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Visual and audiovisual effects of isochronous timing on visual perception and brain activity.

Marchant JL, Driver J - Cereb. Cortex (2012)

Bottom Line: Visual isochrony activated a similar timing-related brain network to that previously found primarily in auditory beat perception work.Finally, activity in multisensory left posterior superior temporal sulcus increased specifically during concurrent isochronous audiovisual presentations.These results indicate that regular isochronous timing can modulate visual processing and this can also involve multisensory audiovisual brain mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London WC1N 3BG, UK. jennifer.marchant@ucl.ac.uk

ABSTRACT
Understanding how the brain extracts and combines temporal structure (rhythm) information from events presented to different senses remains unresolved. Many neuroimaging beat perception studies have focused on the auditory domain and show the presence of a highly regular beat (isochrony) in "auditory" stimulus streams enhances neural responses in a distributed brain network and affects perceptual performance. Here, we acquired functional magnetic resonance imaging (fMRI) measurements of brain activity while healthy human participants performed a visual task on isochronous versus randomly timed "visual" streams, with or without concurrent task-irrelevant sounds. We found that visual detection of higher intensity oddball targets was better for isochronous than randomly timed streams, extending previous auditory findings to vision. The impact of isochrony on visual target sensitivity correlated positively with fMRI signal changes not only in visual cortex but also in auditory sensory cortex during audiovisual presentations. Visual isochrony activated a similar timing-related brain network to that previously found primarily in auditory beat perception work. Finally, activity in multisensory left posterior superior temporal sulcus increased specifically during concurrent isochronous audiovisual presentations. These results indicate that regular isochronous timing can modulate visual processing and this can also involve multisensory audiovisual brain mechanisms.

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Related in: MedlinePlus

Brain activity enhanced by isochronous stimulus timing. (a) Isochrony versus random timing enhanced activity in bilateral IFG, insula, putamen, and globus pallidus; (b) in left DLPFC; and (c) in left IPS, when collapsed across visual (V) and audiovisual (VA) conditions. (d) Conjunction analysis confirmed overlap (purple shading) between isochrony enhancement effects on vision-only (V; blue shading) and audiovisual (VA; red shading) conditions in bilateral insula. (e) Cluster mean beta parameters (±1 s.e.d. for isochrony effect) plotted for each condition (light bars = isochronous; dark bars = random). Thresholds: voxel punc < 0.001 and cluster pFWE < 0.05 displayed on mean anatomical brain images.
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fig2: Brain activity enhanced by isochronous stimulus timing. (a) Isochrony versus random timing enhanced activity in bilateral IFG, insula, putamen, and globus pallidus; (b) in left DLPFC; and (c) in left IPS, when collapsed across visual (V) and audiovisual (VA) conditions. (d) Conjunction analysis confirmed overlap (purple shading) between isochrony enhancement effects on vision-only (V; blue shading) and audiovisual (VA; red shading) conditions in bilateral insula. (e) Cluster mean beta parameters (±1 s.e.d. for isochrony effect) plotted for each condition (light bars = isochronous; dark bars = random). Thresholds: voxel punc < 0.001 and cluster pFWE < 0.05 displayed on mean anatomical brain images.

Mentions: Isochrony enhanced activity in bilateral IFG, insula, putamen and globus pallidus, left DLPFC, and left intraparietal sulcus (IPS) when compared with random timing (Table 1; Fig. 2a–c). A conjunction analysis between the simple effect of isochronous versus random timing on BOLD signal during the vision-only and audiovisual conditions ([VISO > VRAND] and [VAISO > VARAND]) confirmed common activation of the right anterior insula by isochrony regardless of sound presence/absence (cluster pFWE = 0.029, 72 voxels, peak t15 = 4.52, x = 30, y = 24, z = 6; Fig. 2d,e). A similar pattern of activity was observed in the left anterior insula (Fig. 2d,e) but that cluster did not reach full statistical significance and is reported only for completeness (cluster pFWE > 0.05, 8 voxels, peak t15 = 4.08, x = −30, y = 21, z = 6). No regions were preferentially activated for random versus isochronous stimuli.


Visual and audiovisual effects of isochronous timing on visual perception and brain activity.

Marchant JL, Driver J - Cereb. Cortex (2012)

Brain activity enhanced by isochronous stimulus timing. (a) Isochrony versus random timing enhanced activity in bilateral IFG, insula, putamen, and globus pallidus; (b) in left DLPFC; and (c) in left IPS, when collapsed across visual (V) and audiovisual (VA) conditions. (d) Conjunction analysis confirmed overlap (purple shading) between isochrony enhancement effects on vision-only (V; blue shading) and audiovisual (VA; red shading) conditions in bilateral insula. (e) Cluster mean beta parameters (±1 s.e.d. for isochrony effect) plotted for each condition (light bars = isochronous; dark bars = random). Thresholds: voxel punc < 0.001 and cluster pFWE < 0.05 displayed on mean anatomical brain images.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3643713&req=5

fig2: Brain activity enhanced by isochronous stimulus timing. (a) Isochrony versus random timing enhanced activity in bilateral IFG, insula, putamen, and globus pallidus; (b) in left DLPFC; and (c) in left IPS, when collapsed across visual (V) and audiovisual (VA) conditions. (d) Conjunction analysis confirmed overlap (purple shading) between isochrony enhancement effects on vision-only (V; blue shading) and audiovisual (VA; red shading) conditions in bilateral insula. (e) Cluster mean beta parameters (±1 s.e.d. for isochrony effect) plotted for each condition (light bars = isochronous; dark bars = random). Thresholds: voxel punc < 0.001 and cluster pFWE < 0.05 displayed on mean anatomical brain images.
Mentions: Isochrony enhanced activity in bilateral IFG, insula, putamen and globus pallidus, left DLPFC, and left intraparietal sulcus (IPS) when compared with random timing (Table 1; Fig. 2a–c). A conjunction analysis between the simple effect of isochronous versus random timing on BOLD signal during the vision-only and audiovisual conditions ([VISO > VRAND] and [VAISO > VARAND]) confirmed common activation of the right anterior insula by isochrony regardless of sound presence/absence (cluster pFWE = 0.029, 72 voxels, peak t15 = 4.52, x = 30, y = 24, z = 6; Fig. 2d,e). A similar pattern of activity was observed in the left anterior insula (Fig. 2d,e) but that cluster did not reach full statistical significance and is reported only for completeness (cluster pFWE > 0.05, 8 voxels, peak t15 = 4.08, x = −30, y = 21, z = 6). No regions were preferentially activated for random versus isochronous stimuli.

Bottom Line: Visual isochrony activated a similar timing-related brain network to that previously found primarily in auditory beat perception work.Finally, activity in multisensory left posterior superior temporal sulcus increased specifically during concurrent isochronous audiovisual presentations.These results indicate that regular isochronous timing can modulate visual processing and this can also involve multisensory audiovisual brain mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London WC1N 3BG, UK. jennifer.marchant@ucl.ac.uk

ABSTRACT
Understanding how the brain extracts and combines temporal structure (rhythm) information from events presented to different senses remains unresolved. Many neuroimaging beat perception studies have focused on the auditory domain and show the presence of a highly regular beat (isochrony) in "auditory" stimulus streams enhances neural responses in a distributed brain network and affects perceptual performance. Here, we acquired functional magnetic resonance imaging (fMRI) measurements of brain activity while healthy human participants performed a visual task on isochronous versus randomly timed "visual" streams, with or without concurrent task-irrelevant sounds. We found that visual detection of higher intensity oddball targets was better for isochronous than randomly timed streams, extending previous auditory findings to vision. The impact of isochrony on visual target sensitivity correlated positively with fMRI signal changes not only in visual cortex but also in auditory sensory cortex during audiovisual presentations. Visual isochrony activated a similar timing-related brain network to that previously found primarily in auditory beat perception work. Finally, activity in multisensory left posterior superior temporal sulcus increased specifically during concurrent isochronous audiovisual presentations. These results indicate that regular isochronous timing can modulate visual processing and this can also involve multisensory audiovisual brain mechanisms.

Show MeSH
Related in: MedlinePlus