Glossary

cerebral cortex The outer layer of mammalian brains; in humans, approximately 2-5 mm thick with a surface area of approximately 1500-3000 cm2.

coherence A squared correlation coefficient measuring the phase consistency between two signals, expressed as a function of signal frequency.

conductivity (ohm-1 mm1) The property of a material (e.g., living tissue) that determines the ease with which charges move through the medium to produce current.

current density (mA/mm2) The flux of positive plus negative charge passing through a cross-sectional area.

electric potential (mV) The negative gradient of the local electric field vector.

electrocorticogram Electric potential recorded directly from the brain surface.

electroencephalography Electric potential generated by brain tissue, recorded from locations outside of nerve cells, either from scalp or from inside the cranium.

event related potential Brain electric potential produced by a combination of sensory stimulus and cognitive task.

evoked potential Brain electric potential produced as the direct result of a sensory stimulus.

Ohm'slawforavolumeconductor Vector current density equals the product of conductivity and vector electric field. Ohm's law simplifies to the usual scalar expression, voltage change = current x resistance, for current flow confined to one spatial direction, for example, in electric circuit wires.

The first recordings of electrical activity [electroencephalography (EEG)] from the human scalp were obtained in the mid-1920s. EEG provides functional, as opposed to structural, brain information and has important applications in medicine and cognitive science. The field of EEG encompasses evoked and event-related potentials and spontaneous EEG. This article focuses on spontaneous EEG recorded from human scalp.

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

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