High-dimensional brain activity is in many cases organized into lower-dimensional neural manifolds [1,2]. Feedback from V4 to V1 is known to mediate visual attention [3] and computational work has shown that it can also rotate neural manifolds in a context-dependent manner [4]. However, whether feedback signals can modulate neural manifolds in vivo remains to be ascertained. Here, we studied the neural manifolds in macaque (Macaca mulatta) visual cortex during resting state [5] and found two distinct high-dimensional clusters in the activity. The clusters were primarily correlated with behavioral state (eye closure) and had distinct dimensionality. Granger causality analysis revealed that feedback from V4 to V1 was significantly stronger during the eyes-open periods. Finally, spiking neuron model simulations confirmed that signals mimicking V4-to-V1 feedback can modulate neural manifolds. Taken together, the data analysis and simulations suggest that feedback signals actively modulate neural manifolds in the visual cortex of the macaque.

References:
[1] Stringer et al. (2020). Nature 571, 361-365. 10.1038/s41586-019-1346-5
[2] Singh et al. (2008). Journal of Vision 8(8), 11. 10.1167/8.8.11
[3] Poort et al. (2012). Neuron 75 (1), 143-156. 10.1016/j.neuron.2012.04.032
[4] Naumann et al. (2022). eLife 11, 76096. 10.7554/eLife.76096
[5] Chen*, Morales-Gregorio* et al. (2022). Scientific Data 9 (1), 77. 10.1038/s41597-022-01180-1

Note: This is one of two talks in this seminar. The other talk is by Alessandra Stella.

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