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Overlapping functional anatomy for working memory and visual search.

Anderson EJ, Mannan SK, Rees G, Sumner P, Kennard C - Exp Brain Res (2010)

Bottom Line: Using visually matched spatial and non-spatial working memory tasks, we confirmed previous behavioural findings that show significant dual-task interference effects occur when inefficient visual search is performed concurrently with either working memory task.Drawing on previous findings (Anderson et al. in Exp Brain Res 180:289-302, 2007), we propose that the most likely anatomical locus for these interference effects is the inferior and middle frontal cortex of the right hemisphere.These areas are associated with attentional selection from memory as well as manipulation of information in memory, and we propose that the visual search and working memory tasks used here compete for common processing resources underlying these mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Neuroscience, Imperial College London, Charing Cross Hospital, St. Dunstan's Road, London W6 8RP, UK. e.anderson@fil.ion.ucl.ac.uk

ABSTRACT
Recent behavioural findings using dual-task paradigms demonstrate the importance of both spatial and non-spatial working memory processes in inefficient visual search (Anderson et al. in Exp Psychol 55:301-312, 2008). Here, using functional magnetic resonance imaging (fMRI), we sought to determine whether brain areas recruited during visual search are also involved in working memory. Using visually matched spatial and non-spatial working memory tasks, we confirmed previous behavioural findings that show significant dual-task interference effects occur when inefficient visual search is performed concurrently with either working memory task. Furthermore, we find considerable overlap in the cortical network activated by inefficient search and both working memory tasks. Our findings suggest that the interference effects observed behaviourally may have arisen from competition for cortical processes subserved by these overlapping regions. Drawing on previous findings (Anderson et al. in Exp Brain Res 180:289-302, 2007), we propose that the most likely anatomical locus for these interference effects is the inferior and middle frontal cortex of the right hemisphere. These areas are associated with attentional selection from memory as well as manipulation of information in memory, and we propose that the visual search and working memory tasks used here compete for common processing resources underlying these mechanisms.

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Results Experiment 1—the effects of dual-task performance on search times. RTs for inefficient search performed in isolation have been subtracted from search RTs during the dual-task conditions, for target present (filled triangle) and target absent search (filled square). On average, an additional 11 ms per item was required to perform target present search concurrently with the SWM task and 26 ms per item for target absent search, compared to search performed in isolation. Similarly an extra 11 ms per item was required for target present search performed concurrently with the VWM task and 28 ms per item for target absent search. Error bars indicate standard error of the mean
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Fig3: Results Experiment 1—the effects of dual-task performance on search times. RTs for inefficient search performed in isolation have been subtracted from search RTs during the dual-task conditions, for target present (filled triangle) and target absent search (filled square). On average, an additional 11 ms per item was required to perform target present search concurrently with the SWM task and 26 ms per item for target absent search, compared to search performed in isolation. Similarly an extra 11 ms per item was required for target present search performed concurrently with the VWM task and 28 ms per item for target absent search. Error bars indicate standard error of the mean

Mentions: Once the baseline search RT values have been subtracted from the search RTs for the spatial dual-task conditions, there is still a residual search ‘slope’ of 11 ms per item for target present search and 26 ms per item for target absent search. Similarly, once the baseline search RT values have been subtracted from the search RTs for the verbal dual-task conditions, there is still a residual search ‘slope’ of 11/28 ms per item for target present/absent search. Thus both the spatial and verbal memory load significantly interfered with search performance. These data are illustrated in Fig. 3 (see Table 1 for exact RT values). Importantly, analysis of variance, with working memory domain (spatial, verbal), search set size (4, 10), and target presence (present, absent) as within participant factors, confirmed there was no main effect of working memory domain (F(1,11) = 0.639, p = 0.441), no interaction between working memory domain and set size (F(1,11) = 0.044, p = 0.837) and no three-way interaction between memory domain, set size and target presence/absence (F(1,11) = 0.418, p = 0.531). This confirms that the spatial and verbal working memory tasks induced comparable interference effects with the visual search task. There was the expected main effect of set size (F(1,11) = 9.117, p = 0.012) and a trend for a significant interaction between set size and target presence (F(1,11) = 4.006, p = 0.071). All other effects did not reach significance.Fig. 3


Overlapping functional anatomy for working memory and visual search.

Anderson EJ, Mannan SK, Rees G, Sumner P, Kennard C - Exp Brain Res (2010)

Results Experiment 1—the effects of dual-task performance on search times. RTs for inefficient search performed in isolation have been subtracted from search RTs during the dual-task conditions, for target present (filled triangle) and target absent search (filled square). On average, an additional 11 ms per item was required to perform target present search concurrently with the SWM task and 26 ms per item for target absent search, compared to search performed in isolation. Similarly an extra 11 ms per item was required for target present search performed concurrently with the VWM task and 28 ms per item for target absent search. Error bars indicate standard error of the mean
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2800858&req=5

Fig3: Results Experiment 1—the effects of dual-task performance on search times. RTs for inefficient search performed in isolation have been subtracted from search RTs during the dual-task conditions, for target present (filled triangle) and target absent search (filled square). On average, an additional 11 ms per item was required to perform target present search concurrently with the SWM task and 26 ms per item for target absent search, compared to search performed in isolation. Similarly an extra 11 ms per item was required for target present search performed concurrently with the VWM task and 28 ms per item for target absent search. Error bars indicate standard error of the mean
Mentions: Once the baseline search RT values have been subtracted from the search RTs for the spatial dual-task conditions, there is still a residual search ‘slope’ of 11 ms per item for target present search and 26 ms per item for target absent search. Similarly, once the baseline search RT values have been subtracted from the search RTs for the verbal dual-task conditions, there is still a residual search ‘slope’ of 11/28 ms per item for target present/absent search. Thus both the spatial and verbal memory load significantly interfered with search performance. These data are illustrated in Fig. 3 (see Table 1 for exact RT values). Importantly, analysis of variance, with working memory domain (spatial, verbal), search set size (4, 10), and target presence (present, absent) as within participant factors, confirmed there was no main effect of working memory domain (F(1,11) = 0.639, p = 0.441), no interaction between working memory domain and set size (F(1,11) = 0.044, p = 0.837) and no three-way interaction between memory domain, set size and target presence/absence (F(1,11) = 0.418, p = 0.531). This confirms that the spatial and verbal working memory tasks induced comparable interference effects with the visual search task. There was the expected main effect of set size (F(1,11) = 9.117, p = 0.012) and a trend for a significant interaction between set size and target presence (F(1,11) = 4.006, p = 0.071). All other effects did not reach significance.Fig. 3

Bottom Line: Using visually matched spatial and non-spatial working memory tasks, we confirmed previous behavioural findings that show significant dual-task interference effects occur when inefficient visual search is performed concurrently with either working memory task.Drawing on previous findings (Anderson et al. in Exp Brain Res 180:289-302, 2007), we propose that the most likely anatomical locus for these interference effects is the inferior and middle frontal cortex of the right hemisphere.These areas are associated with attentional selection from memory as well as manipulation of information in memory, and we propose that the visual search and working memory tasks used here compete for common processing resources underlying these mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Neuroscience, Imperial College London, Charing Cross Hospital, St. Dunstan's Road, London W6 8RP, UK. e.anderson@fil.ion.ucl.ac.uk

ABSTRACT
Recent behavioural findings using dual-task paradigms demonstrate the importance of both spatial and non-spatial working memory processes in inefficient visual search (Anderson et al. in Exp Psychol 55:301-312, 2008). Here, using functional magnetic resonance imaging (fMRI), we sought to determine whether brain areas recruited during visual search are also involved in working memory. Using visually matched spatial and non-spatial working memory tasks, we confirmed previous behavioural findings that show significant dual-task interference effects occur when inefficient visual search is performed concurrently with either working memory task. Furthermore, we find considerable overlap in the cortical network activated by inefficient search and both working memory tasks. Our findings suggest that the interference effects observed behaviourally may have arisen from competition for cortical processes subserved by these overlapping regions. Drawing on previous findings (Anderson et al. in Exp Brain Res 180:289-302, 2007), we propose that the most likely anatomical locus for these interference effects is the inferior and middle frontal cortex of the right hemisphere. These areas are associated with attentional selection from memory as well as manipulation of information in memory, and we propose that the visual search and working memory tasks used here compete for common processing resources underlying these mechanisms.

Show MeSH