Wednesday, December 18, 2024

Sculpting new visual categories into the human brain.

Fascinating work from Iordan et al. (open source) I pass on the abstract and the first paragraph of the article that makes more clear what they are doing.

Abstract

Learning requires changing the brain. This typically occurs through experience, study, or instruction. We report an alternate route for humans to acquire visual knowledge, through the direct sculpting of activity patterns in the human brain that mirror those expected to arise through learning. We used neurofeedback from closed-loop real-time functional MRI to create new categories of visual objects in the brain, without the participants’ explicit awareness. After neural sculpting, participants exhibited behavioral and neural biases for the learned, but not for the control categories. The ability to sculpt new perceptual distinctions into the human brain offers a noninvasive research paradigm for causal testing of the link between neural representations and behavior. As such, beyond its current application to perception, our work potentially has broad relevance for advancing understanding in other domains of cognition such as decision-making, memory, and motor control.

“For if someone were to mold a horse [from clay], it would be reasonable for us on seeing this to say that this previously did not exist but now does exist.”

Mnesarchus of Athens, ca. 100 BCE (1).

Humans continuously learn through experience, both implicitly [e.g., through statistical learning (2, 3)] and explicitly [e.g., through instruction (4, 5)]. Brain imaging has provided insight into the neural correlates of acquiring new knowledge (6) and learning new skills (7). As humans learn to group distinct items into a novel category, neural patterns of activity for those items become more similar to one another and, simultaneously, more distinct from patterns of other categories (810). We hypothesized that we could leverage this process using neurofeedback to help humans acquire perceptual knowledge, separate from experience, study, or instruction. Specifically, sculpting patterns of activity in the human brain (“molding the neural clay”) that mirror those expected to arise through learning of new visual categories may lead to enhanced perception of the sculpted categories (“they now exist”), relative to similar, control categories that were not sculpted. To test this hypothesis, we implemented a closed-loop system for neurofeedback manipulation (1118) using functional MRI (fMRI) measurements recorded from the human brain in real time (every 2 s) and used this method to create new neural categories for complex visual objects. Crucially, in contrast to prior neurofeedback studies that focused exclusively on reinforcing or suppressing existing neural representations (11, 12), in the present work, we sought to use neurofeedback to create novel categories of objects that previously did not exist in the brain; we test whether this process can be used to generate significant changes in the neural representations of complex stimuli in the human cortex, and, as a result, alter perception.

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