Enhanced Motion Sensitivity Follows Saccadic Suppression in the Superior Temporal Sulcus of the Macaque Cortex

Abstract

The responses of neurons in the middle temporal and medial superior temporal areas of macaque cortex are suppressed during saccades compared with saccade-like stimulus movements. We utilized the short-latency ocular following paradigm to show that this saccadic suppression is followed by postsaccadic enhancement of motion responses. The level of enhancement decays with a time constant of 100 ms from saccade end. The speed of ocular following is also enhanced after saccades and decays over a similar time course, suggesting a link between the neural and behavioral effects. There is some evidence that maximum postsaccadic enhancement occurs when cells are stimulated at their optimum speeds. Latencies of motion responses are saccade dependent: 37 ms for saccade-generated motion, 45 ms for motion in the half-second after saccades, and 70 ms with no prior saccades. The finding that saccades alter response latencies may partially explain perceptual time compression during saccades and time dilation after saccades.

Saccades during Object Viewing Modulate Oscillatory Phase in the Superior Temporal Sulcus

“…Sobotka et al (2002) reported a similar supra-additive interaction in IT and hippocampal evoked responses, when electrical microstimulation was delivered shortly following the end of a saccadic eye movement. These results are consistent with previous studies from early visual areas (Vinje and Gallant, 2000;Ibbotson et al, 2007Ibbotson et al, , 2008MacEvoy et al, 2008;Rajkai et al, 2008;Cloherty et al, 2010;Ito et al, 2011) and psychophysics (Burr et al, 1994;Diamond, 2002) that suggest visual processing is augmented following SEMs. To our knowledge, the present results are the first to show saccadic modulation in an object-selective region during viewing of faces and objects.…”

“…The effect of a moving image on the retina is mitigated through saccadic suppression (i.e., the reduction of visual sensitivity during saccades) (Latour, 1962;Burr et al, 1994). The neural basis of saccadic suppression has been explored in the LGN (Reppas et al, 2002) and motion-sensitive cortex (Thiele et al, 2002), and some of these studies also report that visual responses following saccades can be enhanced (Ibbotson et al, 2007(Ibbotson et al, , 2008Cloherty et al, 2010). For example, in primary visual cortex, fixation onset in darkness leads to a resetting of oscillations to a phase associated with high firing rates (Rajkai et al, 2008), and during visual stimulation, fixation onset leads to increased firing rates (Gallant et al, 1998;MacEvoy et al, 2008), spike synchronization (Maldonado et al, 2008;Ito et al, 2011), and sparseness (Vinje and Gallant, 2000).…”

Saccadic Modulation of Neural Responses: Possible Roles in Saccadic Suppression, Enhancement, and Time Compression

“…That visual responsiveness is enhanced after saccades indicates that saccades are critically related to visual sensitivity: without saccades, visual sensitivity is reduced (Ibbotson et al, 2007;Rajkai et al, 2008). Thus, saccades not only provide a means to shift gaze direction but also to increase visual sensitivity when saccades are frequent.…”

“…Recordings from the lateral geniculate nucleus (LGN), the primary gateway to the visual cortex, show evidence for suppression of neural activity before saccades and enhancement afterward, although the effects are variable and complex (Lee and Malpeli, 1998;Ramcharan et al, 2001;Reppas et al, 2002;Royal et al, 2006). Studies in the parietal cortex [e.g., middle temporal (MT) and medial superior temporal areas (MSTd)] have also revealed suppression during saccades and postsaccadic enhancement (Thiele et al, 2002;Price et al, 2005;Ibbotson et al, 2007). However, the studies in parietal cortex have been limited to stimuli presented after saccade onset.…”

The Geometry of Perisaccadic Visual Perception

“…This would seem to exclude high-level visual areas such as the dorsal medial superior temporal area (MSTd), where retinotopy is crude (Saito et al, 1986), and V1, where saccade-related activity is minimal (Wurtz and Mohler, 1976). Cortical areas such as V3, V4, and the middle temporal area (MT) thus appear to be reasonable candidates, as all three have an approximately logarithmic map of visual space (Albright and Desimone, 1987;Gattass et al, 1988;Motter, 2009) and receive extraretinal signals related to saccadic eye movements (Nakamura and Colby, 2000;Tolias et al, 2001;Thiele et al, 2002;Ibbotson et al, 2007). Indeed, Krekelberg et al (2003) have reported that the population output of MT appears to exhibit a neuronal correlate of perceptual compression.…”