Chelly, J. | bioRxiv Science

bioRxiv2024

Ipsilateral stimulation shows somatotopy of thumb and shoulder auricular points on the left primary somatosensory cortex using high-density fNIRS

SignificanceAuriculotherapy is a technique based on stimulation applied to specific ear points. Its mechanism of active and clinical efficacy remain to be established. This study aims to assess the role that primary somatosensory cortex may play to validate auriculotherapy mechanisms. AimThis study examined whether tactile stimulation at specific auricular points is correlated with distinct cortical activation in the primary somatosensory cortex. ApproachSeventeen healthy adults participated in the study. Tactile stimuli were delivered to the thumb, shoulder, and skin master points on the ear using von Frey filaments. Functional near-infrared spectroscopy was used to measure and spatially map cortical responses. ResultsThis study revealed distinct hemodynamic activity patterns in response to ear point stimulation, consistent with the classic homunculus model of somatotopic organization. Ipsilateral stimulation showed specific cortical activations for the thumb and shoulder points, while contralateral stimulation showed less significant activity. Functional near-infrared spectroscopy effectively captured localized cortical responses to ear tactile stimuli, supporting the somatotopic mapping hypothesis. ConclusionThese findings enhance the understanding of sensory processing with auricular stimulation and supports the concepts of auricular cartography that underpins some schools of auriculotherapy practice. Future research should explore bilateral cortical mapping and the integration of other neuroimaging techniques.

neuroscience↗

bioRxiv2019

Highly clustered de novo frameshift variants in the neuronal splicing factor NOVA2 result in a specific abnormal C terminal part and cause a severe form of intellectual disability with autistic features.

The Neuro-Oncological Ventral Antigen 2 NOVA2 protein is a major factor regulating neuron specific alternative splicing, previously associated with an acquired neurologic condition, the paraneoplastic opsoclonus-myoclonus ataxia (POMA). We report here six individuals with de novo frameshift variants in the NOVA2 gene affected with a severe neurodevelopmental disorder characterized by intellectual disability (ID), motor and speech delay, autistic features, hypotonia, feeding difficulties, spasticity or ataxic gait and abnormal brain MRI. The six variants lead to the same reading frame, adding a common 133 aa long proline rich C-terminus part instead of the last KH RNA binding domain. We detected forty-one genes differentially spliced after NOVA2 inactivation in human neural cells. The mutant NOVA2 protein shows decreased ability to bind a target RNA, to regulate specific splicing events and to rescue the phenotype of altered retinotectal axonal pathfinding induced by loss of NOVA2 ortholog in zebrafish. Our results suggest a partial loss-of-function mechanism rather than a full heterozygous loss of function, although a specific contribution of the novel C terminal extension cannot be excluded on the basis of the genetic findings.

genetics↗