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PubMed2004

Women's collective constructions of embodied practices through memory work: Cartesian dualism in memories of sweating and pain.

The research presented in this paper uses memory work as a method to explore six women's collective constructions of two embodied practices, sweating and pain. The paper identifies limitations in the ways in which social constructionist research has theorized the relationship between discourse and materiality, and it proposes an approach to the study of embodiment which enjoins, rather than bridges, the discursive and the non-discursive. The paper presents an analysis of 25 memories of sweating and pain which suggests that Cartesian dualism is central to the women's accounts of their experiences. However, such dualism does not operate as a stable organizing principle. Rather, it offers two strategies for the performance of a split between mind and body. The paper traces the ways in which dualism can be both functional and restrictive, and explores the tensions between these two forms. The paper concludes by identifiying opportunities and limitations associated with memory work as a method for studying embodiment.

Female↗
PubMed2000

The development of working memory: further note on the comparability of two models of working memory.

This paper is a set of reflections on Kemps, De Rammelaere, and Desmet's article (2000, this issue), in which the two models by Baddeley and Pascual-Leone are compared. First, some of the similarities and differences between the two models which we identified in a 1994 paper (de Ribaupierre & Bailleux, 1994) are briefly summarized and reexamined in the light of more recent work. Second, we debate the issue of whether each model makes a specific contribution to the explanation of some of Kemps et al.'s results, that is, of whether they can be considered to be complementary. Third, we argue for the necessity of theoretical task analyses, in view of the divergent results obtained in the two tasks used (the Corsi and the Peanut tasks), notably different developmental profiles, and an overall higher level of performance in the Corsi task. Finally, we briefly summarize a very similar study in which we also used Mr. Peanut with concurrent tasks in children and in young adults and in which we obtained rather different results. By comparing the experimental procedures used in the two studies, we contribute some exploratory hypotheses, while raising issues that can easily be generalized to other visuo-spatial working memory tasks.

Adult↗
PubMed1997

Deficits in multiple systems of working memory in schizophrenia.

Working memory, the ability to hold and manipulate information 'on-line' in a temporary memory store, is impaired in schizophrenia. This impairment may be characterized within the framework of two opposing theoretical models: (1) central executive as coordinator of component processes of working memory or (2) multiple independent systems of spatial and object memory. In order to test which of these models better explains the working memory deficit of schizophrenia, 14 schizophrenic patients and 12 age- and gender-matched control subjects performed tests of spatial memory (dot location), object memory (shapes, color dots) and a dual paradigm (dot location + shapes). If schizophrenia impairs the central executive, a group-by-task interaction would demonstrate excessively worse performance on the dual than single tasks in schizophrenics relative to controls; however, the absence of an interaction would be consistent with deficits in the multiple working memory systems. The schizophrenic group was significantly impaired on all measures, and both the schizophrenic and control performance was worse on the dual than the single tasks. Despite the schizophrenic group performance deficits on the single tasks, the extent of such deficit did not appear additive and contributive to the dual tasks. The lack of a group-by-task interaction provided no support for the central executive model of dysfunction. Rather, the results uphold the model of working memory deficits arising from compromise of multiple (here spatial and object), relatively independent systems, both of which are affected in schizophrenia.

Adult↗
PubMed2004

Maintenance and manipulation of information in schizophrenia: further evidence for impairment in the central executive component of working memory.

Impairments in working memory (WM) have been proposed to underlie various cognitive and functional impairments in schizophrenia. However, the nature and extent of the dysfunction remain unclear. The present study attempted to examine the integrity of sub-components of working memory in schizophrenia within the framework of the multiple-component working memory model proposed by Baddeley. Two sets of visuospatial and verbal delayed-response tasks were developed which had comparable formats and difficulties across domains. In Experiment 1, demands on the central executive (CE) were manipulated by requiring subjects either (1) to simultaneously maintain and transform information (maintenance-and-manipulation condition) or (2) just to maintain this information (maintenance-only condition). In Experiment 2, the amount of information to be maintained over the delay was parametrically varied to evaluate demands on the temporary maintenance component of working memory. Patients (N=16) performed worse than controls (N=16) in both conditions of Experiment 1; however, simultaneous maintenance and manipulation was associated with a significantly greater performance reduction in the patients. In Experiment 2, both patients (N=15) and controls (N=15) declined in performance, at equivalent rates, with increasing memory load. Parallel findings were observed for the verbal and visuospatial tasks. These results suggest that while both maintenance and central executive aspects of working memory are impaired in schizophrenic patients, the central executive may be more severely affected.

Adult↗
PubMed2006

An examination of the seductive details effect in terms of working memory capacity.

Previous work on learning from text has demonstrated that although illustrated text can enhance comprehension, illustrations can also sometimes lead to poor learning outcomes when they are not relevant to understanding the text This phenomenon is known as the seductive details effect. The first experiment was designed to test whether the ability to control one's attention, as measured by working memory span tasks, would influence the processing of a scientific text that contained seductive (irrelevant) images, conceptually relevant images, or no illustrations. Understanding was evaluated using both an essay response and an inference verification task. Results indicated that low working memory capacity readers are especially vulnerable to the seductive details effect. In the second experiment, this issue was explored further, using eye-tracking methodology to evaluate the reading patterns of individuals who differed in working memory capacity as they read the same seductively illustrated scientific text Results indicated that low working memory individuals attend to seductive illustrations more often than not and, also, for a longer duration than do those individuals high in working memory capacity.

Association Learning↗
PubMed1996

Double dissociations of memory and executive functions in working memory tasks following frontal lobe excisions, temporal lobe excisions or amygdalo-hippocampectomy in man.

Thirty-two neurosurgical patients with unilateral or bilateral frontal lobe excisions, 41 patients with unilateral temporal lobe lesions and 19 patients who had undergone unilateral amygdalo-hippocampectomy were compared with matched controls on a computerized test of spatial working memory. A significant deficit was observed in the frontal lobe group, even at the least challenging level of task difficulty and this impairment was found to relate to the inefficient use of a particular searching strategy shown to improve performance on this task. In contrast, deficits in the temporal lobe group and the amygdalo-hippocampectomy group were only observed at the most difficult level of the task and in neither group could the deficit be related to the inefficient use of any particular searching strategy. In a follow-up study, the three patient groups were compared on analogous computerized tests of visual and verbal working memory. No deficits were observed in the frontal lobe group. By comparison, both the temporal lobe patients and the amygdalo-hippocampectomy group were significantly impaired in the visual working memory condition but not in the verbal working memory condition. These deficits were clearly evident at all levels of task difficulty and were not related to any particular searching strategy. The data are discussed in terms of the relative contributions of "executive' and "mnemonic' mechanisms to the contrasting, material dependent deficits observed in the frontal and temporal lobe groups.

Adult↗
PubMed2006

Encoding and stability of image statistics in working memory.

Visual working memory contains a representation of certain image statistics (Victor & Conte, 2004), in addition to a pixel-by-pixel representation. Here, we show that the representation of statistics is more stable in time (up to 3000 ms) than the pixel-by-pixel representation, especially for changes in luminance and local high-order statistics, and is not affected by visual masking. Bilaterally symmetric arrays and arrays with local correlations are more readily encoded than random ones, but a change in the presence of bilateral symmetry, per se, contributes only modestly to the ability to detect that an array has changed.

Adult↗
PubMed2002

Aging effects on intra- and inter-attribute spatial frequency information for luminance, color, and working memory.

Visual working memory (VWM) for spatial frequency information was assessed in both young and older observers. In the first experiment we assessed the effect of a memory mask on a VWM task. We found no effect of mask on retention for either the young or older groups. This argues against the 'inhibition' hypothesis of aging in regards to visual processing, which suggests that the elderly should have difficulty to inhibit irrelevant information. We conclude that the suggestion of an inefficient inhibition process in aging derived from evidence obtained for higher-level WM tasks cannot be generalized to the discrimination of basic patterns in VWM. The second experiment focused on processing resources within VWM by assessing VWM for intra-attribute (color or luminance), and inter-attribute (color and luminance)-defined spatial frequency information. Results show that retention of spatial frequency information in VWM is robust for both the younger and older group regardless of the defining attribute. Thresholds were significantly higher in the inter-attribute condition, indicating increased processing demands for this task and suggesting that these attributes are initially processed in parallel. Older observers showed higher discrimination thresholds than young observers for all conditions indicating a deficit in perceptual abilities rather than in VWM for basic stimuli. The difference in thresholds for the older group was highest in the inter-attribute condition suggesting that older observers show more deficits on visual tasks with increased processing demands.

Aged↗
PubMed2000

Theta oscillations index human hippocampal activation during a working memory task.

Working memory (WM) is the ability to retain and associate information over brief time intervals. Functional imaging studies demonstrate that WM is mediated by a distributed network including frontal and posterior cortices, hippocampus, and cerebellum. In rodents, the presentation of stimuli in a WM task is followed by a reset of the phase of hippocampal theta. In this paper we report the observation of a similar phenomenon in normal human subjects. Neuromagnetic responses were recorded during presentation of a set of digits and a subsequent probe of the retained items. All stimuli were presented with a fixed temporal pattern. We observed phase reset of approximately 7 Hz theta in left hippocampus approximately 120 ms after probe stimuli, whereas reset of theta in right hippocampus was visible approximately 80 ms prior to these anticipated stimuli. The duration of stimulus-locked theta increased with memory load, with a limiting value of approximately 600 ms for 5-7 retained items. We suggest that, as in rats, stimulus-locked theta may index involvement of human hippocampal networks in the cognitive processing of sensory input. The anticipatory phase reset of theta indicates involvement of hippocampus in right hemisphere and cerebellar timing networks. Hippocampal structures are essential for orientation to perturbations in the sensory scene, a function that requires use of a context established by a constellation of stimuli. We suggest that the initiation and maintenance of stimulus-locked hippocampal theta observed here may facilitate processing of potentially salient and/or novel input with respect to a context established by the contents of WM.

Adult↗
PubMedDate not supplied

Bilateral activation of fronto-parietal networks by incrementing demand in a working memory task.

Working memory (WM) is known to activate the prefrontal cortex. In the present study we hypothesized that when additional contingencies are added to the instruction of a WM task, this would increase the WM load and result in the activation of additional prefrontal areas. With positron emission tomography we measured regional cerebral blood flow in nine subjects performing a control task and two delayed matching to sample tasks, in which the subjects were matching colours and patterns to a reference picture. The second of the two delayed matching tasks had a more complex instruction than the first, with additional contingencies of how to alternate between the matching of colours and patterns. This task thus required the subjects not only to remember a stimulus to match but also to perform this matching according to a specified plan. Both delayed matching tasks activated cortical fields in the middle frontal gyrus, the frontal operculum, upper cingulate gyrus, inferior parietal cortex and cortex lining the intraparietal sulcus, all in the left hemisphere. When alternated delayed matching was compared to simple delayed matching, increases were located in the right superior and middle frontal gyrus and the right anterior inferior parietal cortex. The increased demand during alternated matching thus resulted in bilateral activation of both dorsolateral prefrontal and inferior parietal cortex. The area in the inferior parietal cortex has previously been coactivated with the dorsolateral prefrontal cortex in several WM tasks, irrespective of the sensory modality of the stimuli, and during tasks involving planning.

Adult↗
PubMed2005

Bimodal format effects in working memory.

This work combines presentation formats to test whether bimodal conditions offer advantages or disadvantages relative to single formats in working memory performance. A dual task that included recall of 3 or 6 items while verifying the accuracy of math sentences was used in 2 experiments. When comparisons were made between single- and dual-format conditions, there was an advantage for items presented as spoken words and pictures simultaneously and individually. In Experiment 2, dual-format conditions had incongruent information, and spoken words were found to interfere with recall of long sequences of pictures and printed words. The findings suggest that when dual-format items are the same, there are some performance advantages when spoken words are combined with pictures or printed words. When the dual formats are displaying different items, however, spoken words are a more powerful distractor than pictures or printed words, and verbal and visual short-term stores can demonstrate similar susceptibility to distractor interference.

Attention↗
PubMed2005

Socioaffective factors modulate working memory in schizophrenia patients.

Working memory deficit in schizophrenia is a core cognitive feature of the disorder and is reliably associated with abnormalities of the prefrontal circuitry. Working memory deficits are also associated with impaired social functioning and present a major obstacle toward successful rehabilitation in schizophrenia. Although the role of prefrontal cortex in working memory has been extensively investigated, the intricate relations among the prefrontal circuitry, working memory and social behaviors are not clearly understood. In this study, we manipulated social context and observed its effects on spatial working memory. In experiment 1, the effects of social and asocial reinforcements on spatial working memory were examined in schizophrenic patients and healthy controls. The results show that social but not asocial reinforcements facilitated spatial working memory in schizophrenic patients. In experiment 2, the effects of human voice reinforcements (with or without affect) on working memory was investigated. Voice reinforcements did not facilitate working memory relative to the no-reinforcement condition. There was no difference between high-affect vs flat-affect voice conditions. In experiment 3, the effects of direct and indirect social interactions on spatial working memory were studied. Direct but not indirect social interaction facilitated working memory in schizophrenic patients. These results suggest that social context might facilitate working memory in schizophrenic patients perhaps by activating frontal lobe systems. In addition, the possibility of improving cognitive functions such as working memory using seemingly non-cognitive methods might lead to potential remediation strategies.

Adult↗
PubMed2006

Transient and executive function working memory in schizophrenia.

Transient working memory requires attention and temporary storage of information, whereas executive function working memory requires additional mental manipulation of that information. Working memory impairment is common in schizophrenia patients, but only some studies have found differential impairment in executive function working memory compared to transient working memory. We measured both types of working memory using the Digit Span forward (DF) and backward (DB) tasks in a large sample of schizophrenia patients (n=267) and normal comparison subjects (n=82); in the patients, we also examined associations between performance on the Digit Span tasks and Letter-Number Sequencing (LNS), a putative executive function working memory test. Compared to healthy subjects, the schizophrenia patients showed impairment in the medium effect size range on both DF (d=-0.55) and DB (d=-0.68). DB scores predicted LNS performance, whereas DF scores did not. Worse negative symptoms were associated with worse performance on DF, DB and LNS. These results do not reflect differential executive function working memory dysfunction in schizophrenia, but appear to support transient and executive function working memory as separable constructs.

Adult↗
PubMed1992

Working memory.

The term working memory refers to a brain system that provides temporary storage and manipulation of the information necessary for such complex cognitive tasks as language comprehension, learning, and reasoning. This definition has evolved from the concept of a unitary short-term memory system. Working memory has been found to require the simultaneous storage and processing of information. It can be divided into the following three subcomponents: (i) the central executive, which is assumed to be an attentional-controlling system, is important in skills such as chess playing and is particularly susceptible to the effects of Alzheimer's disease; and two slave systems, namely (ii) the visuospatial sketch pad, which manipulates visual images and (iii) the phonological loop, which stores and rehearses speech-based information and is necessary for the acquisition of both native and second-language vocabulary.

Brain↗
PubMed1996

Effects of reversible inactivations of the medial septal area on reference and working memory versions of the Morris water maze.

Involvement of the medial septal area (MSA) in reference memory and working memory versions of the Morris water maze (MWM) task was investigated in rats with reversible inactivation of this area by drugs injected through a single cannula aimed at the MSA. In Experiment 1, rats were trained in a reference memory version of the MWM with two blocks of four trials per day for 3 consecutive days. Acquisition was impaired by pretrial MSA injection of 10 ng tetrodotoxin (TTX) in 1 microliter saline but not of saline alone into MSA. In Experiment 2, intraseptal injection of TTX (10 ng, 1 microliter) immediately after two blocks of four trials had no effect on the consolidation of spatial reference memory. In Experiment 3, intraseptal injection of TTX (10 ng, 1 microliter) impaired retrieval of well established spatial reference memory in rats which had received 8 trials per day for 3 consecutive days. In Experiments 4 and 5, rats were trained in a working memory version of MWM task to find a new target position in trial 1 and retrieval of this information was tested 75 min later in trial 2. Intraseptal injection of lidocaine (4%, 1 microliter) prior to training impaired working memory performance while immediately posttraining injection of lidocaine had no effect. It is concluded that normal activity of the MSA is necessary for the memory formation at the time of training but its involvement in posttraining consolidation is unlikely. The MSA function is required for retrieval of well established spatial reference memory.

Animals↗
PubMed2005

Representation and working memory in early arithmetic.

Working memory has been implicated in the early acquisition of arithmetic skill, but the relations among different components of working memory, performance on different types of arithmetic problems, and development have not been explored. Preschool and Grade 1 children completed measures of phonological, visual-spatial, and central executive working memory, as well as nonverbal and verbal arithmetic problems, some of which included irrelevant information. For preschool children, accuracy was higher on nonverbal problems than on verbal problems, and the best and only unique predictor of performance on the standard nonverbal problems was visual-spatial working memory. This finding is consistent with the view that most preschoolers use a mental model for arithmetic that requires visual-spatial working memory. For Grade 1 children, performance was equivalent on nonverbal and verbal problems, and phonological working memory was the best predictor of performance on standard verbal problems. For both age groups, problems with added irrelevant information were substantially more difficult than standard problems, and in some cases measures of the central executive predicted performance. Assessing performance on different components of working memory in conjunction with different types of arithmetic problems provided new insights into the developing relations between working memory and how children do arithmetic.

Child↗
PubMed2001

Ethanol-induced impairments in spatial working memory are not due to deficits in learning.

BACKGROUND: Acute ethanol administration impairs spatial reference memory and spatial working memory. However, the experimental designs previously used to test spatial working memory fail to make a distinction between the acquisition, or learning, of spatial information and the retention of this information. This study demonstrates that acute ethanol administration impairs spatial working memory, by using a novel experimental design that eliminates the confound between the learning of new spatial information and the testing of this information. METHODS: Long-Evans male rats received three forced trials to the same place for food reward on an elevated radial arm maze. Subjects were then given six free-choice trials in the first acquisition session, followed by a 30-min consolidation period before an additional six free-choice trials were administered-the retention session. Animals were trained to a criterion of five of six correct in both the acquisition and retention over 2 consecutive days. Once criteria were obtained, subjects received either saline or one of three ethanol doses immediately after the acquisition session to investigate whether ethanol alters retention of the learned spatial information. RESULTS: Acute ethanol administration impaired spatial working memory. Rats tested under saline and low-dose ethanol (1.0 g/kg) made significantly more place choices than rats tested under moderate- or high-dose ethanol (1.5 and 2.0 g/kg, respectively). Ethanol produced a temporary impairment in that no significant differences were found when subjects were retrained and retested 24 hr after initial testing. CONCLUSIONS: These results demonstrate that acute ethanol administration impairs spatial working memory and that such a deficit is not contingent on a learning impairment. These results support earlier findings that acute ethanol administration impairs spatial working memory but provide a significant advance by validating a novel training procedure that allows for direct investigation of working memory. Ethanol's impairment of both spatial working memory and spatial reference memory strengthens the similarities between memory impairments due to ethanol administration and memory impairments due to hippocampal lesions.

Animals↗
PubMed2005

Power-law neuronal fluctuations in a recurrent network model of parametric working memory.

In a working memory system, persistent activity maintains information in the absence of external stimulation, therefore the time scale and structure of correlated neural fluctuations reflect the intrinsic microcircuit dynamics rather than direct responses to sensory inputs. Here we show that a parametric working memory model capable of graded persistent activity is characterized by arbitrarily long correlation times, with Fano factors and power spectra of neural activity described by the power laws of a random walk. Collective drifts of the mnemonic firing pattern induce long-term noise correlations between pairs of cells, with the sign (positive or negative) and amplitude proportional to the product of the gradients of their tuning curves. None of the power-law behavior was observed in a variant of the model endowed with discrete bistable neural groups, where noise fluctuations were unable to cause long-term changes in rate. Therefore such behavior can serve as a probe for a quasi-continuous attractor. We propose that the unusual correlated fluctuations have important implications for neural coding in parametric working memory circuits.

Action Potentials↗