Rosa Lafer-Sousa

Keywords: Perception, Color Vision, Optogenetics, Causal Perturbation, fMRI, Functional Organization,Individual Differences, Bi-stability

Education
BA 2009, Neuroscience, Wellesley College
PhD 2019, Brain and Cognitive Sciences, Massachusetts Institute of Technology

Research
I am interested in understanding how the noisy sensory signals our eyes recover from the world are transformed into meaningful perceptual experiences, thoughts, and actions. This process is carried out, in large part, by a network of cortical areas beginning with early visual cortex and culminating in high-level visual cortex. While much is known about the functional organization and response properties of neurons within this network, fundamental questions about the perceptual and cognitive computations they support remain unanswered and little is known about how their activity causally contributes to perception. Addressing these shortcomings is crucial for advancing our understanding of the neural mechanisms that underlie vision as a behavior and is essential for identifying the neural underpinnings of visual delusions in psychiatric disease and developing effective visual prosthetics for patients with severe visual impairment. To close this gap, my research efforts combine psychophysics, neuroimaging, optogenetics, and electrophysiology, with an emphasis on color as a model system, in human and non-human primates.

To date, my most notable work has 1) shed light on the functional architecture of high-level visual cortex (inferior temporal cortex in macaques and ventral temporal cortex in humans), it’s computational goals, and how it evolved (Lafer-Sousa & Conway, 2013; Lafer-Sousa et al, 2016); 2) probed individual differences in color perception and provided evidence that top-down knowledge can influence perception (Lafer-Sousa et al, 2015; Lafer-Sousa and Conway, 2017; Hassantash et al, 2019, Cohen et al, 2025); and 3) established direct causal links between neural activity and perception (Schalk et al, 2017; Azadi et al, 2023; Lafer-Sousa et al, 2023).

In upcoming projects at UW-Madison, my lab will leverage fMRI-guided behavioral optogenetics, concurrent fMRI-opto, electrophysiology, and machine-learning in non-human primates to characterize the perceptual events and neural dynamics evoked by cortical stimulation in the mid-level visual area V4 and subdomains of inferior temporal cortex. These experiments will reveal when and why artificial activation of cortical circuits induces perceptual effects and how these effects are constrained by the neural state of the visual system. Ultimately, the goal is to recover a causal map of the ventral visual pathway and build a mechanistic understanding of visual perception that could inform treatments for visual disorders and guide the development of visual prosthetics.

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