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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

Schematic of visual task and behavioral performance measures. (a) Schematic of visual intensity-target detection task. (b and c) Timeline for stimulus onset during the 4 isochronous trial types (100, 200, 300, and 400 ms SOAs) and an exemplar random timing trial. (d) Visual target detection sensitivity (d′) was enhanced and (e) RTs reduced by isochronous (light bars) compared with random timing conditions (dark bars), when visual stimuli were presented alone (V; blue bars) or accompanied by synchronous auditory tones (VA; red bars). Group means (±1 standard error of the difference (s.e.d) for isochrony effect).
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fig1: Schematic of visual task and behavioral performance measures. (a) Schematic of visual intensity-target detection task. (b and c) Timeline for stimulus onset during the 4 isochronous trial types (100, 200, 300, and 400 ms SOAs) and an exemplar random timing trial. (d) Visual target detection sensitivity (d′) was enhanced and (e) RTs reduced by isochronous (light bars) compared with random timing conditions (dark bars), when visual stimuli were presented alone (V; blue bars) or accompanied by synchronous auditory tones (VA; red bars). Group means (±1 standard error of the difference (s.e.d) for isochrony effect).

Mentions: Each trial was 14 s in duration and comprised on average 57 rapid visual events (range 36–141), of which up to 6 were higher intensity targets (mean 3). The standard visual stimulus was a red central annulus (33 ms, 8° va diameter, 2° va aperture, 0.06 cd/mm2), and the target stimulus was identical except brighter (by a mean ± standard deviation of 0.17 ± 0.86 cd/mm2 across participants after individual titration). Target luminance was set for each participant prior to the main experiment to achieve approximately 75% hit-rate. Target events were restricted from occurring within 1.5 s from the start of a trial, end of the trial, or another target event. Visual stimuli were presented on a black background and a white central fixation cross (0.5o va, 2.31 cd/mm2) remained visible throughout the experimental session (Fig. 1a). The intertrial interval was 2.01 s. Participants were instructed to make an immediate button press with their right index finger on detection of a brighter visual target.


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

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

Schematic of visual task and behavioral performance measures. (a) Schematic of visual intensity-target detection task. (b and c) Timeline for stimulus onset during the 4 isochronous trial types (100, 200, 300, and 400 ms SOAs) and an exemplar random timing trial. (d) Visual target detection sensitivity (d′) was enhanced and (e) RTs reduced by isochronous (light bars) compared with random timing conditions (dark bars), when visual stimuli were presented alone (V; blue bars) or accompanied by synchronous auditory tones (VA; red bars). Group means (±1 standard error of the difference (s.e.d) for isochrony effect).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3643713&req=5

fig1: Schematic of visual task and behavioral performance measures. (a) Schematic of visual intensity-target detection task. (b and c) Timeline for stimulus onset during the 4 isochronous trial types (100, 200, 300, and 400 ms SOAs) and an exemplar random timing trial. (d) Visual target detection sensitivity (d′) was enhanced and (e) RTs reduced by isochronous (light bars) compared with random timing conditions (dark bars), when visual stimuli were presented alone (V; blue bars) or accompanied by synchronous auditory tones (VA; red bars). Group means (±1 standard error of the difference (s.e.d) for isochrony effect).
Mentions: Each trial was 14 s in duration and comprised on average 57 rapid visual events (range 36–141), of which up to 6 were higher intensity targets (mean 3). The standard visual stimulus was a red central annulus (33 ms, 8° va diameter, 2° va aperture, 0.06 cd/mm2), and the target stimulus was identical except brighter (by a mean ± standard deviation of 0.17 ± 0.86 cd/mm2 across participants after individual titration). Target luminance was set for each participant prior to the main experiment to achieve approximately 75% hit-rate. Target events were restricted from occurring within 1.5 s from the start of a trial, end of the trial, or another target event. Visual stimuli were presented on a black background and a white central fixation cross (0.5o va, 2.31 cd/mm2) remained visible throughout the experimental session (Fig. 1a). The intertrial interval was 2.01 s. Participants were instructed to make an immediate button press with their right index finger on detection of a brighter visual target.

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