New Insights into How the Brain Modulates Sensory Perception in Real-Time

Researchers from the University of Geneva have uncovered a novel mechanism by which the brain dynamically modulates sensory signals, specifically within the somatosensory cortex. The cerebral cortex processes sensory information through intricate neural networks, with the thalamus acting as a critical relay station. This new study reveals that a specific feedback loop from the thalamus to pyramidal neurons in the cortex can alter the excitability of these neurons, thereby influencing perception. Utilizing advanced techniques such as imaging, optogenetics, and electrophysiology, the team discovered that glutamate, a common neurotransmitter, binds to an unconventional receptor on pyramidal neurons. Instead of directly exciting the cell, this interaction primes the neuron, making it more responsive to incoming stimuli.

This pathway represents a previously unknown form of modulation, shifting the understanding from traditional excitatory-inhibitory balance to an active priming process that can affect how sensory inputs are perceived. Such a mechanism could clarify why perceptions of touch or other sensations can vary significantly, depending on focus, attention, or states like sleep. It also has potential implications for understanding neurodevelopmental and mental health disorders, such as autism, where sensory processing often deviates from the norm.

The findings suggest that the thalamus does more than just relay sensory signals; it can selectively amplify or dampen sensory awareness by modulating cortical neuron responsiveness. This dynamic interaction, therefore, plays a crucial role in shaping our perceptual experience in real time, enhancing our understanding of sensory perception and its variations in different mental states and conditions.

Source: https://medicalxpress.com/news/2025-07-brain-real-mechanism-modulating-sensory.html