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Expectations attenuate the negative influence of neural adaptation on the processing of novel stimuli: ERP evidence. Neuroscience 2022; 492:58-66. [DOI: 10.1016/j.neuroscience.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 04/02/2022] [Accepted: 04/04/2022] [Indexed: 11/20/2022]
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2
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Rostalski S, Robinson J, Ambrus GG, Johnston P, Kovács G. Person identity‐specific adaptation effects in the ventral occipito‐temporal cortex. Eur J Neurosci 2022; 55:1232-1243. [DOI: 10.1111/ejn.15604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 11/25/2021] [Accepted: 01/07/2022] [Indexed: 11/03/2022]
Affiliation(s)
- Sophie‐Marie Rostalski
- Department of Biological Psychology and Cognitive Neurosciences, Institute of Psychology Friedrich Schiller University Jena Germany
| | - Jonathan Robinson
- Department of Philosophy Monash University Melbourne Australia
- School of Psychology & Counselling, Faculty of Health Queensland University of Technology Brisbane Australia
| | - Géza Gergely Ambrus
- Department of Biological Psychology and Cognitive Neurosciences, Institute of Psychology Friedrich Schiller University Jena Germany
| | - Patrick Johnston
- School of Psychology & Counselling, Faculty of Health Queensland University of Technology Brisbane Australia
| | - Gyula Kovács
- Department of Biological Psychology and Cognitive Neurosciences, Institute of Psychology Friedrich Schiller University Jena Germany
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3
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Færøvik U, Specht K, Vikene K. Suppression, Maintenance, and Surprise: Neuronal Correlates of Predictive Processing Specialization for Musical Rhythm. Front Neurosci 2021; 15:674050. [PMID: 34512236 PMCID: PMC8429816 DOI: 10.3389/fnins.2021.674050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 06/17/2021] [Indexed: 12/02/2022] Open
Abstract
Auditory repetition suppression and omission activation are opposite neural phenomena and manifestations of principles of predictive processing. Repetition suppression describes the temporal decrease in neural activity when a stimulus is constant or repeated in an expected temporal fashion; omission activity is the transient increase in neural activity when a stimulus is temporarily and unexpectedly absent. The temporal, repetitive nature of musical rhythms is ideal for investigating these phenomena. During an fMRI session, 10 healthy participants underwent scanning while listening to musical rhythms with two levels of metric complexity, and with beat omissions with different positional complexity. Participants first listened to 16-s-long presentations of continuous rhythms, before listening to a longer continuous presentation with beat omissions quasi-randomly introduced. We found deactivation in bilateral superior temporal gyri during the repeated presentation of the normal, unaltered rhythmic stimulus, with more suppression of activity in the left hemisphere. Omission activation of bilateral middle temporal gyri was right lateralized. Persistent activity was found in areas including the supplementary motor area, caudate nucleus, anterior insula, frontal areas, and middle and posterior cingulate cortex, not overlapping with either listening, suppression, or omission activation. This suggests that the areas are perhaps specialized for working memory maintenance. We found no effect of metric complexity for either the normal presentation or omissions, but we found evidence for a small effect of omission position—at an uncorrected threshold—where omissions in the more metrical salient position, i.e., the first position in the bar, showed higher activation in anterior cingulate/medial superior frontal gyrus, compared to omissions in the less salient position, in line with the role of the anterior cingulate cortex for saliency detection. The results are consistent with findings in our previous studies on Parkinson’s disease, but are put into a bigger theoretical frameset.
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Affiliation(s)
- Ulvhild Færøvik
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
| | - Karsten Specht
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.,Department of Education, The Arctic University of Norway, Tromsø, Norway.,Mohn Medical Imaging and Visualization Centre, Haukeland University Hospital, Bergen, Norway
| | - Kjetil Vikene
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.,Mohn Medical Imaging and Visualization Centre, Haukeland University Hospital, Bergen, Norway
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Nie A, Yu Y. External (Versus Internal) Facial Features Contribute Most to Repetition Priming in Facial Recognition: ERP Evidence. Percept Mot Skills 2020; 128:15-47. [DOI: 10.1177/0031512520957150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Previous event-related potential (ERP) research demonstrated four successive ERP components in the repetition priming of human face recognition: P100, N170, N250r, and N400. While these components correspond, respectively, to the four stages proposed by the interactive activation and competition (IAC) model, there has been no emphasis in past research on how internal and external facial features affect repetition priming and the sensitivity of these ERP components to item interval. This study was designed to address these issues. We used faces of celebrities as targets, including completely familiar faces, familiar internal feature faces, and familiar external feature faces. We displayed a target face either immediately following its prime (immediate repetition) or after a delay with interference from a presentation of two other faces (delayed repetition). ERP differences at P100 and N170 were nearly statistically non-significant; familiar faces and familiar external feature faces were associated with reliable ERP signals of N250r and N400 in the immediate repetition condition. For delayed repetition, however, N250r and N400 signals were only preserved for the familiar external feature faces. The differences of these ERP components suggest that, compared with internal facial features, external features of a previously presented face contribute more to brain-based facial repetition priming, particularly during the last two stages of the IAC model.
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Affiliation(s)
- Aiqing Nie
- Department of Psychology and Behavioral Sciences, Zhejiang University, Hangzhou, China
| | - Yao Yu
- Department of Psychology and Behavioral Sciences, Zhejiang University, Hangzhou, China
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5
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Honbolygó F, Kóbor A, Hermann P, Kettinger ÁO, Vidnyánszky Z, Kovács G, Csépe V. Expectations about word stress modulate neural activity in speech-sensitive cortical areas. Neuropsychologia 2020; 143:107467. [PMID: 32305299 DOI: 10.1016/j.neuropsychologia.2020.107467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 03/06/2020] [Accepted: 04/12/2020] [Indexed: 10/24/2022]
Abstract
A recent dual-stream model of language processing proposed that the postero-dorsal stream performs predictive sequential processing of linguistic information via hierarchically organized internal models. However, it remains unexplored whether the prosodic segmentation of linguistic information involves predictive processes. Here, we addressed this question by investigating the processing of word stress, a major component of speech segmentation, using probabilistic repetition suppression (RS) modulation as a marker of predictive processing. In an event-related acoustic fMRI RS paradigm, we presented pairs of pseudowords having the same (Rep) or different (Alt) stress patterns, in blocks with varying Rep and Alt trial probabilities. We found that the BOLD signal was significantly lower for Rep than for Alt trials, indicating RS in the posterior and middle superior temporal gyrus (STG) bilaterally, and in the anterior STG in the left hemisphere. Importantly, the magnitude of RS was modulated by repetition probability in the posterior and middle STG. These results reveal the predictive processing of word stress in the STG areas and raise the possibility that words stress processing is related to the dorsal "where" auditory stream.
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Affiliation(s)
- Ferenc Honbolygó
- Brain Imaging Centre, Research Centre for Natural Sciences, Budapest, Hungary; Institute of Psychology, Eötvös Loránd University, Budapest, Hungary.
| | - Andrea Kóbor
- Brain Imaging Centre, Research Centre for Natural Sciences, Budapest, Hungary
| | - Petra Hermann
- Brain Imaging Centre, Research Centre for Natural Sciences, Budapest, Hungary
| | - Ádám Ottó Kettinger
- Brain Imaging Centre, Research Centre for Natural Sciences, Budapest, Hungary; Department of Nuclear Techniques, Budapest University of Technology and Economics, Budapest, Hungary
| | - Zoltán Vidnyánszky
- Brain Imaging Centre, Research Centre for Natural Sciences, Budapest, Hungary
| | - Gyula Kovács
- Brain Imaging Centre, Research Centre for Natural Sciences, Budapest, Hungary; Department of Biological Psychology and Cognitive Neuroscience, Institute of Psychology, Friedrich Schiller University Jena, Jena, Germany
| | - Valéria Csépe
- Brain Imaging Centre, Research Centre for Natural Sciences, Budapest, Hungary; Faculty of Modern Philology and Social Sciences, University of Pannonia, Veszprém, Hungary
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6
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Korzyukov O, Lee Y, Bronder A, Wagner M, Gumenyuk V, Larson CR, Hammer MJ. Auditory-vocal control system is object for predictive processing within seconds time range. Brain Res 2020; 1732:146703. [PMID: 32032611 DOI: 10.1016/j.brainres.2020.146703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/26/2020] [Accepted: 02/03/2020] [Indexed: 11/28/2022]
Abstract
Predictive processing across hierarchically organized time scales is one of the fundamental principles of neural computations in the cerebral cortex. We hypothesize that relatively complex aggregation of auditory and vocal brain systems that use auditory feedback for reflexive control of vocalizations can be an object for predictive processing. We used repetitive patterns of perturbations in auditory feedback during vocalizations to elicit implicit expectations that were violated by surprising direction of perturbations in one of the experimental conditions. Our results provide empirical support for the idea that formation of expectancy for integrated auditory-vocal brain systems, within the time range of seconds, resulted in two sequential neuronal processes. The first process reflects monitoring and error detection in prediction about perturbations in auditory feedback during vocalizations within the time range of seconds. The second neuronal process can be attributed to the optimization of brain predictions for sensory contingencies during vocalizations at separable and distinct timescales.
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Affiliation(s)
- Oleg Korzyukov
- Airway Sensory Physiology Laboratory, Department of Communication Sciences and Disorders, University of Wisconsin - Whitewater, Whitewater, WI 53190, USA; Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Dr., Evanston, IL 60208, USA.
| | - Yunseon Lee
- Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Dr., Evanston, IL 60208, USA
| | - Alexander Bronder
- Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Dr., Evanston, IL 60208, USA
| | - Michael Wagner
- Compumedics Europe GmbH, Heussweg 25, 20255 Hamburg, Germany
| | - Valentina Gumenyuk
- Airway Sensory Physiology Laboratory, Department of Communication Sciences and Disorders, University of Wisconsin - Whitewater, Whitewater, WI 53190, USA; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Building 149, 13th Street, Charlestown, MA 02129 USA
| | - Charles R Larson
- Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Dr., Evanston, IL 60208, USA
| | - Michael J Hammer
- Airway Sensory Physiology Laboratory, Department of Communication Sciences and Disorders, University of Wisconsin - Whitewater, Whitewater, WI 53190, USA
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7
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Walsh KS, McGovern DP, Clark A, O'Connell RG. Evaluating the neurophysiological evidence for predictive processing as a model of perception. Ann N Y Acad Sci 2020; 1464:242-268. [PMID: 32147856 PMCID: PMC7187369 DOI: 10.1111/nyas.14321] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 01/21/2020] [Accepted: 02/03/2020] [Indexed: 12/12/2022]
Abstract
For many years, the dominant theoretical framework guiding research into the neural origins of perceptual experience has been provided by hierarchical feedforward models, in which sensory inputs are passed through a series of increasingly complex feature detectors. However, the long-standing orthodoxy of these accounts has recently been challenged by a radically different set of theories that contend that perception arises from a purely inferential process supported by two distinct classes of neurons: those that transmit predictions about sensory states and those that signal sensory information that deviates from those predictions. Although these predictive processing (PP) models have become increasingly influential in cognitive neuroscience, they are also criticized for lacking the empirical support to justify their status. This limited evidence base partly reflects the considerable methodological challenges that are presented when trying to test the unique predictions of these models. However, a confluence of technological and theoretical advances has prompted a recent surge in human and nonhuman neurophysiological research seeking to fill this empirical gap. Here, we will review this new research and evaluate the degree to which its findings support the key claims of PP.
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Affiliation(s)
- Kevin S. Walsh
- Trinity College Institute of Neuroscience and School of PsychologyTrinity College DublinDublinIreland
| | - David P. McGovern
- Trinity College Institute of Neuroscience and School of PsychologyTrinity College DublinDublinIreland
- School of PsychologyDublin City UniversityDublinIreland
| | - Andy Clark
- Department of PhilosophyUniversity of SussexBrightonUK
- Department of InformaticsUniversity of SussexBrightonUK
| | - Redmond G. O'Connell
- Trinity College Institute of Neuroscience and School of PsychologyTrinity College DublinDublinIreland
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Neural adaptation and cognitive inflexibility in repeated problem-solving behaviors. Cortex 2019; 119:470-479. [PMID: 31505438 DOI: 10.1016/j.cortex.2019.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 06/21/2019] [Accepted: 08/04/2019] [Indexed: 01/04/2023]
Abstract
Repeated stimulus processing is often associated with a reduction in neural activity, known as neural adaptation. Therefore, people are more sensitive to novelty detection but likely lose flexibility in subsequent novelty processing after detection. To demonstrate the dynamic changes in neural adaption in repeated problem-solving behaviors and test its negative influence on subsequent nonrepetitive problem-solving behaviors, we adopted a Chinese character decomposition task in this fMRI study. Participants were asked to repeatedly perform 3-5 practice problems that could be solved by the same loose chunk decomposition (LCD) solution followed by a test problem that could be solved by a tight chunk decomposition (TCD) solution in the enhanced-set condition. The practice problem gradually elicited lower percent signal changes within the cuneus, superior parietal lobule (SPL), inferior frontal gyrus (IFG) and medial prefrontal cortex (mPFC) in serial positions -1, -2 and -3 of a set, implying that neural adaptation occurred in repeated practice. Both the test problem and the practice problem that following it recruited greater activation of the SPL and IFG in the enhanced-set condition than in the base-set condition when the practice problem and test problem alternately appeared, implying that the task switching cost from a more dominant task to a less dominant task and vice versa was increased after neural adaptation occurred. In other words, repeatedly solving a set of similar problems with the same solution likely leads to neural adaptation and cognitive inflexibility, which in turn have an undifferentiated impact on task switching. This finding expands existing knowledge about the neurocognitive mechanism underlying the formation of the mental set and sheds light on the influence of neural adaptation on subsequent processing.
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Himmer L, Schönauer M, Heib DPJ, Schabus M, Gais S. Rehearsal initiates systems memory consolidation, sleep makes it last. SCIENCE ADVANCES 2019; 5:eaav1695. [PMID: 31032406 PMCID: PMC6482015 DOI: 10.1126/sciadv.aav1695] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 03/07/2019] [Indexed: 05/16/2023]
Abstract
After encoding, memories undergo a transitional process termed systems memory consolidation. It allows fast acquisition of new information by the hippocampus, as well as stable storage in neocortical long-term networks, where memory is protected from interference. Whereas this process is generally thought to occur slowly over time and sleep, we recently found a rapid memory systems transition from hippocampus to posterior parietal cortex (PPC) that occurs over repeated rehearsal within one study session. Here, we use fMRI to demonstrate that this transition is stabilized over sleep, whereas wakefulness leads to a reset to naïve responses, such as observed during early encoding. The role of sleep therefore seems to go beyond providing additional rehearsal through memory trace reactivation, as previously thought. We conclude that repeated study induces systems consolidation, while sleep ensures that these transformations become stable and long lasting. Thus, sleep and repeated rehearsal jointly contribute to long-term memory consolidation.
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Affiliation(s)
- L. Himmer
- University of Tübingen, Institute of Medical Psychology and Behavioral Neurobiology, Silcherstr. 5, 72076 Tübingen, Germany
- Corresponding author. (M. Schönauer); (L.H.)
| | - M. Schönauer
- University of Tübingen, Institute of Medical Psychology and Behavioral Neurobiology, Silcherstr. 5, 72076 Tübingen, Germany
- Princeton Neuroscience Institute, Princeton University, Washington Road, Princeton, NJ 08544, USA
- Corresponding author. (M. Schönauer); (L.H.)
| | - D. P. J. Heib
- University of Salzburg, Centre for Cognitive Neuroscience (CCNS), Laboratory for Sleep, Cognition and Consciousness Research, Hellbrunner Street 34, A-5020 Salzburg, Austria
| | - M. Schabus
- University of Salzburg, Centre for Cognitive Neuroscience (CCNS), Laboratory for Sleep, Cognition and Consciousness Research, Hellbrunner Street 34, A-5020 Salzburg, Austria
| | - S. Gais
- University of Tübingen, Institute of Medical Psychology and Behavioral Neurobiology, Silcherstr. 5, 72076 Tübingen, Germany
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Huang F, Zhao Q, Zhou Z, Luo J. People got lost in solving a set of similar problems. Neuroimage 2019; 186:192-199. [PMID: 30449716 DOI: 10.1016/j.neuroimage.2018.10.063] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 10/18/2018] [Accepted: 10/24/2018] [Indexed: 01/21/2023] Open
Abstract
A mental set generally refers to the human brain's tendency to persist with a familiar solution and stubbornly ignore alternatives. However, if a familiar solution is unable to solve a problem similar to a previous problem, does it continue to hinder alternative solutions, and if so, how and why? To answer these questions, a Chinese character decomposition task was adopted in this study. Participants were asked to perform a practice problem that could be solved by a familiar loose chunk decomposition (LCD) solution followed by a test problem that was similar to the practice problem but could only be solved by an unfamiliar tight chunk decomposition (TCD) solution or were asked to repeatedly perform 3-5 practice problems followed by a test problem; the former is the base-set condition, and the latter is the enhanced-set condition. The results showed that the test problem recruited more activation of the inferior frontal gyrus (IFG), middle occipital cortex (MOG), superior parietal lobule (SPL) and dorsal anterior cingulate cortex (dACC) than the practice problem in the latter operation and verification stage, but almost equal activation of the dACC occurred in the early exploration stage. This likely implied that people did not think that the familiar but currently invalid LCD solution could not be used to solve the test problem; thus, it continuously competed for attention with the unfamiliar TCD solution, which required more executive control to suppress. Moreover, compared with the base-set condition, the test problem in the enhanced-set condition recruited greater activations of the IFG, SPL and dACC in the latter verification stage but less activations of regions in the left IFG and MOG in the early exploration stage. These results revealed that people less actively explored and had to work harder to operate the unfamiliar TCD solution, particularly to resolve competition from the familiar but currently invalid LCD solution. In conclusion, people lost the ability to identify errors in the familiar but currently invalid solution, which in turn decreased the exploration efforts and increased the processing demands associated with alternative solutions in the form of attentional bias and competition. This finding broadly explains the dilemma of creative problem solving.
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Affiliation(s)
- Furong Huang
- School of Psychology, Jiangxi Normal University, Nanchang, 330022, China
| | - Qingbai Zhao
- School of Psychology, Central China Normal University, Wuhan, 430079, China.
| | - Zhijin Zhou
- School of Psychology, Central China Normal University, Wuhan, 430079, China.
| | - Jing Luo
- School of Psychology, Capital Normal University, Beijing, 100048, China; Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, 100101, China.
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Huang F, Tang S, Sun P, Luo J. Neural correlates of novelty and appropriateness processing in externally induced constraint relaxation. Neuroimage 2018; 172:381-389. [PMID: 29408576 DOI: 10.1016/j.neuroimage.2018.01.070] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 12/21/2017] [Accepted: 01/28/2018] [Indexed: 11/27/2022] Open
Abstract
Novelty and appropriateness are considered the two fundamental features of creative thinking, including insight problem solving, which can be performed through chunk decomposition and constraint relaxation. Based on a previous study that separated the neural bases of novelty and appropriateness in chunk decomposition, in this study, we used event-related functional magnetic resonance imaging (fMRI) to further dissociate these mechanisms in constraint relaxation. Participants were guided to mentally represent the method of problem solving according to the externally provided solutions that were elaborately prepared in advance and systematically varied in their novelty and appropriateness for the given problem situation. The results showed that novelty processing was completed by the temporoparietal junction (TPJ) and regions in the executive system (dorsolateral prefrontal cortex [DLPFC]), whereas appropriateness processing was completed by the TPJ and regions in the episodic memory (hippocampus), emotion (amygdala), and reward systems (orbitofrontal cortex [OFC]). These results likely indicate that appropriateness processing can result in a more memorable and richer experience than novelty processing in constraint relaxation. The shared and distinct neural mechanisms of the features of novelty and appropriateness in constraint relaxation are discussed, enriching the representation of the change theory of insight.
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Affiliation(s)
- Furong Huang
- School of Psychology, Jiangxi Normal University, Nanchang 330022, China
| | - Shuang Tang
- School of Psychology, Jiangxi Normal University, Nanchang 330022, China
| | - Pei Sun
- Department of Psychology, Tsinghua University, Beijing 100084, China
| | - Jing Luo
- School of Psychology, Capital Normal University, Beijing 100048, China; Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China.
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12
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The occipital face area is causally involved in the formation of identity-specific face representations. Brain Struct Funct 2017; 222:4271-4282. [DOI: 10.1007/s00429-017-1467-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/20/2017] [Indexed: 10/19/2022]
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13
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Watching the brain recalibrate: Neural correlates of renormalization during face adaptation. Neuroimage 2017; 155:1-9. [DOI: 10.1016/j.neuroimage.2017.04.049] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 04/09/2017] [Accepted: 04/20/2017] [Indexed: 11/20/2022] Open
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Abstract
Previous evidence indicates that the brain stores memory in two complementary systems, allowing both rapid plasticity and stable representations at different sites. For memory to be established in a long-lasting neocortical store, many learning repetitions are considered necessary after initial encoding into hippocampal circuits. To elucidate the dynamics of hippocampal and neocortical contributions to the early phases of memory formation, we closely followed changes in human functional brain activity while volunteers navigated through two different, initially unknown virtual environments. In one condition, they were able to encode new information continuously about the spatial layout of the maze. In the control condition, no information could be learned because the layout changed constantly. Our results show that the posterior parietal cortex (PPC) encodes memories for spatial locations rapidly, beginning already with the first visit to a location and steadily increasing activity with each additional encounter. Hippocampal activity and connectivity between the PPC and hippocampus, on the other hand, are strongest during initial encoding, and both decline with additional encounters. Importantly, stronger PPC activity related to higher memory-based performance. Compared with the nonlearnable control condition, PPC activity in the learned environment remained elevated after a 24-h interval, indicating a stable change. Our findings reflect the rapid creation of a memory representation in the PPC, which belongs to a recently proposed parietal memory network. The emerging parietal representation is specific for individual episodes of experience, predicts behavior, and remains stable over offline periods, and must therefore hold a mnemonic function.
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