Research Article

Modification of Peak Plasticity Induced by Brief Dark Exposure

Figure 1

Illustration of the effect on plasticity capacity following immersion in complete darkness. Profile of the critical period in normally reared cats (based on data from [9]) demonstrates peak plasticity at about 4 weeks of age followed by a progressive decline to low levels that are maintained into adolescence (a). Dark rearing from near birth and for long durations has been postulated to slow the overall time course of the critical period (magenta profile in (b)) so that enhanced plasticity can be observed at ages when normally reared animals exhibit lower plasticity capacity (based on [15]). More recently, short durations of darkness (dark exposure) in rodents and cats have been employed to raise plasticity levels beyond that observed from age-matched controls (c). In the current study, we investigated the possibility that 10 days of dark exposure imposed just prior to the critical period peak can enhance plasticity capacity beyond its natural maximum (d).