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Distinct roles for lateral and medial rostral prefrontal cortex in source monitoring of perceived and imagined events.

Turner MS, Simons JS, Gilbert SJ, Frith CD, Burgess PW - Neuropsychologia (2008)

Bottom Line: Lateral regions of rostral PFC were activated in both tasks.However medial regions of rostral PFC were activated only when participants were required to recollect source information for self-generated, "imagined" stimuli, indicating a specific role in self-referential processing.These results suggest that whilst the processing resources supported by some regions of lateral rostral PFC play a general role in source recollection, those supported by medial rostral PFC structures may be more specialised in their contributions.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cognitive Neuroscience and Department of Psychology, University College London, 17 Queen Square, London WC1N 3AR, UK. martha.turner@ucl.ac.uk

ABSTRACT
Rostral prefrontal cortex (PFC) is known to be involved in source memory, the ability to recollect contextual information about an event. However it is unclear whether subregions of rostral PFC may be differentially engaged during the recollection of different kinds of source detail. We used event related functional MRI to contrast two forms of source recollection: (1) recollection of whether stimuli had previously been perceived or imagined, and (2) recollection of which of two temporally distinct lists those stimuli had been presented in. Lateral regions of rostral PFC were activated in both tasks. However medial regions of rostral PFC were activated only when participants were required to recollect source information for self-generated, "imagined" stimuli, indicating a specific role in self-referential processing. In addition, reduced activity in a region of medial ventro-caudal PFC/basal forebrain was associated with making "imagined-to-perceived" confabulation errors. These results suggest that whilst the processing resources supported by some regions of lateral rostral PFC play a general role in source recollection, those supported by medial rostral PFC structures may be more specialised in their contributions.

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Regions of rostral PFC activated in the critical contrasts. Activations in contiguous regions of bilateral rostral PFC were observed in comparisons of (A) Recollection of Perceived/Imagined and Temporal Source > New Items, and (B) Recollection of Temporal Source > Recollection of Perceived/Imagined Source. These regions are proposed to be involved in several different types of source recollection. By contrast medial regions of rostral PFC were only activated in comparisons of (C) Source Recollection for Items Imagined at Study > Source Recollection for Items Perceived at Study and (D) the interaction term [Imagined at Study (P/I–Temporal source)] − [Perceived at Study (P/I–Temporal source)]. These regions are assumed to be preferentially involved in source recollection involving self-generated information.
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fig2: Regions of rostral PFC activated in the critical contrasts. Activations in contiguous regions of bilateral rostral PFC were observed in comparisons of (A) Recollection of Perceived/Imagined and Temporal Source > New Items, and (B) Recollection of Temporal Source > Recollection of Perceived/Imagined Source. These regions are proposed to be involved in several different types of source recollection. By contrast medial regions of rostral PFC were only activated in comparisons of (C) Source Recollection for Items Imagined at Study > Source Recollection for Items Perceived at Study and (D) the interaction term [Imagined at Study (P/I–Temporal source)] − [Perceived at Study (P/I–Temporal source)]. These regions are assumed to be preferentially involved in source recollection involving self-generated information.

Mentions: In order to find regions involved in correct recollection of both P/I and temporal source information, the two conditions (P/I Source > New and Temporal Source > New) were inclusively masked, both thresholded at p = 0.001 uncorrected, and using an extent threshold of 10 voxels. This analysis is equivalent to a conjunction analysis, using the “conjunction ” as recommended by Nichols, Brett, Andersson, Wager, and Poline (2005). Correct recollection of both types of source information provoked activation in a number of areas that closely replicated previous studies of source recollection (Cansino et al., 2002; Dobbins et al., 2002; Dobbins & Wagner, 2005; Simons, Owen, et al., 2005; Simons, Gilbert, et al., 2005; Simons, Henson, Gilbert, & Fletcher, 2008). As can be seen in Table 2, regions activated included bilateral rostrolateral PFC (BA 10), left dorsolateral PFC (BA 9/46), bilateral inferior PFC (BA 47), and bilateral inferior parietal cortex (BA 40). The bilateral rostrolateral PFC activations are shown in Fig. 2A.


Distinct roles for lateral and medial rostral prefrontal cortex in source monitoring of perceived and imagined events.

Turner MS, Simons JS, Gilbert SJ, Frith CD, Burgess PW - Neuropsychologia (2008)

Regions of rostral PFC activated in the critical contrasts. Activations in contiguous regions of bilateral rostral PFC were observed in comparisons of (A) Recollection of Perceived/Imagined and Temporal Source > New Items, and (B) Recollection of Temporal Source > Recollection of Perceived/Imagined Source. These regions are proposed to be involved in several different types of source recollection. By contrast medial regions of rostral PFC were only activated in comparisons of (C) Source Recollection for Items Imagined at Study > Source Recollection for Items Perceived at Study and (D) the interaction term [Imagined at Study (P/I–Temporal source)] − [Perceived at Study (P/I–Temporal source)]. These regions are assumed to be preferentially involved in source recollection involving self-generated information.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC2697314&req=5

fig2: Regions of rostral PFC activated in the critical contrasts. Activations in contiguous regions of bilateral rostral PFC were observed in comparisons of (A) Recollection of Perceived/Imagined and Temporal Source > New Items, and (B) Recollection of Temporal Source > Recollection of Perceived/Imagined Source. These regions are proposed to be involved in several different types of source recollection. By contrast medial regions of rostral PFC were only activated in comparisons of (C) Source Recollection for Items Imagined at Study > Source Recollection for Items Perceived at Study and (D) the interaction term [Imagined at Study (P/I–Temporal source)] − [Perceived at Study (P/I–Temporal source)]. These regions are assumed to be preferentially involved in source recollection involving self-generated information.
Mentions: In order to find regions involved in correct recollection of both P/I and temporal source information, the two conditions (P/I Source > New and Temporal Source > New) were inclusively masked, both thresholded at p = 0.001 uncorrected, and using an extent threshold of 10 voxels. This analysis is equivalent to a conjunction analysis, using the “conjunction ” as recommended by Nichols, Brett, Andersson, Wager, and Poline (2005). Correct recollection of both types of source information provoked activation in a number of areas that closely replicated previous studies of source recollection (Cansino et al., 2002; Dobbins et al., 2002; Dobbins & Wagner, 2005; Simons, Owen, et al., 2005; Simons, Gilbert, et al., 2005; Simons, Henson, Gilbert, & Fletcher, 2008). As can be seen in Table 2, regions activated included bilateral rostrolateral PFC (BA 10), left dorsolateral PFC (BA 9/46), bilateral inferior PFC (BA 47), and bilateral inferior parietal cortex (BA 40). The bilateral rostrolateral PFC activations are shown in Fig. 2A.

Bottom Line: Lateral regions of rostral PFC were activated in both tasks.However medial regions of rostral PFC were activated only when participants were required to recollect source information for self-generated, "imagined" stimuli, indicating a specific role in self-referential processing.These results suggest that whilst the processing resources supported by some regions of lateral rostral PFC play a general role in source recollection, those supported by medial rostral PFC structures may be more specialised in their contributions.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cognitive Neuroscience and Department of Psychology, University College London, 17 Queen Square, London WC1N 3AR, UK. martha.turner@ucl.ac.uk

ABSTRACT
Rostral prefrontal cortex (PFC) is known to be involved in source memory, the ability to recollect contextual information about an event. However it is unclear whether subregions of rostral PFC may be differentially engaged during the recollection of different kinds of source detail. We used event related functional MRI to contrast two forms of source recollection: (1) recollection of whether stimuli had previously been perceived or imagined, and (2) recollection of which of two temporally distinct lists those stimuli had been presented in. Lateral regions of rostral PFC were activated in both tasks. However medial regions of rostral PFC were activated only when participants were required to recollect source information for self-generated, "imagined" stimuli, indicating a specific role in self-referential processing. In addition, reduced activity in a region of medial ventro-caudal PFC/basal forebrain was associated with making "imagined-to-perceived" confabulation errors. These results suggest that whilst the processing resources supported by some regions of lateral rostral PFC play a general role in source recollection, those supported by medial rostral PFC structures may be more specialised in their contributions.

Show MeSH
Related in: MedlinePlus