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A number of nuclei in the brainstem have diffuse projections throughout the brain influencing concentration levels of neurotransmitters such as norepinephrine, acetylcholine and serotonin. These neurotransmitter systems affect the physiological state, e.g., wakefulness or arousal , and have a pronounced effect on amplitude of different brain ...
A labeled diagram of an action potential.As seen above, repolarization takes place just after the peak of the action potential, when K + ions rush out of the cell.. In neuroscience, repolarization refers to the change in membrane potential that returns it to a negative value just after the depolarization phase of an action potential which has changed the membrane potential to a positive value.
Beta waves were discovered and named by the German psychiatrist Hans Berger, who invented electroencephalography (EEG) in 1924, as a method of recording electrical brain activity from the human scalp. Berger termed the larger amplitude, slower frequency waves that appeared over the posterior scalp when the subject's eye were closed alpha waves ...
Brainwave entrainment is a colloquialism for 'neural entrainment', [25] which is a term used to denote the way in which the aggregate frequency of oscillations produced by the synchronous electrical activity in ensembles of cortical neurons can adjust to synchronize with the periodic vibration of external stimuli, such as a sustained acoustic ...
The frequency of a sound is defined as the number of repetitions of its waveform per second, and is measured in hertz; frequency is inversely proportional to wavelength (in a medium of uniform propagation velocity, such as sound in air). The wavelength of a sound is the distance between any two consecutive matching points on the waveform.
[7] [10] [11] [note 1] The frequency at which a neuron elicits action potentials is often referred to as a firing rate or neural firing rate. Currents produced by the opening of voltage-gated channels in the course of an action potential are typically significantly larger than the initial stimulating current.
Volley Theory of Hearing demonstrated by four neurons firing at a phase-locked frequency to the sound stimulus. The total response corresponds with the stimulus. Volley theory states that groups of neurons of the auditory system respond to a sound by firing action potentials slightly out of phase with one another so that when combined, a ...
In the last two decades, significant advances occurred in our understanding of the neural processing of sounds in primates. Initially by recording of neural activity in the auditory cortices of monkeys [18] [19] and later elaborated via histological staining [20] [21] [22] and fMRI scanning studies, [23] 3 auditory fields were identified in the primary auditory cortex, and 9 associative ...