| synaptic vesicles | Membrane-bound compartments which contain transmitter molecules. Synaptic vesicles are concentrated at presynaptic terminals. They actively sequester transmitter molecules from the cytoplasm. In at least some synapses, transmitter release occurs by fusion of these vesicles with the presynaptic membrane, followed by exocytosis of their contents. (12 Dec 1998) |
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| event-related potentials, p300 | A late-appearing component of the event-related potential. P stands for positive voltage potential and 300 represents 300 millisecond poststimulus. Its amplitude increases with unpredictable, unlikely, or highly significant stimuli and thereby constitutes an index of mental activity. (12 Dec 1998) |
| evoked potentials | <physiology> The use of electrodes to measure the electrical activity of nerves. May be used as a guide during surgical removal of tumours growing around important nerves. (16 Dec 1997) |
| evoked potentials, auditory | The electric response evoked in the cerebral cortex by acoustic stimulation or stimulation of the auditory pathways. (12 Dec 1998) |
| evoked potentials, auditory, brainstem | Electrical waves in the cerebral cortex generated by brainstem structures in response to auditory click stimuli. These are found to be abnormal in many patients with cerebellopontine angle lesions, multiple sclerosis, or other demyelinating diseases. (12 Dec 1998) |
| evoked potentials, motor | The electrical response evoked in a muscle or motor nerve by electrical or magnetic stimulation. Common methods of stimulation are by transcranial electrical and transcranial magnetic stimulation. It is often used for monitoring during neurosurgery. (12 Dec 1998) |
| evoked potentials, somatosensory | The electric response evoked in the cerebral cortex by stimulation of afferent pathways from peripheral nerves to cerebrum. (12 Dec 1998) |
| evoked potentials, visual | The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways. (12 Dec 1998) |
| excitatory postsynaptic potentials | The change in potential produced in the membrane of the next neuron when an impulse which has an excitatory influence arrives at the synapse; it is a local change in the direction of depolarisation; summation of these potentials can lead to discharge of an impulse by the neuron. (12 Dec 1998) |