Evolving schema representations in orbitofrontal ensembles during learning.
Ontology highlight
ABSTRACT:
SUBMITTER: Zhou J
PROVIDER: S-EPMC7906913 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Stopping, or inhibition, is a form of self-control that is a core element of flexible and adaptive behavior. Its neural origins remain unclear. Some views hold that inhibition decisions reflect the aggregation of widespread and diverse pieces of information, including information arising in ostensible core reward regions (i.e., outside the canonical executive system). We recorded activity of single neurons in the orbitofrontal cortex (OFC) of macaques, a region associated with economic decisions, and whose role in inhibition is debated. Subjects performed a classic inhibition task known as the stop signal task. Ensemble decoding analyses reveal a clear firing rate pattern that distinguishes successful from failed inhibition and that begins after the stop signal and before the stop signal reaction time (SSRT). We also found a different and orthogonal ensemble pattern that distinguishes successful from failed stopping before the beginning of the trial. These signals were distinct from, and orthogonal to, value encoding, which was also observed in these neurons. The timing of the early and late signals was, respectively, consistent with the idea that neuronal activity in OFC encodes inhibition both proactively and reactively.
| S-EPMC8214402 | biostudies-literature
Project description:Both hippocampus (HPC) and orbitofrontal cortex (OFC) have been shown to be critical for behavioral tasks that require use of an internal model or cognitive map, composed of the states and the relationships between them, which define the current environment or task at hand. One general idea is that the HPC provides the cognitive map, which is then transformed by OFC to emphasize information of relevance to current goals. Our previous analysis of ensemble activity in OFC in rats performing an odor sequence task revealed a rich representation of behaviorally relevant task structure, consistent with this proposal. Here, we compared those data to recordings from single units in area CA1 of the HPC of rats performing the same task. Contrary to expectations that HPC ensembles would represent detailed, even incidental, information defining the full task space, we found that HPC ensembles-like those in OFC-failed to distinguish states when it was not behaviorally necessary. However, hippocampal ensembles were better than those in OFC at distinguishing task states in which prospective memory was necessary for future performance. These results suggest that, in familiar environments, the HPC and OFC may play complementary roles, with the OFC maintaining the subjects' current position on the cognitive map or state space, supported by HPC when memory demands are high.
| S-EPMC6810873 | biostudies-literature
Project description:The role of the orbitofrontal cortex (OFC) in value processing is a focus of research. Conventional imaging analysis, where smoothing and averaging are employed, may not be sufficiently sensitive in studying the OFC, which has heterogeneous anatomical structures and functions. In this study, we employed representational similarity analysis (RSA) to reveal the multi-voxel fMRI patterns in the OFC associated with value processing during the anticipatory and the consummatory phases. We found that multi-voxel activation patterns in the OFC encoded magnitude and partial valence information (win vs. loss) but not outcome (favourable vs. unfavourable) during reward consummation. Furthermore, the lateral OFC rather than the medial OFC encoded loss information. Also, we found that OFC encoded values in a similar way to the ventral striatum (VS) or the anterior insula (AI) during reward anticipation regardless of motivated response and to the medial prefrontal cortex (MPFC) and the VS in reward consummation. In contrast, univariate analysis did not show changes of activation in the OFC. These findings suggest an important role of the OFC in value processing during reward anticipation and consummation.
| S-EPMC4932626 | biostudies-literature
Project description:Multiscale analysis provides an algorithm for the efficient simulation of macromolecular assemblies. This algorithm involves the coevolution of a quasiequilibrium probability density of atomic configurations and the Langevin dynamics of spatial coarse-grained variables denoted order parameters (OPs) characterizing nanoscale system features. In practice, implementation of the probability density involves the generation of constant OP ensembles of atomic configurations. Such ensembles are used to construct thermal forces and diffusion factors that mediate the stochastic OP dynamics. Generation of all-atom ensembles at every Langevin time step is computationally expensive. Here, multiscale computation for macromolecular systems is made more efficient by a method that self-consistently folds in ensembles of all-atom configurations constructed in an earlier step, history, of the Langevin evolution. This procedure accounts for the temporal evolution of these ensembles, accurately providing thermal forces and diffusions. It is shown that efficiency and accuracy of the OP-based simulations is increased via the integration of this historical information. Accuracy improves with the square root of the number of historical timesteps included in the calculation. As a result, CPU usage can be decreased by a factor of 3-8 without loss of accuracy. The algorithm is implemented into our existing force-field based multiscale simulation platform and demonstrated via the structural dynamics of viral capsomers.
| S-EPMC3721968 | biostudies-literature
Project description:The physical manifestations of memory formation and recall are fundamental questions that remain unresolved. At the cellular level, ensembles of neurons called engrams are activated by learning events and control memory recall. Astrocytes are in close proximity to neurons and engage in a range of activities that support neurotransmission and circuit plasticity. Moreover, astrocytes exhibit experience dependent plasticity; however whether specific ensembles of astrocytes participate in memory recall remains obscure. Here we show that learning events induce c-Fos expression in a subset of hippocampal astrocytes, which subsequently regulates hippocampal circuit function. Intersectional, c-Fos based labeling of these astrocyte ensembles after learning events reveals that they are closely affiliated with engram neurons, while re-activation of these astrocyte ensembles stimulates memory recall. At the molecular level, these astrocyte ensembles exhibit elevated expression of NFIA and its selective deletion from this population suppresses memory recall. Together, our studies identify learning-associated astrocyte ensembles as a new form of plasticity that is sufficient to provoke memory recall, while implicating astrocytes as a reservoir for the storage of memories.
2024-06-30 | GSE254016 | GEO
Project description:Categorically distinct basic drives (for example, for social versus feeding behaviour1-3) can exert potent influences on each other; such interactions are likely to have important adaptive consequences (such as appropriate regulation of feeding in the context of social hierarchies) and can become maladaptive (such as in clinical settings involving anorexia). It is known that neural systems regulating natural and adaptive caloric intake, and those regulating social behaviours, involve related circuitry4-7, but the causal circuit mechanisms of these drive adjudications are not clear. Here we investigate the causal role in behaviour of cellular-resolution experience-specific neuronal populations in the orbitofrontal cortex, a major reward-processing hub that contains diverse activity-specific neuronal populations that respond differentially to various aspects of caloric intake8-13 and social stimuli14,15. We coupled genetically encoded activity imaging with the development and application of methods for optogenetic control of multiple individually defined cells, to both optically monitor and manipulate the activity of many orbitofrontal cortex neurons at the single-cell level in real time during rewarding experiences (caloric consumption and social interaction). We identified distinct populations within the orbitofrontal cortex that selectively responded to either caloric rewards or social stimuli, and found that activity of individually specified naturally feeding-responsive neurons was causally linked to increased feeding behaviour; this effect was selective as, by contrast, single-cell resolution activation of naturally social-responsive neurons inhibited feeding, and activation of neurons responsive to neither feeding nor social stimuli did not alter feeding behaviour. These results reveal the presence of potent cellular-level subnetworks within the orbitofrontal cortex that can be precisely engaged to bidirectionally control feeding behaviours subject to, for example, social influences.
| S-EPMC6447429 | biostudies-literature
Project description:Cerebral cortical gamma-aminobutyric acidergic interneuron dysfunction is hypothesized to lead to cognitive deficits comorbid with human neuropsychiatric disorders, including schizophrenia, autism, and epilepsy. We have previously shown that mice that harbor mutations in the Plaur gene, which is associated with schizophrenia, have deficits in frontal cortical parvalbumin-expressing interneurons. Plaur mice have impaired reversal learning, similar to deficits observed in patients with schizophrenia.We examined the role of parvalbumin interneurons in orbitofrontal cortex during reversal learning by recording single unit activity from 180 control and 224 Plaur mouse neurons during a serial reversal task. Neural activity was analyzed during correct and incorrect decision choices and reward receipt.Neurons in control mice exhibited strong phasic responses both during discrimination and reversal learning to decisions and rewards, and the strength of the response was correlated with behavioral performance. Although baseline firing was significantly enhanced in Plaur mice, neural selectivity for correct or erroneous decisions was diminished and not correlated with behavior, and reward encoding was downscaled. In addition, Plaur mice showed a significant reduction in the number of neurons that encoded expected outcomes across task phases during the decision period.These data indicate that parvalbumin interneurons are necessary for the representation of outcomes in orbitofrontal cortex. Deficits in inhibition blunt selective neural firing during key decisions, contributing to behavioral inflexibility. These data provide a potential explanation for disorders of cognitive control that accompany the loss of these gamma-aminobutyric acidergic interneurons in human neuropsychiatric disorders, such as autism, epilepsy, and schizophrenia.
| S-EPMC4312743 | biostudies-literature
Project description:Value-based decision-making requires different variables-including offer value, choice, expected outcome, and recent history-at different times in the decision process. Orbitofrontal cortex (OFC) is implicated in value-based decision-making, but it is unclear how downstream circuits read out complex OFC responses into separate representations of the relevant variables to support distinct functions at specific times. We recorded from single OFC neurons while macaque monkeys made cost-benefit decisions. Using a novel analysis, we find separable neural dimensions that selectively represent the value, choice, and expected reward of the present and previous offers. The representations are generally stable during periods of behavioral relevance, then transition abruptly at key task events and between trials. Applying new statistical methods, we show that the sensitivity, specificity and stability of the representations are greater than expected from the population's low-level features-dimensionality and temporal smoothness-alone. The separability and stability suggest a mechanism-linear summation over static synaptic weights-by which downstream circuits can select for specific variables at specific times.
| S-EPMC7351792 | biostudies-literature
Project description:The cocktail party problem requires listeners to infer individual sound sources from mixtures of sound. The problem can be solved only by leveraging regularities in natural sound sources, but little is known about how such regularities are internalized. We explored whether listeners learn source "schemas"-the abstract structure shared by different occurrences of the same type of sound source-and use them to infer sources from mixtures. We measured the ability of listeners to segregate mixtures of time-varying sources. In each experiment a subset of trials contained schema-based sources generated from a common template by transformations (transposition and time dilation) that introduced acoustic variation but preserved abstract structure. Across several tasks and classes of sound sources, schema-based sources consistently aided source separation, in some cases producing rapid improvements in performance over the first few exposures to a schema. Learning persisted across blocks that did not contain the learned schema, and listeners were able to learn and use multiple schemas simultaneously. No learning was evident when schema were presented in the task-irrelevant (i.e., distractor) source. However, learning from task-relevant stimuli showed signs of being implicit, in that listeners were no more likely to report that sources recurred in experiments containing schema-based sources than in control experiments containing no schema-based sources. The results implicate a mechanism for rapidly internalizing abstract sound structure, facilitating accurate perceptual organization of sound sources that recur in the environment.
| S-EPMC5889675 | biostudies-literature
Project description:For reliable stimulus identification, sensory codes have to be robust by including redundancy to combat noise, but redundancy sacrifices coding efficiency. To address how experience affects the balance between the robustness and efficiency of sensory codes, we probed odor representations in the mouse olfactory bulb during learning over a week, using longitudinal two-photon calcium imaging. When mice learned to discriminate between two dissimilar odorants, responses of mitral cell ensembles to the two odorants gradually became less discrete, increasing the efficiency. In contrast, when mice learned to discriminate between two very similar odorants, the initially overlapping representations of the two odorants became progressively decorrelated, enhancing the robustness. Qualitatively similar changes were observed when the same odorants were experienced passively, a condition that would induce implicit perceptual learning. These results suggest that experience adjusts odor representations to balance the robustness and efficiency depending on the similarity of the experienced odorants.
| S-EPMC5061050 | biostudies-literature