Biology subjects

Munda, S.

Publications and source records attributed to Munda, S..

3 recordsLinked to original sources

bioRxiv2026

Natural behavior elicits reliable neural signatures in high-level sensory and motor regions of freely moving monkeys

Natural behaviors are challenging to study because they involve large variations in sensory inputs and motor outputs across trials. Even the simple act of eating can involve seeing food from many angles and reaching for it differently each time. The prevailing view is that natural behaviors are more noisy compared to controlled tasks, and involve mixing of sensorimotor information. Alternatively, natural behaviors might elicit reliable neural signatures in high-level visual and motor regions which contain invariant representations, and involve correlated sensory and motor information that leads to apparent mixing. Here, we provide evidence for the latter possibility through wireless recordings in freely moving monkeys performing natural tasks as well as controlled screen tasks. During natural interactions with food, neural activity was decodable with striking fidelity, equivalent to that of food images. Key events during these interactions elicited distinct and reliable neural signatures that reflected the encoding priorities of each region. Visual and motor regions were clearly dissociated in screen tasks, but were dissociated only at specific events in the natural task. Neurons active while seeing food were reactivated during sleep. Taken together, our results reveal that reliable neural signatures in high-level sensory and motor regions form the neural substrates for natural behaviors.

neuroscience↗

bioRxiv2026

Dynamic tracking of social variables in simultaneous brain recordings of socially interacting monkeys

Primates are deeply social, but understanding the neural basis has been challenging since it has previously only been possible to record from single monkeys interacting with a social partner. Here, we performed simultaneous wireless neural recordings from two macaque monkeys interacting socially in a natural, unconstrained setting. Neural activity in each monkey encoded key social variables such as allogrooming state, partner identity and joint movements. Interestingly, neurons in the high-level visual cortex of each monkey continuously tracked a social favor signal, i.e. net duration of allogrooming given versus received, providing a neural basis for grooming reciprocity. In each monkey, neural activity was predicted better by his partners joints and neural activity, particularly while giving compared to receiving grooming. Thus, the receiver of grooming drove the social interaction, not the groomer. Taken together, our findings elucidate the rich and dynamic neural basis of primate social interactions in an ecologically valid setting.

neuroscience↗

bioRxiv2025

Orthographic training finetunes a neuronal letter position code in primate visual cortex

Reading is an acquired skill that enhances brain activity in human visual cortex and is thought to repurpose preexisting ventral visual circuitry for the fast parallel processing of letter strings. However, the neuronal code underlying position-invariant written word recognition remains elusive. Here, we examined this issue in a macaque monkey model before and after orthographic training. Based on prior simulations of reading acquisition in a convolutional neural network model of the ventral visual pathway, we hypothesized the existence of neurons sensitive to both specific letters and their ordinal position within the word, which should be enhanced by orthographic training. By wirelessly recorded neural activity from the inferior temporal (IT) cortex of macaque monkeys trained on orthographic tasks over five successive days, we indeed discovered IT neurons tuned to letters and sensitive to either ordinal or retinotopic positions. Ordinal units existed prior to training, but their responses were enhanced after training, matching with behavioral improvements in word recognition. These findings support the neuronal recycling hypothesis and demonstrate, at the single-cell level, how reading refines pre-existing neural circuits to facilitate fluent word recognition.

neuroscience↗