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Keeping in touch with the visual system: spatial alignment and multisensory integration of visual-somatosensory inputs.

Mahoney JR, Molholm S, Butler JS, Sehatpour P, Gomez-Ramirez M, Ritter W, Foxe JJ - Front Psychol (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: 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.

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.

No MeSH data available.


Simultaneous vs. summed MSI effects – right conditions for selected ROIs. ERP waveforms of both the aligned right and misaligned right VS conditions are depicted for the four ROI. Purple traces represent multisensory simultaneous VS activity and orange traces represent summed V + S activity. All axes are the same and the labels are provided in the top left corner.
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Figure 5: Simultaneous vs. summed MSI effects – right conditions for selected ROIs. ERP waveforms of both the aligned right and misaligned right VS conditions are depicted for the four ROI. Purple traces represent multisensory simultaneous VS activity and orange traces represent summed V + S activity. All axes are the same and the labels are provided in the top left corner.

Mentions: Visual inspection of the group-averaged ERPs for simultaneous VS and summed V + S aligned conditions revealed differences in amplitude starting at around 55 ms for the right conditions and 85 ms for the left conditions over respective contralateral hemispheres (recall that side of presentation in misaligned conditions is with reference to the side of somatosensory presentation; see Figures 4 and 5). The first differences between simultaneous and summed neural activity appeared maximal over contralateral left central-parietal regions for the aligned right condition. More specifically, the ERP elicited to the V + S right condition was more positive in amplitude than the ERPs elicited to the simultaneous VS right condition over contralateral scalp regions. These initial divergences between 55 and 75 ms were not apparent in the aligned left or the misaligned conditions.


Keeping in touch with the visual system: spatial alignment and multisensory integration of visual-somatosensory inputs.

Mahoney JR, Molholm S, Butler JS, Sehatpour P, Gomez-Ramirez M, Ritter W, Foxe JJ - Front Psychol (2015)

Simultaneous vs. summed MSI effects – right conditions for selected ROIs. ERP waveforms of both the aligned right and misaligned right VS conditions are depicted for the four ROI. Purple traces represent multisensory simultaneous VS activity and orange traces represent summed V + S activity. All axes are the same and the labels are provided in the top left corner.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525670&req=5

Figure 5: Simultaneous vs. summed MSI effects – right conditions for selected ROIs. ERP waveforms of both the aligned right and misaligned right VS conditions are depicted for the four ROI. Purple traces represent multisensory simultaneous VS activity and orange traces represent summed V + S activity. All axes are the same and the labels are provided in the top left corner.
Mentions: Visual inspection of the group-averaged ERPs for simultaneous VS and summed V + S aligned conditions revealed differences in amplitude starting at around 55 ms for the right conditions and 85 ms for the left conditions over respective contralateral hemispheres (recall that side of presentation in misaligned conditions is with reference to the side of somatosensory presentation; see Figures 4 and 5). The first differences between simultaneous and summed neural activity appeared maximal over contralateral left central-parietal regions for the aligned right condition. More specifically, the ERP elicited to the V + S right condition was more positive in amplitude than the ERPs elicited to the simultaneous VS right condition over contralateral scalp regions. These initial divergences between 55 and 75 ms were not apparent in the aligned left or the misaligned conditions.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: 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.

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.

No MeSH data available.