Retrieval Deficits Research Articles

Executive dysfunction and autobiographical memory retrieval in recovered depressed women

Background and objectivesDepressed individuals have difficulty remembering specific autobiographical events. These deficits often persist after recovery of mood symptoms, but the mechanisms underlying impaired memory specificity in recovered depressed individuals remain unclear. Here, we sought to examine whether performance on two cognitive measures might be related to deficits in autobiographical memory retrieval in individuals with a history of depression. MethodsTwenty-four recovered depressed women (12 with more than one previous episode) and 24 never depressed women completed two cognitive measures (Digit Span and a Number Generation Task) and tests of autobiographical memory recall. ResultsOverall, the recovered depressed women did not show deficits in autobiographical retrieval. However, those with more than one previous episode had impaired retrieval of categorical autobiographical memories. Moreover, depression history moderated the relationship between Digit Span and retrieval of categoric autobiographical memories such that within the whole recovered depressed group (but not the never depressed group), those with lower Digit Span also had poorer retrieval of categorical autobiographical memories. LimitationsOur sample size was small and included only women. Moreover, order effects may have been a significant factor. ConclusionsThese findings support the notion that working memory is an important factor in impairing autobiographical memory in those who have recovered from depression, but suggest a complex relationship with autobiographical recall.

Effects of phonological neighbourhood on the treatment of naming in aphasia

Background: Phonological treatments to improve naming ability in aphasia focus on re-strengthening connections within the phonological system. Nonetheless, the efficacy of phonological treatments is still being explored with particular consideration of cognitive neuropsychological perspectives. Clinicians may also need to consider lexical factors that interact with the word retrieval process. Researchers have shown that phonological neighbourhood density influences normal language recognition and production, but limited evidence exists for how phonological neighbourhoods may affect the treatment of word retrieval deficits in individuals with aphasia.Aims: The present study explored if manipulating the emphasis on phonological neighbourhood during treatment has an effect on naming ability, particularly in an individual with predominantly phonologically based deficits. We hypothesised that training front- and end-matched words in a condition that emphasised phonological neighbourhood would result in greater naming improvements than training front- and end-matched words in a condition that does not emphasise neighbourhood.Methods & Procedures: In this case study, participant AH had a moderate phonologically based word naming deficit following a stroke. He produced phonemic paraphasias and neologisms in spontaneous speech and other spoken word production tasks. In treatment, AH was asked to name triplets of pictures of items that were phonologically related, sharing initial or final phonemes, or unrelated. Items were from either high- or low-density phonological neighbourhoods. High-density items were trained largely in the context of neighbours, therefore emphasising neighbourhood. Low-density items were not trained within a condition that emphasise neighbourhood. The treatment was administered for 9 weeks (27 sessions), with each condition, front-matched, end-matched and unrelated, trained for 8 consecutive sessions. AH’s naming accuracy on training words was assessed using a basic withdrawal design with three probe naming tests during the treatment phase and at 1-month post-therapy. Naming accuracy was also recorded during treatment sessions.Outcomes & Results: Front-matched words, in a condition that emphasises phonological neighbourhoods, had the greatest treatment effects, with a medium effect size when comparing pre- versus post-measures. A small treatment effect was observed for front-matched items where neighbourhood was not emphasised.Conclusions: Results suggest that front-matched triplets trained within a condition that emphasises phonological neighbourhoods may lead to the greatest treatment effect. Clinicians should be aware that stimulus parameters, such as phonological neighbourhood, may interact with the effectiveness of treatment protocols.

Predicting Progression to Dementia in Elderly Subjects with Mild Cognitive Impairment Using Both Cognitive and Neuroimaging Predictors

The objective of this work was to assess the predictive accuracy of targeted neuroimaging and neuropsychological measures for the detection of incipient dementia in individuals with mild cognitive impairment (MCI), and to examine the potential benefit of combining both classes of measures. Baseline MRI measures included hippocampal volume, cortical thickness, and white matter hyperintensities. Neuropsychological assessment focused on different aspects of episodic memory (i.e., familiarity, free recall, and associative memory) and executive control functions (i.e., working memory, switching, and planning). Global and regional cortical thinning was observed in MCI patients who progressed to dementia compared to those who remained stable, whereas no differences were found between groups for baseline hippocampal volume and white matter hyperintensities. The strongest neuroimaging predictors were baseline cortical thickness in the right anterior cingulate and middle frontal gyri. For cognitive predictors, we found that deficits in both free recall and recognition episodic memory tasks were highly suggestive of progression to dementia. Cortical thinning in the right anterior cingulate gyrus, combined to controlled and familiarity-based retrieval deficits, achieved a classification accuracy of 87.5%, a specificity of 90.9%, and a sensitivity of 83.3%. This predictive model including both classes of measures provided more accurate predictions than those based on neuroimaging or cognitive measures alone. Overall, our findings suggest that detecting preclinical Alzheimer's disease is probably best accomplished by combining complementary information from targeted neuroimaging and cognitive classifiers, and highlight the importance of taking into account both structural and functional changes associated with the disease.

Perceptions of stroke recovery: An exclusion of communication and cognition

Perceptions of stroke recovery can differ substantially between stroke survivors and their healthcare providers. Concordance between the two is important for collaborative goal setting to facilitate optimal outcomes. To explore stroke survivors' perceptions of their own recovery and residual impairments with specific emphasis on communication and cognition. A qualitative analytic approach was used in the study. Nine stroke survivors participated in a focus group discussion as part of a larger study designed to examine post-stroke outcomes. Early in the focus group proceedings, a discussion emphasizing how stroke survivors perceive their overall recovery emerged. Six of the nine participants (67%) perceived their overall stroke recovery to be greater than 90%, and only physical impairments were reported. Later in the course of the interview, eight of the nine participants (89%) reported either word retrieval or memory loss deficits which negatively influenced their daily functional activities. Stroke survivors in this sample did not include communication and cognitive deficits in their perception of their overall recovery despite later reporting these symptoms and related impairment. Failure of patients to include such persisting deficits in their reports of recovery can cause a mismatch between stroke survivor and provider goals.

Word Retrieval Deficits in Malay-speaking Adults with Nonfluent Aphasia

Word Retrieval Deficits in Malay-speaking Adults with Nonfluent Aphasia

The Nature of Verbal Memory Impairment in Multiple Sclerosis: A List-Learning and Meta-analytic Study

The primary purpose of this study was to test the hypothesis that multiple sclerosis (MS) patients have impaired acquisition rather than a retrieval deficit. Verbal memory impairment in MS was examined in 53 relapsing-remitting MS patients and 31 healthy controls (HC), and in a meta-analysis of studies that examined memory functioning in MS with list-learning tasks. The MS group demonstrated significantly lower acquisition and delayed recall performance than the HC group, and the meta-analysis revealed that the largest effect sizes were obtained for acquisition measures relative to delayed recall and recognition. Our data argue against a retrieval deficit as the sole explanation for verbal memory impairment in MS, and make a consistent case for the position that deficient acquisition contributes to the memory dysfunction of MS patients. Deficient acquisition may result from demyelination in relevant white matter tracts that reduces encoding efficiency as a result of impaired speed of information processing.

Beneficios de la codificación profunda en la enfermedad de Alzheimer. Análisis del rendimiento en una tarea de memoria mediante el Item Specific Deficit Approach

Introductionthe aim of this study is to test the encoding deficit hypothesis in Alzheimer disease (AD) using a recent method for correcting memory tests. To this end, a Spanish-language adaptation of the Free and Cued Selective Reminding Test was interpreted using the Item Specific Deficit Approach (ISDA), which provides three indices: Encoding Deficit Index, Consolidation Deficit Index, and Retrieval Deficit Index. MethodsWe compared the performances of 15 patients with AD and 20 healthy control subjects and analysed results using either the task instructions or the ISDA approach. Resultspatients with AD displayed deficient encoding of more than half the information, but items that were encoded properly could be retrieved later with the help of the same semantic clues provided individually during encoding. Virtually all the information retained over the long-term was retrieved by using semantic clues. Encoding was shown to be the most impaired process, followed by retrieval and consolidation. Discriminant function analyses showed that ISDA indices are more sensitive and specific for detecting memory impairments in AD than are raw scores. ConclusionsThese results indicate that patients with AD present impaired information encoding, but they benefit from semantic hints that help them recover previously learned information. This should be taken into account for intervention techniques focusing on memory impairments in AD.

C-12the Neuropsychological Assessment Battery Naming Test Spanish Translation and Validation: Pilot Test Results

Objective: The incidence and prevalence of dementia were higher in Latinos and blacks than in non-Latino whites in a study completed in 1999 (Gurland et al., 1990). Additionally, reports show growth within the Hispanic or Latino population, and an increase in bilingualism in the USA (U.S. Census Bureau, 2010b). Despite demographic and cultural shifts, few measures of language functioning for Spanish speakers are available to providers. The translation and validation of the Neuropsychological Assessment Battery (NAB) naming test is an attempt at improving current methods for assessing lexical retrieval deficits in U.S. Spanish/English bilingual population. Method: Initial translation, back-translation, committee review, and pilot testing were conducted. Pilot testing included a neuromedical questionnaire, Short Acculturation Scale (SAS), Spanish Word Accentuation Test (WAT), and Spanish NAB naming test; inclusion criteria for subjects (n = 5) were age <55, Spanish language proficiency, and no history of neurological abnormality. Results: Participants were diverse in country of origin (Mexico, El Salvador, Honduras), time in the USA (∼ 2–15 years), years of education (8–20 years), acculturation scores (range: 21–33, M = 28, SD = 4.89), and performance on the WAT (range: 9–32, M = 25, SD = 10.34). Of 31 translated test items, 14 items received different than expected responses from one or more participants. Conclusion: Findings support the need for translation refinement, as more than one Spanish name for stimuli presented may be appropriate and commonly used. Country of origin, education, and acculturation variables also appear to impact test performance. Field testing (n = 25) is underway to explore heterogeneity of responses demonstrated in the pilot study.

Restoration of Dopamine Signaling to the Dorsal Striatum Is Sufficient for Aspects of Active Maternal Behavior in Female Mice

Striatal dopamine (DA) is important for motivated behaviors, including maternal behavior. Recent evidence linking the dorsal striatum with goal-directed behavior suggests that DA signaling in the dorsal striatum, not just the nucleus accumbens, could be involved in maternal behavior. To investigate this question, we tested the maternal behavior of mice with DA genetically restricted to the dorsal striatum. These mice had a mild deficit in pup retrieval but had normal licking/grooming and nursing behavior; consequently, pups were weaned successfully. We also tested a separate group of mice with severely depleted DA in all striatal areas. They had severe deficits in pup retrieval and licking/grooming behavior, whereas nursing behavior was left intact; again, pups survived to weaning at normal rates. We conclude that DA signaling in the striatum is a part of the circuitry mediating maternal behavior and is specifically relevant for active, but not passive, maternal behaviors. In addition, DA in the dorsal striatum is sufficient to allow for active maternal behavior.

Memory impairment in multiple sclerosis is due to a core deficit in initial learning

Persons with multiple sclerosis (MS) suffer memory impairment, but research on the nature of MS-related memory problems is mixed. Some have argued for a core deficit in retrieval, while others have identified deficient initial learning as the core deficit. We used a selective reminding paradigm to determine whether deficient initial learning or delayed retrieval represents the primary memory deficit in 44 persons with MS. Brain atrophy was measured from high-resolution MRIs. Regression analyses examined the impact of brain atrophy on (a) initial learning and delayed retrieval separately, and then (b) delayed retrieval controlling for initial learning. Brain atrophy was negatively associated with both initial learning and delayed retrieval (ps < 0.01), but brain atrophy was unrelated to retrieval when controlling for initial learning (p > 0.05). In addition, brain atrophy was associated with inefficient learning across initial acquisition trials, and brain atrophy was unrelated to delayed recall among MS subjects who successfully acquired the word list (although such learning frequently required many exposures). Taken together, memory deficits in MS are a result of deficits in initial learning; moreover, initial learning mediates the relationship between brain atrophy and subsequent retrieval, thereby supporting the core learning-deficit hypothesis of memory impairment in MS.

Specific cerebellar grey matter volume loss is predictive for episodic memory retrieval deficits in early Alzheimer's disease

Alzheimer's & DementiaVolume 9, Issue 4S_Part_3 p. P115-P115 AbstractFree Access IC-P-207: Specific cerebellar grey matter volume loss is predictive for episodic memory retrieval deficits in early Alzheimer's disease Heidi Jacobs, Heidi Jacobs Maastricht University, Maastricht, the NetherlandsSearch for more papers by this authorEd H.B.M. Gronenschild, Ed H.B.M. Gronenschild Maastricht University, Maastricht, the NetherlandsSearch for more papers by this authorLies Clerx, Lies Clerx Maastricht University, Maastricht, the NetherlandsSearch for more papers by this authorPauline Aalten, Pauline Aalten Maastricht University, Maastricht, the NetherlandsSearch for more papers by this authorFrans R.J. Verhey, Frans R.J. Verhey Maastricht University, Maastricht, the NetherlandsSearch for more papers by this author Heidi Jacobs, Heidi Jacobs Maastricht University, Maastricht, the NetherlandsSearch for more papers by this authorEd H.B.M. Gronenschild, Ed H.B.M. Gronenschild Maastricht University, Maastricht, the NetherlandsSearch for more papers by this authorLies Clerx, Lies Clerx Maastricht University, Maastricht, the NetherlandsSearch for more papers by this authorPauline Aalten, Pauline Aalten Maastricht University, Maastricht, the NetherlandsSearch for more papers by this authorFrans R.J. Verhey, Frans R.J. Verhey Maastricht University, Maastricht, the NetherlandsSearch for more papers by this author First published: 01 July 2013 https://doi.org/10.1016/j.jalz.2013.05.1780AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume9, Issue4S_Part_3Alzheimer's Association International Conference 2013July 2013Pages P115-P115 RelatedInformation

Temporally specific divided attention tasks in young adults reveal the temporal dynamics of episodic encoding failures in elderly adults.

Nessler, Johnson, Bersick, and Friedman (D. Nessler, R. Johnson, Jr., M. Bersick, & D. Friedman, 2006, On why the elderly have normal semantic retrieval but deficient episodic encoding: A study of left inferior frontal ERP activity, NeuroImage, Vol. 30, pp. 299-312) found that, compared with young adults, older adults show decreased event-related brain potential (ERP) activity over posterior left inferior prefrontal cortex (pLIPFC) in a 400- to 1,400-ms interval during episodic encoding. This altered brain activity was associated with significantly decreased recognition performance and reduced recollection-related brain activity at retrieval (D. Nessler, D. Friedman, R. Johnson, Jr., & M. Bersick, 2007, Does repetition engender the same retrieval processes in young and older adults? NeuroReport, Vol. 18, pp. 1837-1840). To test the hypothesis that older adults' well-documented episodic retrieval deficit is related to reduced pLIPFC activity at encoding, we used a novel divided attention task in healthy young adults that was specifically timed to disrupt encoding in either the 1st or 2nd half of a 300- to 1,400-ms interval. The results showed that diverting resources for 550 ms during either half of this interval reproduced the 4 characteristic aspects of the older participants' retrieval performance: normal semantic retrieval during encoding, reduced subsequent episodic recognition and recall, reduced recollection-related ERP activity, and the presence of "compensatory" brain activity. We conclude that part of older adults' episodic memory deficit is attributable to altered pLIPFC activity during encoding due to reduced levels of available processing resources. Moreover, the findings also provide insights into the nature and timing of the putative "compensatory" processes posited to be used by older adults in an attempt to compensate for age-related decline in cognitive function. These results support the scaffolding account of compensation, in which the recruitment of additional cognitive processes is an adaptive response across the life span.

The Involvement of the Thalamus in Semantic Retrieval: A Clinical Group Study

There is increasing attention about the role of the thalamus in high cognitive functions, including memory. Although the bulk of the evidence refers to episodic memory, it was recently proposed that the mediodorsal (MD) and the centromedian-parafascicular (CM-Pf) nuclei of the thalamus may process general operations supporting memory performance, not only episodic memory. This perspective agrees with other recent fMRI findings on semantic retrieval in healthy participants. It can therefore be hypothesized that lesions to the MD and the CM-Pf impair semantic retrieval. In this study, 10 patients with focal ischemic lesions in the medial thalamus and 10 healthy controls matched for age, education, and verbal IQ performed a verbal semantic retrieval task. Patients were assigned to a target clinical group and a control clinical group based on lesion localization. Patients did not suffer from aphasia and performed in the range of controls in a categorization and a semantic association task. However, target patients performed poorer than healthy controls on semantic retrieval. The deficit was not because of higher distractibility but of an increased rate of false recall and, in some patients, of a considerably increased rate of misses. The latter deficit yielded a striking difference between the target and the control clinical groups and is consistent with anomia. Follow-up high-resolution structural scanning session in a subsample of patients revealed that lesions in the CM-Pf and MD were primarily associated with semantic retrieval deficits. We conclude that integrity of the MD and the CM-Pf is required for semantic retrieval, possibly because of their role in the activation of phonological representations.

The ventral midline thalamus contributes to strategy shifting in a memory task requiring both prefrontal cortical and hippocampal functions.

Electrophysiological and neuroanatomical evidence for reciprocal connections with the medial prefrontal cortex (mPFC) and the hippocampus make the reuniens and rhomboid (ReRh) thalamic nuclei a putatively major functional link for regulations of cortico-hippocampal interactions. In a first experiment using a new water escape device for rodents, the double-H maze, we demonstrated in rats that a bilateral muscimol (MSCI) inactivation (0.70 vs 0.26 and 0 nmol) of the mPFC or dorsal hippocampus (dHip) induces major deficits in a strategy shifting/spatial memory retrieval task. By way of comparison, only dHip inactivation impaired recall in a classical spatial memory task in the Morris water maze. In the second experiment, we showed that ReRh inactivation using 0.70 nmol of MSCI, which reduced performance without obliterating memory retrieval in the water maze, produces an as large strategy shifting/memory retrieval deficit as mPFC or dHip inactivation in the double-H maze. Thus, behavioral adaptations to task contingency modifications requiring a shift toward the use of a memory for place might operate in a distributed circuit encompassing the mPFC (as the potential set-shifting structure), the hippocampus (as the spatial memory substrate), and the ventral midline thalamus, and therein the ReRh (as the coordinator of this processing). The results of the current experiments provide a significant extension of our understanding of the involvement of ventral midline thalamic nuclei in cognitive processes: they point to a role of the ReRh in strategy shifting in a memory task requiring cortical and hippocampal functions and further elucidate the functional system underlying behavioral flexibility.

Treatment of Proper Name Retrieval Deficits in an Individual With Temporal Lobe Epilepsy

Studies investigating language deficits in individuals with left temporal-lobe epilepsy have consistently demonstrated impairments in proper name retrieval. The aim of this Phase I rehabilitation study was to investigate the effects of a linguistically distributed word retrieval treatment on proper name retrieval in an individual with left temporal-lobe epilepsy. A 61-year old right-handed male with left temporal-lobe epilepsy (clinical onset at the age of 50) and a deficit in proper name retrieval participated in this study. A single-subject, repeated-probe ABAA design with testing before, immediately after, and 3 months after treatment completion was employed. Proper name retrieval treatment was administered 2&emsp14;hr per day for 5 days. Results demonstrated improved naming on trained items and maintenance of trained items 3 months after treatment completion. Treatment, which took advantage of the individual's undamaged linguistic networks, promoted the reorganization of networks supporting proper naming, leading to improved proper name retrieval. Further research replicating these findings in individuals with varying degrees of proper name retrieval impairment is warranted. Additionally, the mechanism behind the observed improvements in proper name retrieval needs to be investigated further using functional neuroimaging.

Semantic Feature Analysis: Incorporating Typicality Treatment and Mediating Strategy Training to Promote Generalization

This investigation was designed to examine the generalization effects of semantic treatment for word retrieval deficits in people with aphasia. Semantic feature analysis (SFA; Boyle & Coelho, 1995), typicality treatment (Kiran & Thompson, 2003), and mediating strategy training were combined to maximize potential generalization effects. Treatment, which included SFA and a semantic feature judgment task, was conducted with 9 participants with chronic aphasia in the context of multiple baseline designs across behaviors. Typical and atypical exemplars were trained across animate and inanimate categories. Treatment was sequentially modified to overtly train the use of SFA as a mediating strategy. Eight of the 9 participants demonstrated improvements in naming of trained stimuli. Positive generalization effects were limited overall; possible response generalization was evident for 5 participants. Instruction in the use of a mediating strategy resulted in improved naming of treated words for all participants; however, generalization to untreated words did not occur. Treatment using SFA resulted in improved naming of treated typical and atypical exemplars in both animate and inanimate categories for 8 of 9 participants. Training in a mediating strategy also resulted in improved retrieval of experimental words. Regardless of intervention approach, generalization to untreated items was limited.

Modulating arithmetic fact retrieval: A single-blind, sham-controlled tDCS study with repeated fMRI measurements

Transcranial direct current stimulation (tDCS) is a non-invasive technique which has been used to modulate various cognitive functions in healthy participants as well as stroke patients. Despite the increasing number of tDCS studies, it still remains questionable whether tDCS is suitable for modulating performance in arithmetic tasks and whether a single tDCS session may cause brain activity changes that can be detected with functional magnetic resonance imaging (fMRI). We asked healthy participants to repeatedly solve simple multiplication tasks in three conditions: STIMULATION (anodal tDCS over the right angular gyrus, AG), SHAM (identical electrode set-up without stimulation), and CONTROL (no electrodes attached). Before and after tDCS, we used fMRI to examine changes in brain activity. Behavioural results indicate that a single session of tDCS did not modulate task performance significantly. However, fMRI measurements revealed that the neural correlates of multiplication were modified following a single session of anodal tDCS. In the bilateral AG, activity was significantly higher for multiplication problems rehearsed during active tDCS, as compared to multiplication problems rehearsed without tDCS or during sham tDCS. In sum, we present first neuro-functional evidence that tDCS modulates arithmetic processing. Implications of these findings for future tDCS studies and for the rehabilitation of acalculic patients with deficits in arithmetic fact retrieval are discussed.

Altered brain structure in Chinese dyslexic children

Due to the logographic nature of the writing system, learning to read Chinese places heavy demands on encoding of orthographic forms through rote memorization. Moreover, phonology has to often be retrieved from memory during reading because of the inconsistent mapping between characters and their pronunciations. Using optimized voxel-based morphometry, we examined differences in volumetrics between children with reading disability (RD, 10–12 years old) and age-matched typically developing (TD) children. Our study shows reduced gray matter volume (GMV) for RD in right inferior occipital gyrus and left inferior frontal gyrus, consistent with previous studies suggesting that Chinese dyslexics have deficits in orthographic and phonological processing. The deficit in phonological processing was further supported by reductions in white matter volumes (WMV) in left precentral gyrus. Greater deficits in ortho-phonological processing may be associated with semantic compensation, as lower skill RD children showed greater GMV in anterior temporal cortex, even though as a group they showed less GMV in this region compared to TD. Perhaps most interestingly, we showed reduced GMV in bilateral ventromedial prefrontal cortices (vmPFC) and this was correlated with reductions in WMV within vmPFC, suggesting that RD have deficits in memory retrieval. Moreover, these GMV alterations in vmPFC for the RD were correlated with alterations in right parahippocampal gyrus, which also showed a reduced GMV, suggesting that RD have a correlated deficit in memory encoding. Our results are consistent with previous studies suggesting that Chinese dyslexics have deficits in visuo-orthographic and phonological processing, but our study importantly suggests deficits in memory encoding and retrieval, perhaps due to the unique demands of the Chinese writing system.

Autobiographical memory in Parkinson's disease: A retrieval deficit

This study examined the effects of providing cues to facilitate autobiographical memory retrieval in Parkinson's disease. Previous findings have shown that individuals with Parkinson's disease retrieve fewer specific autobiographical memories than older adult controls. These findings are clinically significant since the quality of autobiographical memory is linked to identity and sense of self. In the current study, 16 older adults with Parkinson's disease without dementia and 16 matched older adult controls were given 3min in which to recall autobiographical memories associated with five different time periods and to give each memory a short title. Participants were later asked to retrieve the memories in three phases: firstly in a free recall phase; secondly in response to general cues (time periods) and finally in response to specific cues (the short titles previously given). The number of memories and the quality of the memory (general or specific) was recorded in each condition. Compared with matched older adult controls, the Parkinson's disease group was impaired in retrieving the memories that they had previously given in the free recall phase and in response to general cues. The performance of the group with Parkinson's disease was only equivalent to the older adults when they retrieved memories in response to self-generated cues. The findings are discussed in relation to theories of autobiographical memory and the neuropsychology of Parkinson's disease.

Neurobiological Dissociation of Retrieval and Reconsolidation of Cocaine-Associated Memory

Drug use is provoked by the presentation of drug-associated cues, even following long periods of abstinence. Disruption of these learned associations would therefore limit relapse susceptibility. Drug-associated memories are susceptible to long-term disruption during retrieval and shortly after, during memory reconsolidation. Recent evidence reveals that retrieval and reconsolidation are dependent on β-adrenergic receptor (β-AR) activation. Despite this, whether retrieval and reconsolidation are dependent on identical or distinct neural mechanisms is unknown. The prelimbic medial prefrontal cortex (PL-mPFC) and basolateral amygdala (BLA) have been implicated in the expression and reconsolidation of associative memories. Therefore, we investigated the necessity of β-AR activation within the PL-mPFC and BLA for cocaine-associated memory retrieval and reconsolidation in rats. Before or immediately after a cocaine-induced conditioned place preference (CPP) retrieval trial, β-AR antagonists were infused into the PL-mPFC or BLA, followed by daily testing. PL-mPFC infusions before, but not after, a CPP trial disrupted CPP memory retrieval and induced a persistent deficit in retrieval during subsequent trials. In contrast, BLA β-AR blockade had no effect on initial CPP memory retrieval, but prevented CPP expression during subsequent trials indicative of reconsolidation disruption. Our results reveal a distinct dissociation between the neural mechanisms required for cocaine-associated memory retrieval and reconsolidation. Using patch-clamp electrophysiology, we also show that application of a β-AR antagonist prevents norepinephrine-induced potentiation of PL-mPFC pyramidal cell and γ-aminobutyric-acid (GABA) interneuron excitability. Thus, targeted β-AR blockade could induce long-term deficits in drug-associated memory retrieval by reducing neuronal excitability, providing a novel method of preventing cue-elicited drug seeking and relapse.