1
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Ambrus GG. Shared neural codes of recognition memory. Sci Rep 2024; 14:15846. [PMID: 38982142 PMCID: PMC11233521 DOI: 10.1038/s41598-024-66158-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 06/27/2024] [Indexed: 07/11/2024] Open
Abstract
Recognition memory research has identified several electrophysiological indicators of successful memory retrieval, known as old-new effects. These effects have been observed in different sensory domains using various stimulus types, but little attention has been given to their similarity or distinctiveness and the underlying processes they may share. Here, a data-driven approach was taken to investigate the temporal evolution of shared information content between different memory conditions using openly available EEG data from healthy human participants of both sexes, taken from six experiments. A test dataset involving personally highly familiar and unfamiliar faces was used. The results show that neural signals of recognition memory for face stimuli were highly generalized starting from around 200 ms following stimulus onset. When training was performed on non-face datasets, an early (around 200-300 ms) to late (post-400 ms) differentiation was observed over most regions of interest. Successful cross-classification for non-face stimuli (music and object/scene associations) was most pronounced in late period. Additionally, a striking dissociation was observed between familiar and remembered objects, with shared signals present only in the late window for correctly remembered objects, while cross-classification for familiar objects was successful in the early period as well. These findings suggest that late neural signals of memory retrieval generalize across sensory modalities and stimulus types, and the dissociation between familiar and remembered objects may provide insight into the underlying processes.
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Affiliation(s)
- Géza Gergely Ambrus
- Department of Psychology, Bournemouth University, Poole House, Talbot Campus, Fern Barrow, Poole, Dorset, BH12 5BB, UK.
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2
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Klink H, Kaiser D, Stecher R, Ambrus GG, Kovács G. Your place or mine? The neural dynamics of personally familiar scene recognition suggests category independent familiarity encoding. Cereb Cortex 2023; 33:11634-11645. [PMID: 37885126 DOI: 10.1093/cercor/bhad397] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/29/2023] [Accepted: 09/30/2023] [Indexed: 10/28/2023] Open
Abstract
Recognizing a stimulus as familiar is an important capacity in our everyday life. Recent investigation of visual processes has led to important insights into the nature of the neural representations of familiarity for human faces. Still, little is known about how familiarity affects the neural dynamics of non-face stimulus processing. Here we report the results of an EEG study, examining the representational dynamics of personally familiar scenes. Participants viewed highly variable images of their own apartments and unfamiliar ones, as well as personally familiar and unfamiliar faces. Multivariate pattern analyses were used to examine the time course of differential processing of familiar and unfamiliar stimuli. Time-resolved classification revealed that familiarity is decodable from the EEG data similarly for scenes and faces. The temporal dynamics showed delayed onsets and peaks for scenes as compared to faces. Familiarity information, starting at 200 ms, generalized across stimulus categories and led to a robust familiarity effect. In addition, familiarity enhanced category representations in early (250-300 ms) and later (>400 ms) processing stages. Our results extend previous face familiarity results to another stimulus category and suggest that familiarity as a construct can be understood as a general, stimulus-independent processing step during recognition.
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Affiliation(s)
- Hannah Klink
- Department of Neurology, Universitätsklinikum, Kastanienstraße1 Jena, D-07747 Jena, Thüringen, Germany
- Department of Biological Psychology and Cognitive Neurosciences, Institute of Psychology, Friedrich Schiller University Jena, Leutragraben 1, D-07743 Jena, Thüringen, Germany
| | - Daniel Kaiser
- Mathematical Institute, Department of Mathematics and Computer Science, Physics, Geography, Justus-Liebig-University Gießen, Arndtstraße 2, D-35392 Gießen, Hessen, Germany
- Center for Mind, Brain and Behavior (CMBB), Justus-Liebig-University Gießen and Philipps-University Marburg, Hans-Meerwein-Straße 6 Mehrzweckgeb, 03C022, Marburg, D-35032, Hessen, Germany
| | - Rico Stecher
- Mathematical Institute, Department of Mathematics and Computer Science, Physics, Geography, Justus-Liebig-University Gießen, Arndtstraße 2, D-35392 Gießen, Hessen, Germany
| | - Géza G Ambrus
- Department of Psychology, Bournemouth University, Poole House P319, Talbot Campus, Fern Barrow, Poole, Dorset BH12 5BB, United Kingdom
| | - Gyula Kovács
- Department of Biological Psychology and Cognitive Neurosciences, Institute of Psychology, Friedrich Schiller University Jena, Leutragraben 1, D-07743 Jena, Thüringen, Germany
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3
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Yan X, Volfart A, Rossion B. A neural marker of the human face identity familiarity effect. Sci Rep 2023; 13:16294. [PMID: 37770466 PMCID: PMC10539293 DOI: 10.1038/s41598-023-40852-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 08/16/2023] [Indexed: 09/30/2023] Open
Abstract
Human adults associate different views of an identity much better for familiar than for unfamiliar faces. However, a robust and consistent neural index of this behavioral face identity familiarity effect (FIFE)-not found in non-human primate species-is lacking. Here we provide such a neural FIFE index, measured implicitly and with one fixation per face. Fourteen participants viewed 70 s stimulation sequences of a large set (n = 40) of widely variable natural images of a face identity at a rate of 6 images/second (6 Hz). Different face identities appeared every 5th image (1.2 Hz). In a sequence, face images were either familiar (i.e., famous) or unfamiliar, participants performing a non-periodic task unrelated to face recognition. The face identity recognition response identified at 1.2 Hz over occipital-temporal regions in the frequency-domain electroencephalogram was 3.4 times larger for familiar than unfamiliar faces. The neural response to familiar faces-which emerged at about 180 ms following face onset-was significant in each individual but a case of prosopdysgnosia. Besides potential clinical and forensic applications to implicitly measure one's knowledge of a face identity, these findings open new perspectives to clarify the neurofunctional source of the FIFE and understand the nature of human face identity recognition.
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Affiliation(s)
- Xiaoqian Yan
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, 200433, China
- Université de Lorraine, CNRS, 54000, Nancy, France
- Psychological Sciences Research Institute, Université Catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
| | - Angélique Volfart
- Université de Lorraine, CNRS, 54000, Nancy, France
- Psychological Sciences Research Institute, Université Catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
- Faculty of Health, School of Psychology and Counselling, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Bruno Rossion
- Université de Lorraine, CNRS, 54000, Nancy, France.
- Psychological Sciences Research Institute, Université Catholique de Louvain, 1348, Louvain-la-Neuve, Belgium.
- Université de Lorraine, CHRU-Nancy, Service de Neurologie, 54000, Nancy, France.
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4
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Kovács G, Li C, Ambrus GG, Burton AM. The neural dynamics of familiarity-dependent face identity representation. Psychophysiology 2023; 60:e14304. [PMID: 37009756 DOI: 10.1111/psyp.14304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 03/20/2023] [Accepted: 03/20/2023] [Indexed: 04/04/2023]
Abstract
Recognizing a face as belonging to a given identity is essential in our everyday life. Clearly, the correct identification of a face is only possible for familiar people, but 'familiarity' covers a wide range-from people we see every day to those we barely know. Although several studies have shown that the processing of familiar and unfamiliar faces is substantially different, little is known about how the degree of familiarity affects the neural dynamics of face identity processing. Here, we report the results of a multivariate EEG analysis, examining the representational dynamics of face identity across several familiarity levels. Participants viewed highly variable face images of 20 identities, including the participants' own face, personally familiar (PF), celebrity and unfamiliar faces. Linear discriminant classifiers were trained and tested on EEG patterns to discriminate pairs of identities of the same familiarity level. Time-resolved classification revealed that the neural representations of identity discrimination emerge around 100 ms post-stimulus onset, relatively independently of familiarity level. In contrast, identity decoding between 200 and 400 ms is determined to a large extent by familiarity: it can be recovered with higher accuracy and for a longer duration in the case of more familiar faces. In addition, we found no increased discriminability for faces of PF persons compared to those of highly familiar celebrities. One's own face benefits from processing advantages only in a relatively late time-window. Our findings provide new insights into how the brain represents face identity with various degrees of familiarity and show that the degree of familiarity modulates the available identity-specific information at a relatively early time window.
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Affiliation(s)
- Gyula Kovács
- Department of Biological Psychology and Cognitive Neurosciences, Institute of Psychology, Friedrich-Schiller-Universität Jena, Jena, Germany
| | - Chenglin Li
- Department of Biological Psychology and Cognitive Neurosciences, Institute of Psychology, Friedrich-Schiller-Universität Jena, Jena, Germany
- School of Psychology, Zhejiang Normal University, Jinhua, China
| | - Géza Gergely Ambrus
- Department of Psychology, Faculty of Science and Technology, Bournemouth University, Poole, UK
| | - A Mike Burton
- Department of Psychology, University of York, York, UK
- Faculty of Society and Design, Bond University, Gold Coast, Qld, Australia
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Popova T, Wiese H. Developing familiarity during the first eight months of knowing a person: A longitudinal EEG study on face and identity learning. Cortex 2023; 165:26-37. [PMID: 37245406 DOI: 10.1016/j.cortex.2023.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 02/03/2023] [Accepted: 04/23/2023] [Indexed: 05/30/2023]
Abstract
It is well-established that familiar and unfamiliar faces are processed differently, but surprisingly little is known about how familiarity builds up over time and how novel faces gradually become represented in the brain. Here, we used event-related brain potentials (ERPs) in a pre-registered, longitudinal study to examine the neural processes accompanying face and identity learning during the first eight months of knowing a person. Specifically, we examined how increasing real-life familiarity affects visual recognition (N250 Familiarity Effect) and the integration of person-related knowledge (Sustained Familiarity Effect, SFE). Sixteen first-year undergraduates were tested in three sessions, approximately one, five, and eight months after the start of the academic year, with highly variable "ambient" images of a new friend they had met at university and of an unfamiliar person. We observed clear ERP familiarity effects for the new friend after one month of familiarity. While there was an increase in the N250 effect over the course of the study, no change in the SFE was observed. These results suggest that visual face representations develop faster relative to the integration of identity-specific knowledge.
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Baker KA, Mondloch CJ. Unfamiliar face matching ability predicts the slope of face learning. Sci Rep 2023; 13:5248. [PMID: 37002382 PMCID: PMC10066355 DOI: 10.1038/s41598-023-32244-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/23/2023] [Indexed: 04/03/2023] Open
Abstract
We provide the first examination of individual differences in the efficiency of face learning. Investigating individual differences in face learning can illuminate potential mechanisms and provide greater understanding of why certain individuals might be more efficient face learners. Participants completed two unfamiliar face matching tasks and a learning task in which learning was assessed after viewing 1, 3, 6, and 9 images of to-be-learned identities. Individual differences in the slope of face learning (i.e., increases in sensitivity to identity) were predicted by the ability to discriminate between matched (same-identity) vs. mismatched (different-identity) pairs of wholly unfamiliar faces. A Dual Process Signal Detection model showed that three parameters increased with learning: Familiarity (an unconscious type of memory that varies in strength), recollection-old (conscious recognition of a learned identity), and recollection-new (conscious/confident rejection of novel identities). Good (vs. poor) matchers had higher Recollection-Old scores throughout learning and showed a steeper increase in Recollection-New. We conclude that good matchers are better able to capitalize on exposure to within-person variability in appearance, an effect that is attributable to their conscious memory for both learned and novel faces. These results have applied implications and will inform contemporary and traditional models of face identification.
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Affiliation(s)
- Kristen A Baker
- Department of Psychology, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON, L2S 3A1, Canada.
| | - Catherine J Mondloch
- Department of Psychology, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON, L2S 3A1, Canada
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How quickly do we learn new faces in everyday life? Neurophysiological evidence for face identity learning after a brief real-life encounter. Cortex 2023; 159:205-216. [PMID: 36640620 DOI: 10.1016/j.cortex.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/25/2022] [Accepted: 12/07/2022] [Indexed: 12/28/2022]
Abstract
Faces learnt in a single experimental session elicit a familiarity effect in event-related brain potentials (ERPs), with more negative amplitudes for newly learnt relative to unfamiliar faces in the N250 component. However, no ERP study has examined face learning following a brief real-life encounter, and it is not clear how long it takes to learn new faces in such ecologically more valid conditions. To investigate these questions, the present study examined whether robust image-independent representations, as reflected in the N250 familiarity effect, could be established after a brief unconstrained social interaction by analysing the ERPs elicited by highly variable images of the newly learnt identity and an unfamiliar person. Significant N250 familiarity effects were observed after a 30-min (Experiment 1) and a 10-min (Experiment 2) encounter, and a trend was observed after 5 min of learning (Experiment 3), demonstrating that 5-10 min of exposure were sufficient for the initial establishment of image-independent representations. Additionally, the magnitude of the effects reported after 10 and 30 min was comparable suggesting that the first 10 min of a social encounter might be crucial, with extra 20 min from the same encounter not adding further benefit for the initial formation of robust face representations.
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Dalski A, Kovács G, Ambrus GG. No semantic information is necessary to evoke general neural signatures of face familiarity: evidence from cross-experiment classification. Brain Struct Funct 2023; 228:449-462. [PMID: 36244002 PMCID: PMC9944719 DOI: 10.1007/s00429-022-02583-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 10/09/2022] [Indexed: 11/28/2022]
Abstract
Recent theories on the neural correlates of face identification stressed the importance of the available identity-specific semantic and affective information. However, whether such information is essential for the emergence of neural signal of familiarity has not yet been studied in detail. Here, we explored the shared representation of face familiarity between perceptually and personally familiarized identities. We applied a cross-experiment multivariate pattern classification analysis (MVPA), to test if EEG patterns for passive viewing of personally familiar and unfamiliar faces are useful in decoding familiarity in a matching task where familiarity was attained thorough a short perceptual task. Importantly, no additional semantic, contextual, or affective information was provided for the familiarized identities during perceptual familiarization. Although the two datasets originate from different sets of participants who were engaged in two different tasks, familiarity was still decodable in the sorted, same-identity matching trials. This finding indicates that the visual processing of the faces of personally familiar and purely perceptually familiarized identities involve similar mechanisms, leading to cross-classifiable neural patterns.
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Affiliation(s)
- Alexia Dalski
- Department of Psychology, Philipps-Universität Marburg, 35039 Marburg, Germany ,Center for Mind, Brain and Behavior – CMBB, Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, 35039 Marburg, Germany
| | - Gyula Kovács
- Institute of Psychology, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Géza Gergely Ambrus
- Institute of Psychology, Friedrich Schiller University Jena, 07743, Jena, Germany. .,Department of Psychology, Bournemouth University, Poole House, Talbot Campus, Fern Barrow, Poole, BH12 5BB, Dorset, UK.
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