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Brain Mechanisms of Persistent Pain States
Published in Robert M. Bennett, The Clinical Neurobiology of Fibromyalgia and Myofascial Pain, 2020
Donald D. Price, G. Nicholas Verne
The use of the radioactive 2-deoxyglucose [2-DG] tracer in the CCI model has provided maps of increased neural activity that occur in the spinal cord and brain of the rat CCI model (13,14). Such maps are instructive in illustrating the specific regions of the central nervous system that have increased neural activity as a result of this persistent pain condition. These regions include those previously implicated in pain processing in general, as well as those not predicted by previous knowledge of pain mechanisms. The central sensitizing mechanisms discussed earlier result not only in increased responses of dorsal horn neurons to nociceptive and non-nociceptive inputs, but also to expansion of their receptive fields so that they extend across multiple dermatomes (15). The expanded receptive fields and enhanced responsiveness of dorsal horn nociceptive neurons result in a greater number of neurons responding to a nociceptive or non-nociceptive stimulus than they would otherwise. The increased activation of more dorsal horn neurons along the rostral-caudal axis of the spinal cord may be associated with enhanced pain and spatial radiation of the painful sensation.
Neurobiology of the Gustatory Zone of Nucleus Tractus Solitarius
Published in I. Robin A. Barraco, Nucleus of the Solitary Tract, 2019
While some investigators studying different regions of the CNS have reported that neurons with defined intrinsic membrane properties have distinct morphologies,35-38 others have not found correlations.39-41 Moreover, investigators attempting to correlate receptive field properties with neuron morphology have also failed to find correlations between structure and function.42 Failure to find correlations between intrinsic membrane properties and morphology does not necessarily mean that correlations do not exist. As Connor and Gutnick39 point out, even though neurons belong to the same morphological class differences may exist in soma size, number of dendritic branches, and patterns of axonal connections. Furthermore, these morphological differences in the same general class of neuron correlate with different intrinsic membrane properties and, when other factors such as neuronal pharmacology and connections are factored in, it is not surprising that neurons with similar morphology have different functional properties. Thus, a neuron’s role in the rNTS may be determined by several interacting factors so that, until a detailed understanding of the interconnections and pharmacology of these neurons is known, attempting to correlate structure and function is premature.
Non-Synonyms (Similar-Sounding)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Receptive fields (C&S, p. 543): A concept in cellular sensory physiology. The “receptive field” of a receptor or neuron is defined broadly as the range of stimuli to which the receptor or cell responds. Though the concept connotes the spatial range of the stimuli, other variables, such as auditory frequency, can be used to define receptive fields. Visual receptors and neurons clearly have “receptive fields,” but these are not referred to as “visual fields” (see below), “visual areas” (see above), or “eye fields” (see above).
Effect of vitamin D deficiency on spatial contrast sensitivity function
Published in Clinical and Experimental Optometry, 2022
Other important retinal cells that assist in the regulation of visual processing are horizontal cells and amacrine cells. The lateral coupling of these cells plays an important role in visual acuity and contrast sensitivity formation by adjusting the receptive field sizes.20,21 The centre-surround organisation of receptive fields, in which the object (centre) and its background (surround) have different illumination signals is primarily regulated by bipolar cells.22 The large receptive fields of horizontal cells have been considered to form the surround of bipolar cells,23 and as a result of a light-induced increase in dopamine, uncoupling of horizontal cells leads to a reduced surround receptive field that is related with increased local contrast detection.24
A preliminary study of atypical cortical change ability of dynamic whole-brain functional connectivity in autism spectrum disorder
Published in International Journal of Neuroscience, 2022
The occipital lobe is the visual processing center. The primary visual cortex (V1) contains a low-level description of the local orientation, spatial-frequency and color properties within small receptive fields. The V1 projects to the occipital areas of the ventral stream (visual area V2 and visual area V4), and the occipital areas of the dorsal stream—visual area V3, visual area MT (V5), and the dorsomedial area (DM).The ASD participants may have the expected prefrontal and occipital asymmetry by GMV analysis [83]. Meanwhile, there was reported that male homozygotes for the risk alleles characterized by genotype at rs7794745 (susceptibility gene for ASD) showed greater reductions in gray matter of the right frontal pole and in fractional anisotropy values of the right rostral fronto-occipital fasciculus [84].
Dose and time response study to develop retinal degenerative model of zebrafish with lead acetate
Published in Cutaneous and Ocular Toxicology, 2022
Visual behaviour analysis showed change in sensitivity to the contrasts and alteration in visual response which helped to determine the impact of toxicant. Visual response to black bar significantly degraded in increasing dose dependant manner. Escape response was decreased when fish was treated with 0.08 mg/L of PbAc. Highest concentration of lead acetate i.e. 0.1 mg/L augmented the erratic behaviour in zebrafish. Thus 0.08 mg/L concentration showed disruption in the visual efficacy. Similar behavioural deficits such as visual startle response were observed in zebrafish larvae when exposed to 30 nM lead11. In this study, a shift in the sensory response was observed that indicated that the functionality of either the ON or OFF centre receptive fields has been compromised. It has also been observed that treatment with 0.06 mg/L of lead cause clear phenotypic and behavioural effects in zebrafish28.