Neuroscience
-
Seizure control is one of the ultimate aims of epileptology: here acute and prolonged effects of closed loop high-frequency stimulation of the somatosensory cortex on the expression of spontaneously occurring spike-wave discharges (SWD) were investigated in a genetic absence model. Effects of closed loop stimulation in the experimental group were compared with a yoked control group allowing to investigate the effect of timing related to SWD occurrence, while controlling for amount and intensity of stimulation. ⋯ SWD can be aborted by closed-loop stimulation of the somatosensory cortex, and at the same time the number of SWD was reduced. It can be regarded as a relatively safe neuromodulatory technique without habituation. The reduction of SWD during yoked stimulation session might be caused by 3 Hz afterdischarges. The reduction of SWD on the stimulation and post-stimulation sessions demonstrates the critical relevance of timing for the induction of longer lasting neuromodulatory effects: it suggests that absence seizures themselves might be involved in their reoccurrence.
-
Autism spectrum disorder (ASD) is a group of neurodevelopmental conditions characterized by difficulties in communication and social interactions, restricted, repetitive behaviors and sensory abnormalities. Notably, the vast majority of individuals with ASD experience some degree of auditory dysfunction and we have recently reported consistent hypoplasia and dysmorphology in auditory brainstem centers in individuals with ASD. Prenatal exposure to the antiepileptic drug valproic acid (VPA) is associated with an increased risk of ASD. ⋯ Additionally, we observed a larger dispersion of c-Fos-positive neurons and shifted tonotopic bands in VPA-exposed rats. We interpret these findings to suggest hyper-responsiveness to sounds and disrupted mapping of sound frequencies after prenatal VPA exposure. Based on these findings, we suggest that such abnormal patterns of activation may play a role in auditory processing deficits in ASD.
-
Review
The microbiota-gut-brain axis and its potential therapeutic role in autism spectrum disorder.
Autism spectrum disorder (ASD) is a series of neurodevelopmental disorders that are characterized by deficits in both social and cognitive functions. Although the exact etiology and pathology of ASD remain unclear, a disorder of the microbiota-gut-brain axis is emerging as a prominent factor in the generation of autistic behaviors. Clinical studies have shown that gastrointestinal symptoms and compositional changes in the gut microbiota frequently accompany cerebral disorders in patients with ASD. ⋯ The bidirectional microbiota-gut-brain axis acts mainly through neuroendocrine, neuroimmune, and autonomic nervous mechanisms. Application of modulators of the microbiota-gut-brain axis, such as probiotics, helminthes and certain special diets, may be a promising strategy for the treatment of ASD. This review mainly discusses the salient observations of the disruptions of the microbiota-gut-brain axis in the pathogenesis of ASD and reveals its potential therapeutic role in autistic deficits.
-
Comparative Study
Differences in the central-nervous processing of olfactory stimuli according to their hedonic and arousal characteristics.
Given the strong relationship between human olfaction and emotion, it is not surprising that numerous studies have investigated human response to hedonic and arousing qualities of odors. However, neuropsychological research addressed rather the pleasant-unpleasant, and not the arousing-calming dimension of emotional states generated by odorants. The purpose of the presented fMRI study was to evaluate the differences in cerebral processing of olfactory stimuli, focusing on both of these dimensions of emotional experiences, i.e., pleasantness and arousal. ⋯ This design allowed for a new insight to the emotional odor processing with imaging techniques. The pleasantness was related to activation in the cingulate gyrus, the insula, the hippocampal area, the amygdala, and the superior temporal gyrus, whereas arousal affected activation in the thalamic relay. The present study showed also that the emotional states generated by arousing qualities of odorants are an important determinant of magnitude of cerebral activation.