Learning and memory

  • Article
    | Open Access

    Olfactory information from Kenyon cells in the mushroom body and reward information from pPAM dopaminergic neurons is required for appetitive olfactory learning and memory. Here, the authors report evidence for a feedback circuit mechanism between Kenyon cells and pPAM neurons for reward memory that involves short neuropeptide F.

    • Radostina Lyutova
    • , Mareike Selcho
    •  & Dennis Pauls
  • Article
    | Open Access

    How astrocytes influence neuronal plasticity remains unclear, as they are typically considered as modulators of core mechanisms driven by neuronal components. Here, authors show that Long-term depression (LTD) induction in the hippocampus triggers calcium signaling in the astrocyte and enhances SNARE-dependent astrocytic glutamate release, which is then responsible for the activation of postsynaptic NMDA receptors and synaptic depression.

    • Marta Navarrete
    • , María I. Cuartero
    •  & José A. Esteban
  • Article
    | Open Access

    The hippocampus represents an allocentric map of space, however, motor movements used for navigation are defined in an egocentric framework. Here, the authors report that dorsomedial striatal neurons exhibit an egocentric representation of the boundaries in the environment.

    • James R. Hinman
    • , G. William Chapman
    •  & Michael E. Hasselmo
  • Article
    | Open Access

    The brain stores memories through a set of neurons known as engram cells. Here, the authors show that engram cells in the mouse hippocampus are organized into sub-ensembles representing distinct pieces of information, which are then orchestrated to constitute an entire memory.

    • Khaled Ghandour
    • , Noriaki Ohkawa
    •  & Kaoru Inokuchi
  • Article
    | Open Access

    In order to make optimal choices, it is adaptive for the brain to build a model of the world to enable predictions about likely later events. Here, the authors show that activity across learning in the orbitofrontal cortex comes to represent expected states, up to 30 s in the future.

    • G. Elliott Wimmer
    •  & Christian Büchel
  • Article
    | Open Access

    Place cells are neurons in the hippocampus which encode an animal’s location in space. Here, in mice, the authors show that place cell activity is also modulated by the heading-direction of the animal relative to a particular “reference point” that can be either within or outside their enclosure.

    • P. E. Jercog
    • , Y. Ahmadian
    •  & E. R. Kandel
  • Article
    | Open Access

    Little is known about mechanisms that regulate the involvement of cortical engram cells in remote memory. Here, authors demonstrate that memory consolidation by mPFC engram cells requires CREB-mediated transcription, with the functionality of this network hub being gated by memory strength.

    • Mariana R. Matos
    • , Esther Visser
    •  & Michel C. van den Oever
  • Article
    | Open Access

    Episodic memory retrieval is hypothesized to rely on hippocampal reinstatement of item-context associations which drives reinstatement of item information in cortex. Here, the authors confirm this sequence of events, using iEEG recordings from the human hippocampus and lateral temporal cortex.

    • D. Pacheco Estefan
    • , M. Sánchez-Fibla
    •  & P. F. M. J. Verschure
  • Article
    | Open Access

    The molecular mechanisms underlying contextual fear memory consolidation by sparse dentate gyrus (DG) neuronal populations remain unclear. Here using unbiased RNA sequencing of DG engram neurons the authors identify persistent transcriptome modifications during memory consolidation, in which CREB-dependent transcription features prominently

    • Priyanka Rao-Ruiz
    • , Jonathan J. Couey
    •  & Steven A. Kushner
  • Article
    | Open Access

    Performance is generally used as a metric to assay whether an animal has learnt a particular perceptual task. Here the authors demonstrate that in the context of probe trials without the possibility of reward, animals perform the correct instrumental response suggesting a latent knowledge of the task much before it is manifest in their performance.

    • Kishore V. Kuchibhotla
    • , Tom Hindmarsh Sten
    •  & Robert C. Froemke
  • Article
    | Open Access

    The hippocampus is involved both in episodic memory recall and scene processing. Here, the authors show that hippocampal neurons first process scene cues before coordinating memory-guided pattern completion in adjacent entorhinal cortex.

    • Bernhard P. Staresina
    • , Thomas P. Reber
    •  & Florian Mormann
  • Article
    | Open Access

    Sounds vary in the strength of behavioural conditioning they can evoke, a property attributed to stimulus salience. Here, the authors show that stimulus salience the overall level of neuronal activity recruited in the auditory cortex is strongly related with its reinforcing strength.

    • Sebastian Ceballo
    • , Jacques Bourg
    •  & Brice Bathellier
  • Article
    | Open Access

    Medial entorhinal cortex (MEC) is involved in memory processes that entail the replay of sequential firing of hippocampal place cells during rest periods and during behaviour. Here, the authors show that MEC lesioned animals show intact replay after an epoch of rats running on a linear track, while replay during the behavioral epoch is reduced.

    • Alireza Chenani
    • , Marta Sabariego
    •  & Christian Leibold
  • Article
    | Open Access

    Pavlovian conditioning involves model-free learning that associates predictive stimuli with their outcome value. Here, the authors present evidence for activation of OFC and striatum that is consistent with model based information during a pavlovian task with multiple stimuli that predict rewards.

    • Wolfgang M. Pauli
    • , Giovanni Gentile
    •  & John P. O’Doherty
  • Article
    | Open Access

    Synaptic plasticity ensures functionality during perturbations and enables memory formation. Here, the authors describe homeostatic functional and nano-modular active zone modifications for immediate and long-lasting enhancement of neurotransmitter release, and identify Unc13 as a presynaptic molecular target for homeostatic potentiation and learning.

    • Mathias A. Böhme
    • , Anthony W. McCarthy
    •  & Alexander M. Walter
  • Article
    | Open Access

    When learning about rewards and threats in the environment, animals often need to learn the value associated with conjunctions of features, not just individual features. Here, the authors show that the hippocampus forms conjunctive representations that are dissociable from individual feature components.

    • Ian C. Ballard
    • , Anthony D. Wagner
    •  & Samuel M. McClure
  • Article
    | Open Access

    Early neuropsychological studies suggested that different aspects of working memory (WM) are exclusively associated with specific brain areas. Here, the authors show, using machine-learning analysis of fMRI, how WM processes are dynamically coded by large-scale overlapping networks in the human brain.

    • Eyal Soreq
    • , Robert Leech
    •  & Adam Hampshire
  • Article
    | Open Access

    We can recognize an object from one of its features, e.g. hearing a bark leads us to think of a dog. Here, the authors show using fMRI that the brain combines bits of information into object representations, and that presenting a few features of an object activates representations of its other attributes.

    • Sasa L. Kivisaari
    • , Marijn van Vliet
    •  & Riitta Salmelin
  • Article
    | Open Access

    In an open field, the preferential firing of grid cells on a hexagonal lattice is formed by integrating external as well as self-motion cues. Here, the authors show that on a 1D circular track, path integration cues shape the spatial selectivity of grid cells while external cues determine the scale of the grid.

    • Pierre-Yves Jacob
    • , Fabrizio Capitano
    •  & Francesca Sargolini
  • Article
    | Open Access

    The reinforcement learning literature suggests decisions are based on a model-free system, operating retrospectively, and a model-based system, operating prospectively. Here, the authors show that a model-based retrospective inference of a reward’s cause, guides model-free credit-assignment.

    • Rani Moran
    • , Mehdi Keramati
    •  & Raymond J. Dolan
  • Article
    | Open Access

    Alpha power is known to play an important role in cognition and perception, but we do not understand the link between alpha power and perceptual learning efficacy. Here, the authors use neurofeedback training to show that increased alpha power enhances learning while reduced alpha impedes learning.

    • Marion Brickwedde
    • , Marie C. Krüger
    •  & Hubert R. Dinse
  • Article
    | Open Access

    Memories formed around the same time are linked together by a shared temporal context. Here, the authors show that the ability to selectively retrieve distinct episodic memories formed close together in time is related to how quickly neural representations of temporal context change over time during encoding.

    • Mostafa M. El-Kalliny
    • , John H. Wittig Jr
    •  & Kareem A. Zaghloul
  • Article
    | Open Access

    In order to adjust expectations efficiently, prediction errors need to be associated with the features that gave rise to the unexpected outcome. Here, the authors show that neurons in anterior fronto-striatal networks encode prediction errors that are specific to feature values of different stimulus dimensions.

    • Mariann Oemisch
    • , Stephanie Westendorff
    •  & Thilo Womelsdorf
  • Article
    | Open Access

    Motor learning is thought to be mostly procedural, but recent work has suggested that there is a strong cognitive component to it. Here, the authors show that humans use dissociable cognitive strategies, either caching successful responses or using a rule-based strategy, to solve a visuomotor learning task.

    • Samuel D. McDougle
    •  & Jordan A. Taylor
  • Article
    | Open Access

    Previous research on visual memory often relies on image recognition as a test, and the exact nature of memory when freely recalling information is not clear. Here, Bainbridge and colleagues develop a drawing-based memory recall task, and show detailed-rich, quantifiable information diagnostic of previously encountered visual scenes.

    • Wilma A. Bainbridge
    • , Elizabeth H. Hall
    •  & Chris I. Baker
  • Article
    | Open Access

    It is unclear how the basolateral amygdala (BLA) contributes to behaviors driven by aversive or appetitive stimuli. Here, authors simultaneously record the activities of ensembles of BLA neurons in behaving mice to show that distinct but spatially intermingled BLA populations respond to either reward or punishment and that associative learning transforms BLA population activities to represent specific valences

    • Xian Zhang
    •  & Bo Li
  • Article
    | Open Access

    Rewarding events are prioritized in memory, but to support adaptive decision-making memory should also be prioritized for the events leading up to a reward. Here, the authors show that reward retroactively prioritizes memory for proximal, neutral events that precede the reward.

    • Erin Kendall Braun
    • , G. Elliott Wimmer
    •  & Daphna Shohamy
  • Article
    | Open Access

    While memory is often studied using voluntary recollection, the neural correlates of involuntary memory recall and its effect on cognition are unclear. Here, Ren and colleagues show that the effective connectivity from the anterior hippocampus to the precuneus can predict the strength of involuntary retrieval of episodic memory.

    • Yudan Ren
    • , Vinh T. Nguyen
    •  & Christine C. Guo
  • Article
    | Open Access

    The sense of ownership – of which objects belong to us and which to others - is an important part of our lives, but how the brain keeps track of ownership is poorly understood. Here, the authors show that specific brain areas are involved in ownership acquisition for the self, friends, and strangers.

    • Patricia L. Lockwood
    • , Marco K. Wittmann
    •  & Matthew F. S. Rushworth
  • Article
    | Open Access

    Forgetting is ubiquitous across the animal kingdom, but neuroscience is only beginning to address its mechanisms. This study shows that rats, like humans, actively forget memories that interfere with retrieval, and that this retrieval-induced forgetting requires the prefrontal cortex.

    • Pedro Bekinschtein
    • , Noelia V. Weisstaub
    •  & Michael C. Anderson
  • Article
    | Open Access

    Previous work has shown that the thalamic nucleus reuniens (RE) is involved in memory and emotion. Here the authors report that the RE and its inputs from the medial prefrontal cortex are indispensable for the top-down inhibition of fear memories after extinction.

    • Karthik R. Ramanathan
    • , Jingji Jin
    •  & Stephen Maren
  • Article
    | Open Access

    During learning of an association between a neutral cue and an aversive stimulus, there is a time lag between trials. Here, the authors examine how long inter-trial intervals are represented by the basolateral amygdala and anterior cingulate cortex to support learning rate and memory strength.

    • Aryeh H. Taub
    • , Yosef Shohat
    •  & Rony Paz
  • Article
    | Open Access

    The success of extinction learning is not predictive of long-term retrieval of an extinction memory. Using fMRI to study consolidation of fear extinction in human subjects, the authors show that reactivation in the ventromedial prefrontal cortex during memory retrieval predicts extinction memory retrieval, and that increasing dopaminergic signaling increases the number of these activations.

    • A. M. V. Gerlicher
    • , O. Tüscher
    •  & R. Kalisch
  • Article
    | Open Access

    Perceptual learning, the improvement in perceptual abilities with training, is thought to involve changes in neuronal 'tuning'. Here, the authors show that perceptual learning works by making neurons increasingly sensitive to task-relevant differences in stimuli, and by improving population coding mechanisms.

    • Mehdi Sanayei
    • , Xing Chen
    •  & Alexander Thiele
  • Article
    | Open Access

    Although the CA2 region of the hippocampus has been implicated in social memory, its precise role has been unclear. Here, the authors show that the dorsal subregion of CA2 is required for the encoding, consolidation and recall of social memory through a circuit linking it to ventral CA1.

    • Torcato Meira
    • , Felix Leroy
    •  & Steven A. Siegelbaum
  • Article
    | Open Access

    Learning often involves multiple exposures and trials, but it is not known whether those are treated independently, or integrated during dedicated time windows. Here, Chowdhury and Caroni show mice learn new associations during 5 h time windows, where related experiences are integrated in a process requiring coordinated cFos-activated neuronal assemblies.

    • Ananya Chowdhury
    •  & Pico Caroni
  • Article
    | Open Access

    It is believed that fast “ripple” oscillations in the hippocampus play a role in consolidation, a process by which memory traces are stabilized. Here, the authors show that ripples occuring during non-REM sleep trigger “replay” of brain activity associated with previously experienced stimuli.

    • Hui Zhang
    • , Juergen Fell
    •  & Nikolai Axmacher
  • Article
    | Open Access

    The hippocampus is known to 'replay' experiences and memories during rest periods, but it is unclear how particular memories are prioritized for replay. Here, the authors show that information that is remembered less well is replayed more often, suggesting that weaker memories are selected for replay.

    • Anna C. Schapiro
    • , Elizabeth A. McDevitt
    •  & Kenneth A. Norman
  • Article
    | Open Access

    Adaptation is thought to improve discrimination by pulling neural representations of similar stimuli farther apart. Here, the authors separately show that adaptation to a 3D shape class leads to better discrimination performance on similar shapes, and activity patterns diverge in object selective cortical areas.

    • Marcelo G. Mattar
    • , Maria Olkkonen
    •  & Geoffrey K. Aguirre
  • Article
    | Open Access

    Studies of the functional organization of the prefrontal cortex have produced contradicting results depending on the task used. Here, Riley and colleagues demonstrate that prefrontal areas are specialized across the anterior posterior axis and that the effects of the task themselves impact more the anterior areas.

    • Mitchell R. Riley
    • , Xue-Lian Qi
    •  & Christos Constantinidis
  • Article
    | Open Access

    Working memory (WM) is represented in persistent activity of single neurons as well as a dynamic population code. Here, the authors find that neurons flexibly switch their coding according to current attention while those with stable resting activity maintain WM representations through dynamic activity patterns.

    • Sean E. Cavanagh
    • , John P. Towers
    •  & Steven W. Kennerley
  • Article
    | Open Access

    Prefrontal neurons exhibit both transient and persistent firing in working memory tasks. Here the authors report that the intrinsic timescale of neuronal firing outside the task is predictive of the temporal dynamics of coding during working memory in three frontoparietal brain areas.

    • D. F. Wasmuht
    • , E. Spaak
    •  & M. G. Stokes
  • Article
    | Open Access

    Circadian rhythms are known to modulate memory, but it’s not known whether clock genes in the hippocampus are required for memory consolidation. Here, the authors show that epigenetic regulation of clock gene Period1 in the hippocampus regulates memory and contributes to age-related memory decline, independent of circadian rhythms.

    • Janine L. Kwapis
    • , Yasaman Alaghband
    •  & Marcelo A. Wood
  • Article
    | Open Access

    Sleep is important for memory consolidation but its role in reconsolidation is not known. Here, the authors show in starlings that an auditory memory consolidated by sleep can be destabilized by retrieval and impaired by subsequent interference, but the memory recovers and stabilizes after a night of sleep-dependent reconsolidation.

    • Timothy P. Brawn
    • , Howard C. Nusbaum
    •  & Daniel Margoliash
  • Article
    | Open Access

    Single nuclei RNA-seq has been used to characterize transcriptional signature of environment-related activity in cells of the dentate gyrus. Here the authors use this approach to show that whether a neuron will be reactivated in response to re-exposure to a previous environment can be predicted by its transcriptional signature.

    • Baptiste N. Jaeger
    • , Sara B. Linker
    •  & Fred H. Gage