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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.


Amplified SCPs. Differences between simultaneous and summed VS activity are depicted for aligned and misaligned conditions during a time window of 50–180 ms. This figure illustrates three major points: (1) consistent interactions of visual and somatosensory processes across all four multisensory conditions starting at around 110 ms (green shaded area), regardless of spatial alignment; (2) that integrative effects were clearly stronger for the aligned as compared to misaligned conditions; and (3) integrative effects were noticeably stronger in the two conditions where somatosensory information was presented to the right hemi field.
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Figure 7: Amplified SCPs. Differences between simultaneous and summed VS activity are depicted for aligned and misaligned conditions during a time window of 50–180 ms. This figure illustrates three major points: (1) consistent interactions of visual and somatosensory processes across all four multisensory conditions starting at around 110 ms (green shaded area), regardless of spatial alignment; (2) that integrative effects were clearly stronger for the aligned as compared to misaligned conditions; and (3) integrative effects were noticeably stronger in the two conditions where somatosensory information was presented to the right hemi field.

Mentions: To fully explore the spatiotemporal characteristics of the multisensory response, SCPs representing significant results of running t-tests between the simultaneous VS and the summed V + S activity were generated for each of the four multisensory conditions across all time points (between 100 ms pre-stimulus onset and 500 ms post-stimulus onset) and the entire electrode array (Figure 6). Figure 7 represents an enlargement of the SCP plots focused around the earliest time period (50–180 ms) where neural differences between summed and simultaneous VS conditions were noted. This analysis revealed consistent interactions of visual and somatosensory processes across all four multisensory conditions starting at around 110 ms over central and central-parietal areas. Note that the 120 ms time point is also the midpoint of the exploratory 110–130 ms time window that was identified post hoc as a window of particularly vigorous integrative processing during waveform inspections (highlighted in green in Figure 7). Such integrative effects persisted until about 150 ms over central, central-parietal, and parietal regions for all four multisensory 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)

Amplified SCPs. Differences between simultaneous and summed VS activity are depicted for aligned and misaligned conditions during a time window of 50–180 ms. This figure illustrates three major points: (1) consistent interactions of visual and somatosensory processes across all four multisensory conditions starting at around 110 ms (green shaded area), regardless of spatial alignment; (2) that integrative effects were clearly stronger for the aligned as compared to misaligned conditions; and (3) integrative effects were noticeably stronger in the two conditions where somatosensory information was presented to the right hemi field.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 7: Amplified SCPs. Differences between simultaneous and summed VS activity are depicted for aligned and misaligned conditions during a time window of 50–180 ms. This figure illustrates three major points: (1) consistent interactions of visual and somatosensory processes across all four multisensory conditions starting at around 110 ms (green shaded area), regardless of spatial alignment; (2) that integrative effects were clearly stronger for the aligned as compared to misaligned conditions; and (3) integrative effects were noticeably stronger in the two conditions where somatosensory information was presented to the right hemi field.
Mentions: To fully explore the spatiotemporal characteristics of the multisensory response, SCPs representing significant results of running t-tests between the simultaneous VS and the summed V + S activity were generated for each of the four multisensory conditions across all time points (between 100 ms pre-stimulus onset and 500 ms post-stimulus onset) and the entire electrode array (Figure 6). Figure 7 represents an enlargement of the SCP plots focused around the earliest time period (50–180 ms) where neural differences between summed and simultaneous VS conditions were noted. This analysis revealed consistent interactions of visual and somatosensory processes across all four multisensory conditions starting at around 110 ms over central and central-parietal areas. Note that the 120 ms time point is also the midpoint of the exploratory 110–130 ms time window that was identified post hoc as a window of particularly vigorous integrative processing during waveform inspections (highlighted in green in Figure 7). Such integrative effects persisted until about 150 ms over central, central-parietal, and parietal regions for all four multisensory 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.