June 24, 2015

Richards BA, Xia F, Santoro A, Husse J, Woodin MA, Josselyn SA, Frankland PW, “Patterns across multiple memories are identified over time”, Nature Neuroscience, 17(7), 981-986

Memories are not static but continue to be processed after encoding. This is thought to allow the integration of related episodes via the identification of patterns. Although this idea lies at the heart of contemporary theories of systems consolidation, it has yet to be demonstrated experimentally. Using a modified water-maze paradigm in which platforms are drawn stochastically from a spatial distribution, we found that mice were better at matching platform distributions 30 d compared to 1 d after training. Post-training time-dependent improvements in pattern matching were associated with increased sensitivity to new platforms that conflicted with the pattern. Increased sensitivity […]
June 24, 2015

Richards BA and Frankland PW, “The conjunctive trace”, Hippocampus, 23(3), 207-212

Memories serve to establish some permanence to our inner lives despite the fleeting nature of subjective experience. Most neurobiological theories of memory assume that this mental permanence reflects an underlying cellular permanence. Namely, it is assumed that the cellular changes which first occur to store a memory are perpetuated for as long as the memory is stored. But is that really the case? In an opinion piece in this issue of Hippocampus, Aryeh Routtenberg raises the provocative idea that the subjective sense of memory persistence is not in fact a result of persistence at the cellular level, rather, that “supple […]
June 24, 2015

Sekeres MJ, Mercaldo V, Richards BA, Sargin D, Mahadevan V, Woodin MA, Frankland PW and Josselyn SA, “Increasing CRTC1 function in the dentate gyrus during memory formation or reactivation increases memory strength without compromising memory quality”, The Journal of Neuroscience, 32(49), 17857-17868

Memory stabilization following encoding (synaptic consolidation) or memory reactivation (reconsolidation) requires gene expression and protein synthesis (Dudai and Eisenberg, 2004; Tronson and Taylor, 2007; Nader and Einarsson, 2010; Alberini, 2011). Although consolidation and reconsolidation may be mediated by distinct molecular mechanisms (Lee et al., 2004), disrupting the function of the transcription factor CREB impairs both processes (Kida et al., 2002; Mamiya et al., 2009). Phosphorylation of CREB at Ser133 recruits CREB binding protein (CBP)/p300 coactivators to activate transcription (Chrivia et al., 1993; Parker et al., 1996). In addition to this well known mechanism, CREB regulated transcription coactivators (CRTCs), previously called […]
June 24, 2015

Richards BA, van Rheede JJ and Akerman CJ, “Visuospatial information in the retinotectal system of xenopus before correct image formation by the developing eye”, Developmental Neurobiology, 72(4), 507-519

The retinotectal pathway of Xenopus laevis is a well-established experimental model for studying activity-dependent processes during visual system development. Such processes can be guided by stimulus-evoked activity patterns, which depend on the refractive characteristics of the eye. Previous work has shown that many animals are hyperopic at early developmental stages due to immature refractive properties. Whether this is also the case for Xenopus laevis is unknown. Here, we measure the focal length of the lens and the size of the eye of embryos at different stages and find that Xenopus laevis exhibits a similar shift from hyperopia to emmetropia. At […]