lpful in the light of self-preservation. Motion is considered a basic feature and can be searched in parallel ((Thornton & Gilden, 2001; Treisman, 1986; Treisman & Gelade, 1980; Wolfe, 1994). Multiple mechanisms for processing motion information have been identified beyond the early motion energy mechanisms. One such mechanism is a motion trajectory network that would presumably exert its influence somewhere in the middle levels of motion processing at the level of integration.Watamaniuk et al., (1995) examined the ability to track local motion information. Motion can easily be tracked even when it disappears temporarily behind occluders or when moving through or against a moving background. However, motion signals can be degraded by introducing extra information into a display in the much the same way as static visual information (Nakayama & Silverman, 1986). One of the greatest determinants of detectability of motion is the presence of distracting motion signals that match the target motion (Watamaniuk & McKee, 1995; Watamaniuk, McKee, & Grzywacs, 1995). Also, the human visual system prefers objects that move consistently over time. One possible reason for the ease of tracking a trajectory is a putative trajectory network, a network of interconnected neurons with excitatory connections that propagate a local motion signal along a sequence. This trajectory network would have to come into play at a level beyond Reichardt detectors because it is interconnected and has a broad tuning (not just a preferred linear direction) that enables it track circular or arced paths as well as straight linear paths. In order to do this, it not only needs broad tuning, but also requires a signal to be both pooled and propagated. In this network motion detectors send facilitatory signals to adjacent detectors with similar directional tuning. The feed forward nature of this network would cause the signal to strengthen over time and could be a plaus...
