Recent advancements in the field of visual recognition memory (VRM) have shed light on the brain’s ability to differentiate between known and novel stimuli. This progress has resolved previously conflicting findings, demonstrating that an increase in visually evoked potentials (VEPs) coincides with an overall reduction in neural activity. This occurs as the brain swiftly recognizes familiar objects and subsequently diminishes further related neural processes.
For many years, researchers have been exploring why our visual system excels at recognizing familiar items. A recent breakthrough study has resolved a longstanding discrepancy in research findings, offering a novel understanding of this process.
The ability to distinguish new from familiar visuals is crucial for directing our attention effectively. Neuroscientists have dedicated decades to understanding this proficiency. In the course of this research, they encountered seemingly contradictory observations. However, a new study clarifies that these confusing data points actually represent two aspects of the same phenomenon, advancing our comprehension of VRM.
VRM enables the rapid recognition of familiar elements within our environment, allowing us to concentrate on potentially more important new elements. For example, when entering a room to address an urgent matter, VRM helps us focus on the unexpected – like an intruder – rather than familiar surroundings.
Despite these advancements, the specific neural mechanisms underpinning this fundamental learning process remain somewhat elusive, according to Picower Professor Mark Bear and his colleagues in a recent publication in the Journal of Neuroscience.
Diverse Observations in VRM Research
Research dating back to 1991 revealed that familiar visuals result in less cortical neuron activation compared to new stimuli, as observed by researchers who later joined Bear at MIT, including Picower Professor Earl K. Miller and Doris and Don Berkey Professor Bob Desimone. In contrast, Bear’s laboratory discovered in 2003 that familiar stimuli prompted a significant increase in neural activity in mice’s primary visual cortex. This surge, known as a visually evoked potential (VEP), has been linked to VRM in subsequent studies.
The latest study, led by former Bear Lab graduate Dustin Hayden PhD ’22 and postdoc Peter Finnie, reconciles these findings. It shows that VEPs can increase even as overall neural response to familiar stimuli declines, as initially observed by Miller and Desimone. This sheds light on the underlying mechanisms of VRM – the brief excitation of VEPs may instigate inhibition, leading to a general reduction in activity.
Exploring Brain Mechanisms
Bear’s lab has been investigating stimulus-selective response plasticity (SRP) and its role in VRM for two decades. They use a black-and-white striped pattern, which appears to reverse in shade, as a stimulus for mice. Over time, as mice become familiar with this pattern, VEPs
