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John E Desmond - One of the best experts on this subject based on the ideXlab platform.
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Disruption of Cerebellar Prediction in Verbal Working Memory
Frontiers Media S.A., 2019Co-Authors: Yi-shin Sheu, Yu Liang, John E DesmondAbstract:Mounting evidence suggests that the right cerebellum contributes to Verbal Working Memory, but the functional role of this contribution remains unclear. In an established theory of motor control, the cerebellum is thought to predict sensory consequences of movements through an internal “forward model.” Here, we hypothesize a similar predictive process can generalize to cerebellar non-motor function, and that the right cerebellum plays a predictive role that is beneficial for rapidly engaging the phonological loop in Verbal Working Memory. To test this hypothesis, double-pulse transcranial magnetic stimulation (TMS) was administered over either the right cerebellum or right occipital lobe (control site), on half the trials, to interrupt the rehearsal of a 6-letter sequence. We found that cerebellar stimulation resulted in greater errors in participants’ report of the letter in the current position. Additional analyses revealed that immediately after cerebellar TMS, participants were more likely to use out of date information to predict the next letter in the sequence. This pattern of errors is consistent with TMS causing a temporary disruption of state estimation and cerebellar forward model function, leading to prediction errors in the phonological loop
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the association between eye movements and cerebellar activation in a Verbal Working Memory task
Cerebral Cortex, 2016Co-Authors: Dominic T Cheng, Jutta Peterburs, John E DesmondAbstract:: It has been argued that cerebellar activations during cognitive tasks may masquerade as cognition, while actually reflecting processes related to movement planning or motor learning. The present study investigated whether the cerebellar load effect for Verbal Working Memory, that is, increased activations in lobule VI/Crus I and lobule VIIB/VIIIA, is related to eye movements and oculomotor processing. Fifteen participants performed an fMRI-based Sternberg Verbal Working Memory task. Oculomotor and cognitive task demands were manipulated by using closely and widely spaced stimuli, and high and low cognitive load. Trial-based quantitative eye movement parameters were obtained from concurrent eye tracking. Conventional MRI analysis replicated the cerebellar load effect in lobules VI and VIIB/VIIIa. With quantitative eye movement parameters as regressors, analysis yielded very similar activation patterns. While load effect and eye regressor generally recruited spatially distinct neocortical and cerebellar regions, conjunction analysis showed that a small subset of prefrontal areas implicated in the load effect also responded to the eye regressor. The present results indicate that cognitive load-dependent activations in lateral superior and posteroinferior cerebellar regions in the Sternberg task are independent of eye movements occurring during stimulus encoding. This is inconsistent with the notion that cognitive load-dependent cerebellar activations merely reflect oculomotor processing.
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an fmri investigation of cerebellar function during Verbal Working Memory in methadone maintenance patients
The Cerebellum, 2012Co-Authors: Cherie L Marvel, Monica L Faulkner, Eric C. Strain, Miriam Z Mintzer, John E DesmondAbstract:Working Memory is impaired in opioid-dependent individuals, yet the neural underpinnings of Working Memory in this population are largely unknown. Previous studies in healthy adults have demonstrated that Working Memory is supported by a network of brain regions that includes a cerebro-cerebellar circuit. The cerebellum, in particular, may be important for inner speech mechanisms that assist Verbal Working Memory. This study used functional magnetic resonance imaging to examine brain activity associated with Working Memory in five opioid-dependent, methadone-maintained patients and five matched, healthy controls. An item recognition task was administered in two conditions: (1) a low Working Memory load “match” condition in which participants determined whether target letters presented at the beginning of the trial matched a probe item, and (2) a high Working Memory load “manipulation” condition in which participants counted two alphabetical letters forward of each of the targets and determined whether either of these new items matched a probe item. Response times and accuracy scores were not significantly different between the groups. FMRI analyses indicated that, in association with higher Working Memory load (“manipulation” condition), the patient group exhibited hyperactivity in the superior and inferior cerebellum and amygdala relative to that of controls. At a more liberal statistical threshold, patients exhibited hypoactivity in the left prefrontal and medial frontal/pre-SMA regions. These results indicate that Verbal Working Memory in opioid-dependent individuals involves a disrupted cerebro-cerebellar circuit and shed light on the neuroanatomical basis of Working Memory impairments in this population.
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Functional Topography of the Cerebellum in Verbal Working Memory
Neuropsychology Review, 2010Co-Authors: Cherie L Marvel, John E DesmondAbstract:Speech—both overt and covert—facilitates Working Memory by creating and refreshing motor Memory traces, allowing new information to be received and processed. Neuroimaging studies suggest a functional topography within the sub-regions of the cerebellum that subserve Verbal Working Memory. Medial regions of the anterior cerebellum support overt speech, consistent with other forms of motor execution such as finger tapping, whereas lateral portions of the superior cerebellum support speech planning and preparation (e.g., covert speech). The inferior cerebellum is active when information is maintained across a delay, but activation appears to be independent of speech, lateralized by modality of stimulus presentation, and possibly related to phonological storage processes. Motor (dorsal) and cognitive (ventral) channels of cerebellar output nuclei can be distinguished in Working Memory. Clinical investigations suggest that hyper-activity of cerebellum and disrupted control of inner speech may contribute to certain psychiatric symptoms.
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the contributions of cerebro cerebellar circuitry to executive Verbal Working Memory
Cortex, 2010Co-Authors: Cherie L Marvel, John E DesmondAbstract:Abstract Contributions of cerebro-cerebellar function to executive Verbal Working Memory were examined using event-related functional magnetic resonance imaging (fMRI) while 16 subjects completed two versions of the Sternberg task. In both versions subjects were presented with two or six target letters during the encoding phase, which were held in Memory during the maintenance phase. A single probe letter was presented during the retrieval phase. In the “match condition”, subjects decided whether the probe matched the target letters. In the “executive condition”, subjects created a new probe by counting two alphabetical letters forward (e.g., f → h) and decided whether the new probe matched the target letters. Neural activity during the match and executive conditions was compared during each phase of the task. There were four main findings. First, cerebro-cerebellar activity increased as a function of executive load. Second, the dorsal cerebellar dentate co-activated with the supplementary motor area (SMA) during encoding. This likely represented the formation of an articulatory (motor) trajectory. Third, the ventral cerebellar dentate co-activated with anterior prefrontal regions Brodmann Area (BA) 9/46 and the pre-SMA during retrieval. This likely represented the manipulation of information and formation of a response. A functional dissociation between the dorsal “motor” dentate and “cognitive” ventral dentate agrees with neuroanatomical tract tracing studies that have demonstrated separate neural pathways involving each region of the dentate: the dorsal dentate projects to frontal motor areas (including the SMA), and the ventral dentate projects to frontal cognitive areas (including BA 9/46 and the pre-SMA). Finally, activity during the maintenance phase in BA 9, anterior insula, pre-SMA and ventral dentate predicted subsequent accuracy of response to the probe during the retrieval phase. This finding underscored the significant contribution of the pre-SMA/ventral dentate pathway – observed several seconds prior to any motor response to the probe – to executive Verbal Working Memory.
Robert A. Koeppe - One of the best experts on this subject based on the ideXlab platform.
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age differences in behavior and pet activation reveal differences in interference resolution in Verbal Working Memory
Journal of Cognitive Neuroscience, 2000Co-Authors: John Jonides, Edward E. Smith, Robert A. Koeppe, Christy Marshuetz, Patricia A Reuterlorenz, Alan A HartleyAbstract:Older adults were tested on a Verbal Working Memory task that used the item-recognition paradigm. On some trials of this task, response-conflict was created by presenting test-items that were familiar but were not members of a current set of items stored in Memory. These items required a negative response, but their familiarity biased subjects toward a positive response. Younger subjects show an interference effect on such trials, and this interference is accompanied by activation of a region of left lateral prefrontal cortex. However, there has been no evidence that the activation in this region is causally related to the interference that the subjects exhibit. In the present study, we demonstrate that older adults show more behavioral interference than younger subjects on this task, and they also show no reliable activation at the same lateral prefrontal site. This leads to the conclusion that this prefrontal site is functionally involved in mediating resolution among conflicting responses or among conflicting representations in Working Memory.
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inhibition in Verbal Working Memory revealed by brain activation
Proceedings of the National Academy of Sciences of the United States of America, 1998Co-Authors: John Jonides, Edward E. Smith, Robert A. Koeppe, Christy Marshuetz, Patricia A ReuterlorenzAbstract:There are many occasions in which humans and other animals must inhibit the production of some behavior or inhibit the processing of some internal representation. Success in inhibitory processing under normal circumstances can be revealed by the fact that certain brain pathologies render inhibitory processing ineffective. These pathologies often have been associated with damage to frontal cortex, including lateral and inferior aspects. We provide behavioral evidence of a Verbal Working Memory task that, by hypothesis, engaged inhibitory processing, and we show (by using positron emission tomograpny) that the inhibitory processing is associated with a lateral portion of the left prefrontal cortex. The task in which subjects engaged was item-recognition: Four target letters were presented for storage followed, after a brief interval, by a probe letter that could match a target letter or not. On some trials, when the probe did not match a target letter and therefore required a “no” response, the probe had matched a target letter of the previous trial, so on these trials a “yes” response was prepotent and had to be inhibited, by hypothesis. Compared with a condition in which no prepotent response was created, this condition yielded brain activation in left inferior frontal gyrus, in the region of Brodmann’s area 45.
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The Role of Parietal Cortex in Verbal Working Memory
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1998Co-Authors: John Jonides, Eric H. Schumacher, Edward E. Smith, Robert A. Koeppe, Edward Awh, Patricia A. Reuter-lorenz, Christy Marshuetz, Christopher R. WillisAbstract:Neuroimaging studies of normal subjects and studies of patients with focal lesions implicate regions of parietal cortex in Verbal Working Memory (VWM), yet the precise role of parietal cortex in VWM remains unclear. Some evidence (Paulesu et al., 1993; Awh et al., 1996) suggests that the parietal cortex mediates the storage of Verbal information, but these studies and most previous ones included encoding and retrieval processes as well as storage and rehearsal of Verbal information. A recent positron emission tomography (PET) study by Fiez et al. (1996) isolated storage and rehearsal from other VWM processes and did not find reliable activation in parietal cortex. This result suggests that parietal cortex may not be involved in VWM storage, contrary to previous proposals. However, we report two behavioral studies indicating that some of the Verbal material used by Fiez et al. (1996) may not have required phonological representations in VWM. In addition, we report a PET study that isolated VWM encoding, retrieval, and storage and rehearsal processes in different PET scans and used material likely to require phonological codes in VWM. After subtraction of appropriate controls, the encoding condition revealed no reliable activations; the retrieval condition revealed reliable activations in dorsolateral prefrontal, anterior cingulate, posterior parietal, and extrastriate cortices, and the storage condition revealed reliable activations in dorsolateral prefrontal, inferior frontal, premotor, and posterior parietal cortices, as well as cerebellum. These results suggest that parietal regions are part of a network of brain areas that mediate the short-term storage and retrieval of phonologically coded Verbal material.
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components of Verbal Working Memory evidence from neuroimaging
Proceedings of the National Academy of Sciences of the United States of America, 1998Co-Authors: Edward E. Smith, John Jonides, Christy Marshuetz, Robert A. KoeppeAbstract:We review research on the neural bases of Verbal Working Memory, focusing on human neuroimaging studies. We first consider experiments that indicate that Verbal Working Memory is composed of multiple components. One component involves the subvocal rehearsal of phonological information and is neurally implemented by left-hemisphere speech areas, including Broca’s area, the premotor area, and the supplementary motor area. Other components of Verbal Working Memory may be devoted to pure storage and to executive processing of the contents of Memory. These studies rest on a subtraction logic, in which two tasks are imaged, differing only in that one task presumably has an extra process, and the difference image is taken to reflect that process. We then review studies that show that the previous results can be obtained with experimental methods other than subtraction. We focus on the method of parametric variation, in which a parameter that presumably reflects a single process is varied. In the last section, we consider the distinction between Working Memory tasks that require only storage of information vs. those that require that the stored items be processed in some way. These experiments provide some support for the hypothesis that, when a task requires processing the contents of Working Memory, the dorsolateral prefrontal cortex is disproportionately activated.
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Verbal Working Memory load affects regional brain activation as measured by pet
Journal of Cognitive Neuroscience, 1997Co-Authors: John Jonides, Eric H. Schumacher, Edward E. Smith, Edward Awh, Erick J Lauber, Satoshi Minoshima, Robert A. KoeppeAbstract:We report an experiment that assesses the effect of variations in Memory load on brain activations that mediate Verbal Working Memory. The paradigm that forms the basis of this experiment is the “n-back” task in which subjects must decide for each letter in a series whether it matches the one presented n items back in the series. This task is of interest because it recruits processes involved in both the storage and manipulation of information in Working Memory. Variations in task difficulty were accomplished by varying the value of n. As n increased, subjects showed poorer behavioral performance as well as monotonically increasing magnitudes of brain activation in a large number of sites that together have been identified with Verbal Working-Memory processes. By contrast, there was no reliable increase in activation in sites that are unrelated to Working Memory. These results validate the use of parametric manipulation of task variables in neuroimaging research, and they converge with the subtraction paradigm used most often in neuroimaging. In addition, the data support a model of Working Memory that includes both storage and executive processes that recruit a network of brain areas, all of which are involved in task performance.
Burkhard Pleger - One of the best experts on this subject based on the ideXlab platform.
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cerebellar transcranial direct current stimulation modulates Verbal Working Memory
Brain Stimulation, 2013Co-Authors: Andreas Boehringer, Katja Macher, Juergen Dukart, Arno Villringer, Burkhard PlegerAbstract:Background: Neuroimaging studies show cerebellar activations in a wide range of cognitive tasks and patients with cerebellar lesions often present cognitive deficits suggesting a cerebellar role in higherorder cognition. Objective: We used cathodal transcranial direct current stimulation (tDCS), known to inhibit neuronal excitability, over the cerebellum to investigate if cathodal tDCS impairs Verbal Working Memory, an important higher-order cognitive faculty. Method: We tested Verbal Working Memory as measured by forward and backward digit spans in 40 healthy young participants before and after applying cathodal tDCS (2 mA, stimulation duration 25 min) to the right cerebellum using a randomized, sham-controlled, double-blind, cross-over design. In addition, we tested the effect of cerebellar tDCS on word reading, finger tapping and a visually cued sensorimotor task. Results: In line with lower digit spans in patients with cerebellar lesions, cerebellar tDCS reduced forward digit spans and blocked the practice dependent increase in backward digit spans. No effects of tDCS on word reading, finger tapping or the visually cued sensorimotor task were found. Conclusion: Our results support the view that the cerebellum contributes to Verbal Working Memory as measured by forward and backward digit spans. Moreover, the induction of reversible “virtual cerebellar lesions” in healthy individuals by means of tDCS may improve our understanding of the mechanistic basis of Verbal Working Memory deficits in patients with cerebellar lesions.
Daniel J Acheson - One of the best experts on this subject based on the ideXlab platform.
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a common neural substrate for language production and Verbal Working Memory
Journal of Cognitive Neuroscience, 2011Co-Authors: Daniel J Acheson, Massihullah Hamidi, Jeffrey R Binder, Bradley R. PostleAbstract:Verbal Working Memory (VWM), the ability to maintain and manipulate representations of speech sounds over short periods, is held by some influential models to be independent from the systems responsible for language production and comprehension [e.g., Baddeley, A. D. Working Memory, thought, and action. New York, NY: Oxford University Press, 2007]. We explore the alternative hypothesis that maintenance in VWM is subserved by temporary activation of the language production system [Acheson, D. J., & MacDonald, M. C. Verbal Working Memory and language production: Common approaches to the serial ordering of Verbal information. Psychological Bulletin, 135, 50-68, 2009b]. Specifically, we hypothesized that for stimuli lacking a semantic representation (e.g., nonwords such as mun), maintenance in VWM can be achieved by cycling information back and forth between the stages of phonological encoding and articulatory planning. First, fMRI was used to identify regions associated with two different stages of language production planning: the posterior superior temporal gyrus (pSTG) for phonological encoding (critical for VWM of nonwords) and the middle temporal gyrus (MTG) for lexical-semantic retrieval (not critical for VWM of nonwords). Next, in the same subjects, these regions were targeted with repetitive transcranial magnetic stimulation (rTMS) during language production and VWM task performance. Results showed that rTMS to the pSTG, but not the MTG, increased error rates on paced reading (a language production task) and on delayed serial recall of nonwords (a test of VWM). Performance on a lexical-semantic retrieval task (picture naming), in contrast, was significantly sensitive to rTMS of the MTG. Because rTMS was guided by language production-related activity, these results provide the first causal evidence that maintenance in VWM directly depends on the long-term representations and processes used in speech production.
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the interaction of concreteness and phonological similarity in Verbal Working Memory
Journal of Experimental Psychology: Learning Memory and Cognition, 2010Co-Authors: Daniel J Acheson, Bradley R. Postle, Maryellen C MacdonaldAbstract:Although phonological representations have been a primary focus of Verbal Working Memory research, lexical-semantic manipulations also influence performance. In the present study, the authors investigated whether a classic phenomenon in Verbal Working Memory, the phonological similarity effect (PSE), is modulated by a lexical-semantic variable, word concreteness. Phonological overlap and concreteness were factorially manipulated in each of four experiments across which presentation modality (Experiments 1 and 2: visual presentation; Experiments 3 and 4: auditory presentation) and concurrent articulation (present in Experiments 2 and 4) were manipulated. In addition to main effects of each variable, results show a Phonological Overlap × Concreteness interaction whereby the magnitude of the PSE is greater for concrete word lists relative to abstract word lists. This effect is driven by superior item Memory for nonoverlapping, concrete lists and is robust to the modality of presentation and concurrent articulation. These results demonstrate that in Verbal Working Memory tasks, there are multiple routes to the phonological form of a word and that maintenance and retrieval occur over more than just a phonological level.
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Verbal Working Memory and language production common approaches to the serial ordering of Verbal information
Psychological Bulletin, 2009Co-Authors: Daniel J Acheson, Maryellen C MacdonaldAbstract:Verbal Working Memory (WM) tasks typically involve the language production architecture for recall; however, language production processes have had a minimal role in theorizing about WM. A framework for understanding Verbal WM results is presented here. In this framework, domain-specific mechanisms for serial ordering in Verbal WM are provided by the language production architecture, in which positional, lexical, and phonological similarity constraints are highly similar to those identified in the WM literature. These behavioral similarities are paralleled in computational modeling of serial ordering in both fields. The role of long-term learning in serial ordering performance is emphasized, in contrast to some models of Verbal WM. Classic WM findings are discussed in terms of the language production architecture. The integration of principles from both fields illuminates the maintenance and ordering mechanisms for Verbal information.
John Jonides - One of the best experts on this subject based on the ideXlab platform.
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age differences in behavior and pet activation reveal differences in interference resolution in Verbal Working Memory
Journal of Cognitive Neuroscience, 2000Co-Authors: John Jonides, Edward E. Smith, Robert A. Koeppe, Christy Marshuetz, Patricia A Reuterlorenz, Alan A HartleyAbstract:Older adults were tested on a Verbal Working Memory task that used the item-recognition paradigm. On some trials of this task, response-conflict was created by presenting test-items that were familiar but were not members of a current set of items stored in Memory. These items required a negative response, but their familiarity biased subjects toward a positive response. Younger subjects show an interference effect on such trials, and this interference is accompanied by activation of a region of left lateral prefrontal cortex. However, there has been no evidence that the activation in this region is causally related to the interference that the subjects exhibit. In the present study, we demonstrate that older adults show more behavioral interference than younger subjects on this task, and they also show no reliable activation at the same lateral prefrontal site. This leads to the conclusion that this prefrontal site is functionally involved in mediating resolution among conflicting responses or among conflicting representations in Working Memory.
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inhibition in Verbal Working Memory revealed by brain activation
Proceedings of the National Academy of Sciences of the United States of America, 1998Co-Authors: John Jonides, Edward E. Smith, Robert A. Koeppe, Christy Marshuetz, Patricia A ReuterlorenzAbstract:There are many occasions in which humans and other animals must inhibit the production of some behavior or inhibit the processing of some internal representation. Success in inhibitory processing under normal circumstances can be revealed by the fact that certain brain pathologies render inhibitory processing ineffective. These pathologies often have been associated with damage to frontal cortex, including lateral and inferior aspects. We provide behavioral evidence of a Verbal Working Memory task that, by hypothesis, engaged inhibitory processing, and we show (by using positron emission tomograpny) that the inhibitory processing is associated with a lateral portion of the left prefrontal cortex. The task in which subjects engaged was item-recognition: Four target letters were presented for storage followed, after a brief interval, by a probe letter that could match a target letter or not. On some trials, when the probe did not match a target letter and therefore required a “no” response, the probe had matched a target letter of the previous trial, so on these trials a “yes” response was prepotent and had to be inhibited, by hypothesis. Compared with a condition in which no prepotent response was created, this condition yielded brain activation in left inferior frontal gyrus, in the region of Brodmann’s area 45.
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The Role of Parietal Cortex in Verbal Working Memory
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1998Co-Authors: John Jonides, Eric H. Schumacher, Edward E. Smith, Robert A. Koeppe, Edward Awh, Patricia A. Reuter-lorenz, Christy Marshuetz, Christopher R. WillisAbstract:Neuroimaging studies of normal subjects and studies of patients with focal lesions implicate regions of parietal cortex in Verbal Working Memory (VWM), yet the precise role of parietal cortex in VWM remains unclear. Some evidence (Paulesu et al., 1993; Awh et al., 1996) suggests that the parietal cortex mediates the storage of Verbal information, but these studies and most previous ones included encoding and retrieval processes as well as storage and rehearsal of Verbal information. A recent positron emission tomography (PET) study by Fiez et al. (1996) isolated storage and rehearsal from other VWM processes and did not find reliable activation in parietal cortex. This result suggests that parietal cortex may not be involved in VWM storage, contrary to previous proposals. However, we report two behavioral studies indicating that some of the Verbal material used by Fiez et al. (1996) may not have required phonological representations in VWM. In addition, we report a PET study that isolated VWM encoding, retrieval, and storage and rehearsal processes in different PET scans and used material likely to require phonological codes in VWM. After subtraction of appropriate controls, the encoding condition revealed no reliable activations; the retrieval condition revealed reliable activations in dorsolateral prefrontal, anterior cingulate, posterior parietal, and extrastriate cortices, and the storage condition revealed reliable activations in dorsolateral prefrontal, inferior frontal, premotor, and posterior parietal cortices, as well as cerebellum. These results suggest that parietal regions are part of a network of brain areas that mediate the short-term storage and retrieval of phonologically coded Verbal material.
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components of Verbal Working Memory evidence from neuroimaging
Proceedings of the National Academy of Sciences of the United States of America, 1998Co-Authors: Edward E. Smith, John Jonides, Christy Marshuetz, Robert A. KoeppeAbstract:We review research on the neural bases of Verbal Working Memory, focusing on human neuroimaging studies. We first consider experiments that indicate that Verbal Working Memory is composed of multiple components. One component involves the subvocal rehearsal of phonological information and is neurally implemented by left-hemisphere speech areas, including Broca’s area, the premotor area, and the supplementary motor area. Other components of Verbal Working Memory may be devoted to pure storage and to executive processing of the contents of Memory. These studies rest on a subtraction logic, in which two tasks are imaged, differing only in that one task presumably has an extra process, and the difference image is taken to reflect that process. We then review studies that show that the previous results can be obtained with experimental methods other than subtraction. We focus on the method of parametric variation, in which a parameter that presumably reflects a single process is varied. In the last section, we consider the distinction between Working Memory tasks that require only storage of information vs. those that require that the stored items be processed in some way. These experiments provide some support for the hypothesis that, when a task requires processing the contents of Working Memory, the dorsolateral prefrontal cortex is disproportionately activated.
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Verbal Working Memory load affects regional brain activation as measured by pet
Journal of Cognitive Neuroscience, 1997Co-Authors: John Jonides, Eric H. Schumacher, Edward E. Smith, Edward Awh, Erick J Lauber, Satoshi Minoshima, Robert A. KoeppeAbstract:We report an experiment that assesses the effect of variations in Memory load on brain activations that mediate Verbal Working Memory. The paradigm that forms the basis of this experiment is the “n-back” task in which subjects must decide for each letter in a series whether it matches the one presented n items back in the series. This task is of interest because it recruits processes involved in both the storage and manipulation of information in Working Memory. Variations in task difficulty were accomplished by varying the value of n. As n increased, subjects showed poorer behavioral performance as well as monotonically increasing magnitudes of brain activation in a large number of sites that together have been identified with Verbal Working-Memory processes. By contrast, there was no reliable increase in activation in sites that are unrelated to Working Memory. These results validate the use of parametric manipulation of task variables in neuroimaging research, and they converge with the subtraction paradigm used most often in neuroimaging. In addition, the data support a model of Working Memory that includes both storage and executive processes that recruit a network of brain areas, all of which are involved in task performance.
