“…In contrast to traditional assumptions that primary sensory cortical fields function only as stimulus analyzers, associative learning is now known to specifically modify the representations of stimuli in animals and humans in the primary auditory (A1) (Scheich et al, 2011; Weinberger, 2011), somatosensory (S1) (Galvez, Weiss, Weible, & Disterhoft, 2006; Pleger, Blankenburg, Ruff, Driver, & Dolan, 2008), visual (V1) (Hager & Dringenberg, 2010; Miller et al, 2008), olfactory (Li, Howard, Parrish, & Gottfried, 2008) and gustatory (Ifuku, Hirata, Nakamura, & Ogawa, 2003) cortices. Most extensively studied in A1, learning can shift acoustic frequency tuning to strengthen the encoding of sounds that predict reinforcement (Bakin & Weinberger, 1990; Edeline & Weinberger, 1993; Kisley & Gerstein, 2001), which can also produce increased cortical representational area for a tone signal within the tonotopic “map” of A1 (Recanzone, Schreiner, & Merzenich, 1993; Rutkowski & Weinberger, 2005).…”