Nonretinotopic visual processing in the brain

Abstract

A basic principle in visual neuroscience is the retinotopic organization of neural receptive fields. Here, we review behavioral, neurophysiological, and neuroimaging evidence for nonretinotopic processing of visual stimuli. A number of behavioral studies have shown perception depending on object or external-space coordinate systems, in addition to retinal coordinates. Both single-cell neurophysiology and neuroimaging have provided evidence for the modulation of neural firing by gaze position and processing of visual information based on craniotopic or spatiotopic coordinates. Transient remapping of the spatial and temporal properties of neurons contingent on saccadic eye movements has been demonstrated in visual cortex, as well as frontal and parietal areas involved in saliency/priority maps, and is a good candidate to mediate some of the spatial invariance demonstrated by perception. Recent studies suggest that spatiotopic selectivity depends on a low spatial resolution system of maps that operates over a longer time frame than retinotopic processing and is strongly modulated by high-level cognitive factors such as attention. The interaction of an initial and rapid retinotopic processing stage, tied to new fixations, and a longer lasting but less precise nonretinotopic level of visual representation could underlie the perception of both a detailed and a stable visual world across saccadic eye movements.

Pre-saccadic perception: Separate time courses for enhancement and spatial pooling at the saccade target

“…According to active perception and sensorimotor theories, visual processing and eye movements are closely linked and work together to yield continuous, stable perception that can guide our actions (for review: [22], [65], [66]). In terms of psychophysics, evidence for this tight link comes from studies of changes in performance around the time of saccades as well as a number of studies showing non-retinotopic visual perception (for review: [22]).…”

“…In terms of psychophysics, evidence for this tight link comes from studies of changes in performance around the time of saccades as well as a number of studies showing non-retinotopic visual perception (for review: [22]). Likewise changes in the spatial and temporal tuning of receptive fields, as described above, as well as phase resets in neural oscillations [66], [67], [68], point to a process by which visual perception and saccades are actively aligned [66].…”

“…Saccadic landing position spread and undershoots are consistently reported across eye movement studies. Therefore, it might be the case that the optimal strategy for predicting [75], [76] and integrating [77], [78] (for review: see [22]) visual features such as orientation across saccades would be to take into account the distribution of features in the entire potential landing area.…”

“…This finding is of considerable theoretical and practical interest, since previous behavioral and neurophysiological studies have used a wide variety of different experimental paradigms in terms of number, type, location and duration of the stimuli used and have yielded wildly different conclusions (for review: see [21], [22]). The existing literature does not fit well into a single mechanism or a single explanation for visual stability.…”

The reference frame of the tilt aftereffect measured by differential Pavlovian conditioning

“…How this stability is constructed is one of the major questions in the study of the visual system. Spatiotopic representations may contribute to this stability12, which encodes the spatial location in external coordinates, independent of where the eyes look. Neurophysiological studies have provided evidence for spatiotopic representations.…”