DOCSLIB.ORG

A Thesis Submitted for the Degree of Doctor of Philosophy at the University of Queensland in 2019 School of Psychology

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Thesis Submitted for the Degree of Doctor of Philosophy at the University of Queensland in 2019 School of Psychology The Causal Neural Substrates of Statistical Learning Abbey S. Nydam Bachelor of Psychological Science (Hons 1) A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland in 2019 School of Psychology Abstract Although humans often struggle to make rational decisions based on probability, there are types of information processing that appear highly sensitive to statistics. In fact, the human brain can extract information about complex statistical probabilities present in the environment through an automatic statistical learning process. Statistical learning is the primary way that human infants, with no developed frontal cortex or reasoing skills, can learn the complexities of language and grammar. As adults, statistical learning enables us to benefit from the many repetitive and predictable elements of our sensory environment, such as visual scenes or event sequences. Statistical knowledge is often implicit, but it can be used by the explicit system to facilitate other cognitive processes; such as decision-making, skill learning, and social capabilities. The reach of statistical learning across the cognitive landscape is broad, and this brings into question the nature of the neural substrates that govern this process. Neuroscientific research supports there being a critical role of the hippocampus, as it relates to long-term memory. But neuroimaging work suggests a role of higher-level cortical regions, within the frontal and parietal cortices. These areas are more commonly associated with explicit executive functions, and less so for implicit learning abilities. Recent advances in non-invasive brain stimulation allow is to directly control cortical brain acitvity in order to unearth causal relationships between the brain and behaviour. To date, there is little causal evidence regarding the neural substrates of statistical learning outside the hippocampus. In this thesis, I investigate how the direct manipulation of local activity in cortical brain regions is related to the incidental statistical learning process. Chapter 2 examines task parametres that produce the most robust statistical learning behaviour using a well-known contextual cuing paradigm (Chun & Jiang, 1998). In this task, observers search through visual scenes containing statistical regularities. They typically have around 2000 ms to scan the displays. To investigate the speed of statistical processing, I briefly flashed displays for only 300ms and controlled further processing with backward masking. In a series of experiments, I found that learning could occur with briefly presented displays, but only for a reduced amount of information. These findings illustrate an efficient learning mechanism that can operate rapidly, but may be capacity limited at these speeds. In Chapter 3 I report a large-scale tDCS study (n = 120) investigating the causal relationship between cortical activity and statistical learning. I compare bidirectional currents (i.e., anodal and cathodal) and two active brain regions (i.e., left prefrontal cortex and left ii posterior parietal cortex) to a sham stimulation condition - a placebo control. The contextual cuing task was used to tap the statistical learning process, and the stimulation was delivered online, during exposure to regularities. Cathodal currents selectively affected learning, compared to sham and anodal currentsm and this was for both the frontal and pareital target regions. Specifically, cathodal stimulation disrupted the early cuing benefit, suggesting that stimulation delayed learning or the effects of learning on behaviour, but did not abolish it altogether. The effect was not explained by a general change in response times, a change in awareness or a speed/accuracy tradeoff. Instead, the impact of tDCS on performance was specific to the learning effect over time. This revealed a causal link between activity in frontoparietal areas and the evolution of statistical learning in this task. Chapter 4 investigates the causal relationship using a different task believed to tap the same underlying process. Known as Visual Statistical Learning (Fiser & Aslin, 2001), this paradigm involves passive visual exposure to shapes with embeded probabilities, and learning is measured offline, in a recognition test after exposure. I focus on the cathodal effect, and compare stimulation of two brain regions (i.e., left posterior parietal cortex and left orbitofrontal cortex) to sham. Using the offline measure, I found no effect of stimulation (Experiment 1). This was despite having a large sample (n = 150) and observing robust learning at test. In Experiment 2, I develop an online measure of learning to investigate effects of stimulation that may be dynamic across time. Using a double-blind, pre-registerred design, I compare active (cathodal) stimulation to sham (n = 80) and observe that tDCS did influence statistical learning. As with chapter 3, the effect was selective to the early time- window. These findings provide converging evidence on the intervening role that cortical brain areas play in a visual statistical learning process. The empiricle studies provide novel insights into the causal relationship that cortical areas have in producing statistical learning behaviours. The observation of direct cortical involvement has implications for theoretical accounts of statistical learning; and is consistent with the idea that statistical learning should be operationalised as a principal of processing similar to the Bayesian brain hypothesis. The work presented in this thesis broadens our understanding of the neural substrates that support implicit learning abilities, particularly those that involve extracting regularities from the visual scene and using them for implicit prediction. iii Declaration by author This thesis is composed of my original work, and contains no material previously published or written by another person except where due reference has been made in the text. I have clearly stated the contribution by others to jointly-authored works that I have included in my thesis. I have clearly stated the contribution of others to my thesis as a whole, including statistical assistance, survey design, data analysis, significant technical procedures, professional editorial advice, financial support and any other original research work used or reported in my thesis. The content of my thesis is the result of work I have carried out since the commencement of my higher degree by research candidature and does not include a substantial part of work that has been submitted to qualify for the award of any other degree or diploma in any university or other tertiary institution. I have clearly stated which parts of my thesis, if any, have been submitted to qualify for another award. I acknowledge that an electronic copy of my thesis must be lodged with the University Library and, subject to the policy and procedures of The University of Queensland, the thesis be made available for research and study in accordance with the Copyright Act 1968 unless a period of embargo has been approved by the Dean of the Graduate School. I acknowledge that copyright of all material contained in my thesis resides with the copyright holder(s) of that material. Where appropriate I have obtained copyright permission from the copyright holder to reproduce material in this thesis and have sought permission from co-authors for any jointly authored works included in the thesis. iv Publications included in this thesis Nydam, A, S., Sewell., D. S., & Dux, P. E. (2018). Cathodal Electrical Stimulation of Frontoparietal Cortex Disrupts Statistical Learning of Visual Configural Information. Cortex. 10.1016/j.cortex.2017.11.008. Submitted manuscripts included in this thesis Nydam, A, S., Sewell., D. S., & Dux, P. E. (Submitted). The Speed of Processing Contextual Regularities for Learning. Nydam, A, S., Sewell., D. S., & Dux, P. E. (Submitted). Cortical Involvement in Visual Statistical Learning with Identity Structure. Other publications during candidature Peer-Reviewed Papers Sale, M. V., Nydam, A. S., & Mattingley, J. B. (2017). Stimulus Uncertainty Enhances Long- term Potentiation-like Plasticity in Human Motor Cortex. Cortex, 88, 32–41. Kamke, M. R., Nydam, A. S., Sale, M. V., & Mattingley, J. B. (2016). Associative Plasticity in the Human Motor Cortex is Enhanced by Concurrently Targeting Separate Muscle Representations with Excitatory and Inhibitory Protocols. Journal of Neurophysiology, 115(4), 2191–2198. v Conference Abstracts Nydam, A. S., Sewell, D. S., & Dux, P. E. (Nov 2018). Cortical Involvement in Visual Statistical Learning of Shape Identities. Australian Cognitive Neuroscience Society Conference, Melbourne, Australia. Nydam, A. S., Sewell, D.S., & Dux, P. E. (Aug 2017). Cathodal electrical stimulation disrupts incidental learning of visual configural information. International Conference on Cognitive Neuroscience (ICON), Amsterdam, Netherlands. Nydam, A. S., Sewell, D. S., & Dux, P. E. (Sep 2017). Cathodal electrical stimulation disrupts incidental learning of visual configural information, Science of Learning Research Centre Conference, Brisbane, Australia. Nydam, A. S., Sewell, D. S., & Dux, P. E. (Jul 2017). Cathodal electrical stimulation disrupts incidental learning of visual configural information. Model-based Neuroscience Summer School, Amsterdam, Netherlands. Nydam, A. S., Sewell, D. S., & Dux, P. E. (Nov 2016). Statistical Learning of Irrelevant Visual Information is Disrupted by Electrical Stimulation of Frontoparietal
Load more

Recommended publications
  • Limitations of Perceptual Segmentation on Contextual Cueing in Visual Search
    VISUAL COGNITION, 2011, 19 (2), 203Á233 Limitations of perceptual segmentation on contextual cueing in visual search Markus Conci1 and Adrian von Mu¨hlenen2 1Department Psychologie, Ludwig-Maximilians Universita¨tMu¨nchen, Mu¨nchen, Germany 2Department of Psychology, University of Warwick, Warwick, UK In visual search, detection of a target in a repeated layout is faster than search within a novel arrangement, demonstrating that contextual invariances can implicitly guide attention to the target location (‘‘contextual cueing’’; Chun & Jiang, 1998). Here, we investigated how display segmentation processes influence contextual cueing. Seven experiments showed that grouping by colour and by size can considerably reduce contextual cueing. However, selectively attending to a relevant subgroup of items (that contains the target) preserved context-based learning effects. Finally, the reduction of contextual cueing by means of grouping affected both the latent learning and the recall of display layouts. In sum, all experiments show an influence of grouping on contextual cueing. This influence is larger for variations of spatial (as compared to surface) features and is consistent with the view that learning of contextual relations critically interferes with processes that segment a display into segregated groups of items. Keywords: Contextual cueing; Implicit learning; Perceptual grouping; Visual search. Complex, natural environments require the visual system to focus only on Downloaded By: [Bayerische Staatsbibliothek] At: 09:25 9 February 2011 goal-relevant aspects of a scene while suppressing irrelevant information. Therefore, attention is concerned with selecting only a subset of significant Please address all correspondence to Markus Conci, Allgemeine und Experimentelle Psychologie, Department Psychologie, Ludwig-Maximilians Universita¨t, Leopoldstr. 13, D-80802 Mu¨nchen, Germany.
    [Show full text]
  • Sleep-Effects on Implicit and Explicit Memory in Repeated Visual Search
    Sleep-Effects on Implicit and Explicit Memory in Repeated Visual Search Thomas Geyer1*., Hermann J. Mueller1,2., Leonardo Assumpcao2, Steffen Gais1 1 Department Psychologie, Ludwig-Maximilians-Universita¨t, Mu¨nchen, Germany, 2 Department of Psychological Sciences, Birkbeck College, University of London, London, United Kingdom Abstract In repeated visual search tasks, facilitation of reaction times (RTs) due to repetition of the spatial arrangement of items occurs independently of RT facilitation due to improvements in general task performance. Whereas the latter represents typical procedural learning, the former is a kind of implicit memory that depends on the medial temporal lobe (MTL) memory system and is impaired in patients with amnesia. A third type of memory that develops during visual search is the observers’ explicit knowledge of repeated displays. Here, we used a visual search task to investigate whether procedural memory, implicit contextual cueing, and explicit knowledge of repeated configurations, which all arise independently from the same set of stimuli, are influenced by sleep. Observers participated in two experimental sessions, separated by either a nap or a controlled rest period. In each of the two sessions, they performed a visual search task in combination with an explicit recognition task. We found that (1) across sessions, MTL-independent procedural learning was more pronounced for the nap than rest group. This confirms earlier findings, albeit from different motor and perceptual tasks, showing that procedural memory can benefit from sleep. (2) Likewise, the sleep group compared with the rest group showed enhanced context-dependent configural learning in the second session. This is a novel finding, indicating that the MTL-dependent, implicit memory underlying contextual cueing is also sleep-dependent.
    [Show full text]
  • University of Groningen the Long and the Short of Priming in Visual Search
    University of Groningen The long and the short of priming in visual search Kruijne, Wouter; Meeter, Martijn Published in: Attention, Perception & Psychophysics DOI: 10.3758/s13414-015-0860-2 IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2015 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Kruijne, W., & Meeter, M. (2015). The long and the short of priming in visual search. Attention, Perception & Psychophysics, 77(5), 1558-1573. https://doi.org/10.3758/s13414-015-0860-2 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license. More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne- amendment. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum.
    [Show full text]
  • Darby, K. P., Burling, J. M., & Yoshida, H. (2014)
    Cognitive Development 29 (2014) 17–29 Contents lists available at ScienceDirect Cognitive Development The role of search speed in the contextual cueing of children’s attention a,1 b,1 b, Kevin P. Darby , Joseph M. Burling , Hanako Yoshida ∗ a Department of Psychology, The Ohio State University, 267 Psychology Building, 1835 Neil Avenue, Columbus, OH 43210, United States b Department of Psychology, University of Houston, 126 Heyne Building, Houston, TX 77204, United States a r t i c l e i n f o a b s t r a c t Keywords: The contextual cueing effect is a robust phenomenon in which Contextual cueing repeated exposure to the same arrangement of random elements Memory development guides attention to relevant information by constraining search. Attentional learning The effect is measured using an object search task in which a target Visual search task (e.g., the letter T) is located within repeated or nonrepeated visual contexts (e.g., configurations of the letter L). Decreasing response times for the repeated configurations indicates that contextual information has facilitated search. Although the effect is robust among adult participants, recent attempts to document the effect in children have yielded mixed results. We examined the effect of search speed on contextual cueing with school-aged children, com- paring three types of stimuli that promote different search times in order to observe how speed modulates this effect. Reliable effects of search time were found, suggesting that visual search speed uniquely constrains the role of attention toward contextually cued information. Published by Elsevier Inc. 1. Introduction Knowing where to look for relevant information in a cluttered visual environment is crucial to mak- ing rapid responses and learning from that information.
    [Show full text]
  • Eye-Tracking Contribute to Contextual Cueing: Evidence from Fmri And
    Downloaded from learnmem.cshlp.org on October 24, 2012 - Published by Cold Spring Harbor Laboratory Press Procedural learning and associative memory mechanisms contribute to contextual cueing: Evidence from fMRI and eye-tracking Anna Manelis and Lynne M. Reder Learn. Mem. 2012 19: 527-534 Access the most recent version at doi:10.1101/lm.025973.112 References This article cites 50 articles, 9 of which can be accessed free at: http://learnmem.cshlp.org/content/19/11/527.full.html#ref-list-1 Email alerting Receive free email alerts when new articles cite this article - sign up in the box at the service top right corner of the article or click here To subscribe to Learning & Memory go to: http://learnmem.cshlp.org/subscriptions © 2012 Cold Spring Harbor Laboratory Press Downloaded from learnmem.cshlp.org on October 24, 2012 - Published by Cold Spring Harbor Laboratory Press Research Procedural learning and associative memory mechanisms contribute to contextual cueing: Evidence from fMRI and eye-tracking Anna Manelis1,2,3 and Lynne M. Reder1,2 1Department of Psychology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA; 2The Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA Using a combination of eye tracking and fMRI in a contextual cueing task, we explored the mechanisms underlying the facilitation of visual search for repeated spatial configurations. When configurations of distractors were repeated, greater activation in the right hippocampus corresponded to greater reductions in the number of saccades to locate the target. A psychophysiological interactions analysis for repeated configurations revealed that a strong functional connectiv- ity between this area in the right hippocampus and the left superior parietal lobule early in learning was significantly reduced toward the end of the task.
    [Show full text]
  • Awareness in Contextual Cueing of Visual Search As Measured with Concurrent Access- and Phenomenal- Consciousness Tasks
    Journal of Vision (2012) 12(11):25, 1–12 http://www.journalofvision.org/content/12/11/25 1 Awareness in contextual cueing of visual search as measured with concurrent access- and phenomenal- consciousness tasks Department Psychologie, Ludwig-Maximilians-Universita¨tMu¨nchen, Bernhard Schlagbauer Mu¨nchen, Germany $ Department Psychologie, Ludwig-Maximilians-Universita¨tMu¨nchen, Mu¨nchen, Germany School of Psychology, Birkbeck College, # Hermann J. Muller¨ University of London, UK $ Department Psychologie, Ludwig-Maximilians-Universita¨tMu¨nchen, # Michael Zehetleitner Mu¨nchen, Germany $ Department Psychologie, Ludwig-Maximilians-Universita¨tMu¨nchen, # Thomas Geyer Mu¨nchen, Germany $ In visual search, context information can serve as a cue to guide attention to the target location. When observers repeatedly encounter displays with identical target-distractor arrangements, reaction times (RTs) are faster for repeated relative to nonrepeated displays, the latter containing novel configurations. This effect has been termed ‘‘contextual cueing.’’ The present study asked whether information about the target location in repeated displays is ‘‘explicit’’ (or ‘‘conscious’’)in nature. To examine this issue, observers performed a test session (after an initial training phase in which RTs to repeated and nonrepeated displays were measured) in which the search stimuli were presented briefly and terminated by visual masks; following this, observers had to make a target localization response (with accuracy as the dependent measure) and indicate
    [Show full text]
  • Bi-Directional Relationship Between Attention and Long-Term Context Memory
    Bi-directional relationship between attention and long-term context memory Efsun Annaç Dissertation der Graduate School of Systemic Neurosciences der Ludwig-Maximilians-Universität München München th 30 of October 2017 Disputation date: 18th of April 2018 Thesis Advisory Committee: Prof. Dr. Thomas Geyer (1st Supervisor) Prof. Dr. Hermann J. Müller (2nd Supervisor) Prof. Dr. Stefan Pollmann (External Supervisor) Exanimation Committee: Prof. Dr. Thomas Geyer (Supervisor and 1st reviewer) Dr. Virginia L. Flanagin (2nd reviewer) Prof. Dr. Melissa Le-Hoa Võ (3rd reviewer) Prof. Dr. Hermann J. Müller PD Dr. Markus Conci Prof. Dr. Paul C. J. Taylor ~ 2 ~ Table of contents Table of contents ......................................................................................................................... 3 Acknowledgements ..................................................................................................................... 7 Summary ...................................................................................................................................... 8 1. Chapter 1: General Introduction ............................................................................................ 11 1.1 Visual attention .................................................................................................................... 13 1.2 Context-based guidance of visual search: contextual cueing paradigm .............................. 16 1.3 The influence of spatial factors on the adaptation of contextual cueing ............................
    [Show full text]
  • The Long and the Short of Priming in Visual Search
    Atten Percept Psychophys DOI 10.3758/s13414-015-0860-2 The long and the short of priming in visual search Wouter Kruijne · Martijn Meeter © The Author(s) 2015. This article is published with open access at Springerlink.com Abstract Memory affects visual search, as is particularly Introduction evident from findings that when target features are repeated from one trial to the next, selection is faster. Two views A powerful factor determining where we look and what have emerged on the nature of the memory representations we attend is where we have looked and what we have and mechanisms that cause these intertrial priming effects: attended before. The effects of our previous overt and covert independent feature weighting versus episodic retrieval of shifts of attention on our current ones are often investi- previous trials. Previous research has attempted to disen- gated by comparing visual search in which targets must tangle these views focusing on short term effects. Here, be found with either the same features as on previous tri- we illustrate that the episodic retrieval models make the als, or with different features. When compared to feature unique prediction of long-term priming: biasing one target switch trials, feature repetitions have been found to shorten type will result in priming of this target type for a much response times (RT) and decrease the amount of errors longer time, well after the bias has disappeared. We demon- (Maljkovic and Nakayama, 1994). In addition, repetitions strate that such long-term priming is indeed found for the cause shorter saccade latencies (Becker, 2008; McPeek et visual feature of color, but only in conjunction search and al., 1999) and bias target selection (Brascamp et al., 2011a; not in singleton search.
    [Show full text]
  • Neural Correlates of Contextual Cueing Are Modulated by Explicit Learning
    G Model NSY-4235; No. of Pages 9 ARTICLE IN PRESS Neuropsychologia xxx (2011) xxx–xxx Contents lists available at SciVerse ScienceDirect Neuropsychologia jo urnal homepage: www.elsevier.com/locate/neuropsychologia Neural correlates of contextual cueing are modulated by explicit learning a,∗ a a b a Carmen E. Westerberg , Brennan B. Miller , Paul J. Reber , Neal J. Cohen , Ken A. Paller a Department of Psychology, Northwestern University, United States b Department of Psychology, Beckman Institute, University of Illinois at Urbana-Champaign, United States a r t i c l e i n f o a b s t r a c t Article history: Contextual cueing refers to the facilitated ability to locate a particular visual element in a scene due to Received 7 January 2011 prior exposure to the same scene. This facilitation is thought to reflect implicit learning, as it typically Received in revised form 15 August 2011 occurs without the observer’s knowledge that scenes repeat. Unlike most other implicit learning effects, Accepted 19 August 2011 contextual cueing can be impaired following damage to the medial temporal lobe. Here we investigated Available online xxx neural correlates of contextual cueing and explicit scene memory in two participant groups. Only one group was explicitly instructed about scene repetition. Participants viewed a sequence of complex scenes Keywords: that depicted a landscape with five abstract geometric objects. Superimposed on each object was a letter Visual scene perception ◦ fMRI T or L rotated left or right by 90 . Participants responded according to the target letter (T) orientation. Responses were highly accurate for all scenes.
    [Show full text]
  • November 15, 2018 New Orleans, LA
    November 15, 2018 New Orleans, LA 2018 Organizers Caitlin Mullin Briana Kennedy Steve Walenchok Yelda Semizer 2018 Keynote Address Wei Ji Ma, PhD Associate Professor of Neural Science & Psychology, New York University Ma Lab | New York University Meyer Hall | 4 Washington Place | New York, NY 10003 The talk will consist of two parts: a scientific part and a Growing up in Science part. Models of "simple" visual search Visual search is an important task in daily life and arguably has been across evolution. Celebrated models of visual search include those of Anne Treisman and Jeremy Wolfe. In a lesser-known approach, spearheaded by the likes of John Palmer, Preeti Verghese, and Miguel Eckstein, stimuli are kept as simple as possible and search displays are brought under tight experimental control. While this reductionist approach lacks in naturalness, it has the advantage of allowing for precise mathematical models in the tradition of signal detection theory, which can be used to disentangle encoding and decision stages. I will describe a series of studies from my lab in which we use this approach to examine: 1) set size effects on encoding precision; 2) the optimality or suboptimality of decision rules. I hope to convince you that such combinations of a simplified experimental paradigm and rigorous modeling fill an important niche in the study of visual search. Growing up in science: Wei Ji Ma's unofficial story More information about the "Growing up in science" mentorship concept: www.growingupinscience.com Official story Weiji received his Ph.D. in Physics from the University of Groningen, the Netherlands.
    [Show full text]
  • Context Processing and Aging: Older Adults’ Ability to Learn And
    CONTEXT PROCESSING AND AGING: OLDER ADULTS’ ABILITY TO LEARN AND UTILIZE VISUAL CONTEXTS A Dissertation Submitted to the Graduate Faculty of the North Dakota State University of Agriculture and Applied Science By Nora Denise Gayzur In Partial Fulfillment for the degree of DOCTOR OF PHILOSOPHY Major Department: Psychology April 2013 Fargo, North Dakota North Dakota State University Graduate School Title Context Processing and Aging: Older Adults’ Ability to Learn and Use Visual Contexts By Nora Denise Gayzur The Supervisory Committee certifies that this disquisition complies with North Dakota State University’s regulations and meets the accepted standards for the degree of DOCTOR OF PHILOSOPHY SUPERVISORY COMMITTEE: Linda K. Langley, PhD. Chair Robert D. Gordon, PhD. Paul Rokke, PhD. Gregory Sanders, PhD. Approved: 5/31/2013 James Council, PhD. Date Department Chair ABSTRACT The purpose of the present study was to examine how older adults utilize contextual information to guide attention in visual scenes. Studies that have examined context and attentional deployment have used the contextual cueing task. Contextual cueing reflects faster responses to repeated spatial configurations (consistent context-target covaration) than random spatial configurations (inconsistent covariation). Research has shown mixed results in older adults’ ability to utilize context with this task. Young (18-23 years) and older (60-85 years) adults were tested in two contextual cuing experiments to assess age differences in how individuals utilize context in novel and real-world visual scenes. Experiment 1 investigated the development of contextual cueing effects using low-meaning visual contexts (letter arrays). In low-meaning arrays, young and older adults were able to use context effeciently with no age differences in the development of contextual cueing effects.
    [Show full text]
  • Memory-Guided Attention: Bilateral Hippocampal Volume Positively
    Brain Structure and Function (2019) 224:1999–2008 https://doi.org/10.1007/s00429-019-01887-9 ORIGINAL ARTICLE Memory-guided attention: bilateral hippocampal volume positively predicts implicit contextual learning Mario A. Rosero1 · Tobias Winkelmann1 · Sebastian Pohlack1 · Juliana Cavalli1 · Frauke Nees1 · Herta Flor1 Received: 30 May 2018 / Accepted: 4 May 2019 / Published online: 18 May 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract Several studies have begun to demonstrate that contextual memories constitute an important mechanism to guide our atten- tion. Although there is general consensus that the hippocampus is involved in the encoding of contextual memories, it is controversial whether this structure can support implicit forms of contextual memory. Here, we combine automated seg- mentation of structural MRI with neurobehavioral assessment of implicit contextual memory-guided attention to test the hypothesis that hippocampal volume would predict the magnitude of implicit contextual learning. Forty healthy subjects underwent 3T magnetic resonance imaging brain scanning with subsequent automatic measurement of the total brain and hippocampal (right and left) volumes. Implicit learning of contextual information was measured using the contextual cue- ing task. We found that both left and right hippocampal volumes positively predicted the magnitude of implicit contextual learning. Larger hippocampal volume was associated with superior implicit contextual memory performance. This study provides compelling evidence that implicit contextual memory-guided attention is hippocampus-dependent. Keywords Hippocampal volume · Contextual memory · Implicit memory · Visual search · Memory-guided attention Introduction In addition to its traditional role in episodic memory and spatial navigation, a substantial body of research in humans Frauke Nees and Herta Flor joint last authors.
    [Show full text]