Search Results (3)

Emerging evidence links environmental exposures and circadian dysregulation to autism spectrum disorder (ASD), yet whether circadian phase modulates vulnerability to developmental toxicants remains unclear. Here, we investigated whether embryonic bisphenol A (BPA) exposure induces circadian phase-dependent ASD-related behavioral alterations via disruption of nr1d1 rhythmicity in zebrafish. In control larvae, nr1d1 exhibited significant circadian oscillation, whereas BPA exposure reduced expression levels and dampened oscillation amplitude. Two-way ANOVA revealed significant treatment × phase interactions in nr1d1 expression. Pharmacological activation of Nr1d1 partially restored rhythmic expression. Behavioral assessments conducted at defined circadian phases demonstrated a significant treatment × phase interaction in social preference. BPA-exposed larvae exhibited reduced social preference selectively at circadian time 15 (CT15), corresponding to the trough phase of nr1d1 expression, whereas no differences were observed at circadian time 3 (CT3). In contrast, tactile hyper-responsiveness showed a significant treatment effect but no phase interaction. BPA exposure also induced phase-dependent alterations in ASD-related genes, including α-nrxn2a and β-nrxn3a, with significant treatment × phase interactions. At the molecular level, BPA increased reactive oxygen species, impaired antioxidant defense, enhanced neuroinflammatory responses, and disrupted excitatory–inhibitory balance. Several of these endpoints exhibited phase-dependent modulation and were partially attenuated by Nr1d1 activation. These findings indicate that circadian phase modulates embryonic susceptibility to BPA-induced ASD-related behavioral and molecular alterations. Disruption of nr1d1 rhythmicity may contribute to time-of-day-specific neurodevelopmental vulnerability following environmental exposure. Full article

The purpose of the present study was to examine whether spatial or temporal prediction of the tactile stimulus contributes to tactile sensitivity. To investigate the effect of spatial prediction on tactile sensitivity, electrical stimuli were provided for the digit nerve in one of five fingers, and advanced notice of the stimulating finger was provided before the stimulus in some trials but not in others. There was no significant effect of spatial prediction on the intensity at the perceptual threshold of the digit nerve stimulus. This indicates that spatial prediction of the tactile stimulus does not influence tactile sensitivity. To examine the effect of temporal prediction, an auditory warning cue was provided 0, 1, or 10 s before the electrical stimulus to the digit nerve. The stimulus intensity at the perceptual threshold in the trials with the 1 s warning cue was lower than those with the 0 s warning cue. This indicates that temporal prediction enhances tactile sensitivity. The stimulus intensity at the perceptual threshold in the trials with the 1 s warning cue was lower than those with the 10 s warning cue. This means that the contribution of temporal prediction to the tactile sensitivity is greater as the warning cue is closer to the time of the stimulus. This finding may be explained by a defense mechanism activated when humans predict that a tactile stimulus is coming soon. Full article

Tactile defensiveness is a common feature in neurodevelopmental disorders (NDDs). Since the first studies, tactile defensiveness has been described as the result of an abnormal response to sensory stimulation. Moreover, it has been studied how the tactile system is closely linked to socio-communicative development and how the interoceptive sensory system supports both a discriminating touch and an affective touch. Therefore, several neurophysiological studies have been conducted to investigate the neurobiological basis of the development and functioning of the tactile system for a better understanding of the tactile defensiveness behavior and the social touch of NDDs. Given the lack of recent literature on tactile defensiveness, the current study provides a brief overview of the original contributions on this research topic in children with NDDs focusing attention on how this behavior has been considered over the years in the clinical setting. Full article