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Rhoads SA, Vekaria KM, O'Connell K, Elizabeth HS, Rand DG, Kozak Williams MN, Marsh AA. Unselfish traits and social decision-making patterns characterize six populations of real-world extraordinary altruists. Nat Commun 2023; 14:1807. [PMID: 37002205 PMCID: PMC10066349 DOI: 10.1038/s41467-023-37283-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 03/09/2023] [Indexed: 04/04/2023] Open
Abstract
Acts of extraordinary, costly altruism, in which significant risks or costs are assumed to benefit strangers, have long represented a motivational puzzle. But the features that consistently distinguish individuals who engage in such acts have not been identified. We assess six groups of real-world extraordinary altruists who had performed costly or risky and normatively rare (<0.00005% per capita) altruistic acts: heroic rescues, non-directed and directed kidney donations, liver donations, marrow or hematopoietic stem cell donations, and humanitarian aid work. Here, we show that the features that best distinguish altruists from controls are traits and decision-making patterns indicating unusually high valuation of others' outcomes: high Honesty-Humility, reduced Social Discounting, and reduced Personal Distress. Two independent samples of adults who were asked what traits would characterize altruists failed to predict this pattern. These findings suggest that theories regarding self-focused motivations for altruism (e.g., self-enhancing reciprocity, reputation enhancement) alone are insufficient explanations for acts of real-world self-sacrifice.
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Affiliation(s)
| | | | | | | | - David G Rand
- Massachusetts Institute of Technology, Cambridge, MA, USA
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2
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Coppola P, Allanson J, Naci L, Adapa R, Finoia P, Williams GB, Pickard JD, Owen AM, Menon DK, Stamatakis EA. The complexity of the stream of consciousness. Commun Biol 2022; 5:1173. [PMID: 36329176 PMCID: PMC9633704 DOI: 10.1038/s42003-022-04109-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
Typical consciousness can be defined as an individual-specific stream of experiences. Modern consciousness research on dynamic functional connectivity uses clustering techniques to create common bases on which to compare different individuals. We propose an alternative approach by combining modern theories of consciousness and insights arising from phenomenology and dynamical systems theory. This approach enables a representation of an individual's connectivity dynamics in an intrinsically-defined, individual-specific landscape. Given the wealth of evidence relating functional connectivity to experiential states, we assume this landscape is a proxy measure of an individual's stream of consciousness. By investigating the properties of this landscape in individuals in different states of consciousness, we show that consciousness is associated with short term transitions that are less predictable, quicker, but, on average, more constant. We also show that temporally-specific connectivity states are less easily describable by network patterns that are distant in time, suggesting a richer space of possible states. We show that the cortex, cerebellum and subcortex all display consciousness-relevant dynamics and discuss the implication of our results in forming a point of contact between dynamical systems interpretations and phenomenology.
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Affiliation(s)
- Peter Coppola
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Judith Allanson
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
- Department of Neurosciences, Cambridge University Hospitals NHS Foundation, Addenbrooke's Hospital, Cambridge, UK
| | - Lorina Naci
- Trinity College Institute of Neuroscience, School of Psychology, Lloyd Building, Trinity College Dublin, Dublin, Ireland
| | - Ram Adapa
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Paola Finoia
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
- Division of Neurosurgery, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Guy B Williams
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK
| | - John D Pickard
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
- Division of Neurosurgery, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK
| | - Adrian M Owen
- The Brain and Mind Institute, Western Interdisciplinary Research Building, N6A 5B7 University of Western Ontario, London, ON, Canada
| | - David K Menon
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK
| | - Emmanuel A Stamatakis
- Division of Anaesthesia, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
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The unexplored link between aesthetic perception and creativity: a theory-driven meta-analysis of fMRI studies in the visual domain. Neurosci Biobehav Rev 2022; 140:104768. [DOI: 10.1016/j.neubiorev.2022.104768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 07/01/2022] [Accepted: 07/01/2022] [Indexed: 11/23/2022]
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4
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Pramod RT, Arun SP. Improving Machine Vision Using Human Perceptual Representations: The Case of Planar Reflection Symmetry for Object Classification. IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 2022; 44:228-241. [PMID: 32750809 PMCID: PMC7611439 DOI: 10.1109/tpami.2020.3008107] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Achieving human-like visual abilities is a holy grail for machine vision, yet precisely how insights from human vision can improve machines has remained unclear. Here, we demonstrate two key conceptual advances: First, we show that most machine vision models are systematically different from human object perception. To do so, we collected a large dataset of perceptual distances between isolated objects in humans and asked whether these perceptual data can be predicted by many common machine vision algorithms. We found that while the best algorithms explain ∼ 70 percent of the variance in the perceptual data, all the algorithms we tested make systematic errors on several types of objects. In particular, machine algorithms underestimated distances between symmetric objects compared to human perception. Second, we show that fixing these systematic biases can lead to substantial gains in classification performance. In particular, augmenting a state-of-the-art convolutional neural network with planar/reflection symmetry scores along multiple axes produced significant improvements in classification accuracy (1-10 percent) across categories. These results show that machine vision can be improved by discovering and fixing systematic differences from human vision.
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Liu Z, Guo C. Unitization could facilitate item recognition but inhibit verbatim recognition for picture stimuli: behavioral and event-related potential study. PSYCHOLOGICAL RESEARCH 2020; 85:2935-2953. [PMID: 33161503 DOI: 10.1007/s00426-020-01442-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 10/23/2020] [Indexed: 10/23/2022]
Abstract
It is widely accepted that unitization can promote familiarity-based associative recognition, but the effect of unitization on item recognition remains unclear. The goals of this study were to elaborate on how unitization affected item recognition and the neural correlates of familiarity and recollection for item recognition. In study, the participants were asked to learn related and unrelated picture pairs, and in test, they were required to distinguish single old pictures form new pictures. In experiment 1, we used R/K/N paradigm to estimate the contribution of familiarity and recollection to item recognition, the results showed that unitization could improve item recognition through increasing recollection selectively. In experiment 2, we used ERP old/new effects to estimate the neural correlates of familiarity and recollection, the results showed that unitization could improve item recognition through a selective reduction in LPC effect. Inspired by DRM paradigm, in experiment 3, we divided the new pictures into semantically related lure pictures and semantically unrelated new pictures to explore the effects of unitization on item recognition and verbatim recognition (the ability to distinguish old pictures from lure pictures). The behavioral results showed that unitization could improve item recognition, but it damaged verbatim recognition. The ERP results revealed that there were larger LPC effects in the unrelated condition than in the related condition, regardless of item or verbatim recognition. In summary, we believed that unitization could indeed improve item recognition, but it damaged verbatim recognition.
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Affiliation(s)
- Zejun Liu
- Department of Psychology, Capital Normal University, No. 23 Baiduizijia, Fuwaidajie Street, Haidian District, Beijing, 100048, China
| | - Chunyan Guo
- Department of Psychology, Capital Normal University, No. 23 Baiduizijia, Fuwaidajie Street, Haidian District, Beijing, 100048, China.
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6
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Delorme A, Poncet M, Fabre-Thorpe M. Briefly Flashed Scenes Can Be Stored in Long-Term Memory. Front Neurosci 2018; 12:688. [PMID: 30344471 PMCID: PMC6182062 DOI: 10.3389/fnins.2018.00688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 09/13/2018] [Indexed: 11/13/2022] Open
Abstract
The capacity of human memory is impressive. Previous reports have shown that when asked to memorize images, participants can recognize several thousands of visual objects in great details even with a single viewing of a few seconds per image. In this experiment, we tested recognition performance for natural scenes that participants saw for 20 ms only once (untrained group) or 22 times over many days (trained group) in an unrelated task. 400 images (200 previously viewed and 200 novel images) were flashed one at a time and participants were asked to lift their finger from a pad whenever they thought they had already seen the image (go/no-go paradigm). Compared to previous reports of excellent recognition performance with only single presentations of a few seconds, untrained participants were able to recognize only 64% of the 200 images they had seen few minutes before. On the other hand, trained participants, who had processed the flashed images (20 ms) several times, could correctly recognize 89% of them. EEG recordings confirmed these behavioral results. As early as 230 ms after stimulus onset, a significant event-related-potential (ERP) difference between familiar and new images was observed for the trained but not for the untrained group. These results show that briefly flashed unmasked scenes can be incidentally stored in long-term memory when repeated.
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Affiliation(s)
- Arnaud Delorme
- Centre de Recherche Cerveau et Cognition, Université Toulouse III - Paul Sabatier, Toulouse, France.,Centre National de la Recherche Scientifique, Centre de Recherche Cerveau et Cognition, Toulouse, France.,Institute for Neural Computation, University of California, San Diego, La Jolla, CA, United States.,Institute of Noetic Sciences, Petaluma, CA, United States
| | - Marlène Poncet
- Centre de Recherche Cerveau et Cognition, Université Toulouse III - Paul Sabatier, Toulouse, France.,Centre National de la Recherche Scientifique, Centre de Recherche Cerveau et Cognition, Toulouse, France
| | - Michèle Fabre-Thorpe
- Centre de Recherche Cerveau et Cognition, Université Toulouse III - Paul Sabatier, Toulouse, France.,Centre National de la Recherche Scientifique, Centre de Recherche Cerveau et Cognition, Toulouse, France
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7
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Abstract
Although substantial evidence indicates that spacing repeated study events with intervening material generally enhances memory performance relative to massing study events, the mechanism underlying this benefit is less clear. Two experiments examined the role of reminding difficulty during the acquisition of material in modulating final memory performance for spaced repetitions utilizing recognition (Experiment 1) and recall tests (Experiment 2). Specifically, participants studied a list of words presented one or two times separated by one or five items. On each trial participants reported whether the item had been previously presented (i.e., repetition detection judgment), and the response latency served as a proxy for reminding difficulty such that longer response latencies reflected more difficult reminding. A third experiment extended this paradigm with the inclusion of a massed condition and novel lag conditions (three and ten items). Results revealed significant lag effects in final test performance across experiments despite comparable repetition detection difficulty between lag conditions during acquisition. Moreover, results from within-participant point-biserial analyses and mediation analyses converged on overall performance measures in suggesting that repetition detection difficulty failed to modulate final test performance in the current paradigm. Discussion considers the implications of the current results for mechanisms proposed to underlie the benefits of spaced study and spaced retrieval practice.
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Wang B. Positive Arousal Enhances the Consolidation of Item Memory. SWISS JOURNAL OF PSYCHOLOGY 2015. [DOI: 10.1024/1421-0185/a000151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Emotional arousal induced after learning has been shown to modulate memory consolidation. However, it is unclear whether the effect of postlearning arousal can extend to different aspects of memory. This study examined the effect of postlearning positive arousal on both item memory and source memory. Participants learned a list of neutral words and took an immediate memory test. Then they watched a positive or a neutral videoclip and took delayed memory tests after either 25 minutes or 1 week had elapsed after the learning phase. In both delay conditions, positive arousal enhanced consolidation of item memory as measured by overall recognition. Furthermore, positive arousal enhanced consolidation of familiarity but not recollection. However, positive arousal appeared to have no effect on consolidation of source memory. These findings have implications for building theoretical models of the effect of emotional arousal on consolidation of episodic memory and for applying postlearning emotional arousal as a technique of memory intervention.
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Affiliation(s)
- Bo Wang
- Department of Psychology, Central University of Finance and Economics, Beijing, P. R. China
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Baeken C, De Raedt R, Van Schuerbeek P, De Mey J, Bossuyt A, Luypaert R. The influence of emotional priming on the neural substrates of memory: A prospective fMRI study using portrait art stimuli. Neuroimage 2012; 61:876-83. [DOI: 10.1016/j.neuroimage.2012.03.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 02/16/2012] [Accepted: 03/11/2012] [Indexed: 11/24/2022] Open
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Bossong MG, Jager G, van Hell HH, Zuurman L, Jansma JM, Mehta MA, van Gerven JMA, Kahn RS, Ramsey NF. Effects of Δ9-Tetrahydrocannabinol Administration on Human Encoding and Recall Memory Function: A Pharmacological fMRI Study. J Cogn Neurosci 2012; 24:588-99. [DOI: 10.1162/jocn_a_00156] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Abstract
Deficits in memory function are an incapacitating aspect of various psychiatric and neurological disorders. Animal studies have recently provided strong evidence for involvement of the endocannabinoid (eCB) system in memory function. Neuropsychological studies in humans have shown less convincing evidence but suggest that administration of cannabinoid substances affects encoding rather than recall of information. In this study, we examined the effects of perturbation of the eCB system on memory function during both encoding and recall. We performed a pharmacological MRI study with a placebo-controlled, crossover design, investigating the effects of Δ9-tetrahydrocannabinol (THC) inhalation on associative memory-related brain function in 13 healthy volunteers. Performance and brain activation during associative memory were assessed using a pictorial memory task, consisting of separate encoding and recall conditions. Administration of THC caused reductions in activity during encoding in the right insula, the right inferior frontal gyrus, and the left middle occipital gyrus and a network-wide increase in activity during recall, which was most prominent in bilateral cuneus and precuneus. THC administration did not affect task performance, but while during placebo recall activity significantly explained variance in performance, this effect disappeared after THC. These findings suggest eCB involvement in encoding of pictorial information. Increased precuneus activity could reflect impaired recall function, but the absence of THC effects on task performance suggests a compensatory mechanism. These results further emphasize the eCB system as a potential novel target for treatment of memory disorders and a promising target for development of new therapies to reduce memory deficits in humans.
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Affiliation(s)
| | - Gerry Jager
- 1University Medical Center Utrecht
- 2Wageningen University
| | | | - Lineke Zuurman
- 3Centre for Human Drug Research, Leiden, the Netherlands
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Koen JD, Yonelinas AP. Memory variability is due to the contribution of recollection and familiarity, not to encoding variability. J Exp Psychol Learn Mem Cogn 2011; 36:1536-42. [PMID: 20854009 DOI: 10.1037/a0020448] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is well established that the memory strength of studied items is more variable than the strength of new items on tests of recognition memory, but the reason why this occurs is poorly understood. One account for this old item variance effect is based on single-process theory, which proposes that this effect is due to variability in how well items are initially encoded into memory (i.e., the encoding variability account). In contrast, dual-process theory argues that old items are more variable because they are influenced by both recollection and familiarity, whereas recognition of new items relies primarily on familiarity. The present study shows that increasing encoding variability did not increase old item variance and that old item variance is directly related to the contribution of recollection. These results indicate that old item memory variability is due to the relative contribution of recollection and familiarity.
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Affiliation(s)
- Joshua D Koen
- Department of Psychology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
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12
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Abstract
Neuroaesthetics is gaining momentum. At this early juncture, it is worth taking stock of where the field is and what lies ahead. Here, I review writings that fall under the rubric of neuroaesthetics. These writings include discussions of the parallel organizational principles of the brain and the intent and practices of artists, the description of informative anecdotes, and the emergence of experimental neuroaesthetics. I then suggest a few areas within neuroaesthetics that might be pursued profitably. Finally, I raise some challenges for the field. These challenges are not unique to neuroaesthetics. As neuroaesthetics comes of age, it might take advantage of the lessons learned from more mature domains of inquiry within cognitive neuroscience.
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Dörfel D, Werner A, Schaefer M, von Kummer R, Karl A. Distinct brain networks in recognition memory share a defined region in the precuneus. Eur J Neurosci 2009; 30:1947-59. [PMID: 19895564 DOI: 10.1111/j.1460-9568.2009.06973.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Current models of recognition memory performance postulate that there are two fundamentally distinct retrieval processes, i.e. recollection and familiarity. This view has been challenged and little is known from human research about the functional connectivity of the brain areas involved in these processes. In our study we used a Remember-Know procedure to assess the functional connectivity of brain regions under recognition memory in 30 healthy adults. Using functional magnetic resonance imaging, we analysed the blood oxygen level-dependent responses during correct Remember, correct Know, correct Rejection and missed responses of the subjects during recognition of non-emotional nouns. One activation cluster was found in the left precuneus associated with both recollection and familiarity answers. To acquire information about the way in which activity in one brain region modulates activity in another brain region in response to the active task, we performed a psychophysiological interaction analysis with the left precuneus as a seed region. This analysis revealed functionally distinct networks of brain areas underlying recollection and familiarity. Furthermore, we discuss the differential involvement of the hippocampus in a recollection network as compared with a familiarity network. In summary, our results further strengthen the assumptions of a dual-process view of recognition memory [e.g. H. Eichenbaum et al. (2007) Annual Review of Neuroscience, 30, 123-152; A.P. Yonelinas (2001) Philosophical Transactions of the Royal Society London B Biological Sciences, 356, 1363-1374] and add empirical findings about the functional interconnectivity of brain regions supporting either recollection or familiarity.
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Affiliation(s)
- Denise Dörfel
- Department of Psychology, Faculty of Science, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
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Lima B, Singer W, Chen NH, Neuenschwander S. Synchronization dynamics in response to plaid stimuli in monkey V1. Cereb Cortex 2009; 20:1556-73. [PMID: 19812238 PMCID: PMC2882822 DOI: 10.1093/cercor/bhp218] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Gamma synchronization has generally been associated with grouping processes in the visual system. Here, we examine in monkey V1 whether gamma oscillations play a functional role in segmenting surfaces of plaid stimuli. Local field potentials (LFPs) and spiking activity were recorded simultaneously from multiple sites in the opercular and calcarine regions while the monkeys were presented with sequences of single and superimposed components of plaid stimuli. In accord with the previous studies, responses to the single components (gratings) exhibited strong and sustained gamma-band oscillations (30–65 Hz). The superposition of the second component, however, led to profound changes in the temporal structure of the responses, characterized by a drastic reduction of gamma oscillations in the spiking activity and systematic shifts to higher frequencies in the LFP (∼10% increase). Comparisons between cerebral hemispheres and across monkeys revealed robust subject-specific spectral signatures. A possible interpretation of our results may be that single gratings induce strong cooperative interactions among populations of cells that share similar response properties, whereas plaids lead to competition. Overall, our results suggest that the functional architecture of the cortex is a major determinant of the neuronal synchronization dynamics in V1.
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Affiliation(s)
- Bruss Lima
- Max-Planck Institute for Brain Research, 60528 Frankfurt am Main, Germany
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Overlapping brain activity between episodic memory encoding and retrieval: roles of the task-positive and task-negative networks. Neuroimage 2009; 49:1045-54. [PMID: 19647800 DOI: 10.1016/j.neuroimage.2009.07.058] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 07/22/2009] [Accepted: 07/23/2009] [Indexed: 11/22/2022] Open
Abstract
The notion that the brain is organized into two complementary networks, one that is task-positive and supports externally-oriented processing, and the other that is task-negative and supports internally-oriented processing, has recently attracted increasing attention. The goal of the present study was to investigate involvement of the task-positive and task-negative networks in overlapping activity between episodic memory encoding and retrieval. To this end, we performed a functional MRI study that included both encoding and retrieval tasks. We hypothesized that during the study phase, encoding success activity (remembered > forgotten) involves mainly the task-positive network, whereas encoding failure activity (forgotten > remembered) involves mainly the task-negative network. We also hypothesized that during the test phase, retrieval success activity (old > new) involves mainly the task-negative network, whereas novelty detection activity (new > old) involves mainly the task-positive network. Based on these hypotheses, we made 3 predictions regarding study-test overlap. First, there would be relatively high level of overlap between encoding success and novelty detection activity involving the task-positive network. Second, there would be relatively high level of overlap between encoding failure and retrieval success activity involving the task-negative network. Third, there would be relatively low level of overlap between encoding success and retrieval success activity as well as between encoding failure and novelty detection activity. The results fully confirmed our 3 predictions. Taken together, the present findings clarify roles of the task-positive and task-negative networks in encoding and retrieval and the function of overlapping brain activity between encoding and retrieval.
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