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Distinct gamma-band components reflect the short-term memory maintenance of different sound lateralization angles.

Kaiser J, Heidegger T, Wibral M, Altmann CF, Lutzenberger W - Cereb. Cortex (2008)

Bottom Line: Distinct GBA components were found for each sample stimulus in different sensors over parieto-occipital cortex contralateral to the side of stimulation peaking during the middle 200-300 ms of the delay phase.The differentiation between "preferred" and "nonpreferred" stimuli during the final 100 ms of the delay phase correlated with task performance.These findings suggest that the observed GBA components reflect the activity of distinct networks tuned to spatial sound features which contribute to the maintenance of task-relevant information in short-term memory.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Psychology, Johann Wolfgang Goethe-University, 60528 Frankfurt am Main, Germany. j.kaiser@med.uni-frankfurt.de

ABSTRACT
Oscillatory activity in human electro- or magnetoencephalogram has been related to cortical stimulus representations and their modulation by cognitive processes. Whereas previous work has focused on gamma-band activity (GBA) during attention or maintenance of representations, there is little evidence for GBA reflecting individual stimulus representations. The present study aimed at identifying stimulus-specific GBA components during auditory spatial short-term memory. A total of 28 adults were assigned to 1 of 2 groups who were presented with only right- or left-lateralized sounds, respectively. In each group, 2 sample stimuli were used which differed in their lateralization angles (15 degrees or 45 degrees) with respect to the midsagittal plane. Statistical probability mapping served to identify spectral amplitude differences between 15 degrees versus 45 degrees stimuli. Distinct GBA components were found for each sample stimulus in different sensors over parieto-occipital cortex contralateral to the side of stimulation peaking during the middle 200-300 ms of the delay phase. The differentiation between "preferred" and "nonpreferred" stimuli during the final 100 ms of the delay phase correlated with task performance. These findings suggest that the observed GBA components reflect the activity of distinct networks tuned to spatial sound features which contribute to the maintenance of task-relevant information in short-term memory.

Show MeSH
Correct response rates and reaction times (means and standard errors) for S1 stimuli presented at 15° and 45° deviation from the midsagittal plane calculated across the entire group of subjects.
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fig2: Correct response rates and reaction times (means and standard errors) for S1 stimuli presented at 15° and 45° deviation from the midsagittal plane calculated across the entire group of subjects.

Mentions: Separate ANOVAs were conducted for correct response rate and reaction time with group (left vs. right stimulation) as between-subjects factor and stimulus (15° vs. 45°) as within-subject factor. Both analyses yielded main effects for stimulus (correct response rate: F1,26 = 4.3, P = 0.048, reaction time: F1,26 = 8.3, P = 0.008). As there were no significant group main effects or group × stimulus interactions, dependent-samples t tests were calculated for both dependent variables across groups (Fig. 2). Correct response rates tended to be lower for sounds lateralized at 15° than 45° (15°: 86.4% [SD = 8.2%], 45°: 89.4% [SD = 7.8%], t27 = 2.05, P = 0.051), and reaction time was longer for 15° than 45° stimuli (15°: 680% [SD = 139%] ms after the onset of S2, 45°: 648% [SD = 161%] ms, t27 = 2.92, P = 0.007). Across all subjects, correct response rate and reaction time were negatively correlated (r = −0.54, P = 0.003).


Distinct gamma-band components reflect the short-term memory maintenance of different sound lateralization angles.

Kaiser J, Heidegger T, Wibral M, Altmann CF, Lutzenberger W - Cereb. Cortex (2008)

Correct response rates and reaction times (means and standard errors) for S1 stimuli presented at 15° and 45° deviation from the midsagittal plane calculated across the entire group of subjects.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2536701&req=5

fig2: Correct response rates and reaction times (means and standard errors) for S1 stimuli presented at 15° and 45° deviation from the midsagittal plane calculated across the entire group of subjects.
Mentions: Separate ANOVAs were conducted for correct response rate and reaction time with group (left vs. right stimulation) as between-subjects factor and stimulus (15° vs. 45°) as within-subject factor. Both analyses yielded main effects for stimulus (correct response rate: F1,26 = 4.3, P = 0.048, reaction time: F1,26 = 8.3, P = 0.008). As there were no significant group main effects or group × stimulus interactions, dependent-samples t tests were calculated for both dependent variables across groups (Fig. 2). Correct response rates tended to be lower for sounds lateralized at 15° than 45° (15°: 86.4% [SD = 8.2%], 45°: 89.4% [SD = 7.8%], t27 = 2.05, P = 0.051), and reaction time was longer for 15° than 45° stimuli (15°: 680% [SD = 139%] ms after the onset of S2, 45°: 648% [SD = 161%] ms, t27 = 2.92, P = 0.007). Across all subjects, correct response rate and reaction time were negatively correlated (r = −0.54, P = 0.003).

Bottom Line: Distinct GBA components were found for each sample stimulus in different sensors over parieto-occipital cortex contralateral to the side of stimulation peaking during the middle 200-300 ms of the delay phase.The differentiation between "preferred" and "nonpreferred" stimuli during the final 100 ms of the delay phase correlated with task performance.These findings suggest that the observed GBA components reflect the activity of distinct networks tuned to spatial sound features which contribute to the maintenance of task-relevant information in short-term memory.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Psychology, Johann Wolfgang Goethe-University, 60528 Frankfurt am Main, Germany. j.kaiser@med.uni-frankfurt.de

ABSTRACT
Oscillatory activity in human electro- or magnetoencephalogram has been related to cortical stimulus representations and their modulation by cognitive processes. Whereas previous work has focused on gamma-band activity (GBA) during attention or maintenance of representations, there is little evidence for GBA reflecting individual stimulus representations. The present study aimed at identifying stimulus-specific GBA components during auditory spatial short-term memory. A total of 28 adults were assigned to 1 of 2 groups who were presented with only right- or left-lateralized sounds, respectively. In each group, 2 sample stimuli were used which differed in their lateralization angles (15 degrees or 45 degrees) with respect to the midsagittal plane. Statistical probability mapping served to identify spectral amplitude differences between 15 degrees versus 45 degrees stimuli. Distinct GBA components were found for each sample stimulus in different sensors over parieto-occipital cortex contralateral to the side of stimulation peaking during the middle 200-300 ms of the delay phase. The differentiation between "preferred" and "nonpreferred" stimuli during the final 100 ms of the delay phase correlated with task performance. These findings suggest that the observed GBA components reflect the activity of distinct networks tuned to spatial sound features which contribute to the maintenance of task-relevant information in short-term memory.

Show MeSH