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Histamine has two basic centres, namely the aliphatic amino group and whichever nitrogen atom of the imidazole ring does not already have a proton. Under physiological conditions, the aliphatic amino group (having a pK a around 9.4) will be protonated, whereas the second nitrogen of the imidazole ring (pK a ≈ 5.8) will not be protonated. [11]
Hearing range describes the frequency range that can be heard by humans or other animals, though it can also refer to the range of levels. The human range is commonly given as 20 to 20,000 Hz, [ 3 ] [ 4 ] [ note 1 ] although there is considerable variation between individuals, especially at high frequencies, and a gradual loss of sensitivity to ...
Neuronal activity at the microscopic level has a stochastic character, with atomic collisions and agitation, that may be termed "noise." [4] While it isn't clear on what theoretical basis neuronal responses involved in perceptual processes can be segregated into a "neuronal noise" versus a "signal" component, and how such a proposed dichotomy could be corroborated empirically, a number of ...
In order to affect brain (neuronal) activity, sensory stimulation must be within the frequency range of roughly 0.5 to 25 hertz (Hz) [citation needed]. Touch, photic and auditory stimulation are capable of affecting brain wave activity. A large area of skin must be stimulated to affect brainwaves, which leaves both auditory and photic ...
The fundamental function of this part of the ear is to gather sound energy and deliver it to the eardrum. Resonances of the external ear selectively boost sound pressure with frequency in the range 2–5 kHz. [2] The pinna as a result of its asymmetrical structure is able to provide further cues about the elevation from which the sound originated.
[1] [2] Histamine is a neurotransmitter involved in various physiological processes. There are four main types of histamine receptors: H1, H2, H3, and H4. H1 receptors are linked to allergic responses, H2 to gastric acid regulation, H3 to neurotransmitter release modulation, and H4 to immune system function. There are four known histamine ...
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 ...
The brain utilizes subtle differences in loudness, tone and timing between the two ears to allow us to localize sound sources. [10] Localization can be described in terms of three-dimensional position: the azimuth or horizontal angle, the zenith or vertical angle, and the distance (for static sounds) or velocity (for moving sounds). [ 11 ]