Biology subjects

Bekinschtein, P.

Publications and source records attributed to Bekinschtein, P..

7 recordsLinked to original sources

bioRxiv2026

A novel event improves memory retrieval and divergent thinking in a naturalistic school environment

Stored memories are useless unless they are available for retrieval. Thus, investigating different ways to modulate retrieval is crucial. Novelty has been extensively studied as a modulator of memory. In this study, we investigated whether exposure to a novel event, an innovative neuroscience lesson, can enhance memory retrieval and divergent thinking in high school students. Across three experiments, we assessed the timing and mechanisms underlying these effects. In experiment 1, we found that memory retrieval was enhanced when the novel lesson occurred immediately before a memory test, but not when it was presented one hour earlier. In experiment 2, we found that the same immediate novelty exposure improved divergent thinking performance. Finally, in experiment 3, we explored potential shared mechanisms using a competition protocol and revealed that novelty improved divergent thinking regardless of its timing relative to memory retrieval. However, memory retrieval benefited only when tested immediately before the divergent thinking task. These results suggest that novelty boosts both memory retrieval and divergent thinking, but through partially distinct mechanisms. Our findings demonstrate that a simple, real-world classroom intervention can effectively enhance key cognitive functions in students. Significance StatementStored memories are only valuable if they can be retrieved, and memory retrieval plays a key role in creative thinking. Here, we tested whether a simple, novel event, a neuroscience lesson, could enhance memory retrieval and creative thinking in a real-world classroom setting. We found that novelty improved both memory retrieval and divergent thinking, an aspect of creative thinking, when presented immediately before the task. Finally, we revealed a non-reciprocal competition effect between memory retrieval and divergent thinking. These findings highlight a practical, low-cost intervention to boost key cognitive functions in students, demonstrating that brief, well-timed novel experiences can support both learning and creative thinking in educational environments.

neuroscience↗

bioRxiv2025

Cortical Serotonin Type 2A Receptor Activation Shields Episodic-like Memories from Retroactive Interference in Rodents

The acquisition of temporally proximate information can impair the brains ability to consolidate earlier experiences, resulting in retroactive interference (RI). Recognition-based behavioral paradigms are well-suited for investigating RI in rodents, particularly those involving sequential learning episodes. The medial prefrontal cortex (mPFC) integrates multimodal information relevant to the regulation of memory interference and is strongly modulated by the serotonergic system. Serotonin 2A receptors (5-HT2AR), which are densely expressed in the mPFC, have been shown to influence the retrieval of competing object-recognition memories. However, their role in other phases of memory processing, particularly in modulating RI, remains unclear. Using a modified version of the object recognition task designed to induce RI, combined with pharmacological manipulation of 5-HT2AR, we demonstrate that RI specifically impairs the object-related component of memory. Moreover, serotonin signaling through 5-HT2AR is necessary to prevent RI. Strikingly, activating 5-HT2AR before retrieval can rescue the expression of memories affected by RI, suggesting that RI may not erase memory traces but rather hinder their access.

neuroscience↗

bioRxiv2025

Serotonin signaling in the rat prefrontal cortex is required for Retrieval-Induced Forgetting

Forgetting is a ubiquitous phenomenon actively promoted in many species. The act of remembering some experiences can cause forgetting of others in both humans and rats. We previously found that when rats retrieve a memory to guide exploration, it reduces later retention of other competing memories encoded in that environment. As with humans, this retrieval-induced forgetting (RIF) relies on prefrontal control processes, is competition-dependent, and cue-independent. RIF is thought to be driven by inhibitory control signals from the prefrontal cortex that target areas where memories are stored. Serotonin plays a crucial role in behaviors requiring high cognitive demand, including memory processes, partly through its modulation of prefrontal cortex activity. However, its potential involvement in regulating active forgetting remains unexplored. Here, we had rats perform a task known to induce RIF and pharmacologically manipulated the activity and signaling of serotonin receptors 5-HT1A, 5-HT2A, and 5-HT2C in the medial prefrontal cortex (mPFC), as well as to inhibit downstream effectors. Our findings reveal a specific role for prefrontal serotonin signaling in RIF. Whereas 5-HT2C receptor manipulation had no effect, activating 5-HT1A or blocking 5-HT2A receptors in the mPFC abolished RIF. By contrast, activating 5-HT2A receptors promoted RIF under conditions in which it is normally reduced. Further analyses identified the PI3K/AKT pathway as a downstream effector of 5-HT2A receptor signaling, suggesting a specific molecular mechanism through which serotonin modulates inhibitory control over memory. These results uncover a previously unrecognized serotonergic modulation of adaptive forgetting, identifying specific receptor subtypes that link prefrontal serotonin signaling to inhibitory control over memory competition.

animal behavior and cognition↗

bioRxiv2023

Behavioral, molecular and neuronal mechanisms involved in recognition memory retrieval under degraded spatial cues in the rat hippocampus

In a constantly changing environment, organisms face the challenge of adapting their behavior by retrieving previous experiences or acquiring new information. Previous research has postulated that this balance between memory generalization and differentiation manifests in a dichotomic manner. When environmental information exceeds a given threshold, activation of a stored representation could initiate retrieval, but below this threshold, a novel event could be encoded with a concomitant remapping of the internal representation in the hippocampus. Here, we examined the hippocampal molecular and neuronal mechanisms underlying retrieval in a cue-degraded environment by combining in vivo electrophysiological recordings and pharmacological manipulations. We developed a memory recognition task that allows a graded decrease in the contextual cues present during retrieval. We found that the manipulation of the number of visual cues was consistent with the activation or not of the contextual memory trace. Retrieval of a specific context memory was reflected by the level of CA3 remapping, demonstrating a clear relationship between remapping and contextual recognition. Also, manipulation of NMDAR activity in the DG-CA3 circuit bidirectionally modulated contextual memory retrieval. The blockade of NMDAR in CA3 impaired recognition in a cue-degraded, but not in a full-cue context, while their activation has the opposite effect. Conversely, blockade of NMDAR in the DG promoted retrieval under an even more cue-degraded environment, while activation had the opposite effect. Our results provide evidence for a flexible interaction between environmental cues and information stored in the hippocampus and give new insights into the biological mechanisms that balance memory encoding and retrieval.

neuroscience↗

bioRxiv2021

Acute and chronic physical activity improve spatial pattern separation in humans

Physical activity benefits both fitness and cognition. However, its effect on long-term memory is unclear. Successful memory involves not only remembering information over time but also keeping memories distinct and less confusing. The ability to separate similar experiences into distinct memories is one of the main features of episodic memory. In this work, we evaluated the effect of acute and chronic physical activity on a new task to assess spatial pattern separation in a 3D virtual reality environment. We manipulated the load of memory similarity and found that 25 minutes of cycling after encoding - but not before retrieval - was sufficient to improve similar, but not dissimilar memories, 24 hours after encoding. Furthermore, we found that participants who engaged in regular physical activity, but not sedentary subjects, showed memory for the similar condition the next day. Thus, physical activity could be a simple way to improve discrimination of spatial memories in humans.

animal behavior and cognition↗

bioRxiv2021

Dopamine modulates adaptive forgetting in medial prefrontal cortex

Active forgetting occurs in many species, but how the mechanisms that control behavior contribute to determining which memories are forgotten is still unknown. We previously found that when rats need to retrieve particular memories to guide exploration, it reduces later retention of other memories encoded in that environment. As with humans, this retrieval-induced forgetting relies on prefrontal control processes. The dopaminergic input to the prefrontal cortex is important for executive functions and cognitive flexibility. We found that, in a similar way, prefrontal dopamine signaling through D1 receptors is required for retrieval-induced forgetting in rats. Blockade of medial prefrontal cortex D1 receptors as animals encountered a familiar object impaired forgetting of the memory of a competing object in a subsequent long-term memory test. Inactivation of the ventral tegmental area produced the same pattern of behavior, a pattern that could be reversed by concomitant activation of prefrontal D1 receptors. We observed a bidirectional modulation of retrieval-induced forgetting by agonists and antagonists of D1 receptors in the medial prefrontal cortex. These findings establish the essential role of prefrontal dopamine in the active forgetting of competing memories, contributing to the shaping of retention in response to an organisms behavioral goals.

animal behavior and cognition↗

bioRxiv2019

Dentate gyrus somatostatin cells are required for contextual discrimination during episodic memory encoding

Episodic memory establishes and stores relations among the different elements of an experience, which are often similar and difficult to distinguish. Pattern separation, implemented by the dentate gyrus, is a neural mechanism that allows the discrimination of similar experiences by orthogonalizing synaptic inputs. Granule cells support such disambiguation by sparse rate coding, a process tightly controlled by highly diversified GABAergic neuronal populations, such as somatostatin-expressing cells which directly target the dendritic arbor of granule cells, massively innervated by entorhinal inputs reaching the molecular layer and conveying contextual information. Here, we tested the hypothesis that somatostatin neurons regulate the excitability of the dentate gyrus, thus controlling the efficacy of pattern separation during memory encoding in mice. Indeed, optogenetic suppression of dentate gyrus somatostatin neurons increased spiking activity in putative excitatory neurons and triggered dentate spikes. Moreover, optical inhibition of somatostatin neurons impaired both contextual and spatial discrimination of overlapping episodic-like memories during task acquisition. Importantly, effects were specific for similar environments, suggesting that pattern separation was selectively engaged when overlapping conditions ought to be distinguished. Overall, our results suggest that somatostatin cells regulate excitability in the dentate gyrus and are required for effective pattern separation during episodic memory encoding.\n\nSignificance statementMemory systems must be able to discriminate stored representations of similar experiences in order to efficiently guide future decisions. This is solved by pattern separation, implemented in the dentate gyrus by granule cells to support episodic memory formation. The tonic inhibitory bombardment produced by multiple GABAergic cell populations maintains low activity levels in granule cells, permitting the process of pattern separation. Somatostatin-expressing cells are one of those interneuron populations, selectively targeting the distal dendrites of granule cells, where cortical multimodal information reaches the dentate gyrus. Hence, somatostatin cells constitute an ideal candidate to regulate pattern separation. Here, by using optogenetic stimulation in mice, we demonstrate that somatostatin cells are required for the acquisition of both contextual and spatial overlapping memories.

neuroscience↗