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Modulation of ventral prefrontal cortex functional connections reflects the interplay of cognitive processes and stimulus characteristics.

Protzner AB, McIntosh AR - Cereb. Cortex (2008)

Bottom Line: Emerging ideas of brain function emphasize the context-dependency of regional contributions to cognitive operations, where the function of a particular region is constrained by its pattern of functional connectivity.Analysis of right ventral PFC functional connectivity, however, suggested these activity patterns interact.These results underscore the interactive nature of brain processing, where modality-specific and process-specific networks interact for normal cognitive operations.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuropsychology, Toronto Western Hospital and Research Institute, Toronto, M5G 2M9 ON, Canada. protzner@uhnres.utoronto.ca

ABSTRACT
Emerging ideas of brain function emphasize the context-dependency of regional contributions to cognitive operations, where the function of a particular region is constrained by its pattern of functional connectivity. We used functional magnetic resonance imaging to examine how modality of input (auditory or visual) affects prefrontal cortex (PFC) functional connectivity for simple working memory tasks. The hypothesis was that PFC would show contextually dependent changes in functional connectivity in relation to the modality of input despite similar cognitive demands. Participants were presented with auditory or visual bandpass-filtered noise stimuli, and performed 2 simple short-term memory tasks. Brain activation patterns independently mapped onto modality and task demands. Analysis of right ventral PFC functional connectivity, however, suggested these activity patterns interact. One functional connectivity pattern showed task differences independent of stimulus modality and involved ventromedial and dorsolateral prefrontal and occipitoparietal cortices. A second pattern showed task differences that varied with modality, engaging superior temporal and occipital association regions. Importantly, these association regions showed nonzero functional connectivity in all conditions, rather than showing a zero connectivity in one modality and nonzero in the other. These results underscore the interactive nature of brain processing, where modality-specific and process-specific networks interact for normal cognitive operations.

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Correlation profiles for selected voxels identified in from the task demands LV as shown in Figure 6. Correlations are plotted across the time window from stimulus onset (T = 0). (A) The correlation for ventromedial PFC (BA 10, MNI template coordinates: x = 0, y = 60, z = −4); and (B) occipitoparietal cortex (BA 19, MNI template coordinates: x = 16, y = −94, z = 24).
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fig7: Correlation profiles for selected voxels identified in from the task demands LV as shown in Figure 6. Correlations are plotted across the time window from stimulus onset (T = 0). (A) The correlation for ventromedial PFC (BA 10, MNI template coordinates: x = 0, y = 60, z = −4); and (B) occipitoparietal cortex (BA 19, MNI template coordinates: x = 16, y = −94, z = 24).

Mentions: The second LV showed a task main effect (singular value = 152.44, P < 0.016, task demands LV, Fig. 6, see Table 2 for a list of local maxima), with positive correlations for temporal sequencing tasks and negative for comparison tasks. The confidence interval was larger for visual temporal sequencing relative to other tasks, suggesting it was somewhat less stably represented, but the 95% interval did not cross zero. The dominant positive saliences, indicating a more positive correlation in temporal sequencing tasks, were observed in ventromedial PFC (BA 8 and 10) in early lags, and later lags showed strong weights for middle temporal gyrus (BA 21, 22, and 37) and thalamus. Negative saliences, indicating relatively more negative correlations for the comparison tasks, were concentrated on dorsolateral and anterior prefrontal gyrus (BA 9), and occipitoparietal cortices (BA 7 and 19). Representative correlation profiles for maxima from the singular image are presented in Figure 7. The profile for the ventromedial prefrontal region (Fig. 7A) shows a strong differentiation between comparison and temporal sequencing at lags 1 and 2, albeit somewhat less for visual comparison as might be anticipated from the lower overall correlation for this condition. The profile for the occipitoparietal region (Fig. 7B) shows a more sustained differentiation beginning at lag 1 and extending across the remaining temporal window.


Modulation of ventral prefrontal cortex functional connections reflects the interplay of cognitive processes and stimulus characteristics.

Protzner AB, McIntosh AR - Cereb. Cortex (2008)

Correlation profiles for selected voxels identified in from the task demands LV as shown in Figure 6. Correlations are plotted across the time window from stimulus onset (T = 0). (A) The correlation for ventromedial PFC (BA 10, MNI template coordinates: x = 0, y = 60, z = −4); and (B) occipitoparietal cortex (BA 19, MNI template coordinates: x = 16, y = −94, z = 24).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2665153&req=5

fig7: Correlation profiles for selected voxels identified in from the task demands LV as shown in Figure 6. Correlations are plotted across the time window from stimulus onset (T = 0). (A) The correlation for ventromedial PFC (BA 10, MNI template coordinates: x = 0, y = 60, z = −4); and (B) occipitoparietal cortex (BA 19, MNI template coordinates: x = 16, y = −94, z = 24).
Mentions: The second LV showed a task main effect (singular value = 152.44, P < 0.016, task demands LV, Fig. 6, see Table 2 for a list of local maxima), with positive correlations for temporal sequencing tasks and negative for comparison tasks. The confidence interval was larger for visual temporal sequencing relative to other tasks, suggesting it was somewhat less stably represented, but the 95% interval did not cross zero. The dominant positive saliences, indicating a more positive correlation in temporal sequencing tasks, were observed in ventromedial PFC (BA 8 and 10) in early lags, and later lags showed strong weights for middle temporal gyrus (BA 21, 22, and 37) and thalamus. Negative saliences, indicating relatively more negative correlations for the comparison tasks, were concentrated on dorsolateral and anterior prefrontal gyrus (BA 9), and occipitoparietal cortices (BA 7 and 19). Representative correlation profiles for maxima from the singular image are presented in Figure 7. The profile for the ventromedial prefrontal region (Fig. 7A) shows a strong differentiation between comparison and temporal sequencing at lags 1 and 2, albeit somewhat less for visual comparison as might be anticipated from the lower overall correlation for this condition. The profile for the occipitoparietal region (Fig. 7B) shows a more sustained differentiation beginning at lag 1 and extending across the remaining temporal window.

Bottom Line: Emerging ideas of brain function emphasize the context-dependency of regional contributions to cognitive operations, where the function of a particular region is constrained by its pattern of functional connectivity.Analysis of right ventral PFC functional connectivity, however, suggested these activity patterns interact.These results underscore the interactive nature of brain processing, where modality-specific and process-specific networks interact for normal cognitive operations.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuropsychology, Toronto Western Hospital and Research Institute, Toronto, M5G 2M9 ON, Canada. protzner@uhnres.utoronto.ca

ABSTRACT
Emerging ideas of brain function emphasize the context-dependency of regional contributions to cognitive operations, where the function of a particular region is constrained by its pattern of functional connectivity. We used functional magnetic resonance imaging to examine how modality of input (auditory or visual) affects prefrontal cortex (PFC) functional connectivity for simple working memory tasks. The hypothesis was that PFC would show contextually dependent changes in functional connectivity in relation to the modality of input despite similar cognitive demands. Participants were presented with auditory or visual bandpass-filtered noise stimuli, and performed 2 simple short-term memory tasks. Brain activation patterns independently mapped onto modality and task demands. Analysis of right ventral PFC functional connectivity, however, suggested these activity patterns interact. One functional connectivity pattern showed task differences independent of stimulus modality and involved ventromedial and dorsolateral prefrontal and occipitoparietal cortices. A second pattern showed task differences that varied with modality, engaging superior temporal and occipital association regions. Importantly, these association regions showed nonzero functional connectivity in all conditions, rather than showing a zero connectivity in one modality and nonzero in the other. These results underscore the interactive nature of brain processing, where modality-specific and process-specific networks interact for normal cognitive operations.

Show MeSH