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Temporal adaptation to audiovisual asynchrony generalizes across different sound frequencies.

Navarra J, García-Morera J, Spence C - Front Psychol (2012)

Bottom Line: The human brain exhibits a highly adaptive ability to reduce natural asynchronies between visual and auditory signals.In the present study, we investigated whether or not temporal adaptation generalizes across different auditory frequencies.This suggests that temporal recalibration influences the audiovisual perception of sounds in a frequency non-specific manner and may imply the participation of non-primary perceptual areas of the brain that are not constrained by certain physical features such as sound frequency.

View Article: PubMed Central - PubMed

Affiliation: Fundació Sant Joan de Déu, Parc Sanitari Sant Joan de Déu - Hospital Sant Joan de Déu Esplugues de Llobregat, Barcelona, Spain.

ABSTRACT
The human brain exhibits a highly adaptive ability to reduce natural asynchronies between visual and auditory signals. Even though this mechanism robustly modulates the subsequent perception of sounds and visual stimuli, it is still unclear how such a temporal realignment is attained. In the present study, we investigated whether or not temporal adaptation generalizes across different auditory frequencies. In a first exposure phase, participants adapted to a fixed 220-ms audiovisual asynchrony or else to synchrony for 3 min. In a second phase, the participants performed simultaneity judgments (SJs) regarding pairs of audiovisual stimuli that were presented at different stimulus onset asynchronies (SOAs) and included either the same tone as in the exposure phase (a 250 Hz beep), another low-pitched beep (300 Hz), or a high-pitched beep (2500 Hz). Temporal realignment was always observed (when comparing SJ performance after exposure to asynchrony vs. synchrony), regardless of the frequency of the sound tested. This suggests that temporal recalibration influences the audiovisual perception of sounds in a frequency non-specific manner and may imply the participation of non-primary perceptual areas of the brain that are not constrained by certain physical features such as sound frequency.

No MeSH data available.


Related in: MedlinePlus

Temporal recalibration effects seen in audiovisual SJs including beeps of 250, 2500, and 300 Hz [shown in (A–C), respectively]. The proportion of “simultaneous” responses across the different SOAs was fitted with a Gaussian function. The graph shows the observed and fitted data from one of the participants in the experiment. The bar graph shows the point of subjective simultaneity (PSS) group average for synchrony and asynchrony conditions, including data (mean and standard error) from all of the participants. When audiovisual stimuli were presented asynchronously during the exposure phase, a temporal shift was observed (see dashed lines), in the PSS, toward the direction of the asynchrony (vision-first), and regardless of the sound being tested. The sensitivity to physical synchrony decreased (i.e., the SD increased) as a result of exposure to asynchrony.
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Figure 2: Temporal recalibration effects seen in audiovisual SJs including beeps of 250, 2500, and 300 Hz [shown in (A–C), respectively]. The proportion of “simultaneous” responses across the different SOAs was fitted with a Gaussian function. The graph shows the observed and fitted data from one of the participants in the experiment. The bar graph shows the point of subjective simultaneity (PSS) group average for synchrony and asynchrony conditions, including data (mean and standard error) from all of the participants. When audiovisual stimuli were presented asynchronously during the exposure phase, a temporal shift was observed (see dashed lines), in the PSS, toward the direction of the asynchrony (vision-first), and regardless of the sound being tested. The sensitivity to physical synchrony decreased (i.e., the SD increased) as a result of exposure to asynchrony.

Mentions: A temporal shift effect was observed in the PSS in the direction of the pre-exposed asynchrony both for audiovisual combinations including the adapted (33 ms on average)3 and the non-adapted tones (15 ms for the 2500-Hz tone; and 31 ms for the 300-Hz tone; see Figure 2). A non-parametric Wilcoxon signed-rank test, comparing the PSS after exposure to synchrony and asynchrony, showed that this effect was significant for all the tested sound frequencies (Z = −2.37, p = 0.018; Z = −2.37, p = 0.018; and Z = −2.2, p = 0.028, respectively). Further analyses revealed that while the difference in PSS after exposure to synchrony and asynchrony was statistically equivalent for the adapted test tone and the 300 Hz test tone (Wilcoxon signed-rank test: Z = −0.17, p = 0.87), there was a difference between the adapted (250 Hz) and the 2500 Hz-tone conditions (Wilcoxon signed-rank test: Z = −2.4, p = 0.018). In other words, even when the temporal shift was consistently observed in all participants for audiovisual pairs including a 2500 Hz test tone, this effect was significantly smaller in this condition than when the same tone was used in both the exposure and the test phases.


Temporal adaptation to audiovisual asynchrony generalizes across different sound frequencies.

Navarra J, García-Morera J, Spence C - Front Psychol (2012)

Temporal recalibration effects seen in audiovisual SJs including beeps of 250, 2500, and 300 Hz [shown in (A–C), respectively]. The proportion of “simultaneous” responses across the different SOAs was fitted with a Gaussian function. The graph shows the observed and fitted data from one of the participants in the experiment. The bar graph shows the point of subjective simultaneity (PSS) group average for synchrony and asynchrony conditions, including data (mean and standard error) from all of the participants. When audiovisual stimuli were presented asynchronously during the exposure phase, a temporal shift was observed (see dashed lines), in the PSS, toward the direction of the asynchrony (vision-first), and regardless of the sound being tested. The sensitivity to physical synchrony decreased (i.e., the SD increased) as a result of exposure to asynchrony.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3351678&req=5

Figure 2: Temporal recalibration effects seen in audiovisual SJs including beeps of 250, 2500, and 300 Hz [shown in (A–C), respectively]. The proportion of “simultaneous” responses across the different SOAs was fitted with a Gaussian function. The graph shows the observed and fitted data from one of the participants in the experiment. The bar graph shows the point of subjective simultaneity (PSS) group average for synchrony and asynchrony conditions, including data (mean and standard error) from all of the participants. When audiovisual stimuli were presented asynchronously during the exposure phase, a temporal shift was observed (see dashed lines), in the PSS, toward the direction of the asynchrony (vision-first), and regardless of the sound being tested. The sensitivity to physical synchrony decreased (i.e., the SD increased) as a result of exposure to asynchrony.
Mentions: A temporal shift effect was observed in the PSS in the direction of the pre-exposed asynchrony both for audiovisual combinations including the adapted (33 ms on average)3 and the non-adapted tones (15 ms for the 2500-Hz tone; and 31 ms for the 300-Hz tone; see Figure 2). A non-parametric Wilcoxon signed-rank test, comparing the PSS after exposure to synchrony and asynchrony, showed that this effect was significant for all the tested sound frequencies (Z = −2.37, p = 0.018; Z = −2.37, p = 0.018; and Z = −2.2, p = 0.028, respectively). Further analyses revealed that while the difference in PSS after exposure to synchrony and asynchrony was statistically equivalent for the adapted test tone and the 300 Hz test tone (Wilcoxon signed-rank test: Z = −0.17, p = 0.87), there was a difference between the adapted (250 Hz) and the 2500 Hz-tone conditions (Wilcoxon signed-rank test: Z = −2.4, p = 0.018). In other words, even when the temporal shift was consistently observed in all participants for audiovisual pairs including a 2500 Hz test tone, this effect was significantly smaller in this condition than when the same tone was used in both the exposure and the test phases.

Bottom Line: The human brain exhibits a highly adaptive ability to reduce natural asynchronies between visual and auditory signals.In the present study, we investigated whether or not temporal adaptation generalizes across different auditory frequencies.This suggests that temporal recalibration influences the audiovisual perception of sounds in a frequency non-specific manner and may imply the participation of non-primary perceptual areas of the brain that are not constrained by certain physical features such as sound frequency.

View Article: PubMed Central - PubMed

Affiliation: Fundació Sant Joan de Déu, Parc Sanitari Sant Joan de Déu - Hospital Sant Joan de Déu Esplugues de Llobregat, Barcelona, Spain.

ABSTRACT
The human brain exhibits a highly adaptive ability to reduce natural asynchronies between visual and auditory signals. Even though this mechanism robustly modulates the subsequent perception of sounds and visual stimuli, it is still unclear how such a temporal realignment is attained. In the present study, we investigated whether or not temporal adaptation generalizes across different auditory frequencies. In a first exposure phase, participants adapted to a fixed 220-ms audiovisual asynchrony or else to synchrony for 3 min. In a second phase, the participants performed simultaneity judgments (SJs) regarding pairs of audiovisual stimuli that were presented at different stimulus onset asynchronies (SOAs) and included either the same tone as in the exposure phase (a 250 Hz beep), another low-pitched beep (300 Hz), or a high-pitched beep (2500 Hz). Temporal realignment was always observed (when comparing SJ performance after exposure to asynchrony vs. synchrony), regardless of the frequency of the sound tested. This suggests that temporal recalibration influences the audiovisual perception of sounds in a frequency non-specific manner and may imply the participation of non-primary perceptual areas of the brain that are not constrained by certain physical features such as sound frequency.

No MeSH data available.


Related in: MedlinePlus