Researchers discover new connectivity rules in the brain’s visual network

Researchers from Neuro-Electronics Research Flanders (NERF), led by Professor Vincent Bonin, have published two studies revealing how visual information is processed and distributed in the brain. Studies reveal the complexity and flexibility of visual information processing in the brain.

The visual cortex, a key region for interpreting and processing visual information, plays a crucial role in shaping what we see. Vincent Bonin, professor at KU Leuven and group leader at NERF, studies the neural circuits that process sensory information.

“We often think of visual processing in the cortex as a simple, linear process,” explains Professor Bonin, “but our research shows that the cortex functions as a complex network with finely tuned connections between regions, supporting specialized visual functions in distinct brain areas.

Targeting vs. Broadcasting

In a first study published in Current biologypostdoctoral researcher Xu Han revealed how visual information is transmitted across different interconnected regions of the brain.

Using advanced imaging and circuit tracing techniques in mice, Han and Bonin identified pathways that selectively channel visual signals to targeted areas or broadcast information broadly across multiple regions.

“For example, neurons in the pulvinar and some layers of the cortex are finely tuned to their targets, suggesting a role in constructing detailed visual representations,” says Han.

“In contrast, deeper neurons appear to ignore target specificity, broadcasting similar visual information across areas, perhaps to coordinate broader brain activity.” These results challenge the long-held belief that visual information flows in a simple, step-by-step manner, instead revealing a highly dynamic and adaptable network.

Calm or excited

In the second study, published in Cell ReportsBonin and Dr. Karolina Socha (now at the University of California, Los Angeles) explored how the brain’s thalamus, a key relay station for visual signals, adjusts information processing based on behavioral states.

The researchers found that during quiet wakefulness, neurons in the thalamus amplify signals for back-to-forward movement, a transformation absent under anesthesia or during heightened arousal. By imaging the activity of neurons in awake mice, they discovered that this modulation is linked to changes in the size of the pupil, a marker of wakefulness.

“Larger pupils coincided with stronger responses to back-to-forward movements, suggesting that the thalamus integrates sensory input with behavioral context to prioritize certain visual stimuli,” says Bonin. “These results demonstrate how the thalamus integrates behavioral context to dynamically shape visual representations, thereby changing how movement is processed and prioritized.”

Together, the two studies represent a major step toward creating a detailed “functional anatomical map” of the brain’s visual system. “Understanding these pathways and mechanisms allows us to predict and manipulate how perception works,” says Bonin.

These results advance neuroscience research and are promising for the development of targeted interventions aimed at modulating brain functions.