Biology subjects

Becq, G.

Publications and source records attributed to Becq, G..

3 recordsLinked to original sources

bioRxiv2025

Choosing the best or avoiding the worst: complementary and opponent value signals in the human brain

Whether the brain encodes the subjective value of pleasant and unpleasant situations via a single integrated circuit or through distinct pathways remains unresolved. It is also unclear how neural value signals guide choices when the context involves choosing the most favorable option or avoiding the most unfavorable one. To address these questions, we recorded intracerebral activity from 27 participants as they first rated pleasant and unpleasant scenarios and then made binary choices across all combinations of item domain (pleasant/unpleasant) and choice frame (choose best/worst). Ventromedial prefrontal cortex (vmPFC) broadband gamma activity (BGA, 50-150 Hz) tracked the value of pleasant items during rating and pre-choice, correlating positively with the most pleasant item irrespective of choice frame. Similarly, anterior insula (aIns) BGA tracked the value of unpleasant items during rating and pre-choice, correlating negatively with the most unpleasant item irrespective of choice frame. The difference in relative value correlations between the vmPFC and aIns was larger for choices involving a conflict between item domain and choice frame, consistent with slower response times and choices less aligned with value differences in these trials. These findings reveal dissociable yet complementary neural systems for pleasant and unpleasant valuation and highlight how such signals may guide flexible decision-making across contexts.

neuroscience↗

bioRxiv2024

Early alterations of motor learning and corticostriatal network activity in a Huntington's disease mouse model

Huntingtons disease (HD) is a neurodegenerative disorder that presents motor, cognitive and psychiatric symptoms as it progresses. Prior to motor symptoms onset, alterations and dysfunctions in the corticostriatal projections have been described along with cognitive deficits, but the sequence of early defects of brain circuits is largely unknown. There is thus a crucial need to identify early alterations that precede symptoms and that could be used as potential early disease markers. Using an HD knock-In mouse model (HdhCAG140/+) that recapitulates the human genetic alterations and that show a late and progressive appearance of anatomical and behavior deficits, we identified early alterations in the motor learning abilities of young mice, long before any motor coordination defects. In parallel, ex vivo two-photon calcium recordings revealed that young HD mice have altered basal activity patterns in both dorsomedial and dorsolateral parts of the striatum. In addition, while wild-type mice display specific reorganization of the activity upon motor training, network alterations present in the basal state of non-trained mice are not affected by motor training of HD mice. Our results thus identify early behavioral deficits and network alterations that could serve as early markers of the disease.

neuroscience↗

bioRxiv2020

Neuron-gated silicon nanowire field effect transistors to follow single spike propagation within neuronal network

Silicon nanowire field effect transistors SiNW-FETs provide a local probe for sensing neuronal activity at the subcellular scale, thanks to their nanometer size and ultrahigh sensitivity. The combination with micro-patterning or microfluidic techniques to build model neurons networks above SiNW arrays could allow monitoring spike propagation and tailor specific stimulations, being useful to investigate network communications at multiple scales, such as plasticity or computing processes. This versatile device could be useful in many research areas, including diagnosis, prosthesis, and health security. Using top-down silicon nanowires-based array, we show here the ability to record electrical signals from matured neurons with top-down silicon nanowires, such as local field potential and unitary spike within ex-vivo preparations and hippocampal neurons grown on chip respectively. Furthermore, we demonstrate the ability to guide neurites above the sensors array during 3 weeks of cultures and follow propagation of spikes along cells. Silicon nanowire field effect transistors are obtained by top-down approach with CMOS compatible technology, showing the possibility to implement them at manufacturing level. These results confirm further the potentiality of the approach to follow spike propagation over large distances and at precise location along neuronal cells, by providing a multiscale addressing at the nano and mesoscales.

bioengineering↗