Objective Cognitive Outcomes and Subjective Emotional Sequelae in Litigating Adults with a Traumatic Brain Injury: The Impact of Performance and Symptom Validity Measures

OBJECTIVE

This study examined the relative contribution of performance and symptom validity in litigating adults with traumatic brain injury (TBI), as a function of TBI severity, and examined the relationship between self-reported emotional symptoms and cognitive tests scores while controlling for validity test performance.

METHOD

Participants underwent neuropsychological assessment between January 2012 and June 2021 in the context of compensation-seeking claims related to a TBI. All participants completed a cognitive test battery, the Personality Assessment Inventory (including symptom validity tests; SVTs), and multiple performance validity tests (PVTs). Data analyses included independent t-tests, one-way ANOVAs, correlation analyses, and hierarchical multiple regression.

RESULTS

A total of 370 participants were included. Atypical PVT and SVT performance were associated with poorer cognitive test performance and higher emotional symptom report, irrespective of TBI severity. PVTs and SVTs had an additive effect on cognitive test performance for uncomplicated mTBI, but less so for more severe TBI. The relationship between emotional symptoms and cognitive test performance diminished substantially when validity test performance was controlled, and validity test performance had a substantially larger impact than emotional symptoms on cognitive test performance.

CONCLUSION

Validity test performance has a significant impact on the neuropsychological profiles of people with TBI, irrespective of TBI severity, and plays a significant role in the relationship between emotional symptoms and cognitive test performance. Adequate validity testing should be incorporated into every neuropsychological assessment, and associations between emotional symptoms and cognitive outcomes that do not consider validity testing should be interpreted with extreme caution.

Interictal Cognitive Deficits in Migraine Sufferers: A Meta-Analysis

While a significant proportion of the population suffer from migraine, the existing research literature does not provide a clear indication as to whether migraineurs experience objective cognitive deficits outside of acute migraine attacks. This meta-analysis was conducted to investigate which cognitive domains if any were affected by migraine, by synthesising the existing research quantitatively. The meta-analysis was prospectively registered with the PROSPERO International prospective register of systematic reviews (registration no.: CRD42019134138). A search of the electronic databases PubMed, Ovid MEDLINE, and PsycINFO was conducted for journal articles published between January 1980 and January 2020. Seventeen studies met the inclusion criteria, allowing for the calculation of pooled effect sizes between migraineurs (with and without aura) and healthy controls in the several cognitive domains. During the interictal period, migraineurs demonstrated a moderate, negative effect on complex attention immediate and delayed memory, spatial cognition, and executive functioning. This effect was not attributable to migraine history, attack frequency, or participant age. However, the lack of performance validity testing, and limited data on mood symptomatology and migraine medication use in the included studies may be confounds potentially overestimating the magnitude of effect. Comparison with a clinical control group, which may have accounted for some these extraneous variables, was unable to be conducted. Recommendations for comprehensive future neuropsychological research are provided.

An analysis of distinct navigational domains and topographical disorientation syndromes in ABI: A meta-analysis

Topographical disorientation is the impairment or inability to successfully navigate in three-dimensional space. Differing topographical disorientation syndromes have been associated with distinct lesion sites in the acquired brain injury (ABI) literature. This meta-analysis attempted to investigate the relationship between lesion location and dysfunctions in specific navigational abilities resulting in topographical disorientation in individuals with ABI, as measured by their performance on experimental and neuropsychological tests. It was expected that focal lesions would be associated with a specific navigational deficit in one ability, with relative sparing of other navigational abilities. Twenty-six papers met the inclusion criteria for the analysis. Results indicated that ABI populations performed worse on all measures of navigation, with moderate to large effect sizes. Dysfunctions in three core navigational skills were consistent with the available lesion studies: a feature/landmark processing unit, a spatial processing unit, and a spatial/feature binding and associative learning unit. A sequential processing model was created to attempt to best represent the transfer of information between these units and the process by which navigational knowledge is generated. The model was then used to assess the validity of existing models of navigation and topographical disorientation.

Performance on neuropsychological assessment and progression to dementia: A meta-analysis

This meta-analysis examined how performance on various cognitive domains of neuropsychological functioning can contribute to predicting progression to dementia from mild cognitive impairment (MCI) or subjective memory complaints. Studies performed between the years of 1997 and 2018 were identified through a search of the electronic databases Medline and PsycINFO. Data from the articles identified were pooled to determine standardized mean differences, calculated as Hedges g, using a random-effects model. Twenty-four studies were included in the analysis. The majority of studies examined the progression of amnestic mild cognitive impairment (aMCI) to Alzheimer's disease (AD). Nonprogressors performed significantly better than did progressors in the domains of divided attention, executive function, expressive language, immediate recall, processing speed, delayed recall, visuospatial/constructional ability, working memory, and sustained attention. These findings indicate that individuals with MCI or subjective memory complaints who do not progress to dementia, perform better at baseline as compared with individuals that progress to dementia on a range of neuropsychological measures, and lends further support to the contention that neuropsychological assessment can make important contributions to predicting progression to dementia while individuals are still in the MCI or subjective memory complaint stage. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Widespread Cognitive Deficits in Alcoholism Persistent Following Prolonged Abstinence: An Updated Meta-analysis of Studies That Used Standardised Neuropsychological Assessment Tools

Objective

This study presents an updated meta-analysis replicating the study of (Stavro, K., Pelletier, J., & Potvin, S. (2013). Widespread and sustained cognitive deficits in alcoholism: A meta-analysis. Addiction Biology, 18, 203–213. doi:10.1111/j.1369-1600.2011.00418.x) regarding the cognitive functioning of alcoholics as a function of time abstinent.

Methods

A total of 34 studies (including a total of 2,786 participants) that met pre-determined inclusion and exclusion criteria were included in the analyses. The alcoholics were categorised into recently detoxified alcoholics (0–31 days sober), alcoholics 32–365 days sober and alcoholics >365 days sober consistent with the previous study. The current study employed more stringent control on the tests included in the analysis to include only those tasks described in contemporary neuropsychological test compendia. Forty-seven percent of the papers surveyed were not include in the previous meta-analysis.

Results

The results indicated that there was a diffuse and pervasive pattern of cognitive deficit among recently detoxified alcoholics and that these deficits, particularly with regard to memory functioning, persisted even in longer term abstinent alcoholics. This was inconsistent with the prior meta-analysis which contended that significant cognitive recovery was possible after as little as 1 year.

Conclusion

The persisting cognitive deficits were noted across a wide range of cognitive functions, supporting the notion of a diffuse rather than a specific compromise of cognition in alcoholism following discontinuation, as measured using standardised neuropsychological tests. Limitations on the finding included the fact that it was a cross-sectional rather than a longitudinal analysis, was subject to heterogeneity of method, had low representation of females in the samples, and had fewer studies of long-term sober samples.

Comparing the effect of the subcategories of atypical antipsychotic medications on cognition in schizophrenia using a meta-analytic approach

OBJECTIVES

The aim of this study was to compare the two most commonly prescribed classes of atypical antipsychotic medications (i.e., -pines and -dones) with regard to their effects on cognition in patients with schizophrenia.

DATA SOURCES

Ovid Technologies web-based software was used to search the Medline and PsycINFO computerized databases to identify articles that met the inclusion criteria.

REVIEW METHODS

The search was limited to papers published after 1990, written in English, employing human subjects, using atypical antipsychotics, using a within-subjects design or control group of patients with schizophrenia for comparisons, using participants aged from 18-65, and employing standardized neuropsychological measures.

RESULTS

A total of 996 eligible studies were identified, and of these 19 were finally analyzed. Nine domains of cognitive functioning were assessed. The two groups of agents produced equivalent overall effects (-dones = .254 versus -pines = .202). The -pines were found to improve the domains of attention/working memory, executive functioning, fluency, nonverbal memory, processing speed, and verbal memory, each with a significant, small effect size. The -dones were found to improve attention/working memory, executive functioning, motor function, nonverbal memory, processing speed, and verbal memory, each with a significant, small effect size. Failsafe N was robust for all of the domains for the -pines, but only for the verbal memory domain for the -dones, suggesting that the significant findings for the other domains with the -dones are more tenuous.

CONCLUSION

The results indicate that the agents were largely equivalent and that there was no clear evidence that the pattern of cognitive effects differed as a result of the agent applied. The effects themselves, while statistically significant, were small, indicating that some or all of the differences may be attributable to practice effects on the instruments employed.

Cognitive functioning in systemic lupus erythematosus: a meta-analysis

Cognitive deficits are common in patients with systemic lupus erythematosus (SLE) regardless of overt neuropsychiatric involvement; however, a clear neuropsychological profile of SLE has not emerged. This study undertook a literature search of the PubMed, Scopus and Ovid (PsychINFO) databases for studies investigating cognitive alterations in SLE, using standardized neuropsychological (NP) measures. The data were analysed using meta-analytical procedures. The results support the observation that relative to healthy controls, SLE (regardless of overt neuropsychiatric involvement) is associated with statistically significant, small effect-sized deficits in visual attention, cognitive fluency, immediate visual memory and visual reasoning. Moreover, the results support a gradient of cognitive disturbance in SLE with significantly greater cognitive impairment in NPSLE patients relative to non-NPSLE patients. Medium-sized deficits were observed in NPSLE patients relative to healthy controls across the domains of: complex attention, delayed verbal memory, language and verbal reasoning (with small or non-significant differences observed in non-NPSLE patients relative to healthy controls). These results are relevant to the understanding, assessment and rehabilitation of patients living with SLE, with or without overt neuropsychiatric involvement.

The Cognitive Effects of Obstructive Sleep Apnea: An Updated Meta-analysis

This meta-analysis set out to ascertain the cognitive function of obstructive sleep apnea (OSA) patients as measured through objective neuropsychological tests. The meta-analysis investigated the cognitive functioning of these patients prior to them receiving any treatment such as continuous positive airway pressure (CPAP). A total of 19 studies met the study inclusion criteria. Results revealed statistically significant negative effect sizes in the cognitive domains of non-verbal memory, concept formation, psychomotor speed, construction, executive functioning, perception, motor control and performance, attention, speed of processing, working and verbal memory, verbal functioning and verbal reasoning. The clinical implication of these results, the possible causal mechanisms of the cognitive impairments and the implication of these for future research were each discussed. Despite a number of important limitations, the analysis highlights the need for clinicians to comprehensively explore complaints about sleep disturbance, particularly OSA, in all clinical assessments to ensure control for this important confounder in order to ensure appropriate attribution of the source of any observed cognitive compromise.

Material-specific retroactive interference effects of the Wechsler Adult Intelligence Scale-Fourth Edition on the Wechsler Memory Scale-Fourth Edition in a nonclinical sample

INTRODUCTION

This study investigated proactive and retroactive interference effects between the Wechsler Memory Scale-Fourth Edition (WMS-IV) using the flexible approach, and the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV).

METHOD

One hundred and eighty nonclinical participants were assigned to a four (visual interference, verbal interference, visual and verbal interference, vs. no interference) by two (retroactive vs. proactive) between-subjects design. The administration order of the tests was counterbalanced (i.e., administration of the WAIS-IV prior to the WMS-IV, and the WAIS-IV administered during the delay interval of the WMS-IV).

RESULTS

The WAIS-IV produced significant retroactive interference effects on the WMS-IV; however, no proactive interference effect was observed. The retroactive interference effect was dependent on material specificity.

CONCLUSIONS

The results indicate that material presented within the delay of the WMS-IV can have a significant effect on subsequent delayed recall. Clinicians should carefully consider the effects associated with carry-over effects of these tests when using them in combination.

Shame, guilt, and facial emotion processing: initial evidence for a positive relationship between guilt-proneness and facial emotion recognition ability

Shame and guilt are closely related self-conscious emotions of negative affect that give rise to divergent self-regulatory and motivational behaviours. While guilt-proneness has demonstrated positive relationships with self-report measures of empathy and adaptive interpersonal functioning, shame-proneness tends to be unrelated or inversely related to empathy and is associated with interpersonal difficulties. At present, no research has examined relationships between shame and guilt-proneness with facial emotion recognition ability. Participants (N = 363) completed measures of shame and guilt-proneness along with a facial emotion recognition task which assessed the ability to identify displays of anger, sadness, happiness, fear, disgust, and shame. Guilt-proneness was consistently positively associated with facial emotion recognition ability. In contrast, shame-proneness was unrelated to capacity for facial emotion recognition. Findings provide support for theory arguing that guilt and empathy operate synergistically and may also help explain the inverse relationship between guilt-proneness and propensity for aggressive behaviour.

The acute cognitive effects of zopiclone, zolpidem, zaleplon, and eszopiclone: a systematic review and meta-analysis

The "z-drugs" zopiclone, zolpidem, eszopiclone, and zaleplon were introduced in the 1980s for the treatment of insomnia, as it was observed that the side effect profile associated with these medications were more benign than those related to the benzodiazepines. This meta-analysis set out to ascertain which domains of cognitive function, if any, were affected by the ingestion of these medications. A total of 20 studies met the study inclusion criteria. Results revealed medium effect sizes for zopiclone and zolpidem on measures of verbal memory. An additional medium effect size was observed for zolpidem on attention. Finally, smaller effect sizes were observed for zolpidem speed of processing and for zopiclone on working memory. It is clear from these data that the use of a single dose of the z-drugs in healthy adults as measured in the morning following the exposure does produce a specific rather than a generalized negative effect on cognitive function. However, there were only enough studies to evaluate the individual cognitive effects of the zolpidem and zopiclone medications; the specific effects of zaleplon and eszopiclone cannot be ascertained because only one study met the inclusion and exclusion criteria for the review.

Is the Boston Naming Test still fit for purpose?

The Boston Naming Test (BNT) (Kaplan, Goodglass, & Weintraub, 1983) is the most commonly used test of confrontation naming in neuropsychology (Rabin, Barr, & Burton, 2005). However, there are significant criticisms of the BNT which suggest that it might not be the assessment measure of choice. These criticisms are that the BNT has poor psychometric properties, is not adequately standardized, and has inadequate norms. It is further suggested that when considered in the context of contemporary conceptualizations of the neuropsychology of naming, the BNT does not adequately capture the processes known to be required for successful naming, and does not sample widely enough from the content domain of "naming". These criticisms suggest that the BNT is flawed as a measure of naming, and are discussed in detail in this review. Other stand-alone visual confrontation naming tasks are reviewed to evaluate whether any might be viable substitutes for the BNT in clinical neuropsychology. The Naming Test from the Neuropsychological Assessment Battery (Stern & White, 2009) was identified as a possible alternative to the BNT, however, neither of these tests was designed with reference to models of the neuropsychology of naming, and development of a new test of naming is indicated.

Does the presence of posttraumatic anosmia mean that you will be disinhibited?

Dispute has surrounded the issue of whether the relationship between anosmia and executive dysfunction in traumatic brain injury (TBI) may be artefactual due to poor ascertainment. Three groups matched for age, gender, education, Full Scale IQ, and the Wechsler Working Memory Index and showing adequate symptom validity were compared: 30 anosmic TBIs (TBI-A) matched for posttraumatic amnesia (PTA) and working memory functioning with 36 nonanosmic TBIs (TBI-NA) and 51 controls. The groups performed the FAS test, the Animal Fluency test, the Stroop Neurological Screening Test (SNST), the Wisconsin Card Sorting Test-64 (WCST-64) and the Trail Making Test (TMT-B) as well as tests of emotional functioning and return to work outcome. After adjusting for the covariates (i.e., gender; Wechsler Test of Adult Reading, WTAR; and years of education), a significant effect was found for items successfully completed on the SNST, the FAS task, the Animal Fluency task, and the WCST-64 categories completed. After adjusting for the covariates, a significant difference was found for number of errors on the SNST and for the number and type of errors on TMT-B. The two groups did not differ in terms of their affective functioning (i.e., Beck Depression Inventory or Beck Anxiety Inventory), or in terms of their outcome with regard to return to work. The findings support the notion that the TBI-A group demonstrated considerably weaker performance on executive tasks than did the nonanosmic TBIs. These patients were not, however, more prone to an error-prone pattern of performance, and, if anything, their executive deficit was more likely attributable to a reduced productivity of response.

Piracetam, an AMPAkine drug, facilitates memory consolidation in the day-old chick

Piracetam is an AMPAkine drug that may have a range of different mechanisms at the cellular level, and which has been shown to facilitate memory, amongst its other effects. This series of experiments demonstrated that a 10mg/kg dose of piracetam facilitated memory consolidation in the day-old chick when injected from immediately until 120min after weak training (i.e. using a 20% v/v concentration of methyl anthranilate) with the passive avoidance learning task. Administration of piracetam immediately after training led to memory facilitation which lasted for up to 24h following training. This dose of the AMPAkine was not shown to facilitate memory reconsolidation. These findings support the contention that application of the AMPAkine piracetam facilitates memory using a weak training task, and extend the range of actions previously noted with NMDA-related agents to those which also facilitate the AMPA receptor.

Characterization of cerebellar ataxia in chronic alcoholics using the International Cooperative Ataxia Rating Scale (ICARS)

BACKGROUND

Alcoholism is the most common cause of cerebellar dysfunction, yet estimates of the incidence of alcoholic cerebellar degeneration (ACD) vary greatly, with differences in methodologies contributing to these disparate findings. This study set out to characterize the frequency and pattern of clinical signs of ACD in an alcoholic group using the International Cooperative Ataxia Rating Scale (ICARS).

METHODS

We compared the performance of 49 alcoholics and 29 control participants. The relative contributions of demographic and alcohol consumption variables to ICARS scores in the alcoholic group were also examined.

RESULTS

The alcoholic group demonstrated significantly poorer performance on all of the ICARS subscales as compared with the control group. Within the alcoholic group, performance was more impaired on the speech scale than on all of the other scales, except the lower limb component of the kinetic scale, and less impaired on the oculomotor scale compared with all other scales. Years of heavy drinking and lifetime alcohol consumption correlated with total ICARS scores; however, maximum daily consumption was actually negatively correlated with ICARS scores. Of the alcohol history variables, years of heavy drinking was the best predictor of total ICARS scores, making a 19% unique contribution, followed by the period of abstinence from alcohol, which uniquely contributed 7% of the variance. There were high correlations between age and male gender and the alcohol consumption variables; however, age and gender were still found to uniquely contribute 5 and 7% respectively to the variance in total ICARS scores.

CONCLUSIONS

ACD may affect up to two-thirds of chronic alcoholics. Assessing the number of years an individual has been drinking beyond a certain threshold can give a good indication of the likelihood of ACD. Age, gender, and the source of the clinical sample may significantly contribute to the prevalence of ACD and require further detailed investigation.

Brain-derived neurotrophic factor facilitates memory consolidation and reconsolidation of a weak training stimulus in the day-old chick

Recent research has pointed to a role for brain-derived neurotrophic factor (BDNF) in long-term potentiation and memory. The present series of experiments examined the effects of the application of exogenous BDNF on memory consolidation and reconsolidation of a weak training stimulus with the day-old chick, using the passive avoidance learning paradigm. Chicks injected intracranially with 12.5 μg/mL recombinant BDNF immediately after a single-trial training event displayed enhanced retention relative to saline up to 24h post-training. Furthermore, this dose was also shown to enhance retention when administered following initial weak training. Thus, exogenous BDNF was shown to enhance both consolidation and reconsolidation of memory when administered acutely to the day-old chick.

The Effect of Item Type on Performance of the Matrix Reasoning Subtest of the WAIS-III in Traumatically Brain Injured and Non Brain-injured Control Participants

Qualitative analysis of neuropsychological instruments has been a long tradition in neuropsychological assessment. This study extended this type of analysis to the Matrix Reasoning (MR) subtest of the WAIS-III. The study compared the performance of TBI participants on the item types identified within the MR subtest (i.e., pattern completion, classification, analogy and serial reasoning) with a group of normal controls. MR items were classified into categories (as defined respectively by the Psychological Corporation and by our own research definition). Ninety-three non brain-injured control and 72 brain injured control participants were included in the study. One way analysis of variance indicated that the TBI group performed significantly worse than the non brain-injured group the MR performance overall as well as for both the Psychological Corporation classification and on the research defined categories. Within group analysis revealed that both groups performed significantly differently across the item categories with the most difficult categories being analogy and serial reasoning for the research defined categories and the classification and serial reasoning categories for the Psychological Corporation-defined groups. The results of the study indicate that an item type analysis of the MR performance may further contribute to the qualitative aspects of diagnostic formulation.

Traumatic Brain Injury Without Loss of Consciousness: A Case Study

Whilst many investigators concede that traumatic brain injury (TBI) without loss of consciousness (LOC) can occur, the number of times that this phenomena is reported in the literature is small. This case report presents an instance of TBI without LOC as supported by the observation of slowed processing speed, anosmia and a marked post-traumatic dysexecutive syndrome featuring moderately severe disinhibition. The case is discussed with a view to determining the mechanics of the blow necessary to both damage the cerebral substance yet maintain consciousness intact.

A meta-analytic review of the emotional symptoms associated with mild traumatic brain injury

Given the prevalence of mild traumatic brain injury (mTBI) and enduring subjective complaints known as postconcussion symptoms (PCS), it is important to investigate the nature and extent of these difficulties. This study used meta-analytic techniques to integrate the available information on the emotional symptoms associated with mTBI. Small effect sizes were found across all domains (depression, anxiety, coping, and psychosocial disability); however, significance depended upon the weighting method employed. The results indicate that mTBI had a small to negligible effect on emotional symptom reporting. This has implications for the etiology of PCS, the delivery of therapeutic interventions, and medico-legal disputations.

The relationship between naming difficulty and FAS performance following traumatic brain injury

PRIMARY OBJECTIVE

To investigate the relationship between naming difficulty (ND) and FAS performance in traumatic brain injury (TBI).

METHODS AND PROCEDURE

Sixty-three patients with a TBI were divided into two groups based on the presence of a ND and were compared with a control group on FAS performance.

RESULTS

Whilst the group with a TBI performed more poorly than the control group on the FAS task, there was no difference between those participants who featured a ND and those who did not. The TBIs produced fewer words than the control group in the first time slice of the task, but there was no difference between the group with a ND and the non-ND group on this measure.

CONCLUSION

The results indicate that the effect of word finding deficits is not the principal cause of the diminution of phonemic verbal fluency performance in TBI, which is probably more likely due to compromise in speed of information processing associated with the injury.

The relationship between working memory, processing speed, verbal comprehension and FAS performance following traumatic brain injury

PRIMARY OBJECTIVE

To investigate the relationship of working memory, processing speed and verbal comprehension with FAS performance in individuals who had sustained a traumatic brain injury (TBI).

METHODS AND PROCEDURE

Sixty-three patients with a TBI were grouped according to the presence of impaired verbal fluency performance and then compared on a number of cognitive and demographic variables.

RESULTS

Following a TBI, working memory and processing speed had the greatest influence on verbal fluency performance. For those individuals who have not sustained a TBI, education, verbal intelligence, working memory and speed of information processing were related to FAS performance.

CONCLUSIONS

The findings of the study indicate that FAS performance was related to verbal intelligence, working memory ability, attention and speed of information processing. The results further suggest that different variables are related to FAS performance following a TBI as compared with control group performances.

The effect of state worry and trait anxiety on working memory processes in a normal sample

INTRODUCTION

This study investigated the effects of trait anxiety and state worry on working memory performance in a normal sample. Phase one investigated the effects of trait anxiety and state worry on the capacity of specific working memory components. Phase two investigated the validity of Eysenck and Calvo's (1992) Processing Efficiency Theory of worry.

METHOD

Sixty adult participants (40 females and 20 males with a mean age of 26 years) were assigned to a 2 (trait anxiety: Low vs. high)x2 (state worry: Low vs. high) between-subjects design.

RESULTS

Contrary to prediction, worry did not lead to a decrement in performance on verbal working memory tasks but unexpectedly enhanced performance on visual tasks in participants with low trait anxiety (LTA). The results were also in opposition to expectations for Phase two. Individuals in the conditions of high trait anxiety and/or high state worry (LTA/HW, HTA/LW, and HTA/HW) displayed shorter response latencies than individuals in the LTA and low state worry (LTA/LW) condition on both verbal and spatial working memory (i.e., N-back) tasks.

CONCLUSION

Although non-pathological worry is predominantly a verbal-linguistic activity, it may also be complemented by the processing of visual imagery which facilitates problem-solving and adaptive functions.

Interference effects on commonly used memory tasks

This paper reports two studies which investigated the effect of interference on delayed recall scores of the WMS-III and other commonly used memory measures. In Study 1, participants completed the immediate and delayed components of the WMS-III, with or without the introduction of conceptually similar memory tasks between the recall trials. In Study 2, this order of administration was reversed, with the WMS-III subtests used as the interference items. The results indicated that the introduction of interference items during the delay negatively affected delayed recall performance on almost all sub-tests. In addition, equal effects of proactive and retroactive interference were demonstrated. These findings raise concerns regarding the standardization process for memory tasks and highlight the need to consider interference effects in clinical practice, and stand as a caution in the use of memory-related materials during the delay interval in memory testing.

Inhibition of cyclin-dependent kinase 5 by roscovitine impairs memory consolidation and reconsolidation in the day-old chick

Cyclin-dependent kinase 5 (CDK-5) is reported to phosphorylate the NMDA receptor prior to the induction of long-term potentiation (LTP), among its many other effects. Application of CDK-5 inhibitors disrupts LTP and results in impaired task acquisition in behaving animals. In this study, we investigated the effect of exogenously applied roscovitine, a potent CDK-5 inhibitor, on consolidation and reconsolidation processes in day-old male chicks. New Hampshire x White leghorn cockerels were trained using a modified version of the passive avoidance learning task. Intracranial injections of roscovitine (2.5 microM) administered immediately after training induced a memory deficit that evolved from 5-minute post-training and persisted until at least 24 h following training. Injections of roscovitine (2.75 microM) administered immediately after the reminder trial induced a memory deficit observed by 30-minute post-reminder which had resolved by 24 h following the reminder. The comparison between consolidation and reconsolidation demonstrates differences both in the time of the onset of the memory deficit as well as in the permanence of this deficit. The results suggest an important, although different role for CDK-5 in consolidation and reconsolidation processes following passive avoidance learning.

Remembering that things have changed: a review of the cellular mechanisms of memory re-consolidation in the day-old chick

It has been one of the unshakeable orthodoxies of memory research that memory is initially laid down in a labile form for a short period following the experience and that over time the memory is "fixed" or "consolidated" into the physical structure of the brain. Over the last decade a large body of data has gathered which demonstrates that a "consolidated" memory can be returned to a labile state following retrieval of material from the store, which can then be re-consolidated, incorporating the newly acquired information into the representation of the world. The process of re-consolidation thus provides a sensible means for the crucial process of memory updating to occur. The paper focuses on pharmaco-behavioural experiments undertaken in our laboratories as well as in those of other groups which use the day-old chick as subject and the passive avoidance learning (PAL) task to examine the behavioural and metabolic parameters of re-consolidation. The data indicate that the consolidation and the re-consolidation processes are similar but not identical physiological processes. The re-processing of the memory following a re-consolidation involves each of the glutamatergic, adrenergic and dopaminergic neurotransmitter systems as well as re-activation of protein synthesis associated with the respective traces. In the chick model system, the ability to undertake re-consolidation is transient, and is observed only for a maximum of 24-48 h following the initial training event. Controversy persists as to whether the re-consolidated memory represents a new memory or whether it is a modification of the original memory processing.