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.

Understanding And Treating Autism

Understanding And Treating Autism

Whenever a doctor informs the parents that their child is suffering with Autism, the first & foremost question that is thrown over him is - How did it happen? How did my child get this disease? Well, there is no definite answer to what are the exact causes of Autism.

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