Figure 5.

Proposed role of heterosynaptic plasticity in ODP. (i) During normal vision, monocular inputs from the contralateral and ipsilateral eye, as well as binocular inputs, converge onto neurons in the binocular visual cortex. Some visual inputs cluster for similar receptive field preferences and orientation preferences (Iacaruso et al., 2017; Lee et al., 2019). (ii) At 1 or 2 days of MD, low or unpatterned drive from deprived eye inputs lowers CaMKII activity in spines, which causes some spines to undergo homosynaptic LTD due to cell-wide transcription of Arc (McCurry et al., 2010), which binds with inactive CaMKII to induce AMPA receptor endocytosis (Okuno et al., 2012). Heterosynaptic LTD occurs in deprived eye inputs that are functionally clustered with open eye inputs due to the local translation and translocation of Arc (El-Boustani et al., 2018). (iii) At 3 days of MD, synapses exhibiting LTD are decreased in size or lost (Sun et al., 2019). (iv) After 6 days of MD, heterosynaptic potentiation occurs following spine loss (Frank et al., 2018). Existing open eye inputs facilitate the formation and strengthening of neighboring open eye synapses through the diffusion of activated GTPases such as Rac1 and RhoA (Hedrick et al., 2016). Furthermore, new clusters of open eye synapses also form through cooperative plasticity (Lee et al., 2016). Image assets reproduced from smart.servier.com (Servier Medical Art, 2015) (CC-BY).