Clarifying the role of pattern separation in schizophrenia: The role of recognition and visual discrimination deficits

Martinelli, Cristina; Shergill, Sukhwinder S.

doi:10.1016/j.schres.2015.06.004

Cited by 32 publications

(54 citation statements)

References 22 publications

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“…These findings reflects age-related changes in the hippocampal circuit that shifts the balance of processing away from pattern separation to a greater reliance on gist rather than specific details [34]. The MST, in its variety of incarnations, has proven to be a robust measure of age-related memory decline, as well as sensitive to memory decline associated with mild cognitive impairment [10,66,67], depression [40,41,68-70], schizophrenia [71,72], and sleep deprivation [76]. …”

Section: Discussionmentioning

confidence: 99%

Age-related deficits in the mnemonic similarity task for objects and scenes

Stark

2017

Behavioural Brain Research

113

121

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A B S T R A C TUsing the Mnemonic Similarity Task (MST), we have demonstrated an age-related impairment in lure discrimination, or the ability to recognize an item as distinct from one that was similar, but not identical to one viewed earlier. A growing body of evidence links these behavioral changes to age-related alterations in the hippocampus. In this study, we sought to evaluate a novel version of this task, utilizing scenes that might emphasize the role of the hippocampus in contextual and spatial processing. In addition, we investigated whether, by utilizing two stimulus classes (scenes and objects), we could also interrogate the roles of the PRC and PHC in aging. Thus, we evaluated differential contributions to these tasks by relating performance on objects versus scenes to volumes of the hippocampus and surrounding medial temporal lobe structures. We found that while there was an age-related impairment on lure discrimination performance for both objects and scenes, relationships to brain volumes and other measure of memory performance were stronger when using objects. In particular, lure discrimination performance for objects showed a positive relationship with the volume of the hippocampus, specifically the combined dentate gyrus (DG) and CA3 subfields, and the subiculum. We conclude that though using scenes was effective in detecting age-related lure discrimination impairments, it does not provide as strong a brain-behavior relationship as using objects.

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Section: Discussionmentioning

confidence: 99%

Age-related deficits in the mnemonic similarity task for objects and scenes

Stark

2017

Behavioural Brain Research

113

121

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“…Overall, these studies suggest that pattern separation may be impaired in schizophrenia, although neural recording studies (for example, using fMRI) would be needed to draw this conclusion. In addition, the behavioral deficits observed in schizophrenia may be partially explained by visual and perceptual deficits 123 .…”

Section: Neuropsychiatric Diseasementioning

confidence: 99%

“…There are numerous examples of studies that meet either condition 1 34,37,38,49,52,53 or condition 2 34–36,38,43,52,123,146 . A smaller number of studies have met condition 3 35,52,123 , and we find that this condition is often overlooked in clinical samples where performance could be altered on a number of untested conditions. Condition 4 has often been met 20,31,35,36,51,57,114 , but perhaps not in the same studies that satisfy conditions 1-3.…”

Section: Figmentioning

confidence: 99%

Integrating new findings and examining clinical applications of pattern separation

2018

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Pattern separation, the ability to independently represent and store similar experiences, is a crucial facet of episodic memory. Growing evidence suggests that the hippocampus possesses unique circuitry that is computationally capable of resolving mnemonic interference by using pattern separation. In this Review, we discuss recent advances in the understanding of this process and evaluate the caveats and limitations of linking across animal and human studies. We summarize clinical and translational studies using methods that are sensitive to pattern separation impairments, an approach that stems from the fact that the hippocampus is a major site of disruption in many brain disorders. We critically evaluate the assumptions that guide fundamental and translational studies in this area. Finally, we suggest guidelines for future research and offer ways to overcome potential interpretational challenges to increase the utility of pattern separation as a construct that can further understanding of both memory processes and brain disease.

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“…Performance on the Rey Auditory Verbal Learning Test (RAVLT) and Hopkins Verbal Learning Test-Revised (HVLT-R) was correlated with decreased pattern separation scores in older adults, but was less sensitive than the discrimination task in revealing variability within a healthy older adult group (Holden et al, , 2013Roberts et al, 2013;Sheppard et al, 2015). Generalizability of results was limited as 30 out of 62 studies were performed in young, healthy adults, and only two studies gave details on ethnicity of participants (Das et al, 2014;Martinelli and Shergill, 2015).…”

Section: General Validity Factorsmentioning

confidence: 99%

Tests of pattern separation and pattern completion in humans—A systematic review

et al. 2016

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Objective: To systematically review the characteristics, validity and outcome measures of tasks that have been described in the literature as assessing pattern separation and pattern completion in humans.Methods: Electronic databases were searched for articles. Parameters for task validity were obtained from two reviews that described optimal task design factors to evaluate pattern separation and pattern completion processes. These were that pattern separation should be tested during an encoding task using abstract, never-before-seen visual stimuli, and pattern completion during a retrieval task using partial cues; parametric alteration of the degree of interference of stimuli or degradation of cues should be used to generate a corresponding gradient in behavioral output; studies should explicitly identify the specific memory domain under investigation (sensory/perceptual, temporal, spatial, affect, response, or language) and account for the contribution of other potential attributes involved in performance of the task. A systematic, qualitative assessment of validity in relation to these parameters was performed, along with a review of general validity and task outcome measures. Results:Sixty-two studies were included. The majority of studies investigated pattern separation and most tasks were performed on young, healthy adults. Pattern separation and pattern completion were most frequently tested during a retrieval task using familiar or recognizable visual stimuli and cues. Not all studies parametrically altered the degree of stimulus interference or cue degradation, or controlled for potential confounding factors. Conclusion:This review found evidence that some of the parameters for task validity have been followed in some human studies of pattern separation and pattern completion, but no study was judged to have adequately met all the parameters for task validity. The 3 contribution of these parameters and other task design factors towards an optimal behavioral paradigm is discussed and recommendations for future research are made.

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Clarifying the role of pattern separation in schizophrenia: The role of recognition and visual discrimination deficits

Cited by 32 publications

References 22 publications

Age-related deficits in the mnemonic similarity task for objects and scenes

Age-related deficits in the mnemonic similarity task for objects and scenes

Integrating new findings and examining clinical applications of pattern separation

Tests of pattern separation and pattern completion in humans—A systematic review

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