Consistent with numerous earlier reports (Hubel and Wiesel, 1965; Duysens et al., 1982a, b; Rapaport et al., 1982; Dreher, 1986; Pettigrew and Dreher, 1987; Tanaka et al., 1987; Guillemot et al., 1993; Tardif et al., 1997), area 19 neurons exhibit clear orientation selectivity (see however Saito et al., 1988). Orientation selectivity of V1 neurons relies on multiple mechanisms, including mechanisms that are intrinsic to the area as well as the orientation biased inputs from the geniculate (for reviews, see Vidyasagar et al., 1996; Vidyasagar and Eysel, 2015) and feedback signals from layer 5 (Alonso et al., 1993b) or layers 2/3 (Martinez-Conde et al., 1999) of visuotopically corresponding parts of area 18 and/or higher-order visual cortices (e.g., Wang et al., 2000, 2010; Huang et al., 2007). It is likely, that in the case of area 19 neurons, orientation selectivity is to a large extent “inherited” via feedforward projections from the orientation selective neurons in the primary visual cortex. Nevertheless, in a small proportion of area 19 neurons, PTV inactivation caused clear (>10°) shifts in optimal orientation and/or substantial changes in the orientation-tuning widths. It is worth pointing out in this context, that in area 17 of anesthetized cats, shifts in preferred orientation not exceeding 15° do occur “spontaneously” (e.g., Henry et al., 1973).