Miriam Acquafredda¹, Giacomo Mazzotta¹, Laura Biagi^2,3, Michela Tosetti^2,3, Maria Concetta Morrone¹, Paola Binda¹; ¹Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy, ²IRCCS Stella Maris, Calambrone, Pisa, Italy, ³IMAGO7 Center, Pisa, Italy

In adult humans, brief periods of monocular deprivation induce ocular dominance plasticity, transiently enhancing responses to stimuli in the deprived eye in the primary visual cortex V1 (Binda et al., 2018) and the ventral pulvinar (Kurzawski et al., 2022). The connectivity among these regions measured in resting state is also affected, with a selective reduction of the pulvinar-to-V1 pathway (Acquafredda et al., Science Advances 2025). Here we investigated whether and how the connectivity between V1 and the visual thalamus is modulated by visual stimulation. We acquired ultra-high-field 7T fMRI EPI sequences from 25 normally sighted adults, pre- and post-2 hours of monocular deprivation. Participants were presented with monocular band-pass noise stimuli with five contrast levels. Dynamic Causal Modeling (SPM implementation, Zeidman et al., 2019) was used to analyse BOLD signals from three regions of interest: V1, lateral geniculate nucleus, and ventral pulvinar – all showing reliable visually evoked activity. Short-term deprivation differentially modulated V1 connectivity with the two thalamic regions. During deprived eye stimulation, the connectivity between V1 and the pulvinar decreased post-deprivation (like in resting state), while the connectivity between V1 and LGN increased. The opposite was observed during stimulation of the non-deprived eye, resulting in a significant three-way interaction (time x eye x region of interest, F(1,24) = 5.85, p = 0.024). Across participants, the modulation of connectivity between V1 and the pulvinar (but not with LGN) was reliably correlated with the shift of ocular dominance, measured with short binocular rivalry sessions before and after the fMRI acquisitions. We conclude that monocular deprivation produce changes that extend beyond local V1 processes and affect the connectivity between the cortex and the visual thalamus. Our results indicate that the pulvinar participates in regulating activity in the visual cortex and setting its short-term plasticity.

Acknowledgements: European Research Council (ERC) Consolidator grant PredActive (101170249); European Union–Next Generation EU, grant PRIN 2022 (“RIGHTSTRESS - Tuning arousal for optimal perception” Settore SH4, 2022CCPJ3J - CUP I53D23003960006); MUR, program FARE-­2 (grant SmilY); Fondazione Pisa (305/22).