Biology subjects

Pidde, A.

Publications and source records attributed to Pidde, A..

3 recordsLinked to original sources

bioRxiv2026

Neural sensing of surface traction modulates proprioceptive activity and locomotion in Caenorhabditis elegans

Locomotion -- whether walking, running, or crawling -- depends on the precise coordination of forces between the body and its surroundings. Two critical factors in this process are the force that resists the relative motion between two bodies, and mechanosensation, the bodys ability to sense and respond to mechanical forces. Together, they allow organisms to move efficiently, adapt to varying environments, and maintain balance. Here we show that the gentle touch receptor neurons (TRNs) in the Caenorhabditis elegans body wall are sensitive to dynamic surface traction. Using a combination of calcium recordings and traction force microscopy in freely moving animals, microfluidics, and whole connectome computer simulations, we show that MEC-4 DEG/ENaC ion channel activity depends on the crawling velocity and friction force. Mutations disrupting MEC-4 activity and body wall mechanoreceptor function produce lethargic worms with impaired proprioceptive regulation, suggesting functional coupling between surface mechanoreceptors and proprioceptors. Our data reveal a new role for classical touch receptors in locomotion and critically define the mechanical modality sensed by skin mechanosensors.

neuroscience↗

bioRxiv2021

Mechanical Stretch Inhibition SensitizesProprioceptors to Compressive Stresses

A repetitive gait cycle is an archetypical component within the behavioural repertoire of many if not all animals including humans. It originates from mechanical feedback within proprioceptors to adjust the motorprogram during locomotion and thus leads to a periodic orbit in a low dimensional space. Here, we investigate the mechanics, molecules and neurons responsible for proprioception in Caenorhabditis (C.) elegans to gain insight into how mechanosensation shapes the orbital trajectory to a well-defined limit cycle. We used genome editing, force spectroscopy and multiscale modeling and found that alternating tension and compression with the spectrin network of a single proprioceptor encodes body posture and informs TRP-4/NOMPC and TWK-16/TREK2 homologs of mechanosensitive ion channels during locomotion. In contrast to a widely accepted model of proprioceptive stretch reception, we found that proprioceptors activated under compressive stresses in vivo and in vitro, and speculate that this property is conserved across function and species.

neuroscience↗

bioRxiv2017

Sub-threshold resonance organizes activity and optimizes learning in neural networks.

Network oscillations across and within brain areas are critical for learning and performance in memory tasks. While a large amount of work has focused on the generation of neural oscillations, their effects on neuronal populations spiking activity and information encoding is less known. Here, we use computational modeling and in vivo recording to demonstrate that a shift in sub-threshold resonance can interact with oscillating input to ensure that networks of neurons properly encode new information represented in external inputs to the weights of recurrent synaptic connections. Using a neuronal network model, we find that due to an input-current dependent shift in their resonance response, individual neurons in a network will arrange their phases of firing to represent varying strengths of their respective inputs. As networks encode information, neurons fire more synchronously, and this effect limits the extent to which further \"learning\" (in the form of changes in synaptic strength) can occur. We also demonstrate that sequential patterns of neuronal firing can be accurately stored in the network; these sequences are later reproduced without external input (in the context of sub-threshold oscillations) in both the forward and reverse directions (as has been observed following learning in vivo). To test whether a similar mechanism could act in vivo, we show that periodic stimulation of hippocampal neurons coordinates network activity and functional connectivity in a frequency-dependent manner. We conclude that sub-threshold resonance provides a plausible network-level mechanism to accurately encode and retrieve information without over-strengthening connections between neurons.

neuroscience↗