Impairment of the visuo-spatial sketch pad

The domain-specificity of serial order working memory

Making a turn while driving is simple: turn on the indicator, check for cars, then turn. Two types of information are required to perform this sequence of events: information about the items (e.g., the correct indicator), and the serial order of those items (e.g., checking before turning rather than vice-versa). Previous research has found distinct working memory capacities (WMCs) for item and serial order information in both verbal and nonverbal domains. The current study investigates whether the serial order WMC is shared for sequences from different content domains. One hundred and fifty-three participants performed sequence matching tasks with verbal (letters and words) and nonverbal (locations and arrows) stimuli. The accuracy of detecting mismatched item-identity and serial order information in sequences was used to operationalize item and order WMC. Using structural equation modeling analyses, we directly compared models that included either domain-specific or domain-general serial order WMC latent variables, finding that models with domain-specific serial order WMC latent variables for verbal and nonverbal materials fit the data better than models with domain-general latent variables. The findings support the hypothesis that there are separate capacities for serial order working memory depending on the type of material being ordered.

The importance of the body-specificity in the evaluation of visuospatial working memory

This work is rooted in the embodied cognition paradigm applied to the evaluation of visuospatial memory span. We aimed to test whether manuospatial incompatibility affects the evaluation of visuospatial working memory. Older and younger participants were tested under two different spatial field conditions, namely manuospatial incompatibility and manuospatial compatibility, using the standard Corsi Block Tapping Task. The results show that a manuospatial compatibility condition helped both younger and older participants to increase their visuospatial working memory span compared to the traditional manuospatial incompatibility condition. By analyzing the data, our results showed an increase of visuospatial memory span in manuospatial compatibility condition (i.e., the experimenter using his left hand and the participant his right hand) compared to manuospatial incompatibility condition for younger and older adults. We recommend that the interaction between body and cognition would be taken into account in clinical evaluation methods.

Can short-term memory be trained?

Is the capacity of short-term memory fixed, or does it improve with practice? It is already known that training on complex working memory tasks is more likely to transfer to untrained tasks with similar properties, but this approach has not been extended to the more basic short-term memory system responsible for verbal serial recall. Here we investigated this with adaptive training algorithms widely applied in working memory training. Serial recall of visually presented digits was found to improve over the course of 20 training sessions, but this improvement did not extend to recall of either spoken digits or visually presented letters. In contrast, training on a nonserial visual short-term memory color change detection task did transfer to a line orientation change detection task. We suggest that training only generates substantial transfer when the unfamiliar demands of the training activities require the development of novel routines that can then be applied to untrained versions of the same paradigm (Gathercole, Dunning, Holmes, & Norris, 2019). In contrast, serial recall of digits is fully supported by the existing verbal short-term memory system and does not require the development of new routines.

From short-term store to multicomponent working memory: The role of the modal model

The term "modal model" reflects the importance of Atkinson and Shiffrin's paper in capturing the major developments in the cognitive psychology of memory that were achieved over the previous decade, providing an integrated framework that has formed the basis for many future developments. The fact that it is still the most cited model from that period some 50 years later has, we suggest, implications for the model itself and for theorising in psychology more generally. We review the essential foundations of the model before going on to discuss briefly the way in which one of its components, the short-term store, had influenced our own concept of a multicomponent working memory. This is followed by a discussion of recent claims that the concept of a short-term store be replaced by an interpretation in terms of activated long-term memory. We present several reasons to question these proposals. We conclude with a brief discussion of the implications of the longevity of the modal model for styles of theorising in cognitive psychology.

The effects of cannabinoid 1 receptor compounds on memory: a meta-analysis and systematic review across species

RATIONALE

While cannabis-based medicinal products have been shown to be effective for numerous neurological and psychiatric disorders, the evidence base regarding their adverse cognitive effects is poorly understood. The cannabinoid 1 receptor modulates memory performance via intracellular and extracellular mechanisms that alter synaptic transmission and plasticity. While previous literature has consistently shown that chronic cannabis users exhibit marked cognitive impairments, mixed findings have been reported in the context of placebo-controlled experimental trials. It is therefore unclear whether these compounds inherently alter cognitive processes or whether individuals who are genetically predisposed to use cannabis may have underlying cognitive deficits.

OBJECTIVE

We conducted a meta-analysis to investigate the effects of full and partial cannabinoid 1 receptor (CB1R) agonists, antagonists, and negative allosteric modulators on non-spatial and spatial memory.

METHODS

In accordance with the PRISMA guidelines, the EMBASE, MEDLINE, and PsycINFO databases were systematically searched for studies examining the effects of CB1R agonists, antagonists, and negative allosteric modulators on memory performance.

RESULTS

We systematically reviewed 195 studies investigating the effects of cannabinoid compounds on memory. In humans (N = 35 studies, comprising N = 782 subjects), delta-9-tetrahydrocannabinol (THC) (1.5-5 mg/kg) relative to placebo impaired performance on non-spatial memory tests, whereas only high THC doses (67 mg/kg) impaired spatial memory. Similarly, THC (0.2-4 mg/kg) significantly impaired visuospatial memory in monkeys and non-human primates (N = 8 studies, comprising N = 71 subjects). However, acute THC (0.002-10 mg/kg) had no effect on non-spatial (N = 6 studies, comprising 117 subjects; g = 1.72, 95% confidence interval (CI) - 0.18 to 3.63, p = 0.08) or spatial memory (9 studies, comprising 206 subjects; g = 0.75, 95% confidence interval (CI) - 1.09 to 2.58, p = 0.43). However, acute, full CB1R agonists significantly impaired non-spatial memory (N = 23 studies, 519 subjects; g = - 1.39, 95% CI - 2.72 to - 0.06, p = 0.03). By contrast, the chronic administration of CB1R agonists had no effect on non-spatial memory (N = 5 studies, comprising 146 subjects; g = - 0.05, 95% confidence interval (CI) - 1.32 to 1.22, p = 0.94). Moreover, the acute administration of CB1R antagonists had no effect on non-spatial memory in rodents (N = 9 studies, N = 149 subjects; g = 0.40, 95% CI - 0.11 to 0.92, p = 0.12).

CONCLUSIONS

The acute administration of THC, partial CB1R agonist, significantly impaired non-spatial memory in humans, monkeys, and non-human primates but not rodents. However, full CB1R agonists significantly impaired non-spatial memory in a dose-dependent manner but CB1R antagonists had no effect on non-spatial memory in rodents. Moreover, chronic THC administration did not significantly impair spatial or non-spatial memory in rodents, and there is inconclusive evidence on this in humans. Our findings highlight species differences in the effects of cannabinoid compounds on memory.

Forward and backward recall: Different visuospatial processes when you know what's coming

In an immediate memory task, when participants are asked to recall list items in reverse order, benchmark memory phenomena found with more typical forward recall are not consistently reproduced. These inconsistencies have been attributed to the greater involvement of visuospatial representations in backward than in forward recall at the point of retrieval. In the present study, we tested this hypothesis with a dual-task paradigm in which manual-spatial tapping and dynamic visual noise were used as the interfering tasks. The interference task was performed during list presentation or at recall. In the first four experiments, recall direction was only communicated at the point of recall. In Experiments 1 and 2, fewer words were recalled with manual tapping than in the control condition. However, the detrimental effect of manual tapping did not vary as a function of recall direction or processing stage. In Experiment 3, dynamic visual noise did not influence recall performance. In Experiment 4, articulatory suppression was performed on all trials and manual tapping was added on half of them. As in the first two experiments, manual tapping disputed forward and backward recall to the same extent. In Experiment 5, recall direction was known before list presentation. As predicted by the visuospatial hypothesis, when manual tapping was performed during recall, its detrimental effect was limited to backward recall. Overall, results can be explained by calling upon a modified version of the visuospatial hypothesis.

Individual differences in face identity processing

We investigated the relationships between individual differences in different aspects of face-identity processing, using the Glasgow Face Matching Test (GFMT) as a measure of unfamiliar face perception, the Cambridge Face Memory Test (CFMT) as a measure of new face learning, and the Before They Were Famous task (BTWF) as a measure of familiar face recognition. These measures were integrated into two separate studies examining the relationship between face processing and other tasks. For Study 1 we gathered participants' subjective ratings of their own face perception abilities. In Study 2 we used additional measures of perceptual and cognitive abilities, and personality factors to place individual differences in a broader context. Performance was significantly correlated across the three face-identity tasks in both studies, suggesting some degree of commonality of underlying mechanisms. For Study 1 the participants' self-ratings correlated poorly with performance, reaching significance only for judgements of familiar face recognition. In Study 2 there were few associations between face tasks and other measures, with task-level influences seeming to account for the small number of associations present. In general, face tasks correlated with each other, but did not show an overall relation with other perceptual, cognitive or personality tests. Our findings are consistent with the existence of a general face-perception factor, able to account for around 25% of the variance in scores. However, other relatively task-specific influences are also clearly operating.

ELD revisited: A second look at a neuropsychological impairment of working memory affecting retention of visuo-spatial material

Neuropsychological case studies involving putative impairment of the visuo-spatial sketch-pad component of Baddeley's (1986) working memory model have been uncommon, with our own investigation of case ELD still being one of the most comprehensive to date (Hanley, Pearson, & Young, 1990; Hanley, Young, & Pearson, 1991). A recent theoretical review by Morey (2018) has offered a critique of ELD's data that has sought to cast doubt on our claim that she showed a pattern that reflects a problem with a functional component equivalent to the visuo-spatial sketch-pad. The importance of neuropsychological evidence to understanding visuo-spatial short-term memory has prompted us to revisit this case study, correct errors and misunderstandings in Morey's (2018) description of it, and provide some additional statistical information. Whilst acknowledging that cognitive neuropsychological studies will often depend on more than a single patient to offer definitive resolution of such an important issue, we show that there are compelling reasons to reject many of the claims that Morey (2018) made about ELD.

Does working memory training improve dietary self-care in type 2 diabetes mellitus? Results of a double blind randomised controlled trial

AIMS

Controlling food intake despite adequate knowledge remains a struggle for many people with type 2 diabetes. The present study investigated whether working memory training can reduce food intake and improve glycaemic control. It also examined training effects on cognition, food cravings, and dietary self-efficacy and self-care.

METHODS

In a double-blind multicentre parallel-group randomised controlled trial, adults with type 2 diabetes mellitus were randomly allocated to receive 25 sessions of either active (n = 45) or control (n = 36) working memory training. Assessments at baseline, post-training and 3-month follow-up measured cognition, food intake (primary outcomes), glycaemic control (HbA1c) and cholesterol (secondary outcomes). Semi-structured interviews assessed participants' experiences of the training.

RESULTS

Intention-to-treat ANOVAs (N = 81) showed improved non-trained updating ability in active compared to control training from pre-test (active M = 34.37, control M = 32.79) to post-test (active M = 31.35, control M = 33.53) and follow-up (active M = 31.81, control M = 32.65; η² = 0.05). There were no overall effects of training on other measures of cognition, food intake, HbA1c, cholesterol, food cravings and dietary self-efficacy and self-care. In post-hoc analyses, those high in dietary restraint in the active training group showed a greater reduction in fat intake pre to post-test compared to controls. Interviews revealed issues around acceptability and performance of the training.

CONCLUSIONS

Transfer of working memory training effects to non-trained behaviour were limited, but do suggest that training may reduce fat intake in those who are already motivated to do so.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN22806944.

Determining Spatial Span: The Role of Movement Time and Articulation Rate

In studies of verbal memory span individual differences in speech rate have been found to predict the number of items that can be recalled in order. This is thought to happen because overt speech rate is related to the rate of internal verbal rehearsal. For spatial span there may also be an internal rehearsal system linked to overt responding, and if there is a strong analogy to be drawn between the verbal and spatial domains, then movement time between spatial targets should predict the number of spatial locations that can be recalled. In the first study reported, none of the six measures of movement time did predict spatial span, but, as expected, speech rate predicted verbal span. In addition, speech rate predicted spatial span. In a second study the use of articulatory suppression during span presentation showed that verbal span dropped, but was still predicted by speech rate. Spatial span was again predicted by the time it took to say digits rather than the time it took to make movements to spatial targets. There would not seem to be any simple analogy between the limitations on verbal span and those on spatial span. In addition, the relationship between speech rate and sequential memory performance may be more complex than previous studies have suggested.

Short-term memory and long-term memory are still different

A commonly expressed view is that short-term memory (STM) is nothing more than activated long-term memory. If true, this would overturn a central tenet of cognitive psychology-the idea that there are functionally and neurobiologically distinct short- and long-term stores. Here I present an updated case for a separation between short- and long-term stores, focusing on the computational demands placed on any STM system. STM must support memory for previously unencountered information, the storage of multiple tokens of the same type, and variable binding. None of these can be achieved simply by activating long-term memory. For example, even a simple sequence of digits such as "1, 3, 1" where there are 2 tokens of the digit "1" cannot be stored in the correct order simply by activating the representations of the digits "1" and "3" in LTM. I also review recent neuroimaging data that has been presented as evidence that STM is activated LTM and show that these data are exactly what one would expect to see based on a conventional 2-store view. (PsycINFO Database Record

Visuospatial Imagery in Alzheimer Disease

The purpose of the present study was to investigate the imagery ability of 8 “probable” Alzheimer disease patients using a standard task sensitive to the disruption of the imagery system. These patients were selected based on their good performance on a prerequisite clock-setting task, and with 8 matched control subjects were then required to compare the angles made by the hands on clock faces using only imagined stimuli. There were no significant differences between patients and controls in performance on the clock-imagery task. These data are consistent with models of information processing which postulate the relationships between visual imagery and a short-term memory store and include a central executive system for allocation of cognitive resources.

Dissociation of Cross-Sectional Trajectories for Verbal and Visuo-Spatial Working Memory Development in Rubinstein-Taybi Syndrome

Working memory (WM) impairments might amplify behavioural difference in genetic syndromes. Murine models of Rubinstein–Taybi syndrome (RTS) evidence memory impairments but there is limited research on memory in RTS. Individuals with RTS and typically developing children completed WM tasks, with participants with RTS completing an IQ assessment and parents/carers completing the Vineland Adaptive Behavior Scales. A cross-sectional trajectory analysis was conducted. There were significant WM span deficits in RTS relative to mental age. Verbal WM span was positively associated with mental age; however, this was not observed for visuo-spatial span. There is a dissociation between WM domains in RTS. Individuals may have difficulties with tasks relying on WM span, above difficulties predicted by overall ability.

Short-term memory stores organized by information domain

Vision and audition have complementary affinities, with vision excelling in spatial resolution and audition excelling in temporal resolution. Here, we investigated the relationships among the visual and auditory modalities and spatial and temporal short-term memory (STM) using change detection tasks. We created short sequences of visual or auditory items, such that each item within a sequence arose at a unique spatial location at a unique time. On each trial, two successive sequences were presented; subjects attended to either space (the sequence of locations) or time (the sequence of inter item intervals) and reported whether the patterns of locations or intervals were identical. Each subject completed blocks of unimodal trials (both sequences presented in the same modality) and crossmodal trials (Sequence 1 visual, Sequence 2 auditory, or vice versa) for both spatial and temporal tasks. We found a strong interaction between modality and task: Spatial performance was best on unimodal visual trials, whereas temporal performance was best on unimodal auditory trials. The order of modalities on crossmodal trials also mattered, suggesting that perceptual fidelity at encoding is critical to STM. Critically, no cost was attributable to crossmodal comparison: In both tasks, performance on crossmodal trials was as good as or better than on the weaker unimodal trials. STM representations of space and time can guide change detection in either the visual or the auditory modality, suggesting that the temporal or spatial organization of STM may supersede sensory-specific organization.

How does intentionality of encoding affect memory for episodic information?

Episodic memory enables the detailed and vivid recall of past events, including target and wider contextual information. In this paper, we investigated whether/how encoding intentionality affects the retention of target and contextual episodic information from a novel experience. Healthy adults performed (1) a What-Where-When (WWW) episodic memory task involving the hiding and delayed recall of a number of items (what) in different locations (where) in temporally distinct sessions (when) and (2) unexpected tests probing memory for wider contextual information from the WWW task. Critically, some participants were informed that memory for WWW information would be subsequently probed (intentional group), while this came as a surprise for others (incidental group). The probing of contextual information came as a surprise for all participants. Participants also performed several measures of episodic and nonepisodic cognition from which common episodic and nonepisodic factors were extracted. Memory for target (WWW) and contextual information was superior in the intentional group compared with the incidental group. Memory for target and contextual information was unrelated to factors of nonepisodic cognition, irrespective of encoding intentionality. In addition, memory for target information was unrelated to factors of episodic cognition. However, memory for wider contextual information was related to some factors of episodic cognition, and these relationships differed between the intentional and incidental groups. Our results lead us to propose the hypothesis that intentional encoding of episodic information increases the coherence of the representation of the context in which the episode took place. This hypothesis remains to be tested.

Visuo-Spatial Span and Cognitive Functions: A Theoretical Analysis of the “Corsi” Task

The Corsi block tapping task has been widely used in the past 20 years to assess nonverbal/visuo-spatial abilities. However, there have been considerable inconsistencies in the administration and scoring of this measure and, from a theoretical point of view, little effort has been put to interpret this task from a more general model of cognitive functions. Within a working memory paradigm, we presented the Corsi task in association with five different types of interference designed to tap either verbal, visuo-spatial, motor, or more central components. Results showed that, though visuo-spatial abilities are involved in the execution of the task, more central, coordinative abilities seem to play a greater role. In addition, we showed an evident role of motor components that may have often been underestimated. A second experiment featuring the verbal span task allowed us to exclude that results on the Corsi task could be interpreted as general undifferentiated interference effects. In conclusion, the Corsi task seems to tap a set of different abilities: This leads us to suggest that a number of different strategies could be used in the execution of the test and this could be the reason for the anomalous results often reported in the literature.

Processes of Working Memory in Mind and Brain

Working memory is often conceptualized as storage buffers that retain information briefly, rehearsal processes that refresh the buffers, and executive processes that manipulate the contents of the buffers. We review evidence about the brain mechanisms that may underlie storage and rehearsal in working memory. We hypothesize that storage is mediated by the same brain structures that process perceptual information and that rehearsal engages a network of brain areas that also controls attention to external stimuli.

An investigation of the role of some person and situation variables in multiple cue probability learning

Making decisions using judgements of multiple non-deterministic indicators is an important task, both in everyday and professional life. Learning of such decision making has often been studied as the mapping of stimuli (cues) to an environmental variable (criterion); however, little attention has been paid to the effects of situation-by-person interactions on this learning. Accordingly, we manipulated cue and feedback presentation mode (graphic or numeric) and task difficulty, and measured individual differences in working memory capacity (WMC). We predicted that graphic presentation, fewer cues, and elevated WMC would facilitate learning, and that person and task characteristics would interact such that presentation mode compatible with the decision maker's cognitive capability (enhanced visual or verbal WMC) would assist learning, particularly for more difficult tasks. We found our predicted main effects, but no significant interactions, except that those with greater WMC benefited to a larger extent with graphic than with numeric presentation, regardless of which type of working memory was enhanced or number of cues. Our findings suggest that the conclusions of past research based predominantly on tasks using numeric presentation need to be reevaluated and cast light on how working memory helps us learn multiple cue-criterion relationships, with implications for dual-process theories of cognition.

Disentangling the effects of working memory, language, parental education, and non-verbal intelligence on children's mathematical abilities

It is assumed that children’s performance in mathematical abilities is influenced by several factors such as working memory (WM), verbal ability, intelligence, and socioeconomic status. The present study explored the contribution of those factors to mathematical performance taking a componential view of both WM and mathematics. We explored the existing relationship between different WM components (verbal and spatial) with tasks that make differential recruitment of the central executive, and simple and complex mathematical skills in a sample of 102 children in grades 4–6. The main findings point to a relationship between the verbal WM component and complex word arithmetic problems, whereas language and non-verbal intelligence were associated with knowledge of quantitative concepts and arithmetic ability. The spatial WM component was associated with the subtest Series, whereas the verbal component was with the subtest Concepts. The results also suggest a positive relationship between parental educational level and children’s performance on Quantitative Concepts. These findings suggest that specific cognitive skills might be trained in order to improve different aspects of mathematical ability.

Phantabulation: a case of visual imagery interference on visual perception

We report the case of a 52-year old man who, following rupture of an anterior communicating artery aneurysm, presented with a phenomenon not previously described, which we have labelled "Phantabulation." Phantabulation is characterized by frequent and purposeful interactions with contextually appropriate imagined objects. We suggest that this phenomenon results from confusion between real and imagined objects, caused by failure to inhibit florid visual imagery, facilitated by cortical release mechanisms.

Simultaneous encoding of the direction and orientation of potential targets during reach planning: evidence of multiple competing reach plans

Reaches performed in many natural situations involve selecting a specific target from a number of alternatives. Recent studies show that before reaching, multiple potential reach targets are encoded in brain regions involved in action control and that, when people are required to initiate the reach before the target is specified, initial hand direction is biased by the spatial distribution of potential targets. These findings have led to the suggestion that the brain, during planning, simultaneously prepares multiple reaches to potential targets. In addition to hand direction, reach planning often involves specifying other parameters such as wrist orientation. For example, when posting a letter in a mail slot, both the location and orientation of the slot must be encoded to control hand direction and orientation. Therefore, if the brain prepares multiple reaches to potential targets and if these targets require the specification of hand direction and orientation, then both of these variables should be biased by the spatial distribution of potential targets. To test this prediction, we examined a task in which participants moved a hand-held rectangular tool toward multiple rectangular targets of varying location and orientation, one of which was selected, with equal probability as the actual target after movement initiation. We found that initial hand direction and orientation were biased by the spatial distributions of potential target locations and orientations, respectively. This result is consistent with the idea that the brain, in cases of target uncertainty, simultaneously plans fully specified reaching movements to all potential targets.

Selective spatial working memory impairment in a group of children with mathematics learning disabilities and poor problem-solving skills

This study examines visual and spatial working memory skills in 35 third to fifth graders with both mathematics learning disabilities (MLD) and poor problem-solving skills and 35 of their peers with typical development (TD) on tasks involving both low and high attentional control. Results revealed that children with MLD, relative to TD children, failed spatial working memory tasks that had either low or high attentional demands but did not fail the visual tasks. In addition, children with MLD made more intrusion errors in the spatial working memory tasks requiring high attentional control than did their TD peers. Finally, as a post hoc analysis the sample of MLD was divided in two: children with severe MLD and children with low mathematical achievement. Results showed that only children with severe MLD failed in spatial working memory (WM) tasks if compared with children with low mathematical achievement and TD. The findings are discussed on the basis of their theoretical and clinical implications, in particular considering that children with MLD can benefit from spatial WM processes to solve arithmetic word problems, which involves the ability to both maintain and manipulate relevant information.

Insights from neuropsychology: pinpointing the role of the posterior parietal cortex in episodic and working memory

The role of posterior parietal cortex (PPC) in various forms of memory is a current topic of interest in the broader field of cognitive neuroscience. This large cortical region has been linked with a wide range of mnemonic functions affecting each stage of memory processing: encoding, maintenance, and retrieval. Yet, the precise role of the PPC in memory remains mysterious and controversial. Progress in understanding PPC function will require researchers to incorporate findings in a convergent manner from multiple experimental techniques rather than emphasizing a particular type of data. To facilitate this process, here, we review findings from the human neuropsychological research and examine the consequences to memory following PPC damage. Recent patient-based research findings have investigated two typically disconnected fields: working memory (WM) and episodic memory. The findings from patient participants with unilateral and bilateral PPC lesions performing diverse experimental paradigms are summarized. These findings are then related to findings from other techniques including neurostimulation (TMS and tDCS) and the influential and more abundant functional neuroimaging literature. We then review the strengths and weaknesses of hypotheses proposed to account for PPC function in these forms of memory. Finally, we address what missing evidence is needed to clarify the role(s) of the PPC in memory.

When do spatial and visual working memory interact?

This study examined how spatial working memory and visual (object) working memory interact, focusing on two related questions: First, can these systems function independently from one another? Second, under what conditions do they operate together? In a dual-task paradigm, participants attempted to remember locations in a spatial working memory task and colored objects in a visual working memory task. Memory for the locations and objects was subject to independent working memory storage limits, which indicates that spatial and visual working memory can function independently from one another. However, additional experiments revealed that spatial working memory and visual working memory interact in three memory contexts: when retaining (1) shapes, (2) integrated color-shape objects, and (3) colored objects at specific locations. These results suggest that spatial working memory is needed to bind colors and shapes into integrated object representations in visual working memory. Further, this study reveals a set of conditions in which spatial and visual working memory can be isolated from one another.

Performance of Individuals with Left-Hemisphere Stroke and Aphasia and Individuals with Right Brain Damage on Forward and Backward Digit Span Tasks

BACKGROUND: Working memory (WM) limitations have been suggested as a significant source of the linguistic processing deficits observed in individuals with aphasia (IWA). Digits forward (DF) and digits backward (DB) span tasks are frequently used to study WM in both healthy and clinical populations. Unfortunately, only a handful of studies have explored digit span in IWA. AIMS: The purpose of the current study is to measure the DF and DB spans of IWA and compare their digit spans to a group with right brain damage, but no aphasia (RBD). Additionally, DF and DB span is compared within each group to determine if there is indeed a performance differential that may support the idea that DB is a more difficult WM task in these populations. METHODS AND PROCEDURES: Seventeen IWA and 14 individuals with RBD participated in a DF and DB span task. Modifications to the span tasks were implemented to accommodate language deficits. A series of two digits were orally presented to each participant continuing to a maximum of eight digits. There were seven trials per digit series. Participants were asked to point to the correct order of digits on a written 1-9 digit list provided on individual note cards or verbally repeat the numbers if the participant was able to do so. OUTCOMES AND RESULTS: IWA demonstrated shorter digit spans than the RBD group. Both groups performed worse on the DB span tasks than the DF span tasks. CONCLUSIONS: The results are consistent with previous studies suggesting that DB span is shorter than DF span in other populations and that there are differences in performance on digit span tasks between the two groups. The differences between RBD group and IWA may be explained by decreased attentional capacity or inefficient resource allocation in IWA, or alternatively, a deficient phonological loop. Future studies should explore these possibilities.

Memória visuoespacial e cinestésica de curto prazo em crianças de 7 a 10 anos

Nós investigamos a memória visuoespacial e cinestésica de curto prazo em crianças entre 7 e 10 anos utilizando a tarefa de Blocos de Corsi. O desempenho melhora com a idade, é afetado pela extensão das séries e pelo número de cruzamentos. O desempenho é melhor na modalidade visual do que na cinestésica; ambas as modalidades são afetadas da mesma forma pela extensão e pelo número de cruzamentos. As curvas de posição serial apresentam forte efeito de primazia; o efeito de recência está presente apenas na modalidade visual. Nas séries com seis e sete blocos, quando considerado o número de cruzamentos, o desempenho tende a melhorar numa taxa mais elevada para a modalidade visual do que para cinestésica. Os resultados não permitem supor um sistema de memória cinestésico independente do espacial, mas sugere que ambos contribuem para o desempenho na tarefa de Corsi.

Assessment of working memory in patients with mesial temporal lobe epilepsy associated with unilateral hippocampal sclerosis

OBJECTIVE

The aim of the present study was to investigate whether working memory is impaired in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), a controversial and largely unexplored matter.

METHODS

Twenty subjects with left MTLE-HS, 19 with right MTLE-HS, and 21 control right-handed subjects underwent neuropsychological assessment of episodic and semantic memory, executive functions, and specific working memory components.

RESULTS

Left and right epileptogenic foci resulted in impairment of verbal and nonverbal episodic memory (verbal memory deficit greater in left MTLE-HS than in right MTLE-HS). In addition, patients with left MTLE-HS were impaired in learning paired associates, verbal fluency, and Trail Making. No differences were seen in the tests carried out to evaluate the working memory components (except visuospatial short-term memory in right MTLE-HS).

CONCLUSION

In this study we did not detect reliable working memory impairment in patients with MTLE-HS with either a left or right focus in most tasks considered as tests of working memory components.

Some surprising findings on the involvement of the parietal lobe in human memory

The posterior parietal lobe is known to play some role in a far-flung list of mental processes: linking vision to action (saccadic eye movements, reaching, grasping), attending to visual space, numerical calculation, and mental rotation. Here, we review findings from humans and monkeys that illuminate an untraditional function of this region: memory. Our review draws on neuroimaging findings that have repeatedly identified parietal lobe activations associated with short-term or working memory and episodic memory. We also discuss recent neuropsychological findings showing that individuals with parietal lobe damage exhibit both working memory and long-term memory deficits. These deficits are not ubiquitous; they are only evident under certain retrieval demands. Our review elaborates on these findings and evaluates various theories about the mechanistic role of the posterior parietal lobe in memory. The available data point towards the conclusion that the posterior parietal lobe plays an important role in memory retrieval irrespective of elapsed time. However, the available data do not support simple dichotomies such as recall versus recognition, working versus long-term memory. We conclude by formalizing several open questions that are intended to encourage future research in this rapidly developing area of memory research.

Toward a comprehensive test battery for face cognition: assessment of the tasks

Despite the importance of face recognition in everyday life and frequent complaints about its failure, there is no comprehensive test battery for this ability. As a first step in constructing such a battery, we present 18 tasks aimed at measuring face perception, face learning, face recognition, and the recognition of facially expressed emotions. A sample of 153 healthy young adults completed all tasks. In general, reaction time measures showed high estimates of internal consistency; tasks focused on performance accuracy yielded reliabilities that were somewhat lower, yet high enough to support their use in a battery of face cognition measures. Some of the tasks allowed computation of established experimental effects in a within-subjects design, such as the part-whole effect. Most of these experimental effects were confirmed in our large sample, and valuable effect size estimates were obtained. However, in many cases these difference measures showed poor estimates of internal consistency.

Consciousness, accessibility, and the mesh between psychology and neuroscience

How can we disentangle the neural basis of phenomenal consciousness from the neural machinery of the cognitive access that underlies reports of phenomenal consciousness? We see the problem in stark form if we ask how we can tell whether representations inside a Fodorian module are phenomenally conscious. The methodology would seem straightforward: Find the neural natural kinds that are the basis of phenomenal consciousness in clear cases--when subjects are completely confident and we have no reason to doubt their authority--and look to see whether those neural natural kinds exist within Fodorian modules. But a puzzle arises: Do we include the machinery underlying reportability within the neural natural kinds of the clear cases? If the answer is "Yes," then there can be no phenomenally conscious representations in Fodorian modules. But how can we know if the answer is "Yes"? The suggested methodology requires an answer to the question it was supposed to answer! This target article argues for an abstract solution to the problem and exhibits a source of empirical data that is relevant, data that show that in a certain sense phenomenal consciousness overflows cognitive accessibility. I argue that we can find a neural realizer of this overflow if we assume that the neural basis of phenomenal consciousness does not include the neural basis of cognitive accessibility and that this assumption is justified (other things being equal) by the explanations it allows.

Is the posterior parietal lobe involved in working memory retrieval? Evidence from patients with bilateral parietal lobe damage

Neuroimaging evidence suggests that the parietal lobe has an important role in memory retrieval, yet neuropsychology is largely silent on this topic. Recently, we reported that unilateral parietal lobe damage impairs various forms of visual working memory when tested by old/new recognition. Here, we investigate whether parietal lobe working memory deficits are linked to problems at retrieval. We tested two patients with bilateral parietal lobe damage in a series of visual working memory tasks that probed recall and old/new recognition. Stimuli were presented sequentially and several stimulus categories were tested. The results of these experiments show that parietal lobe damage disproportionately impairs old/new recognition as compared to cued recall across stimulus categories. The observed performance dissociation suggests that the posterior parietal lobe plays a particularly vital role in working memory retrieval.