postsynaptic currents (IPSCs) manifest with large-amplitude slow (0.1–1 Hz) and frontally coherent alpha (8–12 Hz) oscillatio...