Mnemonic discrimination of object and context is differentially associated with mental health

Perceived stress associations with hippocampal-dependent behavior and hippocampal subfield volume

“…At the same time, because these two measures of stress accounted for unique variance in behavior, our results do not merely replicate prior links between behavioral pattern separation and perceived stress ( Grupe et al, 2022 ), but extend this work by highlighting a distinct relationship with reactivity to a robust laboratory stressor. In contrast to the PSS, TSST stress ratings were not associated with depression or anxiety scores, suggesting that deficient pattern separation may contribute to increased stress reactivity independent of its associations with negative mood or depression symptoms ( Bernstein and McNally, 2018 ; Dohm-Hansen and Johansson, 2020 ; Leal et al, 2014a ; Shelton and Kirwan, 2013 ).…”

“…The MST and related tasks have been used to demonstrate behavioral pattern separation alterations in aging and disorders of aging ( Stark et al, 2019 ) that correspond to reductions in the volume of DG/CA3 subfields ( Dillon et al, 2017 ; Doxey and Kirwan, 2015 ; but see Bennett et al, 2019 ). Comparatively little research has investigated whether and how behavioral pattern separation is related to individual differences in perceived stress or affective symptomatology, although several studies in participants with elevated depression symptoms have reported deficits in pattern separation behavior ( Bernstein and McNally, 2018 ; Dohm-Hansen and Johansson, 2020 ; Leal et al, 2014b ; Shelton and Kirwan, 2013 ) and DG/CA3 pattern separation signaling ( Leal et al, 2014a ). In a mega-analysis of over 500 participants recruited via Amazon Mechanical Turk, we recently identified an inverse relationship between scores on the Perceived Stress Scale (PSS ( Cohen and Williamson, 1988 ); and behavioral pattern separation on the MST ( Grupe et al, 2022 ).…”

Event segmentation promotes the reorganization of emotional memory

“…Further work could explore how emotional memories can be stabilized, allowing them to be sufficiently generalizable for adaptive behavior while remaining specific enough to not disrupt safety learning. (Bernstein et al, 2020;Dohm-Hansen & Johansson, 2020;Hayes et al, 2023;Laing, Steward, et al, 2022;Leal & Yassa, 2018). Crucially, physiological arousal and negative mood may be more pertinent to the quality and fidelity of emotional memories, rather than their accuracy.…”

“…Next, we examined how participants shifted memory in terms of generalization, which can be dissociable from recognition memory in distinguishing the properties of fear and extinction (safety) memories (Laing & Dunsmoor, 2023). 'Mnemonic generalization' refers to how items that resembled initially encoded (day 1) stimuli are appraised as old (generalized) compared to new (discriminated) (Bernstein et al, 2020;Dohm-Hansen & Johansson, 2020;Stark et al, 2019). Here, generalization (also known as behavioral pattern completion) was calculated as the rate of 'similar' items appraised as old minus the false alarm rate: p(old | sim) -p(old | new) (Ally et al, 2013;Granger et al, 2021;Laing & Dunsmoor, 2023;Starita et al, 2019;Yassa, Lacy, et al, 2011;Yassa, Mattfeld, et al, 2011).…”

Dissociable effects of complement C3 and C3aR on survival and morphology of adult born hippocampal neurons, pattern separation, and cognitive flexibility in male mice

“…In recent years, prominent roles have emerged for the complement system in brain development, including synapse elimination 23 and embryonic neurogenesis 24 , but also in neurodegeneration [25][26][27] though how complement may influence ongoing neurogenesis and cognitive functions within the adult brain have received relatively little focus. Given converging evidence of aberrant adult neurogenesis 28,29 and cognitive dysfunction [30][31][32] in neuropsychiatric disorders associated with abnormal complement activity 33,34 , it is important that we improve our understanding of how complement may regulate ongoing neuroplasticity and neurodevelopment in the context of AHN.…”