Visual Cognitive Neuroscience

Abbreviations: MPH, Mean Position of Hits; MPO, Mean Position of Omissions; MPT, Mean Position of Targets; MOH, Mean Ordinal position of Hits; MdnPH, Median Position of Hits; MPP, Mean Position of Positions; LCR-adjusted, Left-Centre-Right-adjusted; C-adjusted, Centre-adjusted (or centred); CoC, Centre of Cancellation; SD, expected Standard Deviation of MPH (unless otherwise stated); BF, Bayes Factor; H, number of Hits; T, number of targets; G, number of target clusters; CTL, Central Theorem of Limits; l, location parameter; s, slope parameter; c, ceiling parameter; FA, False Alarm (on catch trials); CR, Correct Rejections (on catch trials); SPS, Spatial Processing Stages; EP, Extra Processing stages (different from SPS).

Despite the vital role graduate archival education plays in preparing aspiring archivists for practice, we lack empirical evidence concerning its efficacy. This study is based on a survey of 406 students and new professionals (SNPs) (five or fewer years in the field). It addresses the following research question: based on their graduate education, how well prepared for practice are SNPs in North America? To address this question, the authors explore the topics SNPs suggested were most useful, the assignments they found most fruitful, their perceptions of topics lacking adequate coverage, their overall rating of their professional preparation's effectiveness, and the ways in which they thought professional preparation might be improved. Notably, SNPs lauded the payoff of experiential learning. They also foregrounded topics related to the 2016 "Guidelines for a Graduate Program in Archival Studies" (GPAS) clusters Arrangement and Description and Digital Materials Management. SNPs suggested that improved professional preparation could come from augmented course offerings, enriched course content, and most important, more hands-on/practical experience. SNPs were vocationally preoccupied; they showed only modest interest in "archival thinking." The authors juxtapose their findings with both GPAS and A*CENSUS II and suggest that communities of archival practice (COAPs) are a profitable direction for future archival pedagogy.

It is currently unclear whether objects have to be explicitly identified at encoding for reliable behavioral long-term object priming to occur. We conducted two experiments that investigated long-term object and non-object priming using a selective-attention encoding manipulation that reduces explicit object identification. In Experiment 1, participants either counted dots flashed within an object picture (shallow encoding) or engaged in an animacy task (deep encoding) at study, whereas, at test, they performed an object-decision task. Priming, as measured by reaction times (RTs), was observed for both types of encoding, and was of equivalent magnitude. In Experiment 2, non-object priming (faster RTs for studied relative to unstudied non-objects) was also obtained under the same selective-attention encoding manipulation as in Experiment 1, and the magnitude of the priming effect was equivalent between experiments. In contrast, we observed a linear decrement in recognition memory acc...

Humans can effortlessly recognize others' actions in the presence of complex transformations, such as changes in viewpoint. Several studies have located the regions in the brain involved in invariant action recognition, however, the underlying neural computations remain poorly understood. We use magnetoencephalography (MEG) decoding and a dataset of wellcontrolled, naturalistic videos of five actions (run, walk, jump, eat, drink) performed by different actors at different viewpoints to study the computational steps used to recognize actions across complex transformations. In particular, we ask when the brain discounts changes in 3D viewpoint relative to when it initially discriminates between actions. We measure the latency difference between invariant and non-invariant action decoding when subjects view full videos as well as form-depleted and motion-depleted stimuli. Our results show no difference in decoding latency or temporal profile between invariant and non-invariant action recognition in full videos. However, when either form or motion information is removed from the stimulus set, we observe a decrease and delay in invariant action decoding. Our results suggest that the brain recognizes actions and builds invariance to complex transformations at the same time, and that both form and motion information are crucial for fast, invariant action recognition.

Four experiments were conducted that investigated the role of metric information in the identification and episodic recognition of scenes. A fifth experiment examined whether scene identification showed any hemispheric advantage. For scene identification, a priming paradigm was used in which participants were required to identify scenes that were identical,

Four experiments were conducted that investigated the role of metric information in the identification and episodic recognition of scenes. A fifth experiment examined whether scene identification showed any hemispheric advantage. For scene identification, a priming paradigm was used in which participants were required to identify scenes that were identical,

Previous functional imaging studies have shown that facilitated processing of a visual object on repeated, relative to initial, presentation (i.e., repetition priming) is associated with reductions in neural activity in multiple regions, including fusiform/lateral occipital cortex. Moreover, activity reductions have been found, at diminished levels, when a different exemplar of an object is presented on repetition. In one previous study, the magnitude of diminished priming across exemplars was greater in the right relative to the left fusiform, suggesting greater exemplar specificity in the right. Another previous study, however, observed fusiform lateralization modulated by object viewpoint, but not object exemplar. The present fMRI study sought to determine whether the result of differential fusiform responses for perceptually different exemplars could be replicated. Furthermore, the role of the left fusiform cortex in object recognition was investigated via the inclusion of a lexical/semantic manipulation. Right fusiform cortex showed a significantly greater effect of exemplar change than left fusiform, replicating the previous result of exemplar-specific fusiform lateralization. Right fusiform and lateral occipital cortex were not differentially engaged by the lexical/semantic manipulation, suggesting that their role in visual object recognition is predominantly in the visual discrimination of specific objects. Activation in left fusiform cortex, but not left lateral occipital cortex, was modulated by both exemplar change and lexical/semantic manipulation, with further analysis suggesting a posterior-to-anterior progression between regions involved in processing visuoperceptual and lexical/semantic information about objects. The results are consistent with the view that the right fusiform plays a greater role in processing specific visual form information about objects, whereas the left fusiform is also involved in lexical/semantic processing.

Attention can enhance processing for relevant information and suppress this for ignored stimuli. However, some residual processing may still arise without attention. Here we presented overlapping outline objects at study, with subjects attending to those in one color but not the other. Attended objects were subsequently recognized on a surprise memory test, whereas there was complete amnesia for ignored items on such direct explicit testing; yet reliable behavioral priming effects were found on indirect testing. Event-related fMRI examined neural responses to previously attended or ignored objects, now shown alone in the same or mirror-reversed orientation as before, intermixed with new items. Repetition-related decreases in fMRI responses for objects previously attended and repeated in the same orientation were found in the right posterior fusiform, lateral occipital, and left inferior frontal cortex. More anterior fusiform regions also showed some repetition decreases for ignored ...

It is currently unclear whether objects have to be explicitly identified at encoding for reliable behavioral long-term object priming to occur. We conducted two experiments that investigated long-term object and non-object priming using a selective-attention encoding manipulation that reduces explicit object identification. In Experiment 1, participants either counted dots flashed within an object picture (shallow encoding) or engaged in an animacy task (deep encoding) at study, whereas, at test, they performed an object-decision task. Priming, as measured by reaction times (RTs), was observed for both types of encoding, and was of equivalent magnitude. In Experiment 2, non-object priming (faster RTs for studied relative to unstudied non-objects) was also obtained under the same selective-attention encoding manipulation as in Experiment 1, and the magnitude of the priming effect was equivalent between experiments. In contrast, we observed a linear decrement in recognition memory acc...

It is currently unclear whether objects have to be explicitly identified at encoding for reliable behavioral long-term object priming to occur. We conducted two experiments that investigated long-term object and non-object priming using a selective-attention encoding manipulation that reduces explicit object identification. In Experiment 1, participants either counted dots flashed within an object picture (shallow encoding) or engaged in an animacy task (deep encoding) at study, whereas, at test, they performed an object-decision task. Priming, as measured by reaction times (RTs), was observed for both types of encoding, and was of equivalent magnitude. In Experiment 2, non-object priming (faster RTs for studied relative to unstudied non-objects) was also obtained under the same selective-attention encoding manipulation as in Experiment 1, and the magnitude of the priming effect was equivalent between experiments. In contrast, we observed a linear decrement in recognition memory acc...

This exploratory mixed-methods case study relies on semistructured interviews with tenure-track faculty members from North American graduate archival programs and a survey of North American graduate students and early career professionals to explore how archival education programs incorporate technology. We asked faculty members not only about the technologies they currently teach, but also their curriculum priorities, topical wish lists, and future challenges to and changes in archival education. We asked students and early career professionals whether they wished their graduate program had better prepared them technologically. Findings revealed that although both groups saw technology and digital curation as current and future areas of priority, students and early career professionals felt ill-equipped to engage with technology in practice. We discuss the implications of these findings in light of the previous literature and adumbrate opportunities for future research.

How does the brain recognize natural scenes? We approach this question by decoding natural scene categories from cortically-localized magnetoencephalography (MEG) responses to briefly presented scenes. We apply spatiotemporal searchlight decoding over the whole brain to study how basic- and superordinate-level category information is processed. We report spatiotemporal differences in the extent to which brain activity informs us about categorysensitive information at the two different levels. In particular, regions previously implicated in scene perception were involved at both levels, but the temporal sequence of information processing in these regions were very different as inferred from basic- and superordinate-level decoding accuracies. These fine-grained differences in temporal processing may shed light on the respective roles of individual cortical areas in scene perception.

Highlights d We show how the brain reduces high-dimensional input into decision representations d Occipital cortex reduces features irrelevant for behavior 170 ms post stimulus d Past 170 ms, fusiform gyrus combines the features supporting behavioral decisions

This paper surveys recent research on the application of visualization and visual analytic technologies to address archival and information challenges of sustainability related to access, preservation, and security of archival documents, drawing, in particular on research being conducted at the School of Library, Archival and Information Studies at the University of British Columbia. The paper concludes that visualization and visual analytics are new technologies that hold much promise for a sustainable future of archives, but that much more research is needed to transfer these technologies from the lab to production systems working in archives. Introduction: The Need for Sustainability in the Era of Big Data Like many other organizations, archival institutions are facing a data tsunami. Data are growing massively and rapidly: About 2.5 exabytes (2.5 million terabytes) of data are created every day. 1 Ninety percent of the data in the world today has been created in the last two yea...

What do we do with the large proportion of our waking lives when we are not concerned about satisfying the standard needs for survival and reproductive success (e.g., satisfying hunger, avoidance of harm, etc.)? Possible Answer We attempt to satisfy another drive, one that maximizes the rate at which we acquire new but interpretable information. That is, we are infovores.

Visual scenes are processed in terms of spatial frequencies. Low spatial frequencies (LSF) carry coarse information, whereas high spatial frequencies (HSF) subsequently carry information about fine details. The present magnetic resonance imaging study investigated how cortical thickness covaried with LSF/HSF processing abilities in ten-year-old children and adults. Participants indicated whether natural scenes that were filtered in either LSF or HSF represented outdoor or indoor scenes, while reaction times (RTs) and accuracy measures were recorded. In adults, faster RTs for LSF and HSF images were consistently associated with a thicker cortex (parahippocampal cortex, middle frontal gyrus, and precentral and insula regions for LSF; parahippocampal cortex and fronto-marginal and supramarginal gyri for HSF). On the other hand, in children, faster RTs for HSF were associated with a thicker cortex (posterior cingulate, supramarginal and calcarine cortical regions), whereas faster RTs fo...

This study explored the correspondence between implicit memory and the reactivation of encoding-related brain regions. By using a classification method, we examined whether reactivation reflects only the similarities between study and test or voxels at the reactivated regions are diagnostic of facilitation in the implicit memory task. A simple detection task served as incidental encoding of object-location pairings. A subsequent visual search task served as the indirect (implicit) test of memory. Subjects did not know that their memory would be tested. Half of the subjects were unaware that some stimuli in the search task are the same as those that had appeared during the detection task. Another group of subjects was made aware of this relationship at the onset of the visual search task. Memory performance was superior for the study-test aware, compared to study-test unaware, subjects. Brain reactivation was calculated using a conjunction analysis implemented through overlaying the neural activity at encoding and testing. The conjunction analysis revealed that implicit memory in both groups of subjects was associated with reactivation of parietal and occipital brain regions. We were able to classify study-test aware and study-test unaware subjects based on the per-voxel reactivation values representing the neural dynamics between encoding and test. The classification results indicate that neural dynamics between encoding and test accounts for the differences in implicit memory. Overall, our study demonstrates that implicit memory performance requires and depends upon reactivation of encoding-related brain regions.

Highlights d We show how the brain reduces high-dimensional input into decision representations d Occipital cortex reduces features irrelevant for behavior 170 ms post stimulus d Past 170 ms, fusiform gyrus combines the features supporting behavioral decisions

A half century after the beginnings of records management and institutional archives in American colleges and universities, the authors undertook a broadly based national survey to analyze the state of records management in academe and to identify program characteristics. Campus-wide programs were identified at approximately one-third of the 449 responding colleges and universities, particularly at public institutions subject to state legal requirements for public accountability. The survey also identified widespread implementation of decentralized, office-centered records management programs by registrars and other campus officials. Archivists accounted for most of the survey respondents reporting no campus-wide programs. College and university archivists have long been tireless supporters of academic records management, believing that records management responsibility provides a legally mandated means to identify and accession records of enduring value. But archivists should modify their traditional approach to records management in order to implement and maintain viable programs.

To investigate visual performance during reading under different illumination sources. This experimental quantitative study included 40 (20 females and 20 males) emmetropic participants with no history of ocular pathology. The participants were randomly assigned to read a near visual task under four different illuminations (400-lux constant): compact fluorescent light (CFL), tungsten light (TUNG), fluorescent tube light (FLUO), and light emitting diode (LED). Subsequently, we evaluated the participants' experiences of eight symptoms of visual comfort. The mean age of the participants was 19.86 ± 1.09 (range: 18-21) years. There was no statistically significant difference between the reading rates of males and females under the different illuminations (= 0.99); however, the reading rate was fastest among males under CFL, and among females under FLUO. One way analysis of variance (ANOVA) revealed a strong significant difference (= 0.001) between males and females (= 0.002) regardi...

H ello, I am honored to be speaking to you as SAA's seventy-third president and would like to express my gratitude for having the opportunity to represent our organization this past year. Three years ago, our SAA Annual Meeting theme was Telling the Story of Archives as part of President Kathleen Roe's "Year of Living Dangerously." Recently the term "storytelling" just kept popping up everywhere for me. I subscribe to the Brain Pickings 1 newsletter (edited by Maria Popova), which focuses on the literary arts. While I often delete the messages due to lack of time, I do save them if a subject catches my eye. And so, while I was reading what I had set aside, the word "storytelling" appeared three times in conjunction with authors Iris Murdoch, Ursula K. Le Guin, and Susan Sontag. In the next day or so, the SAA Annual Meeting program came out, and I signed up to attend "A Finding Aid to My Soul," an open-mic storytelling session. In May, I was interviewed for a blog post on diversity in archives created by Pass It Down, which advertises itself as a digital storytelling company. 2 And, finally, I was recently standing at the elevator and saw a Wake Forest flyer advertising the MA in Sports Storytelling Program. These seemingly ordinary appearances of various forms of "storytelling" got me thinking. I realized that beyond simply telling our own archives stories, though, the term can also be used in how we consider the documentary record. Archives storytelling depends, in every way, on recorded evidence and memory.

One of the most robust experience-related cortical dynamics is reduced neural activity when stimuli are repeated. This reduction has been linked to performance improvements due to repetition and also used to probe functional characteristics of neural populations. However, the underlying neural mechanisms are as yet unknown. Here, we consider three models that have been proposed to account for repetition-related reductions in neural activity, and evaluate them in terms of their ability to account for the main properties of this phenomenon as measured with single-cell recordings and neuroimaging techniques. We also discuss future directions for distinguishing between these models, which will be important for understanding the neural consequences of repetition and for interpreting repetition-related effects in neuroimaging data.

Objective: Unilateral neglect is usually investigated by adminstering stimuli (targets) in different positions, with targets being responded to by the patient (Hit) or omitted. In spite of this homogeneity of data type, neglect indices and diagnostic criteria vary considerably, causing inconsistencies in both clinical and experimental settings. We aimed at deriving a standard analysis which would apply to all tasks sharing this data form. Methods: A-priori theoretical reasoning demonstrated that the mean position of Hits in space (MPH) is an optimal index for correctly diagnosing and quantifying neglect. Crucially MPH eliminates the confounding effects of deficits that are different from neglect (non-lateral) but which decrease Hit rate. We ran a Monte Carlo study to assess MPH's (so far overlooked) statistical behavior as a function of numbers of targets and Hits. Results: While average MPH was indeed insensitive to non-lateral deficits, MPH's variance (like that of all other neglect indices) increased dramatically with increasing non-lateral deficits. This instability would lead to alarmingly high false-positive rates (FPRs) when applying a classical diagnostic procedure that compares one patient with a control sample. We solved the problem by developing an equation that takes into account MPH instability and provides correct cutoffs and close-to-nominal FPRs, even without control subjects. We developed a computerized program which, given the raw data, yields the MPH, a z-score and a p-value. Conclusions: We provided a standard method that allows clinical and experimental neuropsychologists to diagnose and measure neglect in a consistent way across the vast majority of tasks.

Objective: Unilateral neglect is usually investigated by adminstering stimuli (targets) in different positions, with targets being responded to by the patient (Hit) or omitted. In spite of this homogeneity of data type, neglect indices and diagnostic criteria vary considerably, causing inconsistencies in both clinical and experimental settings. We aimed at deriving a standard analysis which would apply to all tasks sharing this data form. Methods: A-priori theoretical reasoning demonstrated that the mean position of Hits in space (MPH) is an optimal index for correctly diagnosing and quantifying neglect. Crucially MPH eliminates the confounding effects of deficits that are different from neglect (non-lateral) but which decrease Hit rate. We ran a Monte Carlo study to assess MPH's (so far overlooked) statistical behavior as a function of numbers of targets and Hits. Results: While average MPH was indeed insensitive to non-lateral deficits, MPH's variance (like that of all other neglect indices) increased dramatically with increasing non-lateral deficits. This instability would lead to alarmingly high false-positive rates (FPRs) when applying a classical diagnostic procedure that compares one patient with a control sample. We solved the problem by developing an equation that takes into account MPH instability and provides correct cutoffs and close-to-nominal FPRs, even without control subjects. We developed a computerized program which, given the raw data, yields the MPH, a z-score and a p-value. Conclusions: We provided a standard method that allows clinical and experimental neuropsychologists to diagnose and measure neglect in a consistent way across the vast majority of tasks.

Aims: The main aim of present study is to investigate the effect of luminance on identifying the Ishihara colour vision plates in normal trichromats. Place and Duration of Study: Dr. Rishi Bhardwaj Visual Psychophysics laboratory, School of Medical sciences, University of Hyderabad-INDIA, 1-year (07/2015 to 07/07/2016). Methodology: This experimental quantitative study design conducted with n=60 participants of age group 18 to 21 years both male & female genders and inclusion criteria was trichromats, emmetropes with no history of ocular pathology and randomized sampling was done to study the experiment in lab setting with three different illuminations (Compact fluorescent light-CFL), fluorescent light, LED light) with constant 400-lux is maintained for the experiment followed by colour vision assessment with Ishihara colour vision plates 38 th edition (printed) version. Followed by satisfactory and feedback of comfort was received by participants. Results: The relation between lighting and isochromatic colour vision plates response was not statistically significance (P=0.007) males & females (P=0.056). But the isochromatic plate identifying speed is faster (1-3 sec) under fluorescent lighting compare to CFL and LED, similarly Original Research Article Ram and Bharadwaj; OR, 7(1): 1-6, 2017; Article no.OR.33018 2 the distribution of symptoms related to colour vision was very less in fluorescent lighting (10-30%) followed by CFL (10-55%) and maximum (30 – 75%) under LED lighting, shown more symptomatic. Satisfactory feedback from sixty participants showed that 36 participants recommended (Fluorescent=63%) lighting was good while identifying ishihara colour vision plates followed by CFL and LED similarly, 12 recommended (CFL=20%) and 10 participants recommended (LED=17%). Conclusion: This experiment concludes that ishihara colour vision plates are a tool for red and green deficiency screening. But the luminance intensity and types of lighting play a vital role for discriminating the numerals that imbedded in isochromatic plates, fluorescent lighting showed better results and faster speed to recognize the isochromatic plates compare to CFL and LED luminance in trichromats.

Humans have the ability to reflect upon their perception, thoughts, and actions, known as metacognition (MC). The brain basis of MC is incompletely understood, and it is debated whether MC on different processes is subserved by common or divergent networks. We combined behavioral phe-notyping with multi-modal neuroimaging to investigate whether structural substrates of individual differences in MC on higher-order cognition (MC-C) are dissociable from those underlying MC on perceptual accuracy (MC-P). Motivated by conceptual work suggesting a link between MC and cogni-tive perspective taking, we furthermore tested for overlaps between MC substrates and mentalizing networks. In a large sample of healthy adults, individual differences in MC-C and MC-P did not correlate. MRI-based cortical thickness mapping revealed a structural basis of this independence, by showing that individual differences in MC-P related to right prefrontal cortical thickness, while MC-C scores correlated with measures in lateral prefrontal, temporo-parietal, and posterior midline regions. Surface-based superficial white matter diffusivity analysis revealed substrates resembling those seen for cortical thickness, confirming the divergence of both MC faculties using an independent imaging marker. Despite their specificity, substrates of MC-C and MC-P fell clearly within networks known to participate in mentalizing, confirmed by task-based fMRI in the same subjects, previous meta-analytical findings, and ad-hoc Neurosynth-based meta-analyses. Our integrative multi-method approach indicates domain-specific substrates of MC; despite their divergence, these nevertheless likely rely on component processes mediated by circuits also involved in mentalizing. Hum Brain Mapp 00:000–000, 2016.

One of the most robust experience-related cortical dynamics is reduced neural activity when stimuli are repeated. This reduction has been linked to performance improvements due to repetition and also used to probe functional characteristics of neural populations. However, the underlying neural mechanisms are as yet unknown. Here, we consider three models that have been proposed to account for repetition-related reductions in neural activity, and evaluate them in terms of their ability to account for the main properties of this phenomenon as measured with single-cell recordings and neuroimaging techniques. We also discuss future directions for distinguishing between these models, which will be important for understanding the neural consequences of repetition and for interpreting repetition-related effects in neuroimaging data. † What is the relationship between repetition suppression (RS) and stimulus selectivity? † How does repetition affect the tuning curves of neurons? † How do the Fatigue and Sharpening models account for improved behavioral performance (priming)? † In what time scale does facilitation occur? † Does facilitation require interactions between different brain regions, in particular feedback? † Does RS induced by prolonged adaptation and RS induced by one (or several) presentations with intervening stimuli involve similar or distinct neural mechanisms? † How does RS in lower level regions (e.g. V1) differ from RS in highlevel regions (e.g. MT or LO)?

We investigated the effects of semantic priming on initial encoding of briefly presented pictures of objects and scenes. Pictures in four experiments were presented for varying durations and were followed immediately by a mask. In Experiments 1 and 2, pictures of simple objects were either preceded or not preceded by the object's category name (e.g., dog). In Experiment 1 we measured immediate object identification; in Experiment 2 we measured delayed old/new recognition in which targets and distractors were from the same categories. In Experiment 3 naturalistic scenes were either preceded or not preceded by the scene's category name (e.g., supermarket). We measured delayed recognition in which targets and distractors were described by the same category names. In Experiments 1-3, performance was better for primed than for unprimed pictures. Experiment 4 was similar to Experiment 2 in that we measured delayed recognition for simple objects. As in Experiments 1-3, a prime that...

The view presented here is that visual object recognition is the product of interaction between perception and cognition, a process budding from memories of past events. Our brain is proactive, in that it is continuously aiming to predict how the future will unfold, and this inherent ability allows us to function optimally in our environment. Our memory serves as a database from which we can form analogies from our past experiences, and apply them to the current moment. We are able to recognize an object through top-down and bottom-up processing pathways, which integrate to facilitate successful and timely object recognition. Specifically, it is argued that when we encounter an object our brain asks "what is this like" and therefore draws on years of experience, stored in memory, to generate predictions that directly facilitate perception. These feed-forward and feedback systems tune our perceptive and cognitive faculties based on a number of factors: predictive astuteness, context, personal relevance of the given event, and the degree to which its potential rarity differs from our original expectations. We discuss both computational and theoretical models of object recognition, and review evidence to support the theory that we do not merely process incoming information serially, and that during our attempts to interpret the world around us, perception relies on existing knowledge as much as it does on incoming information.

Task-induced deactivation of the default-mode network (DMN) has been associated in adults with successful episodic memory formation, possibly as a mechanism to focus allocation of mental resources for successful encoding of external stimuli. We investigated developmental changes of deactivation of the DMN (posterior cingulate, medial prefrontal, and bilateral lateral parietal cortices) during episodic memory formation in children, adolescents, and young adults (ages 8-24), who studied scenes during functional magnetic resonance imaging (fMRI). Recognition memory improved with age. We defined DMN regions of interest from a different sample of participants with the same age range, using resting-state fMRI. In adults, there was greater deactivation of the DMN for scenes that were later remembered than scenes that were later forgotten. In children, deactivation of the default-network did not differ reliably between scenes that were later remembered or forgotten. Adolescents exhibited a pattern of activation intermediate to that of children and adults. The hippocampal region, often considered part of the DMN, showed a functional dissociation with the rest of the DMN by exhibiting increased activation for later remembered than later forgotten scene that was similar across age groups. These findings suggest that development of memory ability from childhood through adulthood may involve increased deactivation of the neocortical DMN during learning.

Recent experience identifying objects leads to later improvements in both speed and accuracy ("repetition priming"), along with simultaneous reductions of neural activity ("repetition suppression"). A popular interpretation of these joint behavioral and neural phenomena is that object representations become perceptually "sharper" with stimulus repetition, eliminating cells that are poorly stimulus-selective and responsive and reducing support for competing representations downstream. Here, we test this hypothesis in an fMRI-adaptation experiment using pictures of objects. Prior to fMRI, participants repeatedly named a set of object pictures. During fMRI, participants viewed adaptation sequences composed of rapidly repeated objects (3-6 repetitions over several seconds) that were either named previously or that were new for the fMRI session, followed by single "deviant" object pictures used to measure recovery from adaptation and that shared a ...

Aims: This study examined brain activity using functional magnetic resonance imaging (fMRI) and reaction time (RT) during an implicit repetition priming memory task involving alcohol, polydrug, marijuana and emotional picture cues. Methods: Participants were 5 male and 5 female high-risk college students who had just participated in a cue exposure study (Ray et al., this issue). fMRI and RT data were collected while participants made decisions about previously seen and new picture cues. Results: Both behavioral RT and brain imaging data revealed strong memory priming for drug and alcohol cues. Neurologically, a repetition priming effect (suppression in neural activity for repeated cues) was observed in response to alcohol cues in the left prefrontal, bilateral occipital, and bilateral occipitotemporal regions, as well as right insula and right precuneus (Z ranged from 3.03 to 3.31 P < 0.05). Polydrug cues elicited priming in the occipital and temporal areas, and marijuana cues in the occipital area. Conclusions: Prefrontal and insular cortex involvement both in reactivity to alcohol cues (Ray et al., this issue) and subsequent implicit memory processing of these cues, as found in this study, suggests their potential role in the maintenance of high-risk alcohol use behaviors.

How does the brain recognize natural scenes? We approach this question by decoding natural scene categories from cortically-localized magnetoencephalography (MEG) responses to briefly presented scenes. We apply spatiotemporal searchlight decoding over the whole brain to study how basic- and superordinate-level category information is processed. We report spatiotemporal differences in the extent to which brain activity informs us about categorysensitive information at the two different levels. In particular, regions previously implicated in scene perception were involved at both levels, but the temporal sequence of information processing in these regions were very different as inferred from basic- and superordinate-level decoding accuracies. These fine-grained differences in temporal processing may shed light on the respective roles of individual cortical areas in scene perception.

Rotations in depth are challenging for object vision because features can appear, disappear, be stretched or compressed. Yet we easily recognize objects across views. Are the underlying representations view invariant or dependent? This question has been intensely debated in human vision, but the neuronal representations remain poorly understood. Here, we show that for naturalistic objects, neurons in the monkey inferotemporal (IT) cortex undergo a dynamic transition in time from view dependence to view invariance that depends on object structure. This transition depended strongly on two image properties: foreshortening and dissimilarity. It was also present even on removing internal details of objects, and was partially explained by affine image operations. Our results elucidate the viewpoint debate by showing that view invariance arises dynamically in IT neurons from a representation that is initially view dependent.

Aims: This study examined brain activity using functional magnetic resonance imaging (fMRI) and reaction time (RT) during an implicit repetition priming memory task involving alcohol, polydrug, marijuana and emotional picture cues. Methods: Participants were 5 male and 5 female high-risk college students who had just participated in a cue exposure study (Ray et al., this issue). fMRI and RT data were collected while participants made decisions about previously seen and new picture cues. Results: Both behavioral RT and brain imaging data revealed strong memory priming for drug and alcohol cues. Neurologically, a repetition priming effect (suppression in neural activity for repeated cues) was observed in response to alcohol cues in the left prefrontal, bilateral occipital, and bilateral occipitotemporal regions, as well as right insula and right precuneus (Z ranged from 3.03 to 3.31 P < 0.05). Polydrug cues elicited priming in the occipital and temporal areas, and marijuana cues in the occipital area. Conclusions: Prefrontal and insular cortex involvement both in reactivity to alcohol cues (Ray et al., this issue) and subsequent implicit memory processing of these cues, as found in this study, suggests their potential role in the maintenance of high-risk alcohol use behaviors.

That associative processing provides the vehicle of thought is a long-standing idea. We describe here observations from cognitive neuroimaging that elucidate the neural processing that mediates this element. This account further allows a more specific ascription of a cognitive function to the brain's ''default'' activity in mindwandering. We extend this account to argue that one primary outcome of associative processing is the generation of predictions, which approximate the immediately relevant future and thus facilitate perception, action, and the progression of thought. V V C 2007 Wiley-Liss, Inc.

Cortical analysis related to visual object recognition is traditionally thought to propagate serially along a bottom-up hierarchy of ventral areas. Recent proposals gradually promote the role of top-down processing in recognition, but how such facilitation is triggered remains a puzzle. We tested a specific model, proposing that low spatial frequencies facilitate visual object recognition by initiating top-down processes projected from orbitofrontal to visual cortex. The present study combined magnetoencephalography, which has superior temporal resolution, functional magnetic resonance imaging, and a behavioral task that yields successful recognition with stimulus repetitions. Object recognition elicited differential activity that developed in the left orbitofrontal cortex 50 ms earlier than it did in recognition-related areas in the temporal cortex. This early orbitofrontal activity was directly modulated by the presence of low spatial frequencies in the image. Taken together, the dynamics we revealed provide strong support for the proposal of how top-down facilitation of object recognition is initiated, and our observations are used to derive predictions for future research.

Cortical analysis related to visual object recognition is traditionally thought to propagate serially along a bottom-up hierarchy of ventral areas. Recent proposals gradually promote the role of top-down processing in recognition, but how such facilitation is triggered remains a puzzle. We tested a specific model, proposing that low spatial frequencies facilitate visual object recognition by initiating top-down processes projected from orbitofrontal to visual cortex. The present study combined magnetoencephalography, ...

Cortical analysis related to visual object recognition is traditionally thought to propagate serially along a bottom-up hierarchy of ventral areas. Recent proposals gradually promote the role of top-down processing in recognition, but how such facilitation is triggered remains a puzzle. We tested a specific model, proposing that low spatial frequencies facilitate visual object recognition by initiating top-down processes projected from orbitofrontal to visual cortex. The present study combined magnetoencephalography, which has superior temporal resolution, functional magnetic resonance imaging, and a behavioral task that yields successful recognition with stimulus repetitions. Object recognition elicited differential activity that developed in the left orbitofrontal cortex 50 ms earlier than it did in recognition-related areas in the temporal cortex. This early orbitofrontal activity was directly modulated by the presence of low spatial frequencies in the image. Taken together, the dynamics we revealed provide strong support for the proposal of how top-down facilitation of object recognition is initiated, and our observations are used to derive predictions for future research.

One of the most robust experience-related cortical dynamics is reduced neural activity when stimuli are repeated. This reduction has been linked to performance improvements due to repetition and also used to probe functional characteristics of neural populations. However, the underlying neural mechanisms are as yet unknown. Here, we consider three models that have been proposed to account for repetition-related reductions in neural activity, and evaluate them in terms of their ability to account for the main properties of this phenomenon as measured with single-cell recordings and neuroimaging techniques. We also discuss future directions for distinguishing between these models, which will be important for understanding the neural consequences of repetition and for interpreting repetition-related effects in neuroimaging data.