Similarly, in the phenomenon of induction, in which a temporally varying surround region induces an illusory Dolutegravir cost modulation of a constant center region, the perceived modulation depth of the center is significantly attenuated at high surround TFs. However, when two high TFs are summed and presented in the surround, the center is perceived to modulate at the envelope frequency (D’Antona and Shevell, 2009). The

present results thus suggest that a subcortical demodulating nonlinearity allows high TF information that is otherwise lost in the geniculocortical transformation to affect cortical firing patterns, and possibly perception. Non-Fourier signals are generally associated with the detection of oriented contours and the processing of texture (Rivest and Cavanagh, 1996 and Song and Baker, 2007), but they also arise at occlusion boundaries and under conditions producing transparent motion (Fleet and Langley, 1994). Both occlusion boundaries and transparent motion, the DAPT perception of multiple velocity signals in a local area of retinotopic space (Qian and Andersen, 1994), provide monocular cues for depth order. Non-Fourier signals can consequently elicit salient depth perceptions from non-stereoscopic

stimuli (Hegdé et al., 2004); for instance, the envelope of an interference pattern can be perceived to drift in front of the carrier (Fleet and Langley, 1994; Figure S6). The tuning of Y cells for both the envelope TF and the carrier TF of interference patterns (Figures S5A and S5B) therefore constitutes a joint representation of motions occupying an overlapping area of retinotopic space that can be perceived to be at different depths. Although the processing of occlusion boundaries and transparent why motion is commonly associated with extrastriate cortex (Qian and Andersen, 1994 and Rosenberg et al., 2008), the results of the present study suggest that some aspects of these signals are first represented subcortically.

All procedures were approved by the University of Chicago Institutional Animal Care and Use Committee. These methods have been described previously (Rosenberg et al., 2010 and Zhang et al., 2007) and are summarized here. All experiments were performed in anesthetized adult female cats. Baytril (2.5–5 mg/kg SQ) was given as prophylaxis against infection, dexamethasone (1–2 mg/kg SQ) was given to reduce cerebral edema, and atropine (0.04 mg/kg SQ) was given to decrease tracheal secretions. Ophthalmic atropine (1%) and phenylephrine (10%) were instilled in the eyes to dilate the pupils and retract the nictitating membrane, respectively. Lactated Ringer’s Solution (LRS) with 2.5% dextrose was delivered IV at a rate of 2–10 ml/kg/hr. Pancuronium bromide (0.1 mg/kg loading dose, 0.04–0.125 mg/kg/hr continuous) was given IV as a paralytic and delivered in the LRS.