“…RF mapping studies in the parietal cortex of primates and in optic flow neurons in invertebrate species have typically utilized relatively small stimuli moving throughout the visual field to map visually responsive areas~e.g., primates, Schaafsma & Duysens, 1996;Duhamel et al, 1997;Ben Hamed et al, 2001;Bremmer et al, 2002;Avillac et al, 2005;blowfly, Krapp & Hengstenberg, 1996;Krapp et al, 1998; shore crab, Barnes et al, 2002!. A larger stimulus was used in the present study, as small visual stimuli are not effective modulators of CSA in the VbC~Simpson & Alley, 1974!. Thus, to determine the local motion sensitivity and local preferred direction in different areas of the RFs of expansion, contraction, and rH45c neurons~simply referred to as rotation neurons hereafter!, 24 units were tested with a 45 deg ϫ 37.5 deg square-wave grating drifting in different subfields.…”