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Learning & Memory (Cold Spring Harbor,... Sep 2015The entorhinal cortex (EC)-hippocampal (HPC) network plays an essential role for episodic memory, which preserves spatial and temporal information about the occurrence... (Review)
Review
The entorhinal cortex (EC)-hippocampal (HPC) network plays an essential role for episodic memory, which preserves spatial and temporal information about the occurrence of past events. Although there has been significant progress toward understanding the neural circuits underlying the spatial dimension of episodic memory, the relevant circuits subserving the temporal dimension are just beginning to be understood. In this review, we examine the evidence concerning the role of the EC in associating events separated by time--or temporal associative learning--with emphasis on the function of persistent activity in the medial entorhinal cortex layer III (MECIII) and their direct inputs into the CA1 region of HPC. We also discuss the unique role of Island cells in the medial entorhinal cortex layer II (MECII), which is a newly discovered direct feedforward inhibitory circuit to CA1. Finally, we relate the function of these entorhinal cortical circuits to recent findings concerning hippocampal time cells, which may collectively activate in sequence to bridge temporal gaps between discontiguous events in an episode.
Topics: Animals; Association Learning; Entorhinal Cortex; Hippocampus; Humans; Neural Pathways; Time Perception
PubMed: 26286654
DOI: 10.1101/lm.038687.115 -
Attention, Perception & Psychophysics Nov 2011One important task for the visual system is to group image elements that belong to an object and to segregate them from other objects and the background. We here present... (Review)
Review
One important task for the visual system is to group image elements that belong to an object and to segregate them from other objects and the background. We here present an incremental grouping theory (IGT) that addresses the role of object-based attention in perceptual grouping at a psychological level and, at the same time, outlines the mechanisms for grouping at the neurophysiological level. The IGT proposes that there are two processes for perceptual grouping. The first process is base grouping and relies on neurons that are tuned to feature conjunctions. Base grouping is fast and occurs in parallel across the visual scene, but not all possible feature conjunctions can be coded as base groupings. If there are no neurons tuned to the relevant feature conjunctions, a second process called incremental grouping comes into play. Incremental grouping is a time-consuming and capacity-limited process that requires the gradual spread of enhanced neuronal activity across the representation of an object in the visual cortex. The spread of enhanced neuronal activity corresponds to the labeling of image elements with object-based attention.
Topics: Animals; Association Learning; Attention; Brain Mapping; Color Perception; Depth Perception; Discrimination, Psychological; Gestalt Theory; Humans; Macaca mulatta; Nerve Net; Neurons; Orientation; Pattern Recognition, Visual; Retina; Visual Cortex
PubMed: 21901573
DOI: 10.3758/s13414-011-0200-0 -
Genes, Brain, and Behavior Jan 2016Pavlovian fear or threat conditioning, where a neutral stimulus takes on aversive properties through pairing with an aversive stimulus, has been an important tool for... (Review)
Review
Pavlovian fear or threat conditioning, where a neutral stimulus takes on aversive properties through pairing with an aversive stimulus, has been an important tool for exploring the neurobiology of learning. In the past decades, this neurobehavioral approach has been expanded to include the developing infant. Indeed, protracted postnatal brain development permits the exploration of how incorporating the amygdala, prefrontal cortex and hippocampus into this learning system impacts the acquisition and expression of aversive conditioning. Here, we review the developmental trajectory of these key brain areas involved in aversive conditioning and relate it to pups' transition to independence through weaning. Overall, the data suggests that adult-like features of threat learning emerge as the relevant brain areas become incorporated into this learning. Specifically, the developmental emergence of the amygdala permits cue learning and the emergence of the hippocampus permits context learning. We also describe unique features of learning in early life that block threat learning and enhance interaction with the mother or exploration of the environment. Finally, we describe the development of a sense of time within this learning and its involvement in creating associations. Together these data suggest that the development of threat learning is a useful tool for dissecting adult-like functioning of brain circuits, as well as providing unique insights into ecologically relevant developmental changes.
Topics: Amygdala; Animals; Association Learning; Child Development; Fear; Humans; Infant; Neurogenesis
PubMed: 26534899
DOI: 10.1111/gbb.12261 -
Trends in Cognitive Sciences May 2010In the 20th century it was thought that novel behaviors are mediated primarily in cortex and that the development of automaticity is a process of transferring control to... (Review)
Review
In the 20th century it was thought that novel behaviors are mediated primarily in cortex and that the development of automaticity is a process of transferring control to subcortical structures. However, evidence supports the view that subcortical structures, such as the striatum, make significant contributions to initial learning. More recently, there has been increasing evidence that neurons in the associative striatum are selectively activated during early learning, whereas those in the sensorimotor striatum are more active after automaticity has developed. At the same time, other recent reports indicate that automatic behaviors are striatum- and dopamine-independent, and might be mediated entirely within cortex. Resolving this apparent conflict should be a major goal of future research.
Topics: Association Learning; Automatism; Basal Ganglia; Cerebral Cortex; Habits; Humans; Learning
PubMed: 20207189
DOI: 10.1016/j.tics.2010.02.001 -
Neuron Oct 2020The representation of odor in olfactory cortex (piriform) is distributive and unstructured and can only be afforded behavioral significance upon learning. We performed...
The representation of odor in olfactory cortex (piriform) is distributive and unstructured and can only be afforded behavioral significance upon learning. We performed 2-photon imaging to examine the representation of odors in piriform and in two downstream areas, the orbitofrontal cortex (OFC) and the medial prefrontal cortex (mPFC), as mice learned olfactory associations. In piriform, we observed that odor responses were largely unchanged during learning. In OFC, 30% of the neurons acquired robust responses to conditioned stimuli (CS+) after learning, and these responses were gated by internal state and task context. Moreover, direct projections from piriform to OFC can be entrained to elicit learned olfactory behavior. CS+ responses in OFC diminished with continued training, whereas persistent representations of both CS+ and CS- odors emerged in mPFC. Optogenetic silencing indicates that these two brain structures function sequentially to consolidate the learning of appetitive associations.
Topics: Animals; Appetitive Behavior; Association Learning; Conditioning, Classical; Intravital Microscopy; Mice; Microscopy, Fluorescence, Multiphoton; Neurons; Odorants; Olfactory Pathways; Optogenetics; Piriform Cortex; Prefrontal Cortex
PubMed: 32827456
DOI: 10.1016/j.neuron.2020.07.033 -
Proceedings of the National Academy of... Nov 1996In humans declarative or explicit memory is supported by the hippocampus and related structures of the medial temporal lobe working in concert with the cerebral cortex.... (Review)
Review
In humans declarative or explicit memory is supported by the hippocampus and related structures of the medial temporal lobe working in concert with the cerebral cortex. This paper reviews our progress in developing an animal model for studies of cortical-hippocampal interactions in memory processing. Our findings support the view that the cortex maintains various forms of memory representation and that hippocampal structures extend the persistence and mediate the organization of these codings. Specifically, the parahippocampal region, through direct and reciprocal interconnections with the cortex, is sufficient to support the convergence and extended persistence of cortical codings. The hippocampus itself is critical to the organization cortical representations in terms of relationships among items in memory and in the flexible memory expression that is the hallmark of declarative memory.
Topics: Animals; Association Learning; Brain; Cerebral Cortex; Hippocampus; Memory; Odorants; Olfactory Pathways; Rats; Temporal Lobe
PubMed: 8942963
DOI: 10.1073/pnas.93.24.13500 -
NeuroImage Apr 2020Creative thinking relies on the ability to make remote associations and fruitfully combine unrelated concepts. Hence, original associations and bi-associations (i.e.,...
Creative thinking relies on the ability to make remote associations and fruitfully combine unrelated concepts. Hence, original associations and bi-associations (i.e., associations to one and two concepts, respectively) are considered elementary cognitive processes of creative cognition. In this work, we investigated the cognitive and brain mechanisms underlying these association processes with tasks that asked for original associations to either one or two adjective stimuli. Study 1 showed that the generation of more original associations and bi-associations was related to several indicators of creativity, corroborating the validity of these association performances as basic processes underlying creative cognition. Study 2 assessed brain activity during performance of these association tasks by means of fMRI. The generation of original versus common associations was related to higher activation in bilateral lingual gyri suggesting that cued search for remote representatives of given properties are supported by visually-mediated search strategies. Parametric analyses further showed that the generation of more original associations involved activation of the left inferior frontal cortex and the left ventromedial prefrontal cortex, which are consistently implicated in constrained retrieval and evaluation processes, and relevant for making distant semantic connections. Finally, the generation of original bi-associations involved higher activation in bilateral hippocampus and inferior parietal lobe, indicating that conceptual combination recruits episodic simulation processes. Together, these findings suggest that the generation of verbally cued, original associations relies not only on verbal semantic memory but involves mental imagery and episodic simulation, offering new insights in the nuanced interplay of memory systems in creative thought.
Topics: Adolescent; Adult; Association; Brain Mapping; Cerebral Cortex; Creativity; Cues; Female; Hippocampus; Humans; Imagination; Language; Magnetic Resonance Imaging; Male; Memory, Episodic; Young Adult
PubMed: 32001370
DOI: 10.1016/j.neuroimage.2020.116586 -
Philosophical Transactions of the Royal... Jun 2008Declarative knowledge and experiences are represented in the association cortex and are recalled by reactivation of the neural representation. Electrophysiological... (Review)
Review
Declarative knowledge and experiences are represented in the association cortex and are recalled by reactivation of the neural representation. Electrophysiological experiments have revealed that associations between semantically linked visual objects are formed in neural representations in the temporal and limbic cortices. Memory traces are created by the reorganization of neural circuits. These regions are reactivated during retrieval and contribute to the contents of a memory. Two different types of retrieval signals are suggested as follows: automatic and active. One flows backward from the medial temporal lobe during the automatic retrieval process, whereas the other is conveyed as a top-down signal from the prefrontal cortex to the temporal cortex during the active retrieval process. By sending the top-down signal, the prefrontal cortex manipulates and organizes to-be-remembered information, devises strategies for retrieval and monitors the outcome. To further understand the neural mechanism of memory, the following two complementary views are needed: how the multiple cortical areas in the brain-wide network interact to orchestrate cognitive functions and how the properties of single neurons and their synaptic connections with neighbouring neurons combine to form local circuits and to exhibit the function of each cortical area. We will discuss some new methodological innovations that tackle these challenges.
Topics: Animals; Association Learning; Haplorhini; Humans; Magnetic Resonance Imaging; Memory; Neural Pathways; Prefrontal Cortex; Temporal Lobe
PubMed: 18339600
DOI: 10.1098/rstb.2008.2271 -
Neuron Sep 2005Orbitofrontal cortex is characterized by its unique pattern of connections with subcortical areas, such as basolateral amygdala. Here we distinguish between the critical... (Review)
Review
Orbitofrontal cortex is characterized by its unique pattern of connections with subcortical areas, such as basolateral amygdala. Here we distinguish between the critical role of these areas in associative learning and the pivotal contribution of OFC to the manipulation of this information to control behavior. This contribution reflects the ability of OFC to signal the desirability of expected outcomes, which requires the integration of associative information with information concerning internal states and goals in representational memory.
Topics: Amygdala; Animals; Association Learning; Behavior; Humans; Orbit; Prefrontal Cortex
PubMed: 16129393
DOI: 10.1016/j.neuron.2005.07.018 -
NeuroImage Jun 2020Inappropriate behaviors may result from acquiring maladaptive associations between irrelevant information in the environment and important events, such as reward or...
Inappropriate behaviors may result from acquiring maladaptive associations between irrelevant information in the environment and important events, such as reward or punishment. Pre-exposure effects are believed to prevent the expression of irrelevant associations. For example, learned irrelevance delays the expression of associations between conditioned (CS) and unconditioned (US) stimuli following their uncorrelated presentation. The neuronal substrates of pre-exposure effects in humans are largely unknown because these effects rapidly attenuate when using traditional pre-exposure paradigms. The latter are therefore incompatible with neuroimaging approaches that require many trial repetitions. Moreover, large methodological differences between animal and human research on pre-exposure effects challenge the presumption of shared neurocognitive substrates, and question the prevalent use of pre-exposure effects in animals to model symptoms of human mental disorders. To overcome these limitations, we combined a novel learned irrelevance task with model-based fMRI. We report the results of a model that describes learned irrelevance as a dynamic process, which evolves across trials and integrates the weighting between two state-action values pertaining to 'CS-no US' associations (acquired during pre-exposure) and 'CS-US' associations (acquired during subsequent conditioning). This relative weighting correlated i) positively with the learned irrelevance effect observed in the behavioral task, ii) positively with activity in the entorhinal cortex, and iii) negatively with activity in the nucleus accumbens (NAcc). Furthermore, the model updates the relative weighting of the two state-action values via two separate prediction error (PE) signals that allow the dynamic accumulation of evidence for the CS to predict the 'US' or a 'no US' outcome. One PE signal, designed to increase the relative weight of 'CS-US' associations following 'US' outcomes, correlated with activity in the NAcc, while another PE signal, designed to increase the relative weight of 'CS-no US' associations following 'no US' outcomes, correlated with activity in the basolateral amygdala. By extending previous animal observations to humans, the present study provides a novel approach to foster translational research on pre-exposure effects.
Topics: Adult; Association Learning; Brain; Conditioning, Classical; Decision Making; Female; Humans; Inhibition, Psychological; Magnetic Resonance Imaging; Male
PubMed: 32156624
DOI: 10.1016/j.neuroimage.2020.116719