Homeostatic mechanisms regulate distinct aspects of cortical circuit dynamics

Abstract

Homeostasis is indispensable to counteract the destabilizing effects of Hebbian plasticity. Although it is commonly assumed that homeostasis modulates synaptic strength, membrane excitability, and firing rates, its role at the neural circuit and network level is unknown. Here, we identify changes in higher-order network properties of freely behaving rodents during prolonged visual deprivation. Strikingly, our data reveal that functional pairwise correlations and their structure are subject to homeostatic regulation. Using a computational model, we demonstrate that the interplay of different plasticity and homeostatic mechanisms can capture the initial drop and delayed recovery of firing rates and correlations observed experimentally. Moreover, our model indicates that synaptic scaling is crucial for the recovery of correlations and network structure, while intrinsic plasticity is essential for the rebound of firing rates, suggesting that synaptic scaling and intrinsic plasticity can serve distinct functions in homeostatically regulating network dynamics.

Adaptation of spontaneous activity in the developing visual cortex

“…In contrast to retinal wave manipulations, the effect of altered inhibitory signaling on receptive field refinements is still unknown. It is likely that such manipulations will also affect H-events ( Leighton et al, 2020 ), as well as shape ongoing plasticity in the network ( Wu et al, 2020 ), and hence have less predictable effects on receptive field size and topography.…”

Input-independent homeostasis of developing thalamocortical activity

“…Neuronal firing-rates (as well as higher-order structure such as firing-rate correlations and proximity to criticality) are under homeostatic control in more mature juvenile visual cortex, returning to baseline levels within days following eye-lid suture (Hengen et al 2016; Wu et al 2020). It is still unclear how and when these homeostatic set points are established.…”

Behavioral gain following isolation of attention

“…The boost of attention suggests a rebound in behavior following prolonged imbalance between lateralized attention processing regions. Rebalancing of neural activity is controlled via homeostatic plasticity which compensates for changes in activity levels to maintain stability of neuronal excitability (Wu et al, 2020). The inactivated attention processing regions may benefit from homeostatic gain control in the attempt to equalize visual field attention post-manipulation.…”

“…Our finding of visual field specific attention increase could be critical for the development of clinical rehabilitation for patients with a unilateral lesion and lateralized attention deficits. Both homeostatic (Wu et al, 2020 [3]) and Hebbian plasticity (Pugh & Raman, 2006) [4] may have a role in the interplay between lateralized attention processing regions after visual attention imbalance, which is a crucial avenue of future research. Furthermore, applying our data as a case study for lateralized sensory processing, our results suggest a fundamental characteristic of lateralized processing interaction, which may be useful rehabilitation of unilateral stroke, outside of visual attention.…”