Hierarchy seems to be a basic organizing principle in the brain. In the spatial and temporal domains, hierarchical features of information processing of the brain have been gradually disclosed (Chaudhuri, Knoblauch, Gariel, Kennedy, & Wang,
2015; Dumoulin & Wandell,
2008; Kiebel, Daunizeau, & Friston,
2008). A particular region of the sensory space in which a stimulus can trigger the firing of a neuron is defined as the receptive field of that neuron (Sherrington,
1906). It is well understood that neurons in higher-level brain areas receive many inputs from lower-level brain areas and that spatial receptive fields of the neurons progressively expand along the visual processing streams (Dumoulin & Wandell,
2008; Hubel & Wiesel,
1962; Wallisch & Movshon,
2008). In the temporal domain, mounting evidence has proved the existence of a hierarchy of a progressively longer temporal receptive window (TRW; Honey et al.,
2012)—a neuron's TRW is defined as the length of time within which the processing of present sensory information can be affected by prior information (Hasson, Yang, Vallines, Heeger, & Rubin,
2008). Moreover, higher-order brain regions with longer TRW showed slower dynamics (Honey et al.,
2012; Stephens, Honey, & Hasson,
2013). To investigate the neurobiological mechanisms of the hierarchical timescales, Chaudhuri et al. (
2015) built a large-scale dynamical model in the macaque neocortex. Propagation of the model's response across brain areas can be observed when simulated stimulus input is imposed to the primary visual cortex, and, in particular, progressively longer decay times of autocorrelation along the cortical hierarchy were found. Considering Chaudhuri et al.'s (
2015) and Honey et al.'s (
2012) theories, our findings can be explained as follows. Adaptation mechanisms in the mid-level visual areas may give more weights to their past states than those in the early visual areas. This makes the former more sluggish, producing longer-term adaptation effects. Future work may compare the time courses among a range of adaptation effects associated with different processing levels of the visual hierarchy (e.g., between the mid- and high-level visual areas) to extend our current conclusion.