David T. J. Liley

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A set of nonlinear continuum field equations is presented which describes the dynamics of neural activity in cortex. These take into account the most pertinent anatomical and physiological features found in cortex with all parameter values obtainable from independent experiment. Derivation of a white noise fluctuation spectrum from a linearized set of(More)
Changes to the electroencephalogram (EEG) observed during general anesthesia are modeled with a physiological mean field theory of electrocortical activity. To this end a parametrization of the postsynaptic impulse response is introduced which takes into account pharmacological effects of anesthetic agents on neuronal ligand-gated ionic channels. Parameter(More)
A central difficulty in modeling epileptogenesis using biologically plausible computational and mathematical models is not the production of activity characteristic of a seizure, but rather producing it in response to specific and quantifiable physiologic change or pathologic abnormality. This is particularly problematic when it is considered that the(More)
Neural field models of firing rate activity typically take the form of integral equations with space-dependent axonal delays. Under natural assumptions on the synaptic connectivity we show how one can derive an equivalent partial differential equation (PDE) model that properly treats the axonal delay terms of the integral formulation. Our analysis avoids(More)
A set of non-linear continuum field equations are presented which describe the macroscopic dynamics of neural activity in cortex. Numerical solutions of the coupled non-linear system of partial differential equations show properties analogous to cortical evoked potentials, oscillations at the frequency of the mammalian alpha rhythm and non-stationary(More)
We report simulations of the electrocorticogram of the cat and human, based on estimates of fibre range, fibre density, axonal and dendritic delays, and cortical synaptic density. The long-range cortical connections of real cortex were simplified to couplings of symmetric density, decreasing in density with range, on a closed (toroidal) surface.(More)
BACKGROUND Nitrous oxide (N(2)O) is one of the oldest analgesics/adjuvant agents still in use today; however, its effects on the human electroencephalogram (EEG) remain unclear. It has been proposed that N(2)O may enhance higher-frequency EEG activity (often indicative of alert states and cognition) duration sedation. This possibly paradoxical effect has(More)
Ketamine and propofol are two well-known, powerful anesthetic agents, yet at first sight this appears to be their only commonality. Ketamine is a dissociative anesthetic agent, whose main mechanism of action is considered to be N-methyl-d-aspartate (NMDA) antagonism; whereas propofol is a general anesthetic agent, which is assumed to primarily potentiate(More)
The burst-suppression pattern is well recognized as a distinct feature of the mammalian electroencephalogram (EEG) waveform. Consisting of alternating periods of high amplitude oscillatory and isoelectric activity, it can be induced in health by deep anesthesia as well as being evoked by a range of pathophysiological processes that include coma and anoxia.(More)