Limits...
The Temporal Dynamics of Scene Processing: A Multifaceted EEG Investigation

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Our remarkable ability to process complex visual scenes is supported by a network of scene-selective cortical regions. Despite growing knowledge about the scene representation in these regions, much less is known about the temporal dynamics with which these representations emerge. We conducted two experiments aimed at identifying and characterizing the earliest markers of scene-specific processing. In the first experiment, human participants viewed images of scenes, faces, and everyday objects while event-related potentials (ERPs) were recorded. We found that the first ERP component to evince a significantly stronger response to scenes than the other categories was the P2, peaking ∼220 ms after stimulus onset. To establish that the P2 component reflects scene-specific processing, in the second experiment, we recorded ERPs while the participants viewed diverse real-world scenes spanning the following three global scene properties: spatial expanse (open/closed), relative distance (near/far), and naturalness (man-made/natural). We found that P2 amplitude was sensitive to these scene properties at both the categorical level, distinguishing between open and closed natural scenes, as well as at the single-image level, reflecting both computationally derived scene statistics and behavioral ratings of naturalness and spatial expanse. Together, these results establish the P2 as an ERP marker for scene processing, and demonstrate that scene-specific global information is available in the neural response as early as 220 ms.

No MeSH data available.


Grand average ERP analysis results for Experiment 2. a, Mean P2 peak amplitudes in response to open and closed scenes (orange and purple, respectively) presented separately for the man-made and natural scenes (left and right columns respectively). b, Mean P2 peak amplitudes in response to natural (green) and man-made scenes (cyan). c, Mean N1 peak amplitudes in response to natural (green) and man-made scenes (cyan). All data are plotted for the posterior lateral sites. Significant differences (p < 0.05) between pairs of categories are denoted by asterisk (error bars indicate between-subjects SE).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5037322&req=5

Figure 5: Grand average ERP analysis results for Experiment 2. a, Mean P2 peak amplitudes in response to open and closed scenes (orange and purple, respectively) presented separately for the man-made and natural scenes (left and right columns respectively). b, Mean P2 peak amplitudes in response to natural (green) and man-made scenes (cyan). c, Mean N1 peak amplitudes in response to natural (green) and man-made scenes (cyan). All data are plotted for the posterior lateral sites. Significant differences (p < 0.05) between pairs of categories are denoted by asterisk (error bars indicate between-subjects SE).

Mentions: Using the peak P2 window for each participant identified in Experiment 1 (for details, see Materials and Methods), we extracted amplitudes for each of the eight combinations of the three scene dimensions and submitted them to a four-way repeated-measures ANOVAac with hemisphere (left, right), naturalness (man-made, natural), distance (near, far), and spatial expanse (closed, open) as independent variables (Fig. 4, grand average waveforms depicting the three main effects; Table 3, P2 peak amplitudes ANOVA, full details of the ANOVA). We observed a significant main effect of naturalness (F(1,11) = 26.62, MSE = 1.67, p = 0.0005), with natural scenes evoking a greater positive response (mean = 2.85 mV, SEM = 1.05) than man-made scenes (mean = 1.89 mV, SE = 1.02; Fig. 5b). However, this effect was modulated by a significant interaction between spatial expanse and naturalness (F(1,11) = 4.59, MSE = 1.32, p = 0.05). Follow-up post hoc comparisons showed a significant effect of spatial expanse for the natural scenes (t(11) = 2.16, p = 0.05)ad, but not for the man-made scenes (t(11) = −0.53, p = 0.60)ae, with greater positive response for the closed natural scenes relative to the open natural scenes (Fig. 5a).


The Temporal Dynamics of Scene Processing: A Multifaceted EEG Investigation
Grand average ERP analysis results for Experiment 2. a, Mean P2 peak amplitudes in response to open and closed scenes (orange and purple, respectively) presented separately for the man-made and natural scenes (left and right columns respectively). b, Mean P2 peak amplitudes in response to natural (green) and man-made scenes (cyan). c, Mean N1 peak amplitudes in response to natural (green) and man-made scenes (cyan). All data are plotted for the posterior lateral sites. Significant differences (p < 0.05) between pairs of categories are denoted by asterisk (error bars indicate between-subjects SE).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037322&req=5

Figure 5: Grand average ERP analysis results for Experiment 2. a, Mean P2 peak amplitudes in response to open and closed scenes (orange and purple, respectively) presented separately for the man-made and natural scenes (left and right columns respectively). b, Mean P2 peak amplitudes in response to natural (green) and man-made scenes (cyan). c, Mean N1 peak amplitudes in response to natural (green) and man-made scenes (cyan). All data are plotted for the posterior lateral sites. Significant differences (p < 0.05) between pairs of categories are denoted by asterisk (error bars indicate between-subjects SE).
Mentions: Using the peak P2 window for each participant identified in Experiment 1 (for details, see Materials and Methods), we extracted amplitudes for each of the eight combinations of the three scene dimensions and submitted them to a four-way repeated-measures ANOVAac with hemisphere (left, right), naturalness (man-made, natural), distance (near, far), and spatial expanse (closed, open) as independent variables (Fig. 4, grand average waveforms depicting the three main effects; Table 3, P2 peak amplitudes ANOVA, full details of the ANOVA). We observed a significant main effect of naturalness (F(1,11) = 26.62, MSE = 1.67, p = 0.0005), with natural scenes evoking a greater positive response (mean = 2.85 mV, SEM = 1.05) than man-made scenes (mean = 1.89 mV, SE = 1.02; Fig. 5b). However, this effect was modulated by a significant interaction between spatial expanse and naturalness (F(1,11) = 4.59, MSE = 1.32, p = 0.05). Follow-up post hoc comparisons showed a significant effect of spatial expanse for the natural scenes (t(11) = 2.16, p = 0.05)ad, but not for the man-made scenes (t(11) = −0.53, p = 0.60)ae, with greater positive response for the closed natural scenes relative to the open natural scenes (Fig. 5a).

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Our remarkable ability to process complex visual scenes is supported by a network of scene-selective cortical regions. Despite growing knowledge about the scene representation in these regions, much less is known about the temporal dynamics with which these representations emerge. We conducted two experiments aimed at identifying and characterizing the earliest markers of scene-specific processing. In the first experiment, human participants viewed images of scenes, faces, and everyday objects while event-related potentials (ERPs) were recorded. We found that the first ERP component to evince a significantly stronger response to scenes than the other categories was the P2, peaking &sim;220 ms after stimulus onset. To establish that the P2 component reflects scene-specific processing, in the second experiment, we recorded ERPs while the participants viewed diverse real-world scenes spanning the following three global scene properties: spatial expanse (open/closed), relative distance (near/far), and naturalness (man-made/natural). We found that P2 amplitude was sensitive to these scene properties at both the categorical level, distinguishing between open and closed natural scenes, as well as at the single-image level, reflecting both computationally derived scene statistics and behavioral ratings of naturalness and spatial expanse. Together, these results establish the P2 as an ERP marker for scene processing, and demonstrate that scene-specific global information is available in the neural response as early as 220 ms.

No MeSH data available.