title: Keeping in touch with the visual system: spatial alignment and multisensory integration of visual-somatosensory inputs.
abstract: Correlated sensory inputs coursing along the individual sensory processing hierarchies arrive at multisensory convergence zones in cortex where inputs are processed in an integrative manner. The exact hierarchical level of multisensory convergence zones and the timing of their inputs are still under debate, although increasingly, evidence points to multisensory integration (MSI) at very early sensory processing levels. While MSI is said to be governed by stimulus properties including space, time, and magnitude, violations of these rules have been documented. The objective of the current study was to determine, both psychophysically and electrophysiologically, whether differential visual-somatosensory (VS) integration patterns exist for stimuli presented to the same versus opposite hemifields. Using high-density electrical mapping and complementary psychophysical data, we examined multisensory integrative processing for combinations of visual and somatosensory inputs presented to both left and right spatial locations. We assessed how early during sensory processing VS interactions were seen in the event-related potential and whether spatial alignment of the visual and somatosensory elements resulted in differential integration effects. Reaction times to all VS pairings were significantly faster than those to the unisensory conditions, regardless of spatial alignment, pointing to engagement of integrative multisensory processing in all conditions. In support, electrophysiological results revealed significant differences between multisensory simultaneous VS and summed V + S responses, regardless of the spatial alignment of the constituent inputs. Nonetheless, multisensory effects were earlier in the aligned conditions, and were found to be particularly robust in the case of right-sided inputs (beginning at just 55 ms). In contrast to previous work on audio-visual and audio-somatosensory inputs, the current work suggests a degree of spatial specificity to the earliest detectable multisensory integrative effects in response to VS pairings.
authors: The Cognitive Neurophysiology Laboratory, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg NY, USA ; Division of Cognitive and Motor Aging, Department of Neurology, Albert Einstein College of Medicine, New York NY, USA.
authors: Jeannette R
authors: JR
authors: Mahoney
authors: The Cognitive Neurophysiology Laboratory, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg NY, USA ; The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children's Evaluation and Rehabilitation Center, Department of Pediatrics, Albert Einstein College of Medicine and Montefiore Medical Center, New York NY, USA ; The Dominick P. Purpura Department of Neuroscience, Rose F. Kennedy Center, Albert Einstein College of Medicine, New York NY, USA.
authors: Sophie
authors: S
authors: Molholm
authors: The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children's Evaluation and Rehabilitation Center, Department of Pediatrics, Albert Einstein College of Medicine and Montefiore Medical Center, New York NY, USA.
authors: John S
authors: JS
authors: Butler
authors: The Cognitive Neurophysiology Laboratory, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg NY, USA.
authors: Pejman
authors: P
authors: Sehatpour
authors: The Cognitive Neurophysiology Laboratory, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg NY, USA.
authors: Manuel
authors: M
authors: Gomez-Ramirez
authors: The Cognitive Neurophysiology Laboratory, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg NY, USA ; The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children's Evaluation and Rehabilitation Center, Department of Pediatrics, Albert Einstein College of Medicine and Montefiore Medical Center, New York NY, USA.
authors: Walter
authors: W
authors: Ritter
authors: The Cognitive Neurophysiology Laboratory, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg NY, USA ; The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Children's Evaluation and Rehabilitation Center, Department of Pediatrics, Albert Einstein College of Medicine and Montefiore Medical Center, New York NY, USA ; The Dominick P. Purpura Department of Neuroscience, Rose F. Kennedy Center, Albert Einstein College of Medicine, New York NY, USA.
authors: John J
authors: JJ
authors: Foxe
keywords: cross-modal; high-density electrical mapping; multisensory integration; sensory processing; visual-somatosensory integration