Single Unit Electrophysiological Responses

Much of our understanding of neural function stems from electrophysiological studies of single neurons. By placing microelectrodes made of wire or drawn glass capillary tubing into or next to neurons, it is possible to record signals generated by one or a few cells. Because of the stereotypical shape and amplitude of action potentials (spikes) recorded from a given cell in a given recording configuration, it is often possible to sort a complex record into contributions from a small set of cells. The intensity of neuronal activation is typically assessed on the basis of firing rate; in sensory systems, the intensity of a stimulus is often encoded logarithmically in the firing rate within the sensory nerve. The response properties of neurons are often defined in terms of the receptive field, the region of sensory parameter space (e.g., location on the retina or stimulus properties of an auditory or visual stimulus) that can influence the firing rate of a particular neuron. A growing body of evidence shows that the temporal pattern of firing may also encode information. For example, in measurements across an ensemble of auditory nerve fibers in response to a pure tone stimulus below 1 kHz or so, spikes tend to occur in phase with the stimulus, i.e., a temporal code captures the temporal structure of the stimulus. In the visual system, phase-locked oscillatory activity in widely spaced cells appears to encode higher order features, such as coherent motion, beyond the spatial limits of the conventional receptive field.

Sleeping Sanctuary

Sleeping Sanctuary

Salvation For The Sleep Deprived The Ultimate Guide To Sleeping, Napping, Resting And  Restoring Your Energy. Of the many things that we do just instinctively and do not give much  of a thought to, sleep is probably the most prominent one. Most of us sleep only because we have to. We sleep because we cannot stay awake all 24 hours in the day.

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