memory and perception It seems like an entirely different experience, and neuroscientists were previously convinced that the brain generated them differently. But in the 1990s, neuroimaging studies revealed that parts of the brain that were thought to be active only during sensory perception were also active during memory retrieval.
Sam Ling, Associate Professor of Neuroscience and Director of the Visual Neuroscience Institute at Boston University, said: For example, is our memory of a beautiful forest glade merely a recreation of the neural activity that made it possible to see it before?
“The discussion has shifted from this discussion of whether or not there is even a sensory cortex involved to a discussion of ‘Oh wait, is there any difference?’ Learning and plasticity units.” It swayed to the other side, but it was too much.”
We know that even though there are very strong neurological similarities between memory and experience, they are not exactly the same. “People don’t get confused between them,” said Serra Favila, a postdoctoral scientist at Columbia University and lead author of the recent paper. Nature Communications study. Her team’s research has identified at least one of the ways in which memory and image perception are organized differently at the neurological level.
blurry spot
When we look at the world, visual information about the world flows through the photoreceptors in the retina into the visual cortex, where it is sequentially processed by different groups of neurons. Each group adds a new level of complexity to your image. Simple points of light turn into lines and edges, then contours, shapes, and complete scenes that embody what we see.
In the new study, researchers focused on a function of visual processing that is very important in early groups of neurons. The pixels and contours that make up the image must be in the correct place. Otherwise, the brain creates shuffled, unrecognizable distortions of what we see.
Researchers trained participants to memorize the locations of four different patterns on a dartboard-like background. Each pattern is placed in a very specific location on the board and associated with a color in the center of the board. Each participant was tested to ensure they correctly remembered this information. For example, if you look at the green dot, you know that the star shape is on the far left. The researchers then recorded brain activity as participants recognized and memorized the locations of the patterns.
Brain scans allowed researchers to reveal how neurons recorded where something was, and how they later remembered it. Each neuron participates in one space, or “receptive field,” in the expanse of the visual field, such as the lower left corner. Neurons “only fire when you put something in that little spot,” he said. Neurons tuned to specific locations in space tend to cluster, and brain scans can easily detect their activity.
Previous studies on vision have established that neurons in early, low-level processing have a small receptive field, while neurons in late, high-level processing have a large receptive field. This makes sense because upper-layer neurons compile signals from many lower-layer neurons and capture information across wider patches of the visual field. But a larger receptive field also means less spatial accuracy, creating the effect of showing New Jersey with a large blob of ink on top of North America on a map. In fact, visual processing during perception is a matter of turning small sharp dots into larger, blurry, but more meaningful blobs.
