The Neural Correlates of Abrupt Visual Learning
Post by Megan McCullough
The takeaway
Rapid visual learning, which can be thought of as a moment of insight, is characterized by synchronized neural activity in the inferotemporal and prefrontal cortices.
What's the science?
Although most learning in adult humans requires multiple learning sessions and involves slow changes in the brain, abrupt learning refers to the circumstances in which adults learn after one or only a few exposures to a stimulus. One example of abrupt learning is recognizing a person’s face after one introduction. Previous studies have examined the role of oscillatory synchronization (brainwaves occurring at the same time) in learning over time, but its role in abrupt learning is unknown. This week in Current Biology, Csorba and colleagues aimed to study the role of synchronization of neural activity between the prefrontal (PFC) and inferotemporal (IT) regions in facilitating abrupt learning by recording neuronal activity in non-human primates.
How did they do it?
The authors recorded neuronal activity in the PFC and IT cortex of two adult rhesus macaque monkeys while they participated in an oculomotor foraging task. The task consisted of three phases: the presentation of a scene, a foraging phase, and the reward phase. First, each animal was presented with a natural image. Next, the animals were allowed to explore the image visually. Finally, the animals were rewarded when their gaze reached an unmarked reward zone and the time it took the animals to find the reward zone after being presented with the scene was recorded. This task was chosen because the learning was abrupt, performance improved significantly after only a few trials. To examine the relationship between neural activity in the regions of interest and abrupt learning, the authors measured the relationship between the local field potential (LFP) signals in each area.
What did they find?
The animals learned to recognize the images presented to them and associate them with specific reward areas, showing that this task involved abrupt visual learning. The authors found an increase in synchronization of LFPs in the PFC and IT region around the time the animals had their moment of insight. Furthermore, the synchronized activity in these two brain regions could predict the changes in performance of the monkeys. The data show that the strength of the synchronization was highest around the moment of insight but also carried into the post-learning phases of the task. This coordinated activity appears to link visual inputs with reward outcomes.
What's the impact?
This study uncovered the neural correlates of abrupt visual learning. Because the animals were allowed to freely look at natural images, the results of this study may provide a look into learning that occurs in natural settings outside of a laboratory. This research illustrates the role that coordinated activity between brain regions has in allowing quick visual learning.