Shtiglitz, S. | Search bioRxiv

bioRxiv2026

Thalamo-insular basis for updating physiological needs

Physiological needs, such as thirst and hunger, produce powerful motivation for behaviors that are essential for survival. Yet, how the brain estimates these needs remains unknown. It is unclear whether the brain continuously monitors bodily signals to create real-time representations, or if existing internal representations are only updated when meaningful changes occur. To address this question, we manipulated thalamic internal sensory inputs to the interoceptive insular cortex. We found that inhibiting internal sensory inputs prevents the updating of insular cortex representations of thirst and hunger, thereby keeping its activity closer to its initial physiological need state. Consequently, cued feeding and drinking, as well as free consumption of food and water, persist beyond the current physiological need. We further show that insular cortex activity normally represents both predictions and sensory information. However, violating learned expectations evokes widespread need-specific prediction error signals. Our results thus reveal a thalamo-cortical basis for updating physiological needs in the brain.

neuroscience↗

bioRxiv2026

A cortical basis for perception of internal gut sensations

Interoception, the sensing of internal bodily signals, is essential for brain-body interactions and shapes emotion, cognition, and behavior1-5. Subconscious internal signals, including heartbeats or stomach fullness, can rise to conscious awareness, and this process can improve with practice, as seen in meditation, mindful eating, or toilet training in early infancy. Conversely, disrupted interoception is emerging as a common deficit in diverse psychiatric disorders1,3,6,7. Nevertheless, we still lack a fundamental understanding of the neurobiological basis of perception and conscious reporting of internal sensations. Here, we combine genetic and ultra-sensitive optogenetic tools in mice to establish a quantitative framework for studying internal perception. We developed a behavioral task in which mice report detecting non-invasive optogenetic activation of gut mechanosensory neurons, establishing "interoceptive psychophysics". We combine this approach with cellular-resolution imaging and manipulations to reveal the neuronal basis for perception of these internal gut sensations in the interoceptive insular cortex. While representations of sensory stimuli were consistently observed in insular cortex across different tasks, we found that perceptual reports were only encoded during a more difficult psychophysics task, but not during basic detection. Accordingly, manipulation of insular cortex activity affected behavioral reports only in the psychophysics task. These findings reveal a neural basis for perception of internal gut sensations and provide a blueprint for future quantitative exploration of other interoceptive modalities.

neuroscience↗