Biology subjects

Schorscher-Petcu, A.

Publications and source records attributed to Schorscher-Petcu, A..

4 recordsLinked to original sources

bioRxiv2026

Direct optogenetic activation of inner hair cells improves the efficiency and fidelity of auditory encoding

Severe hearing impairment affects approximately 5% of the global population, with a prevalence projected to increase over the coming decades. Cochlear implant devices pose a neuroprosthetic treatment option to allow sound perception and speech comprehension. However, users are limited in the spectrum of auditory information they can regain because electrical stimulation of the auditory nerve generates a broad spread of current and limits the transmission of sound frequency information. Recently, optogenetic stimulation of the cochlear nerve has emerged as a promising alternative for hearing restoration. Because light can be precisely confined in space, optogenetic stimulation of the cochlea permits to activate auditory neurons within smaller tonotopic regions, thereby improving the encoding of sound frequencies compared to electrical stimulation. However, this approach is limited in terms of dynamic range and ability to follow rapidly varying inputs, thus preventing faithful transmission of auditory information. Here, we developed an alternative approach targeting directly sensory inner hair cells with optogenetics. We demonstrate that this approach decreases the amount of light energy necessary to evoke auditory responses. Direct stimulation of hair cells increases the dynamic range of intensities encoded by neurons in subcortical auditory areas and improves the temporal fidelity of optogenetic responses. Finally, a biophysical model of the auditory system suggests that preserving the synapses between inner hair cells and auditory neurons greatly improves the encoding performance of an optical cochlear implant. Together, our results suggest that targeting sensory inner hair cells is a promising approach for hearing restoration through an optical implant.

neuroscience↗

bioRxiv2026

A stimulus-state geometry in somatosensory cortex reorganizes during inflammatory pain

Adaptive behavior requires external input to be interpreted together with internal state and ongoing behavior. During pain, noxious somatosensory input evokes movement and arousal, and injury reshapes this relationship, yet how cortical activity organizes stimulus content with behavioral state remains unclear. In awake mice, we delivered hindpaw stimuli while tracking movement, arousal and facial expression, and studied primary somatosensory cortex (S1) using widefield and two-photon calcium imaging, single-action-potential activation of nociceptors, and S1 silencing. Here, we show that S1 neurons were broadly recruited by stimulus and state, whereas latent population dimensions carried mechanical stimulus content. Inflammatory injury caused a reorganization of S1 geometry, binding state and protective responses tighter together. Noxious heat drove S1 as strongly, but engaged mostly the state axis. S1 silencing reduced mechanical hypersensitivity, arousal, and facial expressions. S1 thus embeds mechanical input within a stimulus-state geometry, which is reorganized during inflammatory injury to support adaptation of a coordinated protective response.

neuroscience↗

bioRxiv2024

Somatosensory stimulation in moving mice

Somatosensation connects animals to their immediate environment, shaping critical behaviors essential for adaptation, learning, and survival. Probing the relationships between somatosensory inputs and behavior in mice presents substantial challenges, primarily due to the practical difficulties of delivering stimuli to the skin during movement. To address this problem, we have developed a system for precise cutaneous stimulation of mice as they walk and run through environments. The system employs real-time body part tracking and targeted optical stimuli, offering precision while preserving the naturalistic context of the behaviors studied to overcome the traditional trade-offs between precision and animal behavior. We demonstrate the system across nociceptive testing conducted in standard small chambers to behavior in large complex environments, such as mazes. We observed that cutaneous inputs evoke rapid responses, which modify behavior when stimuli are applied during motion. This system provides a means to explore the diverse and integrative nature of somatosensation, from reflexes to decision-making, in naturalistic settings.

neuroscience↗

bioRxiv2020

Scanned optogenetic control of mammalian somatosensory input to map input-specific behavioral outputs

Somatosensory stimuli guide and shape behavior, from immediate protective reflexes to longer-term learning and high-order processes related to pain and touch. However, somatosensory inputs are challenging to control in awake mammals due to the diversity and nature of contact stimuli. Application of cutaneous stimuli is currently limited to relatively imprecise methods as well as subjective behavioral measures. The strategy we present here overcomes these difficulties by achieving spatiotemporally precise, remote and dynamic optogenetic stimulation of skin by projecting light to a small defined area in freely-behaving mice. We mapped behavioral responses to specific nociceptive inputs and revealed a sparse code for stimulus intensity: using the first action potential, the number of activated nociceptors governs the timing and magnitude of rapid protective pain-related behavior. The strategy can be used to define specific behavioral repertoires, examine the timing and nature of reflexes, and dissect sensory, motor, cognitive and motivational processes guiding behavior.

neuroscience↗