Abstract
Memories of the images that we have seen are thought to be reflected in the reduction of neural responses in high-level visual areas such as inferotemporal (IT) cortex, a phenomenon known as repetition suppression (RS). We challenged this hypothesis with a task that required rhesus monkeys to report whether images were novel or repeated while ignoring variations in contrast, a stimulus attribute that is also known to modulate the overall IT response. The monkeys' behavior was largely contrast invariant, contrary to the predictions of an RS-inspired decoder, which could not distinguish responses to images that are repeated from those that are of lower contrast. However, the monkeys' behavioral patterns were well predicted by a linearly decodable variant in which the total spike count was corrected for contrast modulation. These results suggest that the IT neural activity pattern that best aligns with single-exposure visual recognition memory behavior is not RS but rather sensory referenced suppression: reductions in IT population response magnitude, corrected for sensory modulation.
Original language | English (US) |
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Article number | 2021660118 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 118 |
Issue number | 18 |
DOIs | |
State | Published - May 4 2021 |
Keywords
- Contrast
- Familiarity
- Population decoding
- Recognition memory
- Repetition suppression
ASJC Scopus subject areas
- General