the sigmoid relationship is that objects and locations > 50 cm ahead of the rat are initially less distinguishable from more distant landmarks, but as the animal approaches, they are progressively better resolved by the interleaved cell assemblies. Third, the number of cell assemblies that can nest in a given theta period (7 to 9, as reflected by the number of gamma cycles/theta; Bragin et al., 1995; Buzsáki et al., 2003; Chrobak and Buzsáki, 1998), determines the spatial resolution distance representation (approximately 5 cm/theta cycle). A consequence of the limited number of theta-nested assemblies is that distance resolution scales with the size of the environment; temporal lags that represent fine spatial resolution in small enclosures correspond to coarser distance representations in larger environments (Diba and Buzsáki, 2009; Fenton et al., 2008; O’Keefe and Burgess, 1996).13
