nerve impulse

Adrian researched nerve impulses from sense organs, amplifying variations in electrical potential and recording smaller potential changes than had been detectable previously. Later he recorded nerve impulses from single sensory endings and motor nerve fibres, measurements contributing to a better understanding of the physical basis of sensation…

…longer needed to transmit nerve impulses.

…the chemical means by which impulses are communicated or repressed by nerve cells (neurons).

…characteristic wave pattern of an impulse generated in a stimulated nerve fibre, once amplified, could then be seen on the screen and the components of the nerve’s response studied.

…study of the mechanics of nerve impulses.

…studying the barely detectable electrical impulses carried by isolated mammalian nerve fibres. By 1924 they had succeeded in adapting the oscillograph to physiological research, enabling them to visualize amplified nerve impulses on a fluorescent screen. Using this device, they demonstrated that different nerve fibres exist for the transmission of specific…

…to the chemical transmission of nerve impulses.

…a membrane and that a nerve impulse results from a change in the ability of the membrane to allow passage of potassium ions. When it was shown that nerves are made up of thousands of tiny fibres, which are processes that extend from cells located in the brain or spinal…

…sufficiently excited by an oncoming impulse to fire another impulse into the network of which it forms a part, or else the threshold will not be reached because the stimulus is absent or inadequate. In the latter case, the neuron fails to fire and remains quiescent. When several neurons are…

…by decreasing the transmission of nerve impulses by raising the resistance of the nervous system to their passage. Other hallucinogens increase nerve transmission, disrupting the orderly input of information and “jamming the circuits.” Many botanically derived hallucinogens seem to function this way—e.g., LSD and the ergot (a fungus) that grows…

nerve cell ending results in electrical changes, called receptor or generator potentials, at the outer surface of the cell, and this in turn induces the appearance of impulses (“spikes”) in the associated nerve fibre. Various laboratory devices are used to record and observe these electrical…

The nerve impulse is a wave of depolarization traveling along the axon of the motor nerve such that the resting membrane potential of about −70 millivolt is reversed, becoming briefly positive. At the nerve terminal, the nerve impulse causes voltage-gated calcium channels at the active zones…

The nerve impulse that ultimately results in muscle contraction appears as an action potential at the sarcolemma, the membrane that surrounds the muscle fibre. This electrical signal is communicated to the myofilaments inside the fibre in the following way. When the action potential reaches the opening…

…a neuron, propagation of an impulse by an ion wave can be extremely rapid, but the wave can pass along the length of only one cell’s membrane. To pass to the next cell at a synapse, where an axon meets a dendrite, a chemical transmitter is required. This molecule diffuses…

…convert (transduce) stimulus energy into nerve impulses. Thus, auditory cells and vestibular (balance) receptors in the ear and some receptors in the skin all respond similarly to mechanical displacement (distortion). Because many of the same principles apply to other animals, their receptors can be studied as models of the human…

The impulses are picked up by the electrode and transmitted to an instrument with which they can be amplified, observed, and recorded. In both behavioral and electrophysiological observations, the auditory sensitivity of an animal to sounds of different frequencies can be illustrated by a curve.

…electrical impulses generated in the nerve fibres of thermoreceptors. Early studies of thermoreception relied mainly on electrophysiological methods, which were introduced in 1936 for recording the electrical signals from single thermosensitive nerve fibres in the tongue of the cat. These methods were applied to obtain similar recordings from single thermoreceptors…

, in the optic nerve) evoked by simple stimulation. This initial activity appears to be integrated subjectively into a cognitive unit that embraces the rapidly ensuing perceptual processes as well. The optimum range of 0.6 to 0.8 second noted earlier seems to represent the typical duration of this integrating…

…to have faster conducting individual nerve cells; in order to compete successfully, the invertebrates seem to have evolved giant nerves (bundle of individual cell fibres), for the broader a nerve is, the faster it conducts. Among such lower animals, perhaps one-third or more of the nerve cord running the length…

…the electrical nature of the nerve impulse, first suggested by the Italian physician and physicist Luigi Galvani’s experiments in the 1770s and ’80s with frogs and later directly measured by the German physiologist Emil Du Bois-Reymond in 1848–49 using a galvanometer, showed that nerves are not canals by which animal…

…that influence the transmission of nerve impulses. It has long been established that chemical changes are part of the process of neural transmission; and it is widely agreed that, in some way, biochemical activities also are responsible for all forms of learning, including transfer of training.