In the neocortex, inhibition can have either a positive or inverse correlation with excitatory thalamic input (Ferster 1986; Gentet et al., 2010; Wehr and Zador, 2003;). Excitatory and inhibitory inputs interact in a complex manner to shape the response to On and Off transitions of the stimulus (Borg-Graham et al., 1998) or to affect the tuning properties of the principal cells (Monier et al., 2003; Wilent and Contreras, 2005). Similarly, the firing rates of interneurons in the hippocampus often vary as a function of the animal’s position (Figure 9B; McNaughton et al., 1983) and can mimic several signatures of place cells, including positional information, field size, speed modulation of rate and oscillation frequency and phase precession (Ego-Stengel and Wilson, 2007; Marshall et al., 2002; Maurer et al., 2006b; Geisler et al., 2007; Wilent and Nitz, 2007). Importantly, the input-related specific patterns are not only associated with increased but also by selectively decreased firing of inhibitory interneurons in both neocortex and hippocampus (Figure 9B; Gentet et al., 2010; Rao et al., 1999; Wiebe and Staubli 2001; Wilent and Nitz, 2007). Such
