ARC and deafness: Under these conditions, two homeostatic mechanisms actively work for dynamic compensation of the imbalanced bimodal relationship between AC and VC after deafness: (1) imbalanced horizontal cortical feedback (Fig. 11-a), and (2) Up-regulated Arc/Arg3.1 expression (which supports the hypothesis that a reactive homeostatic mechanism compensates for VC over-activation) (Fig. 11-b).