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1

Perceptual Simulations and Linguistic Representations Have Differential Effects on Speeded Relatedness Judgments and Recognition Memory  

PubMed Central

We examined the effect of spatial iconicity (a perceptual simulation of canonical locations of objects) and word-order frequency on language processing and episodic memory of orientation. Participants made speeded relatedness judgments to pairs of words presented in locations typical to their real world arrangements (e.g., ceiling on top and floor on bottom). They then engaged in a surprise orientation recognition task for the word pairs. We replicated Louwerse’s finding (2008) that word-order frequency has a stronger effect on semantic relatedness judgments than spatial iconicity. This is consistent with recent suggestions that linguistic representations have a stronger impact on immediate decisions about verbal materials than perceptual simulations. In contrast, spatial iconicity enhanced episodic memory of orientation to a greater extent than word-order frequency did. This new finding indicates that perceptual simulations have an important role in episodic memory. Results are discussed with respect to theories of perceptual representation and linguistic processing. PMID:19742388

Tse, Chi-Shing; Kurby, Christopher A.; Du, Feng

2010-01-01

2

Perceptual priming and reading speed among fourth grade children.  

PubMed

This study evaluated the perceptual priming in fourth grade primary school children using a word-fragment completion task. The children were classified into two categories according to their reading speed: high and low. Using several sub-scales of the WISC-IV, their working memory was measured, and their total IQ was estimated, in order to control for their effects on priming. The statistical analyses showed that children with high reading speed were significantly better at word-fragment completion and showed greater priming (p < .01); in other words, the prior processing of the words from which the fragments came produced a greater benefit in the performance of the word-fragment completion task. A regression model was developed to explain reading speed based on the following variables: perceptual priming, working memory and percentage of completed fragments belonging to words not previously processed (adjusted R 2 = 0.64). PMID:25012087

Soler, Maria José; Dasí, Carmen; Bellver, Vicente; Ruiz, Juan Carlos

2014-01-01

3

Multiple spatial frequency channels in human visual perceptual memory  

Microsoft Academic Search

Current models of short-term visual perceptual memory invoke mechanisms that are closely allied to low-level perceptual discrimination mechanisms. The purpose of this study was to investigate the extent to which human visual perceptual memory for spatial frequency is based upon multiple, spatially tuned channels similar to those found in the earliest stages of visual processing. To this end we measured

V. A. Nemes; D. Whitaker; J. Heron; D. J. McKeefry

4

On the relationship between autobiographical memory and perceptual learning  

Microsoft Academic Search

Reports experiments designed to explore the relationship between the more aware autobiographical form of memory that is measured by a recognition memory test and the less aware form of memory that is expressed in perceptual learning. Ss were 247 undergraduates. Variables such as the level of processing of words during study influenced recognition memory, but not subsequent perceptual recognition. In

Larry L. Jacoby; Mark Dallas

1981-01-01

5

Visual Perceptual and Working Memory Impairments in Schizophrenia  

Microsoft Academic Search

Background: Impairments in working memory have been proposed to underlie a broad range of cognitive defi- cits seen in schizophrenia. Visual working memory im- pairments are frequently reported in schizophrenia. In- vestigations of visual working memory generally assume intact visual information processing, despite evidence of visual perceptual impairments in schizophrenia. In this study, we evaluated the integrity of the perceptual

Cenk Tek; James Gold; Teresa Blaxton; Christopher Wilk; Robert P. McMahon; Robert W. Buchanan

2002-01-01

6

Memory: Enduring Traces of Perceptual and Reflective Attention  

PubMed Central

Attention and memory are typically studied as separate topics, but they are highly intertwined. Here we discuss the relation between memory and two fundamental types of attention: perceptual and reflective. Memory is the persisting consequence of cognitive activities initiated by and/or focused on external information from the environment (perceptual attention) and initiated by and/or focused on internal mental representations (reflective attention). We consider three key questions for advancing a cognitive neuroscience of attention and memory: To what extent do perception and reflection share representational areas? To what extent are the control processes that select, maintain, and manipulate perceptual and reflective information subserved by common areas and networks? During perception and reflection, to what extent are common areas responsible for binding features together to create complex, episodic memories and for reviving them later? Considering similarities and differences in perceptual and reflective attention helps integrate a broad range of findings and raises important unresolved issues. PMID:22099456

Chun, Marvin M.; Johnson, Marcia K.

2011-01-01

7

False Memories Lack Perceptual Detail: Evidence from Implicit Word-Stem Completion and Perceptual Identification Tests  

ERIC Educational Resources Information Center

We used implicit measures of memory to ascertain whether false memories for critical nonpresented items in the DRM paradigm (Deese, 1959; Roediger & McDermott, 1995) contain structural and perceptual detail. In Experiment 1, we manipulated presentation modality in a visual word-stem-completion task. Critical item priming was significant and…

Hicks, J.L.; Starns, J.J.

2005-01-01

8

The Comparison of Visual Working Memory Representations With Perceptual Inputs  

E-print Network

the observer can make a manual change detection response. Keywords: Visual working memory, visual shortThe Comparison of Visual Working Memory Representations With Perceptual Inputs Joo-seok Hyun Chung University of Iowa Steven J. Luck University of California, Davis The human visual system can notice

Woodman, Geoffrey F.

9

Common and Distinct Neural Correlates of Perceptual and Memorial Selection  

E-print Network

Common and Distinct Neural Correlates of Perceptual and Memorial Selection Derek Evan Nee and John goal-relevant information in the face of competing distraction. A popular account is that common top commonalities of selective attention and memorial selection, our results demonstrate that the SPL and FEF show

Jonides, John

10

The Development of Explicit Memory for Basic Perceptual Features  

E-print Network

memory function across the life span varied with the par- ticular perceptual feature tested and the type memory tests is not a consistent inverted U-shaped function of age across vari- ous features. Explicit of the development and dissolution of function (Jackson, 1880, reprinted in Taylor, 1958). This principle states

Johnson, Marcia K.

11

Eye movements, the perceptual span, and reading speed.  

PubMed

The perceptual span or region of effective vision during eye fixations in reading was examined as a function of reading speed (fast readers were compared with slow readers), font characteristics (fixed width vs. proportional width), and intraword spacing (normal or reduced). The main findings were that fast readers (reading at about 330 wpm) had a larger perceptual span than did slow readers (reading about 200 wpm) and that the span was not affected by whether or not the text was fixed width or proportional width. In addition, there were interesting font and intraword spacing effects that have important implications for the optimal use of space in a line of text. PMID:21169577

Rayner, Keith; Slattery, Timothy J; Bélanger, Nathalie N

2010-12-01

12

Variability in visual working memory ability limits the efficiency of perceptual decision making  

PubMed Central

The ability to make rapid and accurate decisions based on limited sensory information is a critical component of visual cognition. Available evidence suggests that simple perceptual discriminations are based on the accumulation and integration of sensory evidence over time. However, the memory system(s) mediating this accumulation are unclear. One candidate system is working memory (WM), which enables the temporary maintenance of information in a readily accessible state. Here, we show that individual variability in WM capacity is strongly correlated with the speed of evidence accumulation in speeded two-alternative forced choice tasks. This relationship generalized across different decision-making tasks, and could not be easily explained by variability in general arousal or vigilance. Moreover, we show that performing a difficult discrimination task while maintaining a concurrent memory load has a deleterious effect on the latter, suggesting that WM storage and decision making are directly linked. PMID:24695991

Ester, Edward F.; Ho, Tiffany C.; Brown, Scott D.; Serences, John T.

2014-01-01

13

An investigation of false memory in perceptual implicit tasks.  

PubMed

Reports of critical lure priming in perceptual implicit tasks [e.g., McKone, E., & Murphy, B. (2000). Implicit false memory: Effects of modality and multiple study presentations on long-lived semantic priming. Journal of Memory and Language, 43, 89-109] using the Deese-Roediger-McDermott [Roediger, H. L., III, & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21, 803-814] procedure have suggested availability of the lexical form of lure items at study. Three experiments were conducted to further explore "false" implicit priming in perceptual tests. In Experiments 1 and 3, implicit and explicit stem completion tests were given in the DRM procedure with semantic lists; in Experiment 2, a graphemic response test was used in a similar design. For all experiments, explicit instructions resulted in reliable false memory, while implicit instructions resulted in priming for list items and no priming for lure items. Priming for lure items was evident for "test-aware" subjects only in Experiment 1 and in a combined analysis for all three experiments. These results establish boundary conditions for priming for critical lures and indicate that access to the lexical form of critical lures may not occur under incidental learning conditions when strong controls against explicit retrieval are implemented. PMID:16510106

McBride, Dawn M; Coane, Jennifer H; Raulerson, Bascom A

2006-11-01

14

When Does Modality Matter? Perceptual versus Conceptual Fluency-Based Illusions in Recognition Memory  

ERIC Educational Resources Information Center

Previous research has shown that illusions of recognition memory based on enhanced perceptual fluency are sensitive to the perceptual match between the study and test phases of an experiment. The results of the current study strengthen that conclusion, as they show that participants will not interpret enhanced perceptual fluency as a sign of…

Miller, Jeremy K.; Lloyd, Marianne E.; Westerman, Deanne L.

2008-01-01

15

Teaching memory-impaired people to touch type: the acquisition of a useful complex perceptual-motor skill.  

PubMed

This study provides ecological validity for laboratory findings that people with memory difficulties following brain injury can learn new skills. This was done by testing the acquisition of a useful real-world perceptual-motor skill. Using a conventional computer software training package supplemented by one-to-one coaching, a woman with severely impaired memory and a man with poor memory learned to touch type. They achieved the initial criterion of 20 wpm with over 90% accuracy; reached a top speed of 30 wpm and retained their skill a year later. The memory-impaired participants received short sessions of distributed practice and as far as possible were taught under error-free learning conditions. Their performance was broadly comparable with that of two non-memory-impaired comparison participants in terms of acquisition, consolidation and transfer, speed and accuracy, and retention. PMID:18576273

Todd, Mary; Barrow, Corinne

2008-08-01

16

Revisiting a Cognitive Framework for Test Design: Applications for a Computerized Perceptual Speed Test.  

ERIC Educational Resources Information Center

This paper highlights the need for a systematic, content aware, and theoretically-based approach to test design. The cognitive components approach is endorsed, and is applied to the development of a computerized perceptual speed test. Psychometric literature is reviewed and shows that: every major multi-factor theory includes a clerical/perceptual

Alderton, David L.

17

Working memory effects in speeded RSVP tasks.  

PubMed

The present paper examines the effects of memory contents and memory load in rapid serial visual presentation (RSVP) speeded tasks, trying to explain previous inconsistent results. We used a one target (Experiment 1) and a two-target (Experiment 2) RSVP task with a concurrent memory load of one or four items, in a dual-task paradigm. A relation between material in working memory and the target in the RSVP impaired the identification of the target. In Experiments 3 and 4, the single task was to determine whether any information in memory matched the target in the RSVP, while varying the memory load. A match was detected faster than a non-match, although only when there was some distance between targets in the RSVP (Experiment 4). The results suggest that memory contents automatically capture attention, slowing processing when the memory contents are irrelevant to the task, and speeding processing when they are relevant. PMID:23397260

Gil-Gómez de Liaño, Beatriz; Potter, Mary C; Rodríguez, Carmen

2014-01-01

18

Prior perceptual processing enhances the effect of emotional arousal on the neural correlates of memory retrieval.  

PubMed

A fundamental idea in memory research is that items are more likely to be remembered if encoded with a semantic, rather than perceptual, processing strategy. Interestingly, this effect has been shown to reverse for emotionally arousing materials, such that perceptual processing enhances memory for emotional information or events. The current fMRI study investigated the neural mechanisms of this effect by testing how neural activations during emotional memory retrieval are influenced by the prior encoding strategy. Participants incidentally encoded emotional and neutral pictures under instructions to attend to either semantic or perceptual properties of each picture. Recognition memory was tested 2 days later. fMRI analyses yielded three main findings. First, right amygdalar activity associated with emotional memory strength was enhanced by prior perceptual processing. Second, prior perceptual processing of emotional pictures produced a stronger effect on recollection- than familiarity-related activations in the right amygdala and left hippocampus. Finally, prior perceptual processing enhanced amygdalar connectivity with regions strongly associated with retrieval success, including hippocampal/parahippocampal regions, visual cortex, and ventral parietal cortex. Taken together, the results specify how encoding orientations yield alterations in brain systems that retrieve emotional memories. PMID:24380867

Dew, Ilana T Z; Ritchey, Maureen; LaBar, Kevin S; Cabeza, Roberto

2014-07-01

19

Perceptual processing during trauma, priming and the development of intrusive memories  

PubMed Central

Background Intrusive reexperiencing in posttraumatic stress disorder (PTSD) is commonly triggered by stimuli with perceptual similarity to those present during the trauma. Information processing theories suggest that perceptual processing during the trauma and enhanced perceptual priming contribute to the easy triggering of intrusive memories by these cues. Methods Healthy volunteers (N = 51) watched neutral and trauma picture stories on a computer screen. Neutral objects that were unrelated to the content of the stories briefly appeared in the interval between the pictures. Dissociation and data-driven processing (as indicators of perceptual processing) and state anxiety during the stories were assessed with self-report questionnaires. After filler tasks, participants completed a blurred object identification task to assess priming and a recognition memory task. Intrusive memories were assessed with telephone interviews 2 weeks and 3 months later. Results Neutral objects were more strongly primed if they occurred in the context of trauma stories than if they occurred during neutral stories, although the effect size was only moderate (?p2=.08) and only significant when trauma stories were presented first. Regardless of story order, enhanced perceptual priming predicted intrusive memories at 2-week follow-up (N = 51), but not at 3 months (n = 40). Data-driven processing, dissociation and anxiety increases during the trauma stories also predicted intrusive memories. Enhanced perceptual priming and data-driven processing were associated with lower verbal intelligence. Limitations It is unclear to what extent these findings generalize to real-life traumatic events and whether they are specific to negative emotional events. Conclusions The results provide some support for the role of perceptual processing and perceptual priming in reexperiencing symptoms. PMID:23207970

Sündermann, Oliver; Hauschildt, Marit; Ehlers, Anke

2013-01-01

20

Changes in perceptual speed and white matter microstructure in the corticospinal tract are associated in very old age.  

PubMed

The integrity of the brain's white matter is important for neural processing and displays age-related differences, but the contribution of changes in white matter to cognitive aging is unclear. We used latent change modeling to investigate this issue in a sample of very old adults (aged 81-103years) assessed twice with a retest interval of 2.3years. Using diffusion-tensor imaging, we probed white matter microstructure by quantifying mean fractional anisotropy and mean diffusivity of six major white matter tracts. Measures of perceptual speed, episodic memory, letter fluency, category fluency, and semantic memory were collected. Across time, alterations of white matter microstructure in the corticospinal tract were associated with decreases of perceptual speed. This association remained significant after statistically controlling for changes in white matter microstructure in the entire brain, in the other demarcated tracts, and in the other cognitive abilities. Changes in brain volume also did not account for the association. We conclude that white matter microstructure is a potent correlate of changes in sensorimotor aspects of behavior in very old age, but that it is unclear whether its impact extends to higher-order cognition. PMID:25139001

Lövdén, Martin; Köhncke, Ylva; Laukka, Erika J; Kalpouzos, Grégoria; Salami, Alireza; Li, Tie-Qiang; Fratiglioni, Laura; Bäckman, Lars

2014-11-15

21

Perceptual chunking and its effect on memory in speech processing: ERP and behavioral evidence.  

PubMed

We examined how perceptual chunks of varying size in utterances can influence immediate memory of heard items (monosyllabic words). Using behavioral measures and event-related potentials (N400) we evaluated the quality of the memory trace for targets taken from perceived temporal groups (TGs) of three and four items. Variations in the amplitude of the N400 showed a better memory trace for items presented in TGs of three compared to those in groups of four. Analyses of behavioral responses along with P300 components also revealed effects of chunk position in the utterance. This is the first study to measure the online effects of perceptual chunks on the memory trace of spoken items. Taken together, the N400 and P300 responses demonstrate that the perceptual chunking of speech facilitates information buffering and a processing on a chunk-by-chunk basis. PMID:24678304

Gilbert, Annie C; Boucher, Victor J; Jemel, Boutheina

2014-01-01

22

Beyond perceptual load and dilution: a review of the role of working memory in selective attention  

PubMed Central

The perceptual load and dilution models differ fundamentally in terms of the proposed mechanism underlying variation in distractibility during different perceptual conditions. However, both models predict that distracting information can be processed beyond perceptual processing under certain conditions, a prediction that is well-supported by the literature. Load theory proposes that in such cases, where perceptual task aspects do not allow for sufficient attentional selectivity, the maintenance of task-relevant processing depends on cognitive control mechanisms, including working memory. The key prediction is that working memory plays a role in keeping clear processing priorities in the face of potential distraction, and the evidence reviewed and evaluated in a meta-analysis here supports this claim, by showing that the processing of distracting information tends to be enhanced when load on a concurrent task of working memory is high. Low working memory capacity is similarly associated with greater distractor processing in selective attention, again suggesting that the unavailability of working memory during selective attention leads to an increase in distractibility. Together, these findings suggest that selective attention against distractors that are processed beyond perception depends on the availability of working memory. Possible mechanisms for the effects of working memory on selective attention are discussed. PMID:23734139

de Fockert, Jan W.

2013-01-01

23

Disruption of Dorsolateral But Not Ventrolateral Prefrontal Cortex Improves Unconscious Perceptual Memories  

PubMed Central

Attentive encoding often leads to more accurate responses in recognition memory tests. However, previous studies have described conditions under which taxing explicit memory resources by attentional distraction improved perceptual recognition memory without awareness. These findings lead to the hypothesis that explicit memory processes mediated by the prefrontal cortex (PFC) can interfere with memory processes necessary for implicit recognition memory. The present study directly tested this hypothesis by applying transcranial magnetic stimulation separately over either dorsolateral (DLPFC) or ventrolateral PFC (VLPFC) in humans before performance of a visual memory task. Disruption of DLPFC function led to improvement in recognition accuracy only in responses in which the participant's awareness of memory retrieval was absent. However, disruption of VLPFC function led to subtle shifts in recollection and familiarity accuracy. We conclude that explicit memory processes mediated by the DLPFC can indirectly interfere with implicit recognition memory. PMID:23926275

Blumenfeld, Robert S.; D'Esposito, Mark

2013-01-01

24

Implicit perceptual memory modulates early visual processing of ambiguous images.  

PubMed

The way we perceive the present visual environment is influenced by past visual experiences. Here we investigated the neural basis of such experience dependency. We repeatedly presented human observers with an ambiguous visual stimulus (structure-from-motion) that can give rise to two distinct perceptual interpretations. Past visual experience is known to influence the perception of such stimuli. We recorded fast dynamics of neural activity shortly after stimulus onset using event-related electroencephalography. The number of previous occurrences of a certain percept modulated early posterior brain activity starting as early as 50 ms after stimulus onset. This modulation developed across hundreds of percept repetitions, reflecting several minutes of accumulating perceptual experience. Importantly, there was no such modulation when the mere number of previous stimulus presentations was considered regardless of how they were perceived. This indicates that the effect depended on previous perception rather than previous visual input. The short latency and posterior scalp location of the effect suggest that perceptual history modified bottom-up stimulus processing in early visual cortex. We propose that bottom-up neural responses to a given visual presentation are shaped, in part, by feedback modulation that occurred during previous presentations, thus allowing these responses to be biased in light of previous perceptual decisions. PMID:25057199

de Jong, Maartje C; Brascamp, Jan W; Kemner, Chantal; van Ee, Raymond; Verstraten, Frans A J

2014-07-23

25

The time course of protecting a visual memory representation from perceptual interference  

PubMed Central

Cueing a remembered item during the delay of a visual memory task leads to enhanced recall of the cued item compared to when an item is not cued. This cueing benefit has been proposed to reflect attention within visual memory being shifted from a distributed mode to a focused mode, thus protecting the cued item against perceptual interference. Here we investigated the dynamics of building up this mnemonic protection against visual interference by systematically varying the stimulus onset asynchrony (SOA) between cue onset and a subsequent visual mask in an orientation memory task. Experiment 1 showed that a cue counteracted the deteriorating effect of pattern masks. Experiment 2 demonstrated that building up this protection is a continuous process that is completed in approximately half a second after cue onset. The similarities between shifting attention in perceptual and remembered space are discussed. PMID:25628555

van Moorselaar, Dirk; Gunseli, Eren; Theeuwes, Jan; N. L. Olivers, Christian

2015-01-01

26

Infant Visual Recognition Memory: Independent Contributions of Speed and Attention.  

ERIC Educational Resources Information Center

Examined contributions of cognitive processing speed, short-term memory capacity, and attention to infant visual recognition memory. Found that infants who showed better attention and faster processing had better recognition memory. Contributions of attention and processing speed were independent of one another and similar at all ages studied--5,…

Rose, Susan A.; Feldman, Judith F.; Jankowski, Jeffery J.

2003-01-01

27

Action video games do not improve the speed of information processing in simple perceptual tasks.  

PubMed

Previous research suggests that playing action video games improves performance on sensory, perceptual, and attentional tasks. For instance, Green, Pouget, and Bavelier (2010) used the diffusion model to decompose data from a motion detection task and estimate the contribution of several underlying psychological processes. Their analysis indicated that playing action video games leads to faster information processing, reduced response caution, and no difference in motor responding. Because perceptual learning is generally thought to be highly context-specific, this transfer from gaming is surprising and warrants corroborative evidence from a large-scale training study. We conducted 2 experiments in which participants practiced either an action video game or a cognitive game in 5 separate, supervised sessions. Prior to each session and following the last session, participants performed a perceptual discrimination task. In the second experiment, we included a third condition in which no video games were played at all. Behavioral data and diffusion model parameters showed similar practice effects for the action gamers, the cognitive gamers, and the nongamers and suggest that, in contrast to earlier reports, playing action video games does not improve the speed of information processing in simple perceptual tasks. PMID:24933517

van Ravenzwaaij, Don; Boekel, Wouter; Forstmann, Birte U; Ratcliff, Roger; Wagenmakers, Eric-Jan

2014-10-01

28

The Comparison of Visual Working Memory Representations with Perceptual Inputs  

ERIC Educational Resources Information Center

The human visual system can notice differences between memories of previous visual inputs and perceptions of new visual inputs, but the comparison process that detects these differences has not been well characterized. In this study, the authors tested the hypothesis that differences between the memory of a stimulus array and the perception of a…

Hyun, Joo-seok; Woodman, Geoffrey F.; Vogel, Edward K.; Hollingworth, Andrew; Luck, Steven J.

2009-01-01

29

The Effects of Perceptual Encoding on the Magnitude of Object Working Memory Impairment in Schizophrenia  

PubMed Central

Deficits in the visual working memory (WM) system have been consistently reported in schizophrenia patients, but the relative contribution of initial perceptual encoding to these deficits remains unsettled. We assessed the role of visual perceptual encoding on performance on an object WM task. Schizophrenia patients (N=37) and nonpsychiatric control subjects (N=33) were tested on an object WM task involving three delay periods: 200 msec, 3 sec, and 10 sec. Schizophrenia patients performed significantly less accurately than controls on all three conditions. However, after controlling for the effect of perceptual encoding (accuracy on the 200 msec delay condition) on performance in the two memory load conditions, schizophrenia patients demonstrated intact WM in the 3 sec delay condition, and showed a weak trend for decreased accuracy on the 10 sec delay compared with controls. Analysis of individual differences in pattern of performance revealed that a distinct subgroup of poor encoder patients had a significantly greater reduction in accuracy at 3 sec than the other patient subgroups and controls. In contrast, among schizophrenia patients who performed poorly on the 10 sec delay, accuracy was equivalently reduced independent of encoding ability. WM deficits in controls were independent of encoding ability at both delay intervals. These results indicate that encoding ability titrates the magnitude of WM impairment in schizophrenia patients but not in controls, and that heterogeneity has to be taken into account to correctly estimate the effects of perceptual encoding on visual object WM deficits in schizophrenia. PMID:22640637

Coleman, Michael J.; Krastoshevsky, Olga; Tu, Xiawei; Mendell, Nancy R.; Levy, Deborah L.

2012-01-01

30

The effect of numerical magnitude on the perceptual processing speed of a digit.  

PubMed

In this study, we investigated whether the numerical information of a digit would affect perceptual processing speed for that digit. In Experiment 1, participants performed a temporal order judgment (TOJ) task in which they judged the order of two digits presented briefly to the left or right of the fixation point with a short asynchrony. The point of subjective simultaneity (PSS) was significantly shifted such that large numbers had to be presented before small numbers in order to be perceived as simultaneous, implying that small numbers are perceptually processed faster than large numbers. Given the susceptibility of a TOJ task to response bias, this result might have simply reflected the conceptual association between magnitude (e.g., small) and response selection (e.g., first). To exclude the potential influence of response bias, we adopted a simultaneity judgment (SJ) task in Experiment 2. Most participants in Experiment 2 had participated in Experiment 1. The participants judged whether the two digits were presented simultaneously or successively. The maximal possibility of simultaneous response was obtained when a large digit preceded a small digit by 5 ms, suggesting that small numbers were indeed perceived earlier than large numbers. Our findings indicated that small numbers were processed faster than large ones and that perceptual mechanisms contribute to this temporal advantage. In addition, although the TOJ and SJ task produced a similar processing speed advantage for small numbers, the PSSs of the two tasks were not correlated, which implied that different cognitive mechanisms were involved in the two tasks. PMID:25326604

Li, Shuang-Xia; Cai, Yong-Chun

2014-01-01

31

Repetition Priming in Speeded Word Reading: Contributions of Perceptual and Conceptual Processing Episodes  

Microsoft Academic Search

Five experiments investigated repetition priming on an indirect speeded word reading (naming) test, a task intended to circumvent conscious recollection. Reading a word or generating it from a semantic cue (either a phrase or an antonym) produced reliable priming of similar magnitude on this indirect test of memory. Efforts to encourage conscious recollection elevated response latencies in speeded reading and

Colin M MacLeod; Michael E. J. Masson

2000-01-01

32

Age-related effects on perceptual and semantic encoding in memory.  

PubMed

This study examined the age-related subsequent memory effect (SME) in perceptual and semantic encoding using event-related potentials (ERPs). Seventeen younger adults and 17 older adults studied a series of Chinese characters either perceptually (by inspecting orthographic components) or semantically (by determining whether the depicted object makes sounds). The two tasks had similar levels of difficulty. The participants made studied or unstudied judgments during the recognition phase. Younger adults performed better in both conditions, with significant SMEs detected in the time windows of P2, N3, P550, and late positive component (LPC). In the older group, SMEs were observed in the P2 and N3 latencies in both conditions but were only detected in the P550 in the semantic condition. Between-group analyses showed larger frontal and central SMEs in the younger sample in the LPC latency regardless of encoding type. Aging effect appears to be stronger on influencing perceptual than semantic encoding processes. The effects seem to be associated with a decline in updating and maintaining representations during perceptual encoding. The age-related decline in the encoding function may be due in part to changes in frontal lobe function. PMID:24374080

Kuo, M C C; Liu, K P Y; Ting, K H; Chan, C C H

2014-03-01

33

Mental Fatigue Modulates Dynamic Adaptation to Perceptual Demand in Speeded Detection  

PubMed Central

When stimulus intensity in simple reaction-time tasks randomly varies across trials, detection speed usually improves after a low-intensity trial. With auditory stimuli, this improvement was often found to be asymmetric, being greater on current low-intensity trials. Our study investigated (1) whether asymmetric sequential intensity adaptation also occurs with visual stimuli; (2) whether these adjustments reflect decision-criterion shifts or, rather, a modulation of perceptual sensitivity; and (3) how sequential intensity adaptation and its underlying mechanisms are affected by mental fatigue induced through prolonged performance. In a continuous speeded detection task with randomly alternating high- and low-intensity visual stimuli, the reaction-time benefit after low-intensity trials was greater on subsequent low- than high-intensity trials. This asymmetry, however, only developed with time on task (TOT). Signal-detection analyses showed that the decision criterion transiently became more liberal after a low-intensity trial, whereas observer sensitivity increased when the preceding and current stimulus were of equal intensity. TOT-induced mental fatigue only affected sensitivity, which dropped more on low- than on high-intensity trials. This differential fatigue-related sensitivity decrease selectively enhanced the impact of criterion down-shifts on low-intensity trials, revealing how the interplay of two perceptual mechanisms and their modulation by fatigue combine to produce the observed overall pattern of asymmetric performance adjustments to varying visual intensity in continuous speeded detection. Our results have implications for similar patterns of sequential demand adaptation in other cognitive domains as well as for real-world prolonged detection performance. PMID:22145041

Langner, Robert; Eickhoff, Simon B.; Steinborn, Michael B.

2011-01-01

34

Well-Being Affects Changes in Perceptual Speed in Advanced Old Age: Longitudinal Evidence for a Dynamic Link  

ERIC Educational Resources Information Center

This study examined competing hypotheses about dynamic cross-domain associations between perceptual speed and well-being in advanced old age. We applied the bivariate dual change score model (J. J. McArdle & F. Hamagami, 2001) to 13-year incomplete longitudinal data from the Berlin Aging Study (P. B. Baltes & K. U. Mayer, 1999; N = 516, 70-103…

Gerstorf, Denis; Lovden, Martin; Rocke, Christina; Smith, Jacqui; Lindenberger, Ulman

2007-01-01

35

The Perceptual Root of Object-Based Storage: An Interactive Model of Perception and Visual Working Memory  

ERIC Educational Resources Information Center

Mainstream theories of visual perception assume that visual working memory (VWM) is critical for integrating online perceptual information and constructing coherent visual experiences in changing environments. Given the dynamic interaction between online perception and VWM, we propose that how visual information is processed during visual…

Gao, Tao; Gao, Zaifeng; Li, Jie; Sun, Zhongqiang; Shen, Mowei

2011-01-01

36

Language and Short-Term Memory: The Role of Perceptual-Motor Affordance  

PubMed Central

The advantage for real words over nonwords in serial recall—the lexicality effect—is typically attributed to support for item-level phonology, either via redintegration, whereby partially degraded short-term traces are “cleaned up” via support from long-term representations of the phonological material or via the more robust temporary activation of long-term lexical phonological knowledge that derives from its combination with established lexical and semantic levels of representation. The much smaller effect of lexicality in serial recognition, where the items are re-presented in the recognition cue, is attributed either to the minimal role for redintegration from long-term memory or to the minimal role for item memory itself in such retrieval conditions. We show that the reduced lexicality effect in serial recognition is not a function of the retrieval conditions, but rather because previous demonstrations have used auditory presentation, and we demonstrate a robust lexicality effect for visual serial recognition in a setting where auditory presentation produces no such effect. Furthermore, this effect is abolished under conditions of articulatory suppression. We argue that linguistic knowledge affects the readiness with which verbal material is segmentally recoded via speech motor processes that support rehearsal and therefore affects tasks that involve recoding. On the other hand, auditory perceptual organization affords sequence matching in the absence of such a requirement for segmental recoding and therefore does not show such effects of linguistic knowledge. PMID:24797440

2014-01-01

37

Speed of Processing, Working Memory, and Language Impairment in Children  

ERIC Educational Resources Information Center

Purpose: Children with language impairment (LI) often perform below the level of typically developing peers on measures of both processing speed and working memory. This study examined the relationship between these 2 types of measures and attempted to determine whether such measures can account for the LI itself. Method: Fourteen-year-old…

Leonard, Laurence B.; Weismer, Susan Ellis; Miller, Carol A.; Francis, David J.; Tomblin, J. Bruce; Kail, Robert V.

2007-01-01

38

High speed magneto-resistive random access memory  

NASA Technical Reports Server (NTRS)

A high speed read MRAM memory element is configured from a sandwich of magnetizable, ferromagnetic film surrounding a magneto-resistive film which may be ferromagnetic or not. One outer ferromagnetic film has a higher coercive force than the other and therefore remains magnetized in one sense while the other may be switched in sense by a switching magnetic field. The magneto-resistive film is therefore sensitive to the amplitude of the resultant field between the outer ferromagnetic films and may be constructed of a high resistivity, high magneto-resistive material capable of higher sensing currents. This permits higher read voltages and therefore faster read operations. Alternate embodiments with perpendicular anisotropy, and in-plane anisotropy are shown, including an embodiment which uses high permeability guides to direct the closing flux path through the magneto-resistive material. High density, high speed, radiation hard, memory matrices may be constructed from these memory elements.

Wu, Jiin-Chuan (inventor); Stadler, Henry L. (inventor); Katti, Romney R. (inventor)

1992-01-01

39

Topographic amnesia: spatial memory disorder, perceptual dysfunction, or category specific semantic memory impairment?  

PubMed Central

A 60 year old patient, SE, who presented with a severe difficulty in finding his way around previously familiar environments and a mild prosopagnosia is described. SE had herpes simplex encephalitis resulting in selective right temporal lobe damage. He showed normal spatial learning, but was severely imparied in his ability to recognise pictures of buildings and landmarks. The disorder was not confined to the visual modality, but rather involved a loss of knowledge about famous buildings and landmarks when tested from their spoken name. SE was contrasted with a more severely prosopagnosic patient, PHD, who showed normal ability to recognise buildings and landmarks, indicating that recognition of people dissociates from recognition of buildings/landmarks. It is concluded that SE's failure of place knowledge represents a category specific supramodal semantic memory impairment. Images PMID:8609511

McCarthy, R A; Evans, J J; Hodges, J R

1996-01-01

40

Perceptually or conceptually driven recognition: On the specificities of the memory deficit in schizophrenia.  

PubMed

This study explored the effects of exemplar changes on visual object recognition in patients with schizophrenia and paired control subjects. The experimental design was derived from the process-dissociation procedure (PDP: Jacoby, 1991). The objects presented at test could be the same exemplar as at study (physically identical picture), a different exemplar of the same object category, or a new, non-studied object. In the inclusion task, participants had to generalize their recognition to the conceptual level by accepting both different and identical exemplars as old. In the exclusion task, on the other hand, they had to accept only the same exemplars of the studied objects as old. Overall, performance was better on the inclusion task than on the exclusion task; schizophrenia patients performed worse than controls on the inclusion task but not the exclusion task, misrecognizing different exemplars more often than healthy controls. The present findings reveal that both recollection and familiarity are impaired in patients with schizophrenia, who present a relational, conceptually driven memory deficit. This deficit does not allow them to recognize an object as a member of a specific category independently of perceptual variations. This retrieval mode influences their subjective awareness of items? familiarity, and should be considered as a target for remediation. PMID:25535008

Guillaume, Fabrice; Thomas, Emilie; Faget, Catherine; Richieri, Raphaelle; Lançon, Christophe

2015-02-28

41

Sparse distributed memory: understanding the speed and robustness of expert memory  

PubMed Central

How can experts, sometimes in exacting detail, almost immediately and very precisely recall memory items from a vast repertoire? The problem in which we will be interested concerns models of theoretical neuroscience that could explain the speed and robustness of an expert's recollection. The approach is based on Sparse Distributed Memory, which has been shown to be plausible, both in a neuroscientific and in a psychological manner, in a number of ways. A crucial characteristic concerns the limits of human recollection, the “tip-of-tongue” memory event—which is found at a non-linearity in the model. We expand the theoretical framework, deriving an optimization formula to solve this non-linearity. Numerical results demonstrate how the higher frequency of rehearsal, through work or study, immediately increases the robustness and speed associated with expert memory. PMID:24808842

Brogliato, Marcelo S.; Chada, Daniel M.; Linhares, Alexandre

2014-01-01

42

Granger causality analysis reveals distinct spatio-temporal connectivity patterns in motor and perceptual visuo-spatial working memory.  

PubMed

We employed spectral Granger causality analysis on a full set of 56 electroencephalographic recordings acquired during the execution of either a 2D movement pointing or a perceptual (yes/no) change detection task with memory and non-memory conditions. On the basis of network characteristics across frequency bands, we provide evidence for the full dissociation of the corresponding cognitive processes. Movement-memory trial types exhibited higher degree nodes during the first 2 s of the delay period, mainly at central, left frontal and right-parietal areas. Change detection-memory trial types resulted in a three-peak temporal pattern of the total degree with higher degree nodes emerging mainly at central, right frontal, and occipital areas. Functional connectivity networks resulting from non-memory trial types were characterized by more sparse structures for both tasks. The movement-memory trial types encompassed an apparent coarse flow from frontal to parietal areas while the opposite flow from occipital, parietal to central and frontal areas was evident for the change detection-memory trial types. The differences among tasks and conditions were more profound in ? (8-12 Hz) and ? (12-30 Hz) and less in ? (30-45 Hz) band. Our results favor the hypothesis which considers spatial working memory as a by-product of specific mental processes that engages common brain areas under different network organizations. PMID:25431557

Protopapa, Foteini; Siettos, Constantinos I; Evdokimidis, Ioannis; Smyrnis, Nikolaos

2014-01-01

43

Ganzfeld perceptual field and gender effects on short-term memory as a function of rate of digit presentation.  

PubMed

Efforts to enhance short term memory for digit span (in serial recall) included the Ganzfeld perceptual field and variation in the rate (interstimulus interval: 1 sec., 2 sec., 3 sec.) of 25 auditorily presented computer-generated random numbers (1 to 5). Undergraduate volunteers (52 men and 91 women) wore goggles consisting of halves of translucent ping-pong balls while viewing a red lamp and listening to 60 decibels of white noise. Control subjects wore goggles with clear plastic lenses. Participants were instructed to recall 25 random digits in the correct series (vocalized sequentially through headphones worn by the subjects) immediately after their presentations. A mixed 2 x 2 x 3 split plot analysis of variance yielded a significant effect for digit rates, and post hoc Scheffe tests of multiple comparisons showed differences in recall between interstimulus intervals of 1 and 2 sec., 1 and 3 sec., and 2 and 3 sec. Other Scheffe comparisons showed that men scored higher than women with the 3-sec. interstimulus interval and with the "clear" perceptual field. Ganzfeld may have reduced distractibility for women as compared with recall following the "clear" perceptual field. Serial-position effects favored "primacy," yet the "recency effect" was seen within the last 5 serial positions. PMID:8823899

Vitulli, W F; Laconsay, K L; Shepard, H A

1996-06-01

44

The influence of perceptual speed regulation on speed perception, choice, and control: Tunnel wall characteristics and influences  

Microsoft Academic Search

The present work sought to determine if the type of visual pattern and presence of texture applied to transportation tunnel walls differentially affected driving performance. Choice of speed and speed control were measured with 32 participants who drove through a simulated transportation tunnel environment. Participants experienced three visual patterns consisting of vertical segments that decreased, increased, and remained a constant

M. P. Manser; P. A. Hancock

2007-01-01

45

Your brain on speed: cognitive performance of a spatial working memory task is not affected by walking speed  

PubMed Central

When humans walk in everyday life, they typically perform a range of cognitive tasks while they are on the move. Past studies examining performance changes in dual cognitive-motor tasks during walking have produced a variety of results. These discrepancies may be related to the type of cognitive task chosen, differences in the walking speeds studied, or lack of controlling for walking speed. The goal of this study was to determine how young, healthy subjects performed a spatial working memory task over a range of walking speeds. We used high-density electroencephalography to determine if electrocortical activity mirrored changes in cognitive performance across speeds. Subjects stood (0.0 m/s) and walked (0.4, 0.8, 1.2, and 1.6 m/s) with and without performing a Brooks spatial working memory task. We hypothesized that performance of the spatial working memory task and the associated electrocortical activity would decrease significantly with walking speed. Across speeds, the spatial working memory task caused subjects to step more widely compared with walking without the task. This is typically a sign that humans are adapting their gait dynamics to increase gait stability. Several cortical areas exhibited power fluctuations time-locked to memory encoding during the cognitive task. In the somatosensory association cortex, alpha power increased prior to stimulus presentation and decreased during memory encoding. There were small significant reductions in theta power in the right superior parietal lobule and the posterior cingulate cortex around memory encoding. However, the subjects did not show a significant change in cognitive task performance or electrocortical activity with walking speed. These findings indicate that in young, healthy subjects walking speed does not affect performance of a spatial working memory task. These subjects can devote adequate cortical resources to spatial cognition when needed, regardless of walking speed. PMID:24847239

Kline, Julia E.; Poggensee, Katherine; Ferris, Daniel P.

2014-01-01

46

Effects of Animation's Speed of Presentation on Perceptual Processing and Learning  

ERIC Educational Resources Information Center

Animations presented at different speed are assumed to differentially interact with learners' perception and cognition due to the constraints imposed by learners' limited sensitivity to incoming dynamic information. To investigate the effects of high and low presentation speed of animation, two studies were conducted. In Study 1, participants were…

Meyer, Katja; Rasch, Thorsten; Schnotz, Wolfgang

2010-01-01

47

FoxP Influences the Speed and Accuracy of a Perceptual Decision in Drosophila+  

PubMed Central

Decisions take time if information gradually accumulates to a response threshold, but the neural mechanisms of integration and thresholding are unknown. We characterized a decision process in Drosophila that bears the behavioral signature of evidence accumulation. As stimulus contrast in trained odor discriminations decreased, reaction times increased and perceptual accuracy declined, in quantitative agreement with a drift-diffusion model. FoxP mutants took longer than wild-type flies to form decisions of similar or reduced accuracy, especially in difficult, low-contrast tasks. RNAi knock-down of FoxP in ?? core Kenyon cells, or the overexpression of a potassium conductance in these neurons, recapitulated the FoxP mutant phenotype. A mushroom body subdomain whose development or function require the transcription factor FoxP thus supports the progression of a decision towards commitment. PMID:24855268

DasGupta, Shamik; Ferreira, Clara Howcroft; Miesenböck, Gero

2014-01-01

48

Music perception involves complex brain functions underlying feature extraction, perceptual grouping of these features, memory, processing of emotion, and so on.  

E-print Network

: Music perception involves complex brain functions underlying feature extraction, perceptual grouping of these features, memory, processing of emotion, and so on. Numerous studies used neuroimaging), or magnetoencephalography (MEG), and have reported neural correlates of these processing in the brain. Also, it is well

Tanaka, Jiro

49

Perceptual Filtering in L2 Lexical Memory: A Neural Network Approach to Second Language Acquisition  

ERIC Educational Resources Information Center

A number of asymmetries in lexical memory emerge when monolinguals and early bilinguals are compared to (relatively) late second language (L2) learners. Their study promises to provide insight into the internal processes that both support and ultimately limit L2 learner achievement. Generally, theory building in L2 and bilingual lexical memory has…

Nelson, Robert

2012-01-01

50

Refining Our Approach to Perceptual Disorders.  

ERIC Educational Resources Information Center

A model of perceptual processing which posits four primary components of perceptual processing (sensory encoding, perceptual integration, memorial classification and retrieval, and cognitive abstraction) is explained to be helpful in identifying the nature of the learning disabled child's perceptual disorders and in designing a remediation…

Melamed, Lawrence E.; Melamed, Esther C.

1982-01-01

51

Untangling perceptual memory: hysteresis and adaptation map into separate cortical networks.  

PubMed

Perception is an active inferential process in which prior knowledge is combined with sensory input, the result of which determines the contents of awareness. Accordingly, previous experience is known to help the brain "decide" what to perceive. However, a critical aspect that has not been addressed is that previous experience can exert 2 opposing effects on perception: An attractive effect, sensitizing the brain to perceive the same again (hysteresis), or a repulsive effect, making it more likely to perceive something else (adaptation). We used functional magnetic resonance imaging and modeling to elucidate how the brain entertains these 2 opposing processes, and what determines the direction of such experience-dependent perceptual effects. We found that although affecting our perception concurrently, hysteresis and adaptation map into distinct cortical networks: a widespread network of higher-order visual and fronto-parietal areas was involved in perceptual stabilization, while adaptation was confined to early visual areas. This areal and hierarchical segregation may explain how the brain maintains the balance between exploiting redundancies and staying sensitive to new information. We provide a Bayesian model that accounts for the coexistence of hysteresis and adaptation by separating their causes into 2 distinct terms: Hysteresis alters the prior, whereas adaptation changes the sensory evidence (the likelihood function). PMID:23236204

Schwiedrzik, Caspar M; Ruff, Christian C; Lazar, Andreea; Leitner, Frauke C; Singer, Wolf; Melloni, Lucia

2014-05-01

52

Effects of repetition priming on recognition memory: testing a perceptual fluency-disfluency model.  

PubMed

Five experiments explored the effects of immediate repetition priming on episodic recognition (the "Jacoby-Whitehouse effect") as measured with forced-choice testing. These experiments confirmed key predictions of a model adapted from D. E. Huber and R. C. O'Reilly's (2003) dynamic neural network of perception. In this model, short prime durations pre-activate primed items, enhancing perceptual fluency and familiarity, whereas long prime durations result in habituation, causing perceptual disfluency and less familiarity. Short duration primes produced a recognition preference for primed words (Experiments 1, 2, and 5), whereas long duration primes produced a preference against primed words (Experiments 3, 4, and 5). Experiment 2 found prime duration effects even when participants accurately identified short duration primes. A cued-recall task included in Experiments 3, 4, and 5 found priming effects only for recognition trials that were followed by cued-recall failure. These results suggest that priming can enhance as well as lower familiarity, without affecting recollection. Experiment 4 provided a manipulation check on this procedure through a delay manipulation that preferentially affected recognition followed by cued-recall success. PMID:18980396

Huber, David E; Clark, Tedra F; Curran, Tim; Winkielman, Piotr

2008-11-01

53

Predictors of Memory and Processing Speed Dysfunctions after Traumatic Brain Injury  

PubMed Central

Background. The aims of this study were to evaluate the predictive value of admission Glasgow Coma Scale (GCS) scores, duration of unconsciousness, neurosurgical intervention, and countercoup lesion on the impairment of memory and processing speed functions six months after a traumatic brain injury (TBI) based on a structural equation modeling. Methods. Thirty TBI patients recruited from Neurosurgical Department at the Kaohsiung Medical University Hospital were administered the Wechsler Memory Scale-III (WMS-III) and the Wechsler Adult Intelligence Scale-III processing speed index to evaluate the memory and processing speed functions. Results. The study showed that GCS scores accounted for 40% of the variance in memory/processing speed. No significant predictive effects were found for the other three variables. GCS classification at the time of TBI seems to correspond moderately to the severity of memory/processing speed dysfunctions. Conclusions. The present study demonstrated that admission GCS score is a robust predictor of memory/processing speed dysfunctions after TBI. The results should be replicated with a large sample of patients with TBI, or be extended by examining other potential clinical predictors. PMID:24877054

Winardi, William; Kwan, Aij-Lie; Wang, Tse-Lun; Su, Yu-Feng; Yen, Chun-Po; Tsai, Hung-Pei; Sheehan, Jason; Su, Chwen-Yng

2014-01-01

54

The Ineluctable Modality of the Audible: Perceptual Determinants of Auditory Verbal Short-Term Memory  

ERIC Educational Resources Information Center

Classical cognitive accounts of verbal short-term memory (STM) invoke an abstract, phonological level of representation which, although it may be derived differently via different modalities, is itself amodal. Key evidence for this view is that serial recall of phonologically similar verbal items (e.g., the letter sounds "b", "c", "g", and "d") is…

Maidment, David W.; Macken, William J.

2012-01-01

55

Working Memory Is Related to Perceptual Processing: A Case from Color Perception  

ERIC Educational Resources Information Center

We explored the relation between individual differences in working memory (WM) and color constancy, the phenomenon of color perception that allows us to perceive the color of an object as relatively stable under changes in illumination. Successive color constancy (measured by first viewing a colored surface under a particular illumination and…

Allen, Elizabeth C.; Beilock, Sian L.; Shevell, Steven K.

2011-01-01

56

The Effects of Alcohol on the Speed of Memory Retrieval.  

ERIC Educational Resources Information Center

Recent research has clearly indicated that intoxication with alcohol impairs memory. The present study investigated the effects of alcohol on retrieval from long-term memory by using a set of cognitive decision tasks. Subjects (N=24) were female college students in good health not taking oral contraceptives. Subjects were administered 0 or 1.0…

Stempel, Jennifer J.; And Others

57

Accuracy and Speed of Memory in Depressed and Organic Aged  

ERIC Educational Resources Information Center

Subjects (N=43) aged 50 and more were tested on a Sternberg recognition-memory task to explore the relative effects of depression and altered brain function on short-term memory in later life. Many performance differnces were best accounted for by the additive effects of depression and educational background, rather than by either variable…

Hilbert, Nancy M.; And Others

1976-01-01

58

A Latent Variables Examination of Processing Speed, Response Inhibition, and Working Memory during Typical Development  

PubMed Central

The present study addressed three related aims: (1) to replicate and extend previous work regarding the non-unitary nature of processing speed, response inhibition, and working memory during development, (2) to quantify the rate at which processing speed, response inhibition, and working memory develop and the extent to which the development of these latter abilities reflect general changes in processing speed, and (3) to evaluate whether commonly used tasks of processing speed, response inhibition, and working memory are valid and reliable when used with a developmentally diverse group. To address these aims, a latent variables approach was used to analyze data from 147 participants 6 to 24 years of age. Results showed that processing speed, response inhibition, and working memory were separable abilities and that the extent of this separability was stable cross the age range of participants. All three constructs improved as a function of age; however, only the effect of age on working memory remained significant after processing speed was controlled. The psychometric properties of tasks used to assess the constructs were age invariant, thus validating their use in studies of executive development. PMID:20888572

McAuley, Tara; White, Desirée

2010-01-01

59

Design of a GHz high-speed memory system  

NASA Astrophysics Data System (ADS)

Digital application has moved towards operating speed of hundreds of Mega Hertz, with the sampling speed of ADC moving into Giga Hertz range. There is an increasing need for the design and development of a high-speed data acquisition system that is capable of capturing and processing digitized analogue signal at high speed. Due to the tight timing budget, high operating speed components, Emitter-Coupled-Logic families components with rise time of typically less than 300 ps were used in the design. With this operating speed and short rise time, signal integrity issues like reflections due to impedance mismatches and crosstalk among the traces of the printed circuit board can no longer be neglected. A quick and reliable approach was taken in the design and implementation of a 1 GHz high-speed data acquisition system using commercial-off-the-shelf discrete components. High-speed digital design issues and methodology were explored in this project and verified with the implemented hardware. This paper gives an overview of the system and focuses on the use of functional and signal- integrity computer simulation software to confirm system performance at the early design stage before actual hardware implementation. Simulation results were further confirmed with the actual hardware implemented, and was found to be close. This has helped to reduce the design cycle time and development cost of the project.

Lim, Teck Y.; Foo, Say W.; Chan, Kheng Kang

1999-12-01

60

Speeding in school zones: violation or lapse in prospective memory?  

PubMed

Inappropriate speed is a causal factor in around one third of fatal accidents (OECD/ECMT, 2006). But are drivers always consciously responsible for their speeding behavior? Two studies are reported which show that an interruption to a journey, caused by stopping at a red traffic light, can result in failure to resume the speed of travel prior to the interruption (Study 1). In Study 2 we showed that the addition of a reminder cue could offset this interruption. These studies were conducted in a number of Australian school zone sites subject to a 40 km/h speed limit, requiring a reduction of between 20 km/h and 40 km/h. Motorists who had stopped at a red traffic signal sped on average, 8.27 km/h over the speed limit compared with only 1.76 km/h over the limit for those who had not been required to stop. In the second study a flashing "check speed" reminder cue, placed 70 m after the traffic lights, in the same school zones as those in Study 1 eliminated the interruptive effect of stopping with drivers resuming their journey at the legal speed. These findings have practical implications for the design of road environments, enforcement of speed limits, and the safety of pedestrians. PMID:24884545

Gregory, Bree; Irwin, Julia D; Faulks, Ian J; Chekaluk, Eugene

2014-09-01

61

Long-Term Speeding in Perceptual Switches Mediated by Attention-Dependent Plasticity in Cortical Visual Processing  

Microsoft Academic Search

SUMMARY Binocular rivalry has been extensively studied to understand the mechanisms that control switches in visual awareness and much has been revealed about the contributions of sti- mulus and cognitive factors. Because visual processes are fundamentally adaptive, how- ever, it is also important to understand how ex- perience alters the dynamics of perceptual switches. When observers viewed binocular rivalry repeatedly

Satoru Suzuki; Marcia Grabowecky

2007-01-01

62

The relationship between IQ, memory, executive function, and processing speed in recent-onset psychosis: 1-year stability and clinical outcome.  

PubMed

Studies commonly report poor performance in psychotic patients compared with controls on tasks testing a range of cognitive functions, but, because current IQ is often not matched between these groups, it is difficult to determine whether this represents a generalized deficit or specific abnormalities. Fifty-three first-episode psychosis patients and 53 healthy controls, one-to-one matched for sex, age, and full-scale current IQ, were compared on Wechsler Adult Intelligence Scale (WAIS) subtests representing indices of perceptual organization, verbal comprehension, processing speed, and working memory as well as other tests of executive function and episodic memory. The groups showed an equivalent pattern of performance on all WAIS subtests except digit symbol processing speed, on which the patients were significantly worse. Patients were also worse on measures where performance correlated with digit symbol score, namely working and verbal memory tasks. Standardized residual scores for each subtest were calculated for each patient using the difference between their actual subtest score and a predicted subtest score based on their full-scale IQ and the performance of controls. Scaled scores and residual scores were examined for relationships with clinical measures. Digit symbol-scaled score was significantly correlated with concurrent negative syndrome score at baseline, and digit symbol residual score significantly predicted residual negative symptoms at 1-year follow-up. In summary, our comparison of patients and controls precisely matched for IQ revealed that processing speed was attenuated in recent-onset schizophrenia, contributed significantly to working and episodic memory deficits, and was a prognostic factor for poor outcome at 1 year. PMID:18682375

Leeson, Verity C; Barnes, Thomas R E; Harrison, Masuma; Matheson, Elizabeth; Harrison, Isobel; Mutsatsa, Stanley H; Ron, Maria A; Joyce, Eileen M

2010-03-01

63

Perceptual Constraints in Phonotactic Learning  

ERIC Educational Resources Information Center

Structural regularities in language have often been attributed to symbolic or statistical general purpose computations, whereas perceptual factors influencing such generalizations have received less interest. Here, we use phonotactic-like constraints as a case study to ask whether the structural properties of specific perceptual and memory

Endress, Ansgar D.; Mehler, Jacques

2010-01-01

64

Intelligence and the Effects of Perceptual Processing Demands, Task Difficulty, and Processing Speed on P300, Reaction Time and Movement Time.  

ERIC Educational Resources Information Center

The latency and amplitude of the P300, an event-related potential, during the performance of a memory-scanning task were used as indices of the efficiency of information processing that may mediate individual differences in intelligence. Results with 61 female college students contradict a pure speed of processing explanation of the relationship…

Houlihan, Michael; Stelmack, Robert; Campbell, Kenneth

1998-01-01

65

Delayed Perceptual Awareness in Rapid Perceptual Decisions  

PubMed Central

The flourishing of studies on the neural correlates of decision-making calls for an appraisal of the relation between perceptual decisions and conscious perception. By exploiting the long integration time of noisy motion stimuli, and by forcing human observers to make difficult speeded decisions – sometimes a blind guess – about stimulus direction, we traced the temporal buildup of motion discrimination capability and perceptual awareness, as assessed trial by trial through direct rating. We found that both increased gradually with motion coherence and viewing time, but discrimination was systematically leading awareness, reaching a plateau much earlier. Sensitivity and criterion changes contributed jointly to the slow buildup of perceptual awareness. It made no difference whether motion discrimination was accomplished by saccades or verbal responses. These findings suggest that perceptual awareness emerges on the top of a developing or even mature perceptual decision. We argue that the middle temporal (MT) cortical region does not confer us the full phenomenic depth of motion perception, although it may represent a precursor stage in building our subjective sense of visual motion. PMID:21379582

Gregori-Grgi?, Regina; Balderi, Monica; de'Sperati, Claudio

2011-01-01

66

Perceptual-Gestural (Mis)Mapping in Serial Short-Term Memory: The Impact of Talker Variability  

ERIC Educational Resources Information Center

The mechanisms underlying the poorer serial recall of talker-variable lists (e.g., alternating female-male voices) as compared with single-voice lists were examined. We tested the novel hypothesis that this "talker variability effect" arises from the tendency for perceptual organization to partition the list into streams based on voice such that…

Hughes, Robert W.; Marsh, John E.; Jones, Dylan M.

2009-01-01

67

Do working memory-driven attention shifts speed up visual awareness?  

PubMed

Previous research has shown that content representations in working memory (WM) can bias attention in favor of matching stimuli in the scene. Using a visual prior-entry procedure, we here investigate whether such WM-driven attention shifts can speed up the conscious awareness of memory-matching relative to memory-mismatching stimuli. Participants were asked to hold a color cue in WM and to subsequently perform a temporal order judgment (TOJ) task by reporting either of two different-colored circles (presented to the left and right of fixation with a variable temporal interval) as having the first onset. One of the two TOJ circles could match the memory cue in color. We found that awareness of the temporal order of the circle onsets was not affected by the contents of WM, even when participants were explicitly informed that one of the TOJ circles would always match the WM contents. The null effect of WM on TOJs was not due to an inability of the memory-matching item to capture attention, since response times to the target in a follow-up experiment were improved when it appeared at the location of the memory-matching item. The present findings suggest that WM-driven attention shifts cannot accelerate phenomenal awareness of matching stimuli in the visual field. PMID:21837542

Pan, Yi; Cheng, Qiu-Ping

2011-11-01

68

Room-temperature high-speed nuclear-spin quantum memory in diamond  

E-print Network

Quantum memories provide intermediate storage of quantum information until it is needed for the next step of a quantum algorithm or a quantum communication process. Relevant figures of merit are therefore the fidelity with which the information can be written and retrieved, the storage time, and also the speed of the read-write process. Here, we present experimental data on a quantum memory consisting of a single $^{13}$C nuclear spin that is strongly coupled to the electron spin of a nitrogen-vacancy (NV) center in diamond. The strong hyperfine interaction of the nearest-neighbor carbon results in transfer times of 300 ns between the register qubit and the memory qubit, with an overall fidelity of 88 % for the write - storage - read cycle. The observed storage times of 3.3 ms appear to be limited by the T$_1$ relaxation of the electron spin. We discuss a possible scheme that may extend the storage time beyond this limit.

J. H. Shim; I. Niemeyer; J. Zhang; D. Suter

2013-01-03

69

Assessing the validity of computer-game-like tests of processing speed and working memory  

Microsoft Academic Search

Processing speed (Gs) and working memory (WM) tasks have received considerable interest as correlates of more complex cognitive\\u000a performance measures. Gs and WM tasks are often repetitive and are often rigidly presented, however. The effects of Gs and\\u000a WM may, therefore, be confounded with those of motivation and anxiety. In an effort to address this problem, we assessed the\\u000a concurrent

Jason McPherson; Nicholas R. Burns

2008-01-01

70

Dissociable mechanisms of speed-accuracy tradeoff during visual perceptual learning are revealed by a hierarchical drift-diffusion model  

PubMed Central

Two phenomena are commonly observed in decision-making. First, there is a speed-accuracy tradeoff (SAT) such that decisions are slower and more accurate when instructions emphasize accuracy over speed, and vice versa. Second, decision performance improves with practice, as a task is learnt. The SAT and learning effects have been explained under a well-established evidence-accumulation framework for decision-making, which suggests that evidence supporting each choice is accumulated over time, and a decision is committed to when the accumulated evidence reaches a decision boundary. This framework suggests that changing the decision boundary creates the tradeoff between decision speed and accuracy, while increasing the rate of accumulation leads to more accurate and faster decisions after learning. However, recent studies challenged the view that SAT and learning are associated with changes in distinct, single decision parameters. Further, the influence of speed-accuracy instructions over the course of learning remains largely unknown. Here, we used a hierarchical drift-diffusion model to examine the SAT during learning of a coherent motion discrimination task across multiple training sessions, and a transfer test session. The influence of speed-accuracy instructions was robust over training and generalized across untrained stimulus features. Emphasizing decision accuracy rather than speed was associated with increased boundary separation, drift rate and non-decision time at the beginning of training. However, after training, an emphasis on decision accuracy was only associated with increased boundary separation. In addition, faster and more accurate decisions after learning were due to a gradual decrease in boundary separation and an increase in drift rate. The results suggest that speed-accuracy instructions and learning differentially shape decision-making processes at different time scales. PMID:24782701

Zhang, Jiaxiang; Rowe, James B.

2014-01-01

71

Relationships Among Linguistic Processing Speed, Phonological Working Memory, and Attention in Children Who Stutter  

PubMed Central

Relatively recently, experimental studies of linguistic processing speed in children who stutter (CWS) have emerged, some of which suggest differences in performance among CWS compared to children who do not stutter (CWNS). What is not yet well understood is the extent to which underlying cognitive skills may impact performance on timed tasks of linguistic performance. The purpose of this study was to explore possible relationships between measures of linguistic processing speed and two aspects of cognition: phonological working memory and attention. Participants were 9 CWS and 14 CWNS between the ages of 3;6 and 5;2. Children participated in a computerized picture naming task (an index of linguistic processing speed) and a nonword repetition task (an index of phonological working memory). Parents completed a temperament behavior questionnaire, from which information about the children’s attentional skills was collected. Findings revealed that the groups did not differ from each other on speed of picture naming or attention; however, the CWS performed significantly worse in nonword repetition. In addition, after partialling out the effects of age, (a) for CWS only, there was a significant negative relationship between picture naming speed and nonword repetition; (b) there were no significant relationships for either group between aspects of attention and picture naming speed; and (c) only the CWNS showed a significant relationship between nonword repetition and focused attentional skills. These results underscore the need to consider the underlying skills associated with lexically-related aspects of language production when examining the task performances of CWS and CWNS. PMID:20831969

Anderson, Julie D.; Wagovich, Stacy A.

2010-01-01

72

Cycles in Speed-Working Memory-G Relations: Towards a Developmental-Differential Theory of the Mind  

ERIC Educational Resources Information Center

This article presents three studies, two of them longitudinal, which investigated the relations between age, processing speed, working memory (WM), and fluid intelligence ("g[subscript f]") from 4 to 16 years of age. Structural equation modeling showed that speed was a powerful covariate of age ([approximately] - 0.6 to - 0.7) from 4 to 13 years,…

Demetriou, Andreas; Spanoudis, George; Shayer, Michael; Mouyi, Antigoni; Kazi, Smaragda; Platsidou, Maria

2013-01-01

73

An ultrahigh-speed color video camera operating at 1,000,000 fps with 288 frame memories  

Microsoft Academic Search

We developed an ultrahigh-speed color video camera that operates at 1,000,000 fps (frames per second) and had capacity to store 288 frame memories. In 2005, we developed an ultrahigh-speed, high-sensitivity portable color camera with a 300,000-pixel single CCD (ISIS-V4: In-situ Storage Image Sensor, Version 4). Its ultrahigh-speed shooting capability of 1,000,000 fps was made possible by directly connecting CCD storages,

K. Kitamura; T. Arai; J. Yonai; T. Hayashida; T. Kurita; H. Maruyama; J. Namiki; T. Yanagi; T. Yoshida; H. van Kuijk; Jan T. Bosiers; A. Saita; S. Kanayama; K. Hatade; S. Kitagawa; T. Goji Etoh

2008-01-01

74

Lisdexamfetamine dimesylate improves processing speed and memory in cognitively impaired MS patients: a phase II study.  

PubMed

Multiple sclerosis (MS) causes cognitive impairment including slowed processing speed and problems with learning and memory. Stimulants are attractive candidates for improving mental speed but carry risk of addiction and other adverse behavioral effects. Lisdexamfetamine dimesylate (LDX) is a D-amphetamine prodrug currently approved for attention deficit (hyperactivity) disorder with the potential to be better tolerated due to its prolonged clinical effect. This phase II placebo-controlled, double-blind study aimed to assess the safety and efficacy of LDX in cognitively impaired MS patients. Subjects were patients with clinically definite MS, aged 18-56 years, and impaired on either of two primary outcomes: the Symbol Digit Modalities Test (SDMT) or the Paced Auditory Serial Addition Test (PASAT). Both SDMT and PASAT are measures of cognitive processing speed. Of 174 MS patients screened, 63 were randomized to 30 mg of LDX or placebo in a 2:1 fashion; the dose was increased as tolerated to 70 mg over 4 weeks and then maintained for another 4 weeks. Secondary outcomes were the Brief Visuospatial Memory Test Revised (BVMTR), the California Verbal Learning Test 2nd edition (CVLT2), both measures of episodic memory, and the Behavioral Rating Inventory of Executive Function for adults (BRIEF-A), a self-report measure of executive function. Fatigue and depression were also evaluated. There was significant improvement in the SDMT score (+4.6 vs. +1.3) and CVLT2 score (+4.7 vs. -0.9) in the LDX group compared with the placebo group among the 49 completers. There was no change on the other outcomes. A high proportion of both LDX-treated and placebo-treated subjects reported adverse events (73.5 % vs. 68.4 %). However, there were no serious adverse events noted in the study. These preliminary data indicate that LDX has the potential to be an efficacious treatment for MS patients with cognitive impairment. PMID:23001556

Morrow, Sarah A; Smerbeck, Audrey; Patrick, Kara; Cookfair, Diane; Weinstock-Guttman, Bianca; Benedict, Ralph H B

2013-02-01

75

Perceptual-Cognitive Expertise in Elite Volleyball Players  

PubMed Central

The goal of the current study was to investigate the relationship between sport expertise and perceptual and cognitive skills, as measured by the component skills approach. We hypothesized that athletes would outperform non-athlete controls in a number of perceptual and cognitive domains and that sport expertise would minimize gender differences. A total of 154 individuals (87 professional volleyball players and 67 non-athlete controls) participated in the study. Participants performed a cognitive battery, which included tests of executive control, memory, and visuo-spatial attention. Athletes showed superior performance speed on three tasks (two executive control tasks and one visuo-spatial attentional processing task). In a subset of tasks, gender effects were observed mainly in the control group, supporting the notion that athletic experience can reduce traditional gender effects. The expertise effects obtained substantiate the view that laboratory tests of cognition may indeed enlighten the sport-cognition relationship. PMID:23471100

Alves, Heloisa; Voss, Michelle W.; Boot, Walter R.; Deslandes, Andrea; Cossich, Victor; Salles, Jose Inacio; Kramer, Arthur F.

2013-01-01

76

Menstrual Cycle Effects on Perceptual Closure Mediate Changes in Performance on a Fragmented Objects Test of Implicit Memory  

ERIC Educational Resources Information Center

Healthy premenopausal women with regular menstrual cycles were assessed on a fragmented objects test of implicit memory. Testing took place at either the low estrogen (n=17) or the high estrogen (n=16) stages of the menstrual cycle. Concentrations of ovarian hormones were confirmed by saliva assays. Both groups of women exhibited a priming effect,…

Hampson, E.; Finestone, J.M.; Levy, N.

2005-01-01

77

Auditory perceptual consolidation in early-onset blindness.  

PubMed

Early-onset blindness (EB) produces measurable advantages in auditory perception, attention, memory and language. Neville and Bavelier [Neville, H. J., & Bavelier, D. (2001) Variability of developmental plasticity. In J. L. McClelland, R. S. Siegler (Eds.) Mechanisms of cognitive development: Behavioral andellon symposia on cognition (pp. 271-301)] hypothesized that faster temporal processing underlies many auditory compensatory effects in the blind. We tested this hypothesis by comparing early-onset blind individuals and sighted counterparts (SC) by assessing their rates of perceptual consolidation, the accurate perceptual representation of auditory stimuli. Firstly, we first tested both groups on a temporal-order judgment task (TOJ). EB subjects had significantly lower TOJ thresholds than the SC subjects. Secondly, we assessed perceptual consolidation speed using auditory backward masking tasks, taking into account individual TOJ thresholds. Discrimination performance was unaffected at all mask delays in the EB group while the SC subjects needed a mask delay of 160 ms to perform comparably. A backward masking task using single tone stimuli found no differences between the EB and SC groups any mask delay. A simultaneous masking task demonstrated that the mask effectively impaired discrimination in EB subjects at sensory stages. These results suggest that advantages in perceptual consolidation may reflect a mechanism responsible for the short response times and better performance reported in early blind individuals across a number of complex auditory tasks. PMID:15869766

Stevens, Alexander A; Weaver, Kurt

2005-01-01

78

The contribution of sleep to improvements in working memory scanning speed: a study of prolonged sleep restriction.  

PubMed

Working memory scanning and motor response speeds were assessed in chronically sleep restricted participants using the Sternberg item recognition paradigm (SIRP). Twenty-two healthy volunteers (ages 21-30) living in a controlled hospital environment were allowed either 4h of sleep opportunity (50% of habitual sleep) or 8h of sleep opportunity (100% of habitual sleep) for 12 days. Working memory scanning efficiency (time taken to access an item in working memory) was tested for the first 9 days of sleep restriction and improved over time in participants permitted an 8h sleep period, but did not change significantly in participants permitted a 4h sleep period. Speed of motor response (reaction time independent of cognitive processing) did not change significantly in either group. These results indicate that the efficiency of working memory scanning can improve with repeated practice given sufficient sleep, and that prolonged sleep restriction to 50% of habitual sleep prevents this improvement. PMID:16384630

Casement, Melynda D; Broussard, Josiane L; Mullington, Janet M; Press, Daniel Z

2006-05-01

79

Comprehension of Linguistic Dependencies: Speed-Accuracy Tradeoff Evidence for Direct-Access Retrieval From Memory  

PubMed Central

Comprehenders can rapidly and efficiently interpret expressions with various types of non-adjacent dependencies. In the sentence The boy that the teacher warned fell, boy is readily interpreted as the subject of the verb fall despite the fact that a relative clause, that the teacher warned, intervenes between the two dependent elements. We review research investigating three memory operations proposed for resolving this and other types of non-adjacent dependencies: serial search retrieval, in which the dependent constituent is recovered by a search process through representations in memory, direct-access retrieval in which the dependent constituent is recovered directly by retrieval cue operations without search, and active maintenance of the dependent constituent in focal attention. Studies using speed-accuracy tradeoff methodology to examine the full timecourse of interpreting a wide range of non-adjacent dependencies indicate that comprehenders retrieve dependent constituents with a direct-access operation, consistent with the claim that representations formed during comprehension are accessed with a cue-driven, content-addressable retrieval process. The observed timecourse profiles are inconsistent with a broad class of models based on several search operations for retrieval. The profiles are also inconsistent with active maintenance of a constituent while concurrently processing subsequent material, and suggest that, with few exceptions, direct-access retrieval is required to process non-adjacent dependencies. PMID:22448181

Foraker, Stephani; McElree, Brian

2012-01-01

80

Visual Perceptual Learning  

PubMed Central

Perceptual learning refers to the phenomenon that practice or training in perceptual tasks often substantially improves perceptual performance. Often exhibiting stimulus or task specificities, perceptual learning differs from learning in the cognitive or motor domains. Research on perceptual learning reveals important plasticity in adult perceptual systems, and as well as the limitations in the information processing of the human observer. In this article, we review the behavioral results, mechanisms, physiological basis, computational models, and applications of visual perceptual learning. PMID:20870024

Lu, Zhong-Lin; Hua, Tianmiao; Huang, Chang-Bing; Zhou, Yifeng; Dosher, Barbara Anne

2010-01-01

81

The Influence of Time of Testing on Interference, Working Memory, Processing Speed, and Vocabulary: Age Differences in Adulthood  

Microsoft Academic Search

This research examines the effect of time of testing on adult age differences in resistance to interference, working memory, processing speed, and vocabulary. Results show that time of testing modulates age-related differences only in the ability to resist automatic and prepotent responses. Older adults tested in the afternoon were more susceptible to interference than young adults tested at the same

Erika Borella; Catherine Ludwig; Judith Dirk; Anik de Ribaupierre

2010-01-01

82

Stochastic accumulation of feature information in perception and memory  

PubMed Central

It is now well established that the time course of perceptual processing influences the first second or so of performance in a wide variety of cognitive tasks. Over the last 20 years, there has been a shift from modeling the speed at which a display is processed, to modeling the speed at which different features of the display are perceived and formalizing how this perceptual information is used in decision making. The first of these models (Lamberts, 1995) was implemented to fit the time course of performance in a speeded perceptual categorization task and assumed a simple stochastic accumulation of feature information. Subsequently, similar approaches have been used to model performance in a range of cognitive tasks including identification, absolute identification, perceptual matching, recognition, visual search, and word processing, again assuming a simple stochastic accumulation of feature information from both the stimulus and representations held in memory. These models are typically fit to data from signal-to-respond experiments whereby the effects of stimulus exposure duration on performance are examined, but response times (RTs) and RT distributions have also been modeled. In this article, we review this approach and explore the insights it has provided about the interplay between perceptual processing, memory retrieval, and decision making in a variety of tasks. In so doing, we highlight how such approaches can continue to usefully contribute to our understanding of cognition. PMID:24860530

Kent, Christopher; Guest, Duncan; Adelman, James S.; Lamberts, Koen

2014-01-01

83

Working Memory and Arithmetic Calculation in Children: The Contributory Roles of Processing Speed, Short-Term Memory, and Reading  

ERIC Educational Resources Information Center

The cognitive underpinnings of arithmetic calculation in children are noted to involve working memory; however, cognitive processes related to arithmetic calculation and working memory suggest that this relationship is more complex than stated previously. The purpose of this investigation was to examine the relative contributions of processing…

Berg, Derek H.

2008-01-01

84

High-speed and localized resistive switching characteristics of double-layer SrZrO3 memory devices  

NASA Astrophysics Data System (ADS)

The fabrication of SrZrO3 (SZO) memory devices with oxygen-rich (OR) and oxygen-deficient (OD) double layers, their resistive switching (RS) characteristics and mechanisms are investigated in this study. Due to the difference in oxygen content between the OR and OD layers formed by an oxygen flow control (OFC) process during SZO deposition, the RS region is effectively reduced and localized within the OR layer, which leads to a low operation voltage and stable RS behaviours. Furthermore, the OFC SZO device exhibits high-speed switching (10 ns) over 400 times and long retention (>106 s), showing promising potential for next-generation nonvolatile memory applications.

Lin, Meng-Han; Wu, Ming-Chi; Huang, Chun-Yang; Lin, Chen-Hsi; Tseng, Tseung-Yuen

2010-07-01

85

Perceptual learning depends on perceptual constancy  

PubMed Central

Perceptual learning refers to experience-induced improvements in the pick-up of information. Perceptual constancy describes the fact that, despite variable sensory input, perceptual representations typically correspond to stable properties of objects. Here, we show evidence of a strong link between perceptual learning and perceptual constancy: Perceptual learning depends on constancy-based perceptual representations. Perceptual learning may involve changes in early sensory analyzers, but such changes may in general be constrained by categorical distinctions among the high-level perceptual representations to which they contribute. Using established relations of perceptual constancy and sensory inputs, we tested the ability to discover regularities in tasks that dissociated perceptual and sensory invariants. We found that human subjects could learn to classify based on a perceptual invariant that depended on an underlying sensory invariant but could not learn the identical sensory invariant when it did not correlate with a perceptual invariant. These results suggest that constancy-based representations, known to be important for thought and action, also guide learning and plasticity. PMID:18250303

Garrigan, Patrick; Kellman, Philip J.

2008-01-01

86

An ultrahigh-speed color video camera operating at 1,000,000 fps with 288 frame memories  

NASA Astrophysics Data System (ADS)

We developed an ultrahigh-speed color video camera that operates at 1,000,000 fps (frames per second) and had capacity to store 288 frame memories. In 2005, we developed an ultrahigh-speed, high-sensitivity portable color camera with a 300,000-pixel single CCD (ISIS-V4: In-situ Storage Image Sensor, Version 4). Its ultrahigh-speed shooting capability of 1,000,000 fps was made possible by directly connecting CCD storages, which record video images, to the photodiodes of individual pixels. The number of consecutive frames was 144. However, longer capture times were demanded when the camera was used during imaging experiments and for some television programs. To increase ultrahigh-speed capture times, we used a beam splitter and two ultrahigh-speed 300,000-pixel CCDs. The beam splitter was placed behind the pick up lens. One CCD was located at each of the two outputs of the beam splitter. The CCD driving unit was developed to separately drive two CCDs, and the recording period of the two CCDs was sequentially switched. This increased the recording capacity to 288 images, an increase of a factor of two over that of conventional ultrahigh-speed camera. A problem with the camera was that the incident light on each CCD was reduced by a factor of two by using the beam splitter. To improve the light sensitivity, we developed a microlens array for use with the ultrahigh-speed CCDs. We simulated the operation of the microlens array in order to optimize its shape and then fabricated it using stamping technology. Using this microlens increased the light sensitivity of the CCDs by an approximate factor of two. By using a beam splitter in conjunction with the microlens array, it was possible to make an ultrahigh-speed color video camera that has 288 frame memories but without decreasing the camera's light sensitivity.

Kitamura, K.; Arai, T.; Yonai, J.; Hayashida, T.; Kurita, T.; Maruyama, H.; Namiki, J.; Yanagi, T.; Yoshida, T.; van Kuijk, H.; Bosiers, Jan T.; Saita, A.; Kanayama, S.; Hatade, K.; Kitagawa, S.; Etoh, T. Goji

2008-11-01

87

Enhancement of erase speed using silicide drain in nanowire SONOS NAND flash memory  

Microsoft Academic Search

Since recent mobile electronic devices have started to adopt NAND flash memory as their main data storage device, the demand for low cost and high density NAND flash memory has been rapidly increasing. As a promising candidate, nanowire SONOS NAND flash memory array has been introduced and reported for highly scalable device structure. However, since it is hard to bias

Wandong Kim; Il Han Park; Seongjae Cho; Dong Hua Li; Jang-Gn Yun; Byung-Gook Park

2009-01-01

88

Perceptual asynchrony for motion  

PubMed Central

Psychophysical experiments show that two different visual attributes, color and motion, processed in different areas of the visual brain, are perceived at different times relative to each other (Moutoussis and Zeki, 1997a). Here we demonstrate psychophysically that two variants of the same attribute, motion, which have the same temporal structure and are processed in the same visual areas, are also processed asynchronously. When subjects were asked to pair up–down motion of dots in one half of their hemifield with up-right motion in the other, they perceived the two directions of motion asynchronously, with the advantage in favor of up-right motion; when they were asked to pair the motion of white dots moving against a black background with that of red dots moving against an equiluminant green background, they perceived the luminant motion first, thus demonstrating a perceptual advantage of luminant over equiluminant motion. These results were not affected by motion speed or perceived motion “streaks.” We thus interpret these results to reflect the different processing times produced by luminant and equiluminant motion stimuli or by different degrees of motion direction change, thus adding to the evidence that processing time within the visual system is a major determinant of perceptual time. PMID:24624071

Lo, Yu Tung; Zeki, Semir

2014-01-01

89

High speed, very large (8 megabyte) first in/first out buffer memory (FIFO)  

DOEpatents

A fast FIFO (First In First Out) memory buffer capable of storing data at rates of 100 megabytes per second. The invention includes a data packer which concatenates small bit data words into large bit data words, a memory array having individual data storage addresses adapted to store the large bit data words, a data unpacker into which large bit data words from the array can be read and reconstructed into small bit data words, and a controller to control and keep track of the individual data storage addresses in the memory array into which data from the packer is being written and data to the unpacker is being read.

Baumbaugh, Alan E. (Batavia, IL); Knickerbocker, Kelly L. (Aurora, IL)

1989-01-01

90

Memory.  

ERIC Educational Resources Information Center

Discusses current research (including that involving amnesiacs and snails) into the nature of the memory process, differentiating between and providing examples of "fact" memory and "skill" memory. Suggests that three brain parts (thalamus, fornix, mammilary body) are involved in the memory process. (JN)

McKean, Kevin

1983-01-01

91

A 4096-bit high-speed emitter-coupled-logic (ECL) compatible random-access memory  

Microsoft Academic Search

A 4096-bit pseudostatic MOS random-access memory with emitter-coupled (ECL) compatibility on all inputs including clocks is described. This device exhibits access times of under 80 ns and cycle times of under 150 ns with a standby dissipation of 300 mW. The fully decoded memory is fabricated on a 204×237 mil silicon chip and is assembled in a 22-lead ceramic dual-in-line

M. S. Ebel; J. Gionis; W. M. Regitz

1975-01-01

92

Cache Memories  

Microsoft Academic Search

Cache memories are used in modern, medium and high-speed CPUs to hold temporarily those portions of the contents of main memory which are {believed to be) currently in use. Since instructions and data in cache memories can usually be referenced in 10 to 25 percent of the time required to access main memory, cache memories permit the executmn rate of

Alan Jay Smith

1982-01-01

93

Cache memories  

E-print Network

Cache memories are used in modern, medium and high-speed CPUs to hold temporarily those portions of the contents of main memory which are {believed to be) currently in use. Since instructions and data in cache memories can usually be referenced in 10 to 25 percent of the time required to access main memory, cache memories permit the

Alan Jay Smith

1982-01-01

94

Resistance to Interference of Olfactory Perceptual Learning  

ERIC Educational Resources Information Center

Olfactory memory is especially persistent. The current study explored whether this applies to a form of perceptual learning, in which experience of an odor mixture results in greater judged similarity between its elements. Experiment 1A contrasted 2 forms of interference procedure, "compound" (mixture AW, followed by presentation of new mixtures…

Stevenson, Richard J.; Case, Trevor I.; Tomiczek, Caroline

2007-01-01

95

INDIVIDUAL DIFFERENCES IN TASK-SPECIFIC PAIRED ASSOCIATES LEARNING IN OLDER ADULTS: THE ROLE OF PROCESSING SPEED AND WORKING MEMORY  

PubMed Central

Background The role of processing speed and working memory was investigated in terms of individual differences in task-specific paired associates learning in a sample of older adults. Task-specific learning, as distinct from content-oriented item-specific learning, refers to gains in performance due to repeated practice on a learning task in which the to-be-learned material changes over trials. Methods Learning trajectories were modeled within an intensive repeated-measures design based on participants obtained from an opt-in internet-based sampling service (Mage = 65.3, SD = 4.81). Participants completed an eight-item paired associates task daily over a seven-day period. Results Results indicated that a three-parameter hyperbolic model (i.e., initial level, learning rate, and asymptotic performance) best described learning trajectory. After controlling for age-related effects, both higher working memory and higher processing speed had a positive effect on all three learning parameters. Conclusion These results emphasize the role of cognitive abilities for individual differences in task-specific learning of older adults. PMID:24151913

Kurtz, Tanja; Mogle, Jacqueline; Sliwinski, Martin J.; Hofer, Scott M.

2013-01-01

96

Speeded retrieval abolishes the false-memory suppression effect: evidence for the distinctiveness heuristic.  

PubMed

We examined two different accounts of why studying distinctive information reduces false memories within the DRM paradigm. The impoverished relational encoding account predicts that less memorial information, such as overall familiarity, is elicited by the critical lure after distinctive encoding than after nondistinctive encoding. By contrast, the distinctiveness heuristic predicts that participants use a deliberate retrieval strategy to withhold responding to the critical lures. This retrieval strategy refers to a decision rule whereby the absence of memory for expected distinctive information is taken as evidence for an event's nonoccurrence. We show that the typical false-recognition suppression effect only occurs when the recognition test is self paced. This suppression effect is abolished when participants make recognition decisions under time pressure, such as within 1 second of seeing the test item. These results are consistent with the distinctiveness heuristic that a time-consuming retrieval strategy is used to reduce false-recognition responses. PMID:16447388

Dodson, Chad S; Hege, Amanda C G

2005-08-01

97

High speed spatially multimode Lambda-type atomic memory with arbitrary frequency detuning  

E-print Network

We present a general model for an atomic memory using ultra-short pulses of light, which allows both spatial and temporal multimode storage. The process involves the storage of a faint quantum light pulse into the spin coherence of the ground state of Lambda-type 3-level atoms, in the presence of a strong driving pulse. Our model gives a full description of the evolution of the field and of the atomic coherence in space and time throughout the writing and the read-out processes. It is valid for any frequency detuning, from the resonant case to the Raman case, and allows a detailed optimization of the memory efficiency.

T. Golubeva; Yu. Golubev; O. Mishina; A. Bramati; J. Laurat; E. Giacobino

2011-12-20

98

Placing Inspection Time, Reaction Time, and Perceptual Speed in the Broader Context of Cognitive Ability: The VPR Model in the Lothian Birth Cohort 1936  

ERIC Educational Resources Information Center

The idea that information processing speed is related to cognitive ability has a long history. Much evidence has been amassed in its support, with respect to both individual differences in general intelligence and developmental trajectories. Two so-called elementary cognitive tasks, reaction time and inspection time, have been used to compile this…

Johnson, Wendy; Deary, Ian J.

2011-01-01

99

Conceptual representations of perceptual knowledge.  

PubMed

Many neuroimaging studies of semantic memory have argued that knowledge of an object's perceptual properties are represented in a modality-specific manner. These studies often base their argument on finding activation in the left-hemisphere fusiform gyrus-a region assumed to be involved in perceptual processing-when the participant is verifying verbal statements about objects and properties. In this paper, we report an extension of one of these influential papers-Kan, Barsalou, Solomon, Minor, and Thompson-Schill (2003 )-and present evidence for an amodal component in the representation and processing of perceptual knowledge. Participants were required to verify object-property statements (e.g., "cat-whiskers?"; "bear-wings?") while they were being scanned by functional magnetic resonance imaging (fMRI). We replicated Kan et al.'s activation in the left fusiform gyrus, but also found activation in regions of left inferior frontal gyrus (IFG) and middle-temporal gyrus, areas known to reflect amodal processes or representations. Further, only activations in the left IFG, an amodal area, were correlated with measures of behavioural performance. PMID:22994286

Smith, Edward E; Myers, Nicholas; Sethi, Umrao; Pantazatos, Spiro; Yanagihara, Ted; Hirsch, Joy

2012-01-01

100

Relationship between perceptual learning in speech and statistical learning in younger and older adults  

PubMed Central

Within a few sentences, listeners learn to understand severely degraded speech such as noise-vocoded speech. However, individuals vary in the amount of such perceptual learning and it is unclear what underlies these differences. The present study investigates whether perceptual learning in speech relates to statistical learning, as sensitivity to probabilistic information may aid identification of relevant cues in novel speech input. If statistical learning and perceptual learning (partly) draw on the same general mechanisms, then statistical learning in a non-auditory modality using non-linguistic sequences should predict adaptation to degraded speech. In the present study, 73 older adults (aged over 60 years) and 60 younger adults (aged between 18 and 30 years) performed a visual artificial grammar learning task and were presented with 60 meaningful noise-vocoded sentences in an auditory recall task. Within age groups, sentence recognition performance over exposure was analyzed as a function of statistical learning performance, and other variables that may predict learning (i.e., hearing, vocabulary, attention switching control, working memory, and processing speed). Younger and older adults showed similar amounts of perceptual learning, but only younger adults showed significant statistical learning. In older adults, improvement in understanding noise-vocoded speech was constrained by age. In younger adults, amount of adaptation was associated with lexical knowledge and with statistical learning ability. Thus, individual differences in general cognitive abilities explain listeners' variability in adapting to noise-vocoded speech. Results suggest that perceptual and statistical learning share mechanisms of implicit regularity detection, but that the ability to detect statistical regularities is impaired in older adults if visual sequences are presented quickly. PMID:25225475

Neger, Thordis M.; Rietveld, Toni; Janse, Esther

2014-01-01

101

Verbal Knowledge, Working Memory, and Processing Speed as Predictors of Verbal Learning in Older Adults  

ERIC Educational Resources Information Center

The present study aimed at modeling individual differences in a verbal learning task by means of a latent structured growth curve approach based on an exponential function that yielded 3 parameters: initial recall, learning rate, and asymptotic performance. Three cognitive variables--speed of information processing, verbal knowledge, working…

Rast, Philippe

2011-01-01

102

Relationships among Linguistic Processing Speed, Phonological Working Memory, and Attention in Children Who Stutter  

ERIC Educational Resources Information Center

Relatively recently, experimental studies of linguistic processing speed in children who stutter (CWS) have emerged, some of which suggest differences in performance among CWS compared to children who do not stutter (CWNS). What is not yet well understood is the extent to which underlying cognitive skills may impact performance on timed tasks of…

Anderson, Julie D.; Wagovich, Stacy A.

2010-01-01

103

Genetic Variance in Processing Speed Drives Variation in Aging of Spatial and Memory Abilities  

ERIC Educational Resources Information Center

Previous analyses have identified a genetic contribution to the correlation between declines with age in processing speed and higher cognitive abilities. The goal of the current analysis was to apply the biometric dual change score model to consider the possibility of temporal dynamics underlying the genetic covariance between aging trajectories…

Finkel, Deborah; Reynolds, Chandra A.; McArdle, John J.; Hamagami, Fumiaki; Pedersen, Nancy L.

2009-01-01

104

Conceptual priming in perceptual identification for patients with Alzheimer's disease and a patient with right occipital lobectomy  

Microsoft Academic Search

Two experiments examined explicit recognition memory and perceptual and conceptual contribu- tions to implicit perceptual-identification repetition priming for patients with Alzheimer's disease (AD) and Patient M.S. with right-occipital lobectomy. Participants read words (perceptual encoding) and generated words (conceptual encoding) from a definition and letter cue (e.g., \\

Debra A. Fleischman; John D. E. Gabrieli; Sheryl Reminger; Julie Rinaldi

1995-01-01

105

A reward semi-Markov process with memory for wind speed modeling  

NASA Astrophysics Data System (ADS)

The increasing interest in renewable energy leads scientific research to find a better way to recover most of the available energy. Particularly, the maximum energy recoverable from wind is equal to 59.3% of that available (Betz law) at a specific pitch angle and when the ratio between the wind speed in output and in input is equal to 1/3. The pitch angle is the angle formed between the airfoil of the blade of the wind turbine and the wind direction. Old turbine and a lot of that actually marketed, in fact, have always the same invariant geometry of the airfoil. This causes that wind turbines will work with an efficiency that is lower than 59.3%. New generation wind turbines, instead, have a system to variate the pitch angle by rotating the blades. This system able the wind turbines to recover, at different wind speed, always the maximum energy, working in Betz limit at different speed ratios. A powerful system control of the pitch angle allows the wind turbine to recover better the energy in transient regime. A good stochastic model for wind speed is then needed to help both the optimization of turbine design and to assist the system control to predict the value of the wind speed to positioning the blades quickly and correctly. The possibility to have synthetic data of wind speed is a powerful instrument to assist designer to verify the structures of the wind turbines or to estimate the energy recoverable from a specific site. To generate synthetic data, Markov chains of first or higher order are often used [1,2,3]. In particular in [1] is presented a comparison between a first-order Markov chain and a second-order Markov chain. A similar work, but only for the first-order Markov chain, is conduced by [2], presenting the probability transition matrix and comparing the energy spectral density and autocorrelation of real and synthetic wind speed data. A tentative to modeling and to join speed and direction of wind is presented in [3], by using two models, first-order Markov chain with different number of states, and Weibull distribution. All this model use Markov chains to generate synthetic wind speed time series but the search for a better model is still open. Approaching this issue, we applied new models which are generalization of Markov models. More precisely we applied semi-Markov models to generate synthetic wind speed time series. The primary goal of this analysis is the study of the time history of the wind in order to assess its reliability as a source of power and to determine the associated storage levels required. In order to assess this issue we use a probabilistic model based on indexed semi-Markov process [4] to which a reward structure is attached. Our model is used to calculate the expected energy produced by a given turbine and its variability expressed by the variance of the process. Our results can be used to compare different wind farms based on their reward and also on the risk of missed production due to the intrinsic variability of the wind speed process. The model is used to generate synthetic time series for wind speed by means of Monte Carlo simulations and backtesting procedure is used to compare results on first and second oder moments of rewards between real and synthetic data. [1] A. Shamshad, M.A. Bawadi, W.M.W. Wan Hussin, T.A. Majid, S.A.M. Sanusi, First and second order Markov chain models for synthetic gen- eration of wind speed time series, Energy 30 (2005) 693-708. [2] H. Nfaoui, H. Essiarab, A.A.M. Sayigh, A stochastic Markov chain model for simulating wind speed time series at Tangiers, Morocco, Re- newable Energy 29 (2004) 1407-1418. [3] F. Youcef Ettoumi, H. Sauvageot, A.-E.-H. Adane, Statistical bivariate modeling of wind using first-order Markov chain and Weibull distribu- tion, Renewable Energy 28 (2003) 1787-1802. [4]F. Petroni, G. D'Amico, F. Prattico, Indexed semi-Markov process for wind speed modeling. To be submitted.

Petroni, F.; D'Amico, G.; Prattico, F.

2012-04-01

106

Preferred longitudes of sunspot groups and high-speed solar wind streams - Evidence for a 'solar memory'  

NASA Astrophysics Data System (ADS)

Correlation analysis of the mean longitude distribution of sunspot groups (taken from the Greenwich Photoheliographic Results) and high-speed solar wind streams (inferred from the C9 index for geomagnetic disturbances) with the Bartels rotation period P = 27.0 days shows anticorrelation for individual cycles. In particular, the longitudes of post-maximum stable streams of cycle 18 and 19 are well anticorrelated with the preferred longitudes of sunspot groups during the maximum activity periods of these cycles. This is further analyzed using the daily Zuerich sunspot number, R, between 1932 and 1980, which reveals a conspicuous similarity of cycle 18 and 19 as well as cycle 20 and 21. It is concluded that there is a 'solar memory' for preferred longitudes of activity extending at least over one, probably two cycles (i.e., one magnetic cycle of 22 years). It is conjectured that this memory extends over longer intervals of time as a long-term feature of solar activity.

Balthasar, H.; Schuessler, M.

1983-08-01

107

Explicit pre-training instruction does not improve implicit perceptual-motor sequence learning  

E-print Network

theory argues for separate neural systems supporting implicit and expli- cit memory in the human brain in the human brain consistent with multiple memory systems theory. Ã? 2012 Elsevier B.V. All rights reserved. 1 2012 Keywords: Sequence learning Perceptual-motor Implicit Skill Memory a b s t r a c t Memory systems

Stehr, Mark-Oliver

108

A generalized perceptual space.  

PubMed

Based upon experimental results on certain visual spatial discrimination tasks, we have developed a formalism for a non-Euclidian perceptual space. In this formalism, the transformation from real to perceptual space is given by a generalized covariant tensor. The concept of parallel transport of vectors in a curved space is used to prove that closed loops in real space imply closed loops with the same orientation in the perceptual space also. PMID:11091975

Lakshminarayanan, V; Parthasarathy, R; DeValois, K K

2000-10-01

109

ADHD Subtypes and Co-Occurring Anxiety, Depression, and Oppositional-Defiant Disorder: Differences in Gordon Diagnostic System and Wechsler Working Memory and Processing Speed Index Scores  

ERIC Educational Resources Information Center

Objective: Wechsler Intelligence Scale for Children Freedom-from-Distractibility/Working Memory Index (FDI/WMI), Processing Speed Index (PSI), and Gordon Diagnostic System (GDS) scores in ADHD children were examined as a function of subtype and coexisting anxiety, depression, and oppositional-defiant disorder. Method: Participants were 587…

Mayes, Susan Dickerson; Calhoun, Susan L.; Chase, Gary A.; Mink, Danielle M.; Stagg, Ryan E.

2009-01-01

110

Visual Working Memory and Perception Speed of 3- to 6-Year-Old Children Tested with a Matrix Film Battery Test  

ERIC Educational Resources Information Center

In this study the visual working memory (VWM) and perception speed of 60 children between the ages of three and six years were tested with an age-based, easy-to-handle Matrix Film Battery Test (reliability R?=?0.71). It was thereby affirmed that the VWM is age dependent (correlation coefficient r?=?0.66***) as expected. Furthermore, a significant…

Pittorf, Martin L.; Lehmann, Wolfgang; Huckauf, Anke

2014-01-01

111

Effect of 60 minutes exposure to electromagnetic field on fecundity, learning and memory, speed of movement and whole body protein of the fruit fly Drosophila melanogaster.  

PubMed

This study investigated the effect of four different electrical devices as source of electromagnetic field on fecundity, learning and memory function, speed of movement, in addition to the whole body proteins of the fruit fly Drosophila melanogaster. The results showed that exposure to EMF has no significant effect on adult fecundity (ANOVA and Duncan's test) but alters learning and memory function in Drosophila larvae, especially those exposed to mobile phone. Highly significant differences occurred in the larval speed of movement after exposure to EMF, with maximal effect occurred for larvae exposed to mobile phone (their speed of movement increased 2.5 times of wild type). Some protein bands serve as characters for exposure to certain electrical devices which suggest that exposure to EMF may affect the whole body proteins. PMID:23469637

El Kholy, Samar E; El Husseiny, Eman M

2012-12-01

112

Memory  

MedlinePLUS

... mind works a lot like a computer. Your brain puts information it judges to be important into "files." When you remember something, you pull up a file. Memory doesn't always work perfectly. As people grow ...

113

Effects of load and maintenance duration on the time course of information encoding and retrieval in working memory: from perceptual analysis to post-categorization processes  

PubMed Central

Working memory (WM) involves three cognitive events: information encoding, maintenance, and retrieval; these are supported by brain activity in a network of frontal, parietal and temporal regions. Manipulation of WM load and duration of the maintenance period can modulate this activity. Although such modulations have been widely studied using the event-related potentials (ERP) technique, a precise description of the time course of brain activity during encoding and retrieval is still required. Here, we used this technique and principal component analysis to assess the time course of brain activity during encoding and retrieval in a delayed match to sample task. We also investigated the effects of memory load and duration of the maintenance period on ERP activity. Brain activity was similar during information encoding and retrieval and comprised six temporal factors, which closely matched the latency and scalp distribution of some ERP components: P1, N1, P2, N2, P300, and a slow wave. Changes in memory load modulated task performance and yielded variations in frontal lobe activation. Moreover, the P300 amplitude was smaller in the high than in the low load condition during encoding and retrieval. Conversely, the slow wave amplitude was higher in the high than in the low load condition during encoding, and the same was true for the N2 amplitude during retrieval. Thus, during encoding, memory load appears to modulate the processing resources for context updating and post-categorization processes, and during retrieval it modulates resources for stimulus classification and context updating. Besides, despite the lack of differences in task performance related to duration of the maintenance period, larger N2 amplitude and stronger activation of the left temporal lobe after long than after short maintenance periods were found during information retrieval. Thus, results regarding the duration of maintenance period were complex, and future work is required to test the time-based decay theory predictions. PMID:24744715

Pinal, Diego; Zurrón, Montserrat; Díaz, Fernando

2014-01-01

114

Information processing speed, neural efficiency, and working memory performance in multiple sclerosis: differential relationships with structural magnetic resonance imaging.  

PubMed

Multiple sclerosis (MS), a central nervous system (CNS) neurodegenerative disorder, involves lesions of both white and gray matter and reported cognitive impairments that include processing speed (PS), executive function, and working memory (WM). This study closely examined the specifics of these cognitive deficits and their relationship to structural brain damage. A visual n-back task with 3 WM load conditions was used to assess WM performance (task accuracy), PS (reaction time, RT), and a novel measure of processing efficiency (standard deviation of RT, RTSD) in MS patients and controls. These behavioral measures were related to quantitative magnetic resonance imaging (MRI) measures of white and gray matter integrity. Even when MS patients performed as well as controls, as seen for low WM load (0-back), they responded more slowly and were less efficient in their speed of responding. Accuracy findings indicated that the correct match trials were superior to correct nonmatch trials at differentiating MS patients from controls. Further, decreased accuracy during the highest WM load condition was associated with global damage that included both gray and white matter atrophy, while slowed PS and particularly processing inefficiency were associated primarily with white matter atrophy in MS. Importantly, relationships between PS, processing efficiency, performance accuracy, and structural MRI measures were seen only during the highest WM load condition, the condition that required the most executive control. These findings suggest that the MRI/behavioral relationships that were present exclusively during the 2-back condition may reflect connectivity involving frontal cortical systems, the site for executive control. PMID:22047454

Covey, Thomas J; Zivadinov, Robert; Shucard, Janet L; Shucard, David W

2011-12-01

115

Phase Evolution in Fe-Mn-Si Shape Memory Alloys due to Forging Speed  

NASA Astrophysics Data System (ADS)

The objective of this investigation is to compare the crystallographic characteristics of two different compositions of Fe-Mn-Si alloys forged with the newly designed and constructed High Energy Rate Forming (HERF) hammer with conventional hydraulic and mechanical presses. The degree of martensite formation may depend on metal forming conditions. For both of the alloys, one of the specimens was investigated in as "prepared form", the other specimen was investigated after air cooling with homogenization treatment and three specimens were deformed in different velocities after homogenization treatments. The changes which occurred in the transformation parameters of two FeMnSi alloys with different compositions due to the effects of thermal and mechanical procedures have been studied by using X-ray diffraction. In the alloy specimens cooled to different conditions from the high-temperature ? phase region, ??? and ?????? martensitic transformations were observed. The lattice parameters (LP) of fcc ? and hcp ? structures were determined, and changes in forging speed on the LPs were found.

Eskil, Murat; Kanca, Erdogan

2013-09-01

116

Hafnium aluminum oxide as charge storage and blocking-oxide layers in SONOS-type nonvolatile memory for high-speed operation  

Microsoft Academic Search

The charge storage and program\\/erase mechanisms in polysilicon-oxide-nitride-oxide-silicon (SONOS) memory structures with charge-storage layers of different materials are investigated in this paper. In particular, the use of a HfAlO charge-storage layer in a SONOS-type memory structure is proposed. Compared to other high-? charge-storage layers, HfAlO has the advantage of high-speed program\\/erase of HfO2 as well as the good charge-retention time

Yan Ny Tan; W. K. Chim; Wee Kiong Choi; Moon Sig Joo; Byung Jin Cho

2006-01-01

117

Processing speed enhances model-based over model-free reinforcement learning in the presence of high working memory functioning  

PubMed Central

Theories of decision-making and its neural substrates have long assumed the existence of two distinct and competing valuation systems, variously described as goal-directed vs. habitual, or, more recently and based on statistical arguments, as model-free vs. model-based reinforcement-learning. Though both have been shown to control choices, the cognitive abilities associated with these systems are under ongoing investigation. Here we examine the link to cognitive abilities, and find that individual differences in processing speed covary with a shift from model-free to model-based choice control in the presence of above-average working memory function. This suggests shared cognitive and neural processes; provides a bridge between literatures on intelligence and valuation; and may guide the development of process models of different valuation components. Furthermore, it provides a rationale for individual differences in the tendency to deploy valuation systems, which may be important for understanding the manifold neuropsychiatric diseases associated with malfunctions of valuation. PMID:25566131

Schad, Daniel J.; Jünger, Elisabeth; Sebold, Miriam; Garbusow, Maria; Bernhardt, Nadine; Javadi, Amir-Homayoun; Zimmermann, Ulrich S.; Smolka, Michael N.; Heinz, Andreas; Rapp, Michael A.; Huys, Quentin J. M.

2014-01-01

118

Two Thirds of the Age-Based Changes in Fluid and Crystallized Intelligence, Perceptual Speed, and Memory in Adulthood Are Shared  

ERIC Educational Resources Information Center

Many aspects of cognition decline from middle to late adulthood, but the dimensionality and generality of this decline have rarely been examined. We analyzed 20-year longitudinal data of 6203 middle-aged to very old adults from Greater Manchester and Newcastle-upon-Tyne, UK. Participants were assessed up to eight times on 20 tasks of fluid…

Ghisletta, Paolo; Rabbitt, Patrick; Lunn, Mary; Lindenberger, Ulman

2012-01-01

119

The apolipoprotein E ?2 allele and decline in episodic memory  

PubMed Central

Objectives: The apolipoprotein E (apoE) ?4 allele is related to decline in multiple cognitive domains, especially episodic memory, but the effect of the ?2 allele on change in different forms of cognitive function has been difficult to establish. Methods: Participants are from the Religious Orders Study. At baseline, they were at least 65 years old and free of clinical evidence of dementia. For up to eight years, they underwent annual clinical evaluations that included detailed cognitive function assessment from which previously established summary measures of episodic memory, semantic memory, working memory, perceptual speed, and visuospatial ability were derived. Growth curve models were used to assess change in each measure and its relation to apoE genotype, controlling for age, sex, education, and baseline level of cognition. Follow up data were available in 669 persons (98% of those eligible). We treated those with the ?3/3 genotype as the reference group (n=425), which was contrasted with ?2 (?2/2, ?2/3; n=86), and ?4 (?3/4, ?4/4; n=158) subgroups. Results: Rate of episodic memory change in the three subgroups significantly differed, with an average annual increase of 0.016 units in the ?2 subgroup and annual decreases of 0.022 units in those with ?3/3 and of 0.073 units in the ?4 subgroup. The ?2 subgroup did not differ from those with ?3/3 in rate of decline in other cognitive systems. The ?4 subgroup declined more rapidly than those with ?3/3 in semantic memory and perceptual speed but not in working memory or visuospatial ability. Conclusion: Possession of one or more apoE ?2 alleles is associated with reduced decline in episodic memory in older persons. PMID:12438469

Wilson, R; Bienias, J; Berry-Kravis, E; Evans, D; Bennett, D

2002-01-01

120

Memories.  

ERIC Educational Resources Information Center

This theme issue of the journal "Exploring" covers the topic of "memories" and describes an exhibition at San Francisco's Exploratorium that ran from May 22, 1998 through January 1999 and that contained over 40 hands-on exhibits, demonstrations, artworks, images, sounds, smells, and tastes that demonstrated and depicted the biological,…

Brand, Judith, Ed.

1998-01-01

121

Normative perceptual estimates for 91 healthy subjects age 60–75: impact of age, education, employment, physical exercise, alcohol, and video gaming  

PubMed Central

Visual perception serves as the basis for much of the higher level cognitive processing as well as human activity in general. Here we present normative estimates for the following components of visual perception: the visual perceptual threshold, the visual short-term memory (VSTM) capacity and the visual perceptual encoding/decoding speed (processing speed) of VSTM based on an assessment of 91 healthy subjects aged 60–75. The estimates were modeled from input from a whole-report assessment based on a theory of visual attention. In addition to the estimates themselves, we present correlational data, and multiple regression analyses between the estimates and self-reported demographic data and lifestyle variables. The regression statistics suggest that education level, video gaming activity, and employment status may significantly impact the encoding/decoding speed of VTSM but not the capacity of VSTM nor the visual perceptual threshold. The estimates will be useful for future studies into the effects of various types of intervention and training on cognition in general and visual attention in particular. PMID:25339932

Wilms, Inge L.; Nielsen, Simon

2014-01-01

122

Brief Daily Exposures to Asian Females Reverses Perceptual Narrowing for Asian Faces in Caucasian Infants  

ERIC Educational Resources Information Center

Perceptual narrowing in the visual, auditory, and multisensory domains has its developmental origins during infancy. The current study shows that experimentally induced experience can reverse the effects of perceptual narrowing on infants' visual recognition memory of other-race faces. Caucasian 8- to 10-month-olds who could not discriminate…

Anzures, Gizelle; Wheeler, Andrea; Quinn, Paul C.; Pascalis, Olivier; Slater, Alan M.; Heron-Delaney, Michelle; Tanaka, James W.; Lee, Kang

2012-01-01

123

Implicit Recognition Based on Lateralized Perceptual Fluency  

PubMed Central

In some circumstances, accurate recognition of repeated images in an explicit memory test is driven by implicit memory. We propose that this “implicit recognition” results from perceptual fluency that influences responding without awareness of memory retrieval. Here we examined whether recognition would vary if images appeared in the same or different visual hemifield during learning and testing. Kaleidoscope images were briefly presented left or right of fixation during divided-attention encoding. Presentation in the same visual hemifield at test produced higher recognition accuracy than presentation in the opposite visual hemifield, but only for guess responses. These correct guesses likely reflect a contribution from implicit recognition, given that when the stimulated visual hemifield was the same at study and test, recognition accuracy was higher for guess responses than for responses with any level of confidence. The dramatic difference in guessing accuracy as a function of lateralized perceptual overlap between study and test suggests that implicit recognition arises from memory storage in visual cortical networks that mediate repetition-induced fluency increments. PMID:24962684

Vargas, Iliana M.; Voss, Joel L.; Paller, Ken A.

2012-01-01

124

Implicit recognition based on lateralized perceptual fluency.  

PubMed

In some circumstances, accurate recognition of repeated images in an explicit memory test is driven by implicit memory. We propose that this "implicit recognition" results from perceptual fluency that influences responding without awareness of memory retrieval. Here we examined whether recognition would vary if images appeared in the same or different visual hemifield during learning and testing. Kaleidoscope images were briefly presented left or right of fixation during divided-attention encoding. Presentation in the same visual hemifield at test produced higher recognition accuracy than presentation in the opposite visual hemifield, but only for guess responses. These correct guesses likely reflect a contribution from implicit recognition, given that when the stimulated visual hemifield was the same at study and test, recognition accuracy was higher for guess responses than for responses with any level of confidence. The dramatic difference in guessing accuracy as a function of lateralized perceptual overlap between study and test suggests that implicit recognition arises from memory storage in visual cortical networks that mediate repetition-induced fluency increments. PMID:24962684

Vargas, Iliana M; Voss, Joel L; Paller, Ken A

2012-01-01

125

Creating Perceptual Features Using a BAM-inspired Architecture  

Microsoft Academic Search

In this paper, it shown that the Feature-Extracting Bidirectional Associative Memory (FEBAM) can create its own set of perceptual features. Using a bidirectional associative memory (BAM)-inspired architecture, FEBAM inherits properties such as attractor-like behavior and successful processing of noisy inputs, while being able to achieve principal component analysis (PCA) tasks such as feature extraction. The model is tested by simulating

Gyslain Giguère; Sylvain Chartier; Robert Proulx; S LEINA

126

Perceptual presence without counterfactual richness.  

PubMed

In this commentary, I suggest that non-visual perceptual modalities provide counterexamples to Seth's claim that perceptual presence depends on counterfactual richness. Then I suggest a modification to Seth's view that is not vulnerable to these counterexamples. PMID:24739124

Madary, Michael

2014-01-01

127

Prediction Error Associated with the Perceptual Segmentation of Naturalistic Events  

ERIC Educational Resources Information Center

Predicting the near future is important for survival and plays a central role in theories of perception, language processing, and learning. Prediction failures may be particularly important for initiating the updating of perceptual and memory systems and, thus, for the subjective experience of events. Here, we asked observers to make predictions…

Zacks, Jeffrey M.; Kurby, Christopher A.; Eisenberg, Michelle L.; Haroutunian, Nayiri

2011-01-01

128

Perceptual Learning of Acoustic Noise by Individuals with Dyslexia  

ERIC Educational Resources Information Center

Purpose: A phonological deficit is thought to affect most individuals with developmental dyslexia. The present study addresses whether the phonological deficit is caused by difficulties with perceptual learning of fine acoustic details. Method: A demanding test of nonverbal auditory memory, "noise learning," was administered to both…

Agus, Trevor R.; Carrión-Castillo, Amaia; Pressnitzer, Daniel; Ramus, Franck

2014-01-01

129

Integrating Sensory and Perceptual Training in the Classroom.  

ERIC Educational Resources Information Center

Perceptual training activities are described for use in the regular primary or intermediate class that will not disrupt the academic program. Materials and procedures are considered for developing visual and haptic abilities, visual memory and figure-ground discrimination, and auditory, olfactory, taste, and motor skills. (CL)

Worby, Carole

1983-01-01

130

Perceptual skill in soccer: Implications for talent identification and development  

Microsoft Academic Search

In this review, key components of perceptual skill in soccer are identified and implications for talent identification and development highlighted. Skilled soccer players can recall and recognize patterns of play more effectively than their less skilled counterparts. This ability to encode, retrieve and recognize sport-specific information is due to complex and discriminating long-term memory structures and is crucial to anticipation

A. M. Williams

2000-01-01

131

Working Memory Capacity in a Go/No-Go Task: Age Differences in Interference, Processing Speed, and Attentional Control  

ERIC Educational Resources Information Center

We tested the limits of working-memory capacity (WMC) of young adults, old adults, and children with a memory-updating task. The task consisted of mentally shifting spatial positions within a grid according to arrows, their color signaling either only go (control) or go/no-go conditions. The interference model (IM) of Oberauer and Kliegl (2006)…

Rodríguez-Villagra, Odir Antonio; Göthe, Katrin; Oberauer, Klaus; Kliegl, Reinhold

2013-01-01

132

Perceptual Aspects of Motor Performance.  

ERIC Educational Resources Information Center

Perceptual-motor functioning is a cyclic process involving: (1) organizing incoming sensory stimuli with past or stored perceptual information; (2) making motor (internal) decisions based on the combination of sensory (present) and perceptual (past) information; (3) executing the actual movement (observable act) itself; and (4) evaluating the act…

Gallahue, David L.

133

Acetylcholine and Olfactory Perceptual Learning  

ERIC Educational Resources Information Center

Olfactory perceptual learning is a relatively long-term, learned increase in perceptual acuity, and has been described in both humans and animals. Data from recent electrophysiological studies have indicated that olfactory perceptual learning may be correlated with changes in odorant receptive fields of neurons in the olfactory bulb and piriform…

Wilson, Donald A.; Fletcher, Max L.; Sullivan, Regina M.

2004-01-01

134

Memory Systems Doug Burger  

E-print Network

Memory Systems Doug Burger University of Wisconsin-Madison A computer's memory system and produces. A perfect memory system is one that can supply immediately any datum that the CPU requests. This ideal memory is not practically implementable, however, as the three factors of memory capacity, speed

Burger, Doug

135

Neural mechanisms underlying the induction and relief of perceptual curiosity  

PubMed Central

Curiosity is one of the most basic biological drives in both animals and humans, and has been identified as a key motive for learning and discovery. Despite the importance of curiosity and related behaviors, the topic has been largely neglected in human neuroscience; hence little is known about the neurobiological mechanisms underlying curiosity. We used functional magnetic resonance imaging (fMRI) to investigate what happens in our brain during the induction and subsequent relief of perceptual curiosity. Our core findings were that (1) the induction of perceptual curiosity, through the presentation of ambiguous visual input, activated the anterior insula and anterior cingulate cortex (ACC), brain regions sensitive to conflict and arousal; (2) the relief of perceptual curiosity, through visual disambiguation, activated regions of the striatum that have been related to reward processing; and (3) the relief of perceptual curiosity was associated with hippocampal activation and enhanced incidental memory. These findings provide the first demonstration of the neural basis of human perceptual curiosity. Our results provide neurobiological support for a classic psychological theory of curiosity, which holds that curiosity is an aversive condition of increased arousal whose termination is rewarding and facilitates memory. PMID:22347853

Jepma, Marieke; Verdonschot, Rinus G.; van Steenbergen, Henk; Rombouts, Serge A. R. B.; Nieuwenhuis, Sander

2012-01-01

136

The cognitive effects of listening to background music on older adults: processing speed improves with upbeat music, while memory seems to benefit from both upbeat and downbeat music  

PubMed Central

Background music refers to any music played while the listener is performing another activity. Most studies on this effect have been conducted on young adults, while little attention has been paid to the presence of this effect in older adults. Hence, this study aimed to address this imbalance by assessing the impact of different types of background music on cognitive tasks tapping declarative memory and processing speed in older adults. Overall, background music tended to improve performance over no music and white noise, but not always in the same manner. The theoretical and practical implications of the empirical findings are discussed. PMID:25360112

Bottiroli, Sara; Rosi, Alessia; Russo, Riccardo; Vecchi, Tomaso; Cavallini, Elena

2014-01-01

137

Adaptation and perceptual norms  

NASA Astrophysics Data System (ADS)

We used adaptation to examine the relationship between perceptual norms--the stimuli observers describe as psychologically neutral, and response norms--the stimulus levels that leave visual sensitivity in a neutral or balanced state. Adapting to stimuli on opposite sides of a neutral point (e.g. redder or greener than white) biases appearance in opposite ways. Thus the adapting stimulus can be titrated to find the unique adapting level that does not bias appearance. We compared these response norms to subjectively defined neutral points both within the same observer (at different retinal eccentricities) and between observers. These comparisons were made for visual judgments of color, image focus, and human faces, stimuli that are very different and may depend on very different levels of processing, yet which share the property that for each there is a well defined and perceptually salient norm. In each case the adaptation aftereffects were consistent with an underlying sensitivity basis for the perceptual norm. Specifically, response norms were similar to and thus covaried with the perceptual norm, and under common adaptation differences between subjectively defined norms were reduced. These results are consistent with models of norm-based codes and suggest that these codes underlie an important link between visual coding and visual experience.

Webster, Michael A.; Yasuda, Maiko; Haber, Sara; Leonard, Deanne; Ballardini, Nicole

2007-02-01

138

Perceptual-Motor Dysfunction.  

ERIC Educational Resources Information Center

Discussed are theoretical and treatment aspects of perceptual motor dysfunction and rehabilitation in 4- to 12-year-old academically failing children involved in a 3-year investigation at the University of Kansas. The program is said to stress increasing the amount of stimulation received by sensory receptors of the vestibular, reflex, and haptic…

Pyfer, Jean L.

139

Early Experience & Multisensory Perceptual Narrowing  

PubMed Central

Perceptual narrowing is a reflection of early experience and contributes in key ways to perceptual and cognitive development. In general, findings have shown that unisensory perceptual sensitivity in early infancy is broadly tuned such that young infants respond to, and discriminate, native as well as non-native sensory inputs, whereas older infants only respond to native inputs. Recently, my colleagues and I discovered that perceptual narrowing occurs at the multisensory processing level as well. The present article reviews this new evidence and puts it in the larger context of multisensory perceptual development and the role that perceptual experience plays in it. Together, the evidence on unisensory and multisensory narrowing shows that early experience shapes the emergence of perceptual specialization and expertise. PMID:24435505

Lewkowicz, David J.

2014-01-01

140

Perceptual learning and human expertise  

NASA Astrophysics Data System (ADS)

We consider perceptual learning: experience-induced changes in the way perceivers extract information. Often neglected in scientific accounts of learning and in instruction, perceptual learning is a fundamental contributor to human expertise and is crucial in domains where humans show remarkable levels of attainment, such as language, chess, music, and mathematics. In Section 2, we give a brief history and discuss the relation of perceptual learning to other forms of learning. We consider in Section 3 several specific phenomena, illustrating the scope and characteristics of perceptual learning, including both discovery and fluency effects. We describe abstract perceptual learning, in which structural relationships are discovered and recognized in novel instances that do not share constituent elements or basic features. In Section 4, we consider primary concepts that have been used to explain and model perceptual learning, including receptive field change, selection, and relational recoding. In Section 5, we consider the scope of perceptual learning, contrasting recent research, focused on simple sensory discriminations, with earlier work that emphasized extraction of invariance from varied instances in more complex tasks. Contrary to some recent views, we argue that perceptual learning should not be confined to changes in early sensory analyzers. Phenomena at various levels, we suggest, can be unified by models that emphasize discovery and selection of relevant information. In a final section, we consider the potential role of perceptual learning in educational settings. Most instruction emphasizes facts and procedures that can be verbalized, whereas expertise depends heavily on implicit pattern recognition and selective extraction skills acquired through perceptual learning. We consider reasons why perceptual learning has not been systematically addressed in traditional instruction, and we describe recent successful efforts to create a technology of perceptual learning in areas such as aviation, mathematics, and medicine. Research in perceptual learning promises to advance scientific accounts of learning, and perceptual learning technology may offer similar promise in improving education.

Kellman, Philip J.; Garrigan, Patrick

2009-06-01

141

Real-time neural signals of perceptual priming with unfamiliar geometric shapes.  

PubMed

Perceptual priming is a type of item-specific implicit memory that is distinct from explicit memory. Neural signals of the processing responsible for perceptual priming can be difficult to isolate due to concurrent conceptual processing and explicit recognition. We successfully identified neural correlates of perceptual priming by using minimally meaningful, difficult-to-recognize, kaleidoscope images. Human participants were required to quickly indicate the number of colors present in each stimulus, and priming was shown by faster and more accurate visual discriminations for repeated compared with initial presentations. Electroencephalographic responses linked with this differential perceptual fluency were identified as negative potentials 100-300 ms poststimulus onset. Furthermore, different potentials recorded during initial presentations were indicative of perceptual learning, in that their amplitude predicted the magnitude of later priming. These electrophysiological findings show that the degree of perceptual learning engaged upon first encountering a novel visual stimulus predicts the degree of perceptual fluency experienced when the stimulus is processed a second time. It is thus possible to isolate multiple neural processing stages relevant to perceptual priming by using real-time measures of relevant neurophysiological activity in conjunction with experimental circumstances that limit the contaminating influences of other neurocognitive events. PMID:20610752

Voss, Joel L; Paller, Ken A

2010-07-01

142

Modulation of cortical activity during comprehension of familiar and unfamiliar text topics in speed reading and speed listening.  

PubMed

Brain activation associated with normal and speeded comprehension of expository texts on familiar and unfamiliar topics was investigated in reading and listening. The goal was to determine how brain activation and the comprehension processes it reflects are modulated by comprehension speed and topic familiarity. Passages on more familiar topics differentially activated a set of areas in the anterior temporal lobe and medial frontal gyrus, areas often associated with text-level integration processes, which we interpret to reflect integration of previous knowledge with the passage content. Passages presented at the faster presentation resulted in more activation of a network of frontal areas associated with strategic and working-memory processes (as well as visual or auditory sensory-related regions), which we interpret to reflect maintenance of local coherence among briefly available passage segments. The implications of this research is that the brain system for text comprehension adapts to varying perceptual and knowledge conditions. PMID:25463816

Buchweitz, Augusto; Mason, Robert A; Meschyan, Gayane; Keller, Timothy A; Just, Marcel Adam

2014-10-28

143

Abstraction in perceptual symbol systems.  

PubMed Central

After reviewing six senses of abstraction, this article focuses on abstractions that take the form of summary representations. Three central properties of these abstractions are established: ( i ) type-token interpretation; (ii) structured representation; and (iii) dynamic realization. Traditional theories of representation handle interpretation and structure well but are not sufficiently dynamical. Conversely, connectionist theories are exquisitely dynamic but have problems with structure. Perceptual symbol systems offer an approach that implements all three properties naturally. Within this framework, a loose collection of property and relation simulators develops to represent abstractions. Type-token interpretation results from binding a property simulator to a region of a perceived or simulated category member. Structured representation results from binding a configuration of property and relation simulators to multiple regions in an integrated manner. Dynamic realization results from applying different subsets of property and relation simulators to category members on different occasions. From this standpoint, there are no permanent or complete abstractions of a category in memory. Instead, abstraction is the skill to construct temporary online interpretations of a category's members. Although an infinite number of abstractions are possible, attractors develop for habitual approaches to interpretation. This approach provides new ways of thinking about abstraction phenomena in categorization, inference, background knowledge and learning. PMID:12903648

Barsalou, Lawrence W

2003-01-01

144

Working Memory, Processing Speed, and Set-Shifting in Children with Developmental Coordination Disorder and Attention-Deficit-Hyperactivity Disorder  

ERIC Educational Resources Information Center

It has been suggested that the high levels of comorbidity between attention-deficit-hyperactivity disorder (ADHD) and developmental coordination disorder (DCD) may be attributed to a common underlying neurocognitive mechanism. This study assessed whether children with DCD and ADHD share deficits on tasks measuring working memory, set-shifting, and…

Piek, Jan P.; Dyck, Murray J.; Francis, Mona; Conwell, Alistair

2007-01-01

145

Learning, memory, and synesthesia.  

PubMed

People with color-grapheme synesthesia experience color when viewing written letters or numerals, usually with a particular color evoked by each grapheme. Here, we report on data from 11 color-grapheme synesthetes who had startlingly similar color-grapheme pairings traceable to childhood toys containing colored letters. These are the first and only data to show learned synesthesia of this kind in more than a single individual. Whereas some researchers have focused on genetic and perceptual aspects of synesthesia, our results indicate that a complete explanation of synesthesia must also incorporate a central role for learning and memory. We argue that these two positions can be reconciled by thinking of synesthesia as the automatic retrieval of highly specific mnemonic associations, in which perceptual contents are brought to mind in a manner akin to mental imagery or the perceptual-reinstatement effects found in memory studies. PMID:23307940

Witthoft, Nathan; Winawer, Jonathan

2013-03-01

146

Synergistic effect of self-assembled carbon nanopaper and multi-layered interface on shape memory nanocomposite for high speed electrical actuation  

NASA Astrophysics Data System (ADS)

The synergistic effect of self-assembled carbon nanofiber (CNF) nanopaper and the multi-layered interface on the electrical properties and electro-activated recovery behavior of shape memory polymer (SMP) nanocomposites is investigated. The CNFs were self-assembled by deposition into sheets of multi-layered nanopaper form to significantly enhance the bonding strength between the nanopaper and SMP via van der Waals force. The self-assembled multi-layered CNF nanopaper resulted in improved electrical conductivity and temperature distribution in the SMP nanocomposites. This not only significantly enhances the reliability of bonding between the nanopaper and the SMP, resulting in an improved recovery ratio, but also provides high speed electrical actuation.

Lu, Haibao; Liang, Fei; (Jan) Gou, Jihua; Min Huang, Wei; Leng, Jinsong

2014-02-01

147

Recovery of short-term memory and psychomotor speed but not postural stability with long-term sobriety in alcoholic women.  

PubMed

The authors assessed effects of extended abstinence on cognitive and motor function deficits previously observed in a group of alcoholic women (n = 43) initially tested after 15 weeks of sobriety. Alcoholic women were retested 1 and 4 years later, and control women were retested 3 years later. At Year 1, 14 of 23 returners had maintained sobriety, but they did not perform significantly better than relapsers; the group as a whole continued to show deficits relative to age norms. By Year 4, 13 of 14 returners had maintained sobriety for more than 30 months; as a group, these women had returned to normal levels on tests of memory and psychomotor speed but remained impaired in standing balance. PMID:15291737

Rosenbloom, Margaret J; Pfefferbaum, Adolf; Sullivan, Edith V

2004-07-01

148

Writing to dictation and handwriting performance among Chinese children with dyslexia: relationships with orthographic knowledge and perceptual-motor skills.  

PubMed

The purpose of this study was to investigate the relationships between writing to dictation, handwriting, orthographic, and perceptual-motor skills among Chinese children with dyslexia. A cross-sectional design was used. A total of 45 third graders with dyslexia were assessed. Results of stepwise multiple regression models showed that Chinese character naming was the only predictor associated with word dictation (?=.32); handwriting speed was related to deficits in rapid automatic naming (?=-.36) and saccadic efficiency (?=-.29), and visual-motor integration predicted both of the number of characters exceeded grid (?=-.41) and variability of character size (?=-.38). The findings provided support to a multi-stage working memory model of writing for explaining the possible underlying mechanism of writing to dictation and handwriting difficulties. PMID:23911643

Cheng-Lai, Alice; Li-Tsang, Cecilia W P; Chan, Alan H L; Lo, Amy G W

2013-10-01

149

Perceptual Load Alters Visual Excitability  

ERIC Educational Resources Information Center

Increasing perceptual load reduces the processing of visual stimuli outside the focus of attention, but the mechanism underlying these effects remains unclear. Here we tested an account attributing the effects of perceptual load to modulations of visual cortex excitability. In contrast to stimulus competition accounts, which propose that load…

Carmel, David; Thorne, Jeremy D.; Rees, Geraint; Lavie, Nilli

2011-01-01

150

Conflict-Induced Perceptual Filtering  

ERIC Educational Resources Information Center

In a variety of conflict paradigms, target and distractor stimuli are defined in terms of perceptual features. Interference evoked by distractor stimuli tends to be reduced when the ratio of congruent to incongruent trials is decreased, suggesting conflict-induced perceptual filtering (i.e., adjusting the processing weights assigned to stimuli…

Wendt, Mike; Luna-Rodriguez, Aquiles; Jacobsen, Thomas

2012-01-01

151

Understanding processing speed weaknesses among pedophilic child molesters: response style vs. neuropathology.  

PubMed

Research shows that pedophilic (PED) child molesters exhibit slower performance speed and greater performance accuracy when compared to nonpedophilic (N-PED) child molesters or other criminal and noncriminal controls. The purpose of the present study was to examine whether these differences reflect a slow/deliberate response style among PEDS (as we have previously hypothesized; Eastvold, Suchy, & Strassberg, 2011; Suchy, Whittaker, Strassberg, & Eastvold, 2009a, 2009b), or a fundamental neuropathological weakness in processing speed. Data came from a larger study examining neurocognition among sex offenders. Processing speed in three different domains (motor speed, visual-perceptual speed, and visual-motor integration) was examined in 20 phallometrically identified PEDs, 20 N-PEDs, and 20 nonsexual offenders, using both clinical (Finger Tapping, Symbol Search, Digit Symbol Coding) and experimental measures (Inspection Time Task [ITT]). The ITT assessed speed of visual-perceptual processing independent of response speed. On clinical measures, PEDs exhibited slower visual perception [F(2, 57) = 5.24, p = .008] and visual-motor integration [F(2, 57) = 5.02, p = .010] than the other groups, with no differences for simple motor speed. On the ITT, PEDs performed less accurately than the other groups [F(2, 57) = 3.95, p = .025], clearly indicating that slow processing speed cannot be explained by a deliberate response style. Group differences persisted after controlling for other potential confounds (age, estimate IQ, working memory, ethnicity, and substance use). PEDs' slower performance is due to a fundamental neurocognitive weakness, rather than a slow/deliberate response style. These results are consistent with Cantor et al.'s (2008) work identifying white matter abnormalities among PEDs and provide further support for a neurodevelopmental etiology of pedophilia. PMID:24661177

Suchy, Yana; Eastvold, Angela D; Strassberg, Donald S; Franchow, Emilie I

2014-02-01

152

Perceptual basis for reactive teleoperation.  

SciTech Connect

To enhance task performance in partially structured environment, enhancement of teleoperation was proposed by introducing autonomous behaviors. Such autonomy is implemented based on reactive robotic architecture, where reactive motor agents that directly couples sensory inputs and motor actions become the building blocks. To this end, presented in this paper is a perceptual basis for the motor agents. The perceptual basis consists of perceptual agents that extracts environmental information from a structured light vision system and provide action oriented perception for the corresponding motor agents. Rather than performing general scene reconstruction, a perceptual agent directly provides the motion reference for the motor behavior. Various sensory mechanisms--sensor fission, fusion, and fashion--becomes basic building blocks of the perception process. Since perception is a process deeply intertwined with the motor actions, active perception may also incorporate motor behaviors as an integral perceptual process.

Park, Y. S.; Ewing, T. F.; Boyle, J. M.; Yule, T. J.

2001-08-28

153

The effect of generation on long-term repetition priming in auditory and visual perceptual identification.  

PubMed

Perceptual implicit memory is typically most robust when the perceptual processing at encoding matches the perceptual processing required during retrieval. A consistent exception is the robust priming that semantic generation produces on the perceptual identification test (Masson & MacLeod, 2002), a finding which has been attributed to either (1) conceptual influences in this nominally perceptual task, or (2) covert orthographic processing during generative encoding. The present experiments assess these possibilities using both auditory and visual perceptual identification, tests in which participants identify auditory words in noise or rapidly-presented visual words. During the encoding phase of the experiments, participants generated some words and perceived others in an intermixed study list. The perceptual control condition was visual (reading) or auditory (hearing), and varied across participants. The reading and hearing conditions exhibited the expected modality-specificity, producing robust intra-modal priming and non-significant cross-modal priming. Priming in the generate condition depended on the perceptual control condition. With a read control condition, semantic generation produced robust visual priming but no auditory priming. With a hear control condition, the results were reversed: semantic generation produced robust auditory priming but not visual priming. This set of results is not consistent with a straightforward application of either the conceptual-influence or covert-orthography account, and implies that the nature of encoding in the generate condition is influenced by the broader list context. PMID:21388613

Mulligan, Neil W

2011-05-01

154

Geometry of the perceptual space  

NASA Astrophysics Data System (ADS)

The concept of space and geometry varies across the subjects. Following Poincare, we consider the construction of the perceptual space as a continuum equipped with a notion of magnitude. The study of the relationships of objects in the perceptual space gives rise to what we may call perceptual geometry. Computational modeling of objects and investigation of their deeper perceptual geometrical properties (beyond qualitative arguments) require a mathematical representation of the perceptual space. Within the realm of such a mathematical/computational representation, visual perception can be studied as in the well-understood logic-based geometry. This, however, does not mean that one could reduce all problems of visual perception to their geometric counterparts. Rather, visual perception as reported by a human observer, has a subjective factor that could be analytically quantified only through statistical reasoning and in the course of repetitive experiments. Thus, the desire to experimentally verify the statements in perceptual geometry leads to an additional probabilistic structure imposed on the perceptual space, whose amplitudes are measured through intervention by human observers. We propose a model for the perceptual space and the case of perception of textured surfaces as a starting point for object recognition. To rigorously present these ideas and propose computational simulations for testing the theory, we present the model of the perceptual geometry of surfaces through an amplification of theory of Riemannian foliation in differential topology, augmented by statistical learning theory. When we refer to the perceptual geometry of a human observer, the theory takes into account the Bayesian formulation of the prior state of the knowledge of the observer and Hebbian learning. We use a Parallel Distributed Connectionist paradigm for computational modeling and experimental verification of our theory.

Assadi, Amir H.; Palmer, Stephen; Eghbalnia, Hamid; Carew, John

1999-09-01

155

Perceptual qualities and material classes.  

PubMed

Under typical viewing conditions, we can easily group materials into distinct classes (e.g., woods, plastics, textiles). Additionally, we can also make many other judgments about material properties (e.g., hardness, rigidity, colorfulness). Although these two types of judgment (classification and inferring material properties) have different requirements, they likely facilitate one another. We conducted two experiments to investigate the interactions between material classification and judgments of material qualities in both the visual and semantic domains. In Experiment 1, nine students viewed 130 images of materials from 10 different classes. For each image, they rated nine subjective properties (glossiness, transparency, colorfulness, roughness, hardness, coldness, fragility, naturalness, prettiness). In Experiment 2, 65 subjects were given the verbal names of six material classes, which they rated in terms of 42 adjectives describing material qualities. In both experiments, there was notable agreement between subjects, and a relatively small number of factors (weighted combinations of different qualities) were substantially independent of one another. Despite the difficulty of classifying materials from images (Liu, Sharan, Adelson, & Rosenholtz, 2010), the different classes were well clustered in the feature space defined by the subjective ratings. K-means clustering could correctly identify class membership for over 90% of the samples, based on the average ratings across subjects. We also found a high degree of consistency between the two tasks, suggesting subjects access similar information about materials whether judging their qualities visually or from memory. Together, these findings show that perceptual qualities are well defined, distinct, and systematically related to material class membership. PMID:23847302

Fleming, Roland W; Wiebel, Christiane; Gegenfurtner, Karl

2013-01-01

156

Adaptive image coding with perceptual distortion control  

Microsoft Academic Search

This paper presents a discrete cosine transform (DCT)-based locally adaptive perceptual image coder, which discriminates between image components based on their perceptual relevance for achieving increased performance in terms of quality and bit rate. The new coder uses a locally adaptive perceptual quantization scheme based on a tractable perceptual distortion metric. Our strategy is to exploit human visual masking properties

Ingo S. Hontsch; Lina J. Karam

2002-01-01

157

Perceptual Load Modulates Object-Based Attention  

ERIC Educational Resources Information Center

Two experimental series are reported using both reaction time (RT) and a data-limited perceptual report to examine the effects of perceptual load on object-based attention. Perceptual load was manipulated across 3 levels by increasing the complexity of perceptual judgments. Data from the RT-based experiments showed object-based effects when the…

Ho, Ming-Chou; Atchley, Paul

2009-01-01

158

APOE and Change in Episodic Memory in Blacks and Whites  

PubMed Central

Background APOE ?4 is related to faster decline in episodic memory in Whites but the relation is unknown in Blacks. The purpose of this study was to determine whether ?4 has a selective effect on decline in episodic memory in Blacks. METHODS Data are from two cohort studies with similar design. The sample consisted of 1,211 participants (28.4% Black, mean age = 78.6 (sd=7.4), education = 14.7 (sd=3.1)) without dementia at baseline, who underwent annual clinical evaluations for up to six years. Summary measures of five cognitive abililites were derived from 18 neuropsychological tests. RESULTS In mixed models that controlled for age, sex, education, and race, possession of ?4 (present in 32.9% of Blacks; 21.0% of Whites, p<.001) was related to faster decline in episodic memory and four other cognitive abilities (all p’s <.01). In separate models that examined the interaction of race and ?4 on decline, there was no significant difference between Blacks and Whites in the effect of ?4 on decline in episodic memory, perceptual speed, or visuospatial ability. By contrast, the effect of ?4 differed for semantic memory and working memory. Results were similar after adjusting for vascular conditions. CONCLUSIONS The results suggest that APOE ?4 is related to a faster rate of decline in episodic memory in Blacks similar to Whites. In addition, there were racial differences in the effect of ?4 in other cognitive abilities such that the ?4 allele was related to faster decline in semantic memory and working memory for Whites but not for Blacks. PMID:23364031

Barnes, LL; Arvanitakis, Z; Yu, L; Kelly, J; De Jager, PL; Bennett, DA

2013-01-01

159

Ferroelectric memories  

Microsoft Academic Search

In the past year it has become possible to fabricate ferroelectric thin-film memories onto standard silicon integrated circuits that combine very high speed (30-nanosecond read\\/erase\\/rewrite operation), 5-volt standard silicon logic levels, very high density (2 by 2 micrometer cell size), complete nonvolatility (no standby power required), and extreme radiation hardness. These ferroelectric random-access memories are expected to replace magnetic core

J. F. Scott; C. A. Paz de Araujo

1989-01-01

160

Perceptual experience : relations and representations/  

E-print Network

The aim of this dissertation is to elaborate and assess the Relational View of perceptual experience, and to compare it to its main rival, the Representational View. Roughly stated, the core claim of the Relational View ...

Logue, Heather, 1979-

2009-01-01

161

Perceptual Anomalies in Schizophrenia: Integrating Phenomenology and Cognitive Neuroscience  

PubMed Central

From phenomenological and experimental perspectives, research in schizophrenia has emphasized deficits in “higher” cognitive functions, including attention, executive function, as well as memory. In contrast, general consensus has viewed dysfunctions in basic perceptual processes to be relatively unimportant in the explanation of more complex aspects of the disorder, including changes in self-experience and the development of symptoms such as delusions. We present evidence from phenomenology and cognitive neuroscience that changes in the perceptual field in schizophrenia may represent a core impairment. After introducing the phenomenological approach to perception (Husserl, the Gestalt School), we discuss the views of Paul Matussek, Klaus Conrad, Ludwig Binswanger, and Wolfgang Blankenburg on perception in schizophrenia. These 4 psychiatrists describe changes in perception and automatic processes that are related to the altered experience of self. The altered self-experience, in turn, may be responsible for the emergence of delusions. The phenomenological data are compatible with current research that conceptualizes dysfunctions in perceptual processing as a deficit in the ability to combine stimulus elements into coherent object representations. Relationships of deficits in perceptual organization to cognitive and social dysfunction as well as the possible neurobiological mechanisms are discussed. PMID:17118973

Uhlhaas, Peter J.; Mishara, Aaron L.

2007-01-01

162

Mental imagery of speech: linking motor and perceptual systems through internal simulation and estimation  

PubMed Central

The neural basis of mental imagery has been investigated by localizing the underlying neural networks, mostly in motor and perceptual systems, separately. However, how modality-specific representations are top-down induced and how the action and perception systems interact in the context of mental imagery is not well understood. Imagined speech production (“articulation imagery”), which induces the kinesthetic feeling of articulator movement and its auditory consequences, provides a new angle because of the concurrent involvement of motor and perceptual systems. On the basis of previous findings in mental imagery of speech, we argue for the following regarding the induction mechanisms of mental imagery and the interaction between motor and perceptual systems: (1) Two distinct top-down mechanisms, memory retrieval and motor simulation, exist to induce estimation in perceptual systems. (2) Motor simulation is sufficient to internally induce the representation of perceptual changes that would be caused by actual movement (perceptual associations); however, this simulation process only has modulatory effects on the perception of external stimuli, which critically depends on context and task demands. Considering the proposed simulation-estimation processes as common mechanisms for interaction between motor and perceptual systems, we outline how mental imagery (of speech) relates to perception and production, and how these hypothesized mechanisms might underpin certain neural disorders. PMID:23226121

Tian, Xing; Poeppel, David

2012-01-01

163

Recent progress in perceptual learning research  

PubMed Central

Perceptual learning is defined as long-term improvement in perceptual or sensory systems resulting from repeated practice or experience. As the number of perceptual learning studies has increased, controversies and questions have arisen regarding divergent aspects of perceptual learning, including: (1) stages in which perceptual learning occurs, (2) effects of training type, (3) changes in neural processing during the time course of learning, (4) effects of feedback as to correctness of a subject’s responses and (5) double-training. Here we review each of these aspects and suggest fruitful directions for future perceptual learning research. PMID:24179564

Sasaki, Yuka; Náñez, José E.

2013-01-01

164

Perceptually Lossless Wavelet Compression  

NASA Technical Reports Server (NTRS)

The Discrete Wavelet Transform (DWT) decomposes an image into bands that vary in spatial frequency and orientation. It is widely used for image compression. Measures of the visibility of DWT quantization errors are required to achieve optimal compression. Uniform quantization of a single band of coefficients results in an artifact that is the sum of a lattice of random amplitude basis functions of the corresponding DWT synthesis filter, which we call DWT uniform quantization noise. We measured visual detection thresholds for samples of DWT uniform quantization noise in Y, Cb, and Cr color channels. The spatial frequency of a wavelet is r 2(exp -1), where r is display visual resolution in pixels/degree, and L is the wavelet level. Amplitude thresholds increase rapidly with spatial frequency. Thresholds also increase from Y to Cr to Cb, and with orientation from low-pass to horizontal/vertical to diagonal. We propose a mathematical model for DWT noise detection thresholds that is a function of level, orientation, and display visual resolution. This allows calculation of a 'perceptually lossless' quantization matrix for which all errors are in theory below the visual threshold. The model may also be used as the basis for adaptive quantization schemes.

Watson, Andrew B.; Yang, Gloria Y.; Solomon, Joshua A.; Villasenor, John

1996-01-01

165

The effect of haptic cues on motor and perceptual based implicit sequence learning  

PubMed Central

We introduced haptic cues to the serial reaction time (SRT) sequence learning task alongside the standard visual cues to assess the relative contributions of visual and haptic stimuli to the formation of motor and perceptual memories. We used motorized keys to deliver brief pulse-like displacements to the resting fingers, expecting that the proximity and similarity of these cues to the subsequent response motor actions (finger-activated key-presses) would strengthen the motor memory trace in particular. We adopted the experimental protocol developed by Willingham (1999) to explore whether haptic cues contribute differently than visual cues to the balance of motor and perceptual learning. We found that sequence learning occurs with haptic stimuli as well as with visual stimuli and we found that irrespective of the stimuli (visual or haptic) the SRT task leads to a greater amount of motor learning than perceptual learning. PMID:24734013

Kim, Dongwon; Johnson, Brandon J.; Gillespie, R. Brent; Seidler, Rachael D.

2014-01-01

166

Prediction of Later Cognitive Behavior from Early School Perceptual-Motor, Perceptual, and Cognitive Performances.  

ERIC Educational Resources Information Center

The battery of perceptual and perceptual-motor tests (including one fine and two gross perceptual-motor tasks, and one visual and two auditory perceptual tasks) were useful for prediction of cognitive performance one year later at kindergarten age. However, cognitive achievement in first grade, and even more so in second grade, was best predicted…

Belka, David E.; Williams, Harriet G.

1979-01-01

167

Exploring the Perceptual Spaces of Faces, Cars and Birds in Children and Adults  

ERIC Educational Resources Information Center

While much developmental research has focused on the strategies that children employ to recognize faces, less is known about the principles governing the organization of face exemplars in perceptual memory. In this study, we tested a novel, child-friendly paradigm for investigating the organization of face, bird and car exemplars. Children ages…

Tanaka, James W.; Meixner, Tamara L.; Kantner, Justin

2011-01-01

168

Motor and Tactile-Perceptual Skill Differences between Individuals with High-Functioning Autism and Typically Developing Individuals Ages 5-21  

ERIC Educational Resources Information Center

We examined motor and tactile-perceptual skills in individuals with high-functioning autism (IHFA) and matched typically developing individuals (TDI) ages 5-21 years. Grip strength, motor speed and coordination were impaired in IHFA compared to matched TDI, and the differences between groups varied with age. Although tactile-perceptual skills of…

Abu-Dahab, Sana M. N.; Skidmore, Elizabeth R.; Holm, Margo B.; Rogers, Joan C.; Minshew, Nancy J.

2013-01-01

169

Increased Signal Complexity Improves the Breadth of Generalization in Auditory Perceptual Learning  

PubMed Central

Perceptual learning can be specific to a trained stimulus or optimally generalized to novel stimuli with the breadth of generalization being imperative for how we structure perceptual training programs. Adapting an established auditory interval discrimination paradigm to utilise complex signals, we trained human adults on a standard interval for either 2, 4, or 10 days. We then tested the standard, alternate frequency, interval, and stereo input conditions to evaluate the rapidity of specific learning and breadth of generalization over the time course. In comparison with previous research using simple stimuli, the speed of perceptual learning and breadth of generalization were more rapid and greater in magnitude, including novel generalization to an alternate temporal interval within stimulus type. We also investigated the long term maintenance of learning and found that specific and generalized learning was maintained over 3 and 6 months. We discuss these findings regarding stimulus complexity in perceptual learning and how they can inform the development of effective training protocols. PMID:24349800

Brown, David J.; Proulx, Michael J.

2013-01-01

170

Proceedings Region East Perceptual Motor Conference.  

ERIC Educational Resources Information Center

This book of conference proceeding presents speeches and panel discussions from the Region East Perceptual-Motor Conference. The purpose of the conference was to seek an understanding of children and their perceptual-motor development through (a) exchange of knowledge and practices in perceptual-motor development, (b) examination of program…

American Alliance for Health, Physical Education, and Recreation, Washington, DC.

171

Neurally Constrained Modeling of Perceptual Decision Making  

ERIC Educational Resources Information Center

Stochastic accumulator models account for response time in perceptual decision-making tasks by assuming that perceptual evidence accumulates to a threshold. The present investigation mapped the firing rate of frontal eye field (FEF) visual neurons onto perceptual evidence and the firing rate of FEF movement neurons onto evidence accumulation to…

Purcell, Braden A.; Heitz, Richard P.; Cohen, Jeremiah Y.; Schall, Jeffrey D.; Logan, Gordon D.; Palmeri, Thomas J.

2010-01-01

172

Integrated perceptual information for designers  

NASA Astrophysics Data System (ADS)

The Integrated Perceptual Information for Designers (IPID) program has been developed in order to optimize the operator's contribution to system effectiveness. Information management objectives of the IPID program are: the consolidation of relevant sensory and perceptual data, the effective presentation of data to the designer, and accessibility to the data. Data pertain particularly to aircrew simulator and operational control/display designer needs. IPID data can be useful in generating design options, specifications, and standards, and in evaluating standards and examining alternatives. Specific applications of IPID data include supervisory control, operator interface definition in automated systems, and visual standards definitions.

Boff, K. R.

173

Subcortical hyperintensity volumetrics in Alzheimer’s disease and normal elderly in the Sunnybrook Dementia Study: correlations with atrophy, executive function, mental processing speed, and verbal memory  

PubMed Central

Introduction Subcortical hyperintensities (SHs) are radiological entities commonly observed on magnetic resonance imaging (MRI) of patients with Alzheimer’s disease (AD) and normal elderly controls. Although the presence of SH is believed to indicate some form of subcortical vasculopathy, pathological heterogeneity, methodological differences, and the contribution of brain atrophy associated with AD pathology have yielded inconsistent results in the literature. Methods Using the Lesion Explorer (LE) MRI processing pipeline for SH quantification and brain atrophy, this study examined SH volumes of interest and cognitive function in a sample of patients with AD (n?=?265) and normal elderly controls (n?=?100) from the Sunnybrook Dementia Study. Results Compared with healthy controls, patients with AD were found to have less gray matter, less white matter, and more sulcal and ventricular cerebrospinal fluid (all significant, P <0.0001). Additionally, patients with AD had greater volumes of whole-brain SH (P <0.01), periventricular SH (pvSH) (P <0.01), deep white SH (dwSH) (P <0.05), and lacunar lesions (P <0.0001). In patients with AD, regression analyses revealed a significant association between global atrophy and pvSH (P?=?0.02) and ventricular atrophy with whole-brain SH (P <0.0001). Regional volumes of interest revealed significant correlations with medial middle frontal SH volume and executive function (P <0.001) in normal controls but not in patients with AD, global pvSH volume and mental processing speed (P <0.01) in patients with AD, and left temporal SH volume and memory (P <0.01) in patients with AD. Conclusions These brain-behavior relationships and correlations with brain atrophy suggest that subtle, yet measurable, signs of small vessel disease may have potential clinical relevance as targets for treatment in Alzheimer’s dementia. PMID:25478020

2014-01-01

174

Perceptual hysteresis as a marker of perceptual inflexibility in schizophrenia.  

PubMed

People with schizophrenia are known to exhibit difficulties in the updating of their current belief states even in the light of disconfirmatory evidence. In the present study we tested the hypothesis that people with schizophrenia could also manifest perceptual inflexibility, or difficulties in the updating of their current sensory states. The presence of perceptual inflexibility might contribute both to the patients' altered perception of reality and the formation of some delusions as well as to their social cognition deficits. Here, we addressed this issue with a protocol of auditory hysteresis, a direct measure of sensory persistence, on a population of stabilized antipsychotic-treated schizophrenia patients and a sample of control subjects. Trials consisted of emotional signals (i.e., screams) and neutral signals (i.e., spectrally-rotated versions of the emotional stimuli) progressively emerging from white noise - Ascending Sequences - or progressively fading away in white noise - Descending Sequences. Results showed that patients presented significantly stronger hysteresis effects than control subjects, as evidenced by a higher rate of perceptual reports in Descending Sequences. The present study thus provides direct evidence of perceptual inflexibility in schizophrenia. PMID:25147080

Martin, Jean-Rémy; Dezecache, Guillaume; Pressnitzer, Daniel; Nuss, Philippe; Dokic, Jérôme; Bruno, Nicolas; Pacherie, Elisabeth; Franck, Nicolas

2014-11-01

175

The Sensory Nature of Episodic Memory: Sensory Priming Effects Due to Memory Trace Activation  

ERIC Educational Resources Information Center

The aim of this study was to provide evidence that memory and perceptual processing are underpinned by the same mechanisms. Specifically, the authors conducted 3 experiments that emphasized the sensory aspect of memory traces. They examined their predictions with a short-term priming paradigm based on 2 distinct phases: a learning phase consisting…

Brunel, Lionel; Labeye, Elodie; Lesourd, Mathieu; Versace, Remy

2009-01-01

176

Synesthesia and Memory: Color Congruency, Von Restorff, and False Memory Effects  

ERIC Educational Resources Information Center

In the current study, we explored the influence of synesthesia on memory for word lists. We tested 10 grapheme-color synesthetes who reported an experience of color when reading letters or words. We replicated a previous finding that memory is compromised when synesthetic color is incongruent with perceptual color. Beyond this, we found that,…

Radvansky, Gabriel A.; Gibson, Bradley S.; McNerney, M. Windy

2011-01-01

177

Improving pulse oximetry pitch perception with multisensory perceptual training.  

PubMed

The pulse oximeter is a critical monitor in anesthesia practice designed to improve patient safety. Here, we present an approach to improve the ability of anesthesiologists to monitor arterial oxygen saturation via pulse oximetry through an audiovisual training process. Fifteen residents' abilities to detect auditory changes in pulse oximetry were measured before and after perceptual training. Training resulted in a 9% (95% confidence interval, 4%-14%, P = 0.0004, t(166) = 3.60) increase in detection accuracy, and a 72-millisecond (95% confidence interval, 40-103 milliseconds, P < 0.0001, t(166) = -4.52) speeding of response times in attentionally demanding and noisy conditions that were designed to simulate an operating room. This study illustrates the benefits of multisensory training and sets the stage for further work to better define the role of perceptual training in clinical anesthesiology. PMID:24846194

Schlesinger, Joseph J; Stevenson, Ryan A; Shotwell, Matthew S; Wallace, Mark T

2014-06-01

178

Visual-perceptual-kinesthetic inputs on influencing writing performances in children with handwriting difficulties.  

PubMed

This study investigated the role of visual-perceptual input in writing Chinese characters among senior school-aged children who had handwriting difficulties (CHD). The participants were 27 CHD (9-11 years old) and 61 normally developed control. There were three writing conditions: copying, and dictations with or without visual feedback. The motor-free subtests of the Developmental Test of Visual Perception (DTVP-2) were conducted. The CHD group showed significantly slower mean speeds of character production and less legibility of produced characters than the control group in all writing conditions (ps<0.001). There were significant deteriorations in legibility from copying to dictation without visual feedback. Nevertheless, the Group by Condition interaction effect was not statistically significant. Only position in space of DTVP-2 was significantly correlated with the legibility among CHD (r=-0.62, p=0.001). Poor legibility seems to be related to the less-intact spatial representation of the characters in working memory, which can be rectified by viewing the characters during writing. Visual feedback regarding one's own actions in writing can also improve legibility of characters among these children. PMID:24333804

Tse, Linda F L; Thanapalan, Kannan C; Chan, Chetwyn C H

2014-02-01

179

Locally adaptive perceptual image coding  

Microsoft Academic Search

Most existing efforts in image and video compression have focused on developing methods to minimize not perceptual but rather mathematically tractable, easy to measure, distortion metrics. While nonperceptual distortion measures were found to be reasonably reliable for higher bit rates (high-quality applications), they do not correlate well with the perceived quality at lower bit rates and they fail to guarantee

Ingo S. Hontsch; Lina J. Karam

2000-01-01

180

Perceptual Learning, Cognition, and Expertise  

ERIC Educational Resources Information Center

Recent research indicates that perceptual learning (PL)--experience-induced changes in the way perceivers extract information--plays a larger role in complex cognitive tasks, including abstract and symbolic domains, than has been understood in theory or implemented in instruction. Here, we describe the involvement of PL in complex cognitive tasks…

Kellman, Philip J.; Massey, Christine M.

2013-01-01

181

Perceptual grouping impairs temporal resolution.  

PubMed

Performance on multisensory temporal order judgment (TOJ) tasks is enhanced when the sensory stimuli are presented at different locations rather than the same location. In our first experiment, we replicated this result for spatially separated stimuli within the visual modality. In Experiment 2, we investigated the effect of perceptual grouping on this spatial effect. Observers performed a visual TOJ task in which two stimuli were presented in a configuration that encouraged perceptual grouping or not (i.e., one- and two-object conditions respectively). Despite a constant spatial disparity between targets across the two conditions, a smaller just noticeable difference (i.e., better temporal resolution) was found when the two targets formed two objects than when they formed one. This effect of perceptual grouping persisted in Experiment 3 when we controlled for apparent motion by systematically varying the spatial distance between the targets. Thus, in contrast to the putative same-object advantage observed in spatial discrimination tasks, these findings indicate that perceptual grouping impairs visual temporal resolution. PMID:17639362

Nicol, Jeffrey R; Shore, David I

2007-11-01

182

Perceptual Adjustments to Multiple Speakers  

ERIC Educational Resources Information Center

Different speakers may pronounce the same sounds very differently, yet listeners have little difficulty perceiving speech accurately. Recent research suggests that listeners adjust their preexisting phonemic categories to accommodate speakers' pronunciations ("perceptual learning"). In some cases, these adjustments appear to reflect general…

Kraljic, Tanya; Samuel, Arthur G.

2007-01-01

183

Odor identification: perceptual and semantic dimensions.  

PubMed

Five studies explored identification of odors as an aspect of semantic memory. All dealt in one way or another with the accessibility of acquired olfactory information. The first study examined stability and showed that, consistent with personal reports, people can fail to identify an odor one day yet succeed another. Failure turned more commonly to success than vice versa, and once success occurred it tended to recur. Confidence ratings implied that subjects generally knew the quality of their answers. Even incorrect names, though, often carried considerable information which sometimes reflected a semantic and sometimes a perceptual source of errors. The second study showed that profiling odors via the American Society of Testing and Materials list of attributes, an exercise in depth of processing, effected no increment in the identifiability/accessibility beyond an unelaborated second attempt at retrieval. The third study showed that subjects had only a weak ability to predict the relative recognizability of odors they had failed to identify. Whereas the strength of the feeling that they would 'know' an answer if offered choices did not associate significantly with performance for odors, it did for trivia questions. The fourth study demonstrated an association between ability to discriminate among one set of odors and to identify another, but this emerged only after subjects had received feedback about identity, which essentially changed the task to one of recognition and effectively stabilized access. The fifth study illustrated that feedback improves performance dramatically only for odors involved with it, but that mere retrieval leads to some improvement. The studies suggest a research agenda that could include supplemental use of confidence judgments both retrospectively and prospectively in the same subjects to indicate the amount of accessible semantic information; use of second and third guesses to examine subjects' simultaneously held hypotheses about identity; use of category cuing or similar techniques to discover the minimum semantic information needed to precipitate identification; some use of subjects trained in quantitative descriptive analysis to explore whether such training enhances semantic memory; and judicious use of mixtures to explore perceptual versus semantic errors of identification. PMID:9669044

Cain, W S; de Wijk, R; Lulejian, C; Schiet, F; See, L C

1998-06-01

184

Priming and implicit recognition depend on similar temporal changes in perceptual representations.  

PubMed

Previous studies have reported that longer stimulus presentation decreases the magnitude of priming. In the present study, we used meaningless kaleidoscope images, which were reported to minimize conceptual processing, to investigate the mechanism of the phenomenon. We assessed the impact of stimulus duration on perceptual priming (Experiment 1) and implicit recognition memory (Experiment 2). Both the magnitude of priming and the accuracy of implicit recognition were lower with the longer stimulus presentation (350 ms) compared with the shorter presentation (250 ms). This coincidence of temporal dynamics between priming and implicit recognition suggests similar underlying memory mechanisms. In both cases, the decrease of performance with longer presentation can be explained by either changes in perceptual processes or interference from explicit memory retrieval. PMID:24486801

Miyoshi, Kiyofumi; Ashida, Hiroshi

2014-05-01

185

Musically cued gait-training improves both perceptual and motor timing in Parkinson's disease.  

PubMed

It is well established that auditory cueing improves gait in patients with idiopathic Parkinson's disease (IPD). Disease-related reductions in speed and step length can be improved by providing rhythmical auditory cues via a metronome or music. However, effects on cognitive aspects of motor control have yet to be thoroughly investigated. If synchronization of movement to an auditory cue relies on a supramodal timing system involved in perceptual, motor, and sensorimotor integration, auditory cueing can be expected to affect both motor and perceptual timing. Here, we tested this hypothesis by assessing perceptual and motor timing in 15 IPD patients before and after a 4-week music training program with rhythmic auditory cueing. Long-term effects were assessed 1?month after the end of the training. Perceptual and motor timing was evaluated with a battery for the assessment of auditory sensorimotor and timing abilities and compared to that of age-, gender-, and education-matched healthy controls. Prior to training, IPD patients exhibited impaired perceptual and motor timing. Training improved patients' performance in tasks requiring synchronization with isochronous sequences, and enhanced their ability to adapt to durational changes in a sequence in hand tapping tasks. Benefits of cueing extended to time perception (duration discrimination and detection of misaligned beats in musical excerpts). The current results demonstrate that auditory cueing leads to benefits beyond gait and support the idea that coupling gait to rhythmic auditory cues in IPD patients relies on a neuronal network engaged in both perceptual and motor timing. PMID:25071522

Benoit, Charles-Etienne; Dalla Bella, Simone; Farrugia, Nicolas; Obrig, Hellmuth; Mainka, Stefan; Kotz, Sonja A

2014-01-01

186

Musically Cued Gait-Training Improves Both Perceptual and Motor Timing in Parkinson’s Disease  

PubMed Central

It is well established that auditory cueing improves gait in patients with idiopathic Parkinson’s disease (IPD). Disease-related reductions in speed and step length can be improved by providing rhythmical auditory cues via a metronome or music. However, effects on cognitive aspects of motor control have yet to be thoroughly investigated. If synchronization of movement to an auditory cue relies on a supramodal timing system involved in perceptual, motor, and sensorimotor integration, auditory cueing can be expected to affect both motor and perceptual timing. Here, we tested this hypothesis by assessing perceptual and motor timing in 15 IPD patients before and after a 4-week music training program with rhythmic auditory cueing. Long-term effects were assessed 1?month after the end of the training. Perceptual and motor timing was evaluated with a battery for the assessment of auditory sensorimotor and timing abilities and compared to that of age-, gender-, and education-matched healthy controls. Prior to training, IPD patients exhibited impaired perceptual and motor timing. Training improved patients’ performance in tasks requiring synchronization with isochronous sequences, and enhanced their ability to adapt to durational changes in a sequence in hand tapping tasks. Benefits of cueing extended to time perception (duration discrimination and detection of misaligned beats in musical excerpts). The current results demonstrate that auditory cueing leads to benefits beyond gait and support the idea that coupling gait to rhythmic auditory cues in IPD patients relies on a neuronal network engaged in both perceptual and motor timing. PMID:25071522

Benoit, Charles-Etienne; Dalla Bella, Simone; Farrugia, Nicolas; Obrig, Hellmuth; Mainka, Stefan; Kotz, Sonja A.

2014-01-01

187

Memory for musical tempo: Additional evidence that auditory memory is absolute  

Microsoft Academic Search

We report evidence that long-term memory retains absolute (accurate) features of perceptual events. Specifically, we show\\u000a that memory for music seems to preserve the absolute tempo of the musical performance. In Experiment 1, 46 subjects sang two\\u000a different popular songs from memory, and their tempos were compared with recorded versions of the songs. Seventy-two percent\\u000a of the productions on two

Daniel J. Levitin; Perry R. Cook

1996-01-01

188

Perceptual color characterization of cameras.  

PubMed

Color camera characterization, mapping outputs from the camera sensors to an independent color space, such as \\(XYZ\\), is an important step in the camera processing pipeline. Until now, this procedure has been primarily solved by using a \\(3 \\times 3\\) matrix obtained via a least-squares optimization. In this paper, we propose to use the spherical sampling method, recently published by Finlayson al., to perform a perceptual color characterization. In particular, we search for the \\(3 \\times 3\\) matrix that minimizes three different perceptual errors, one pixel based and two spatially based. For the pixel-based case, we minimize the CIE \\(\\Delta E\\) error, while for the spatial-based case, we minimize both the S-CIELAB error and the CID error measure. Our results demonstrate an improvement of approximately 3for the \\(\\Delta E\\) error, 7& for the S-CIELAB error and 13% for the CID error measures. PMID:25490586

Vazquez-Corral, Javier; Connah, David; Bertalmío, Marcelo

2014-01-01

189

Perceptual Color Characterization of Cameras  

PubMed Central

Color camera characterization, mapping outputs from the camera sensors to an independent color space, such as XY Z, is an important step in the camera processing pipeline. Until now, this procedure has been primarily solved by using a 3 × 3 matrix obtained via a least-squares optimization. In this paper, we propose to use the spherical sampling method, recently published by Finlayson et al., to perform a perceptual color characterization. In particular, we search for the 3 × 3 matrix that minimizes three different perceptual errors, one pixel based and two spatially based. For the pixel-based case, we minimize the CIE ?E error, while for the spatial-based case, we minimize both the S-CIELAB error and the CID error measure. Our results demonstrate an improvement of approximately 3% for the ?E error, 7% for the S-CIELAB error and 13% for the CID error measures. PMID:25490586

Vazquez-Corral, Javier; Connah, David; Bertalmío, Marcelo

2014-01-01

190

Visual Working Memory Contents Bias Ambiguous Structure from Motion Perception  

PubMed Central

The way we perceive the visual world depends crucially on the state of the observer. In the present study we show that what we are holding in working memory (WM) can bias the way we perceive ambiguous structure from motion stimuli. Holding in memory the percept of an unambiguously rotating sphere influenced the perceived direction of motion of an ambiguously rotating sphere presented shortly thereafter. In particular, we found a systematic difference between congruent dominance periods where the perceived direction of the ambiguous stimulus corresponded to the direction of the unambiguous one and incongruent dominance periods. Congruent dominance periods were more frequent when participants memorized the speed of the unambiguous sphere for delayed discrimination than when they performed an immediate judgment on a change in its speed. The analysis of dominance time-course showed that a sustained tendency to perceive the same direction of motion as the prior stimulus emerged only in the WM condition, whereas in the attention condition perceptual dominance dropped to chance levels at the end of the trial. The results are explained in terms of a direct involvement of early visual areas in the active representation of visual motion in WM. PMID:23527141

Scocchia, Lisa; Valsecchi, Matteo; Gegenfurtner, Karl R.; Triesch, Jochen

2013-01-01

191

Perceptual Learning (2) Tsodyks and Gilbert, Neural networks and perceptual learning (2004)  

E-print Network

responses in M1. · Visio- spatial processing · see also research on players of video games (Daphne BavelierPerceptual Learning (2) Readings: Tsodyks and Gilbert, Neural networks and perceptual learning (2004) Seitz and Watanabe, A unified model for perceptual learning (2005) [Thanks to Aaron Seitz

Seriès, Peggy

192

Predictive Context Influences Perceptual Selection during Binocular Rivalry  

PubMed Central

Prediction may be a fundamental principle of sensory processing: it has been proposed that the brain continuously generates predictions about forthcoming sensory information. However, little is known about how prediction contributes to the selection of a conscious percept from among competing alternatives. Here, we used binocular rivalry to investigate the effects of prediction on perceptual selection. In binocular rivalry, incompatible images presented to the two eyes result in a perceptual alternation between the images, even though the visual stimuli remain constant. If predictive signals influence the competition between neural representations of rivalrous images, this influence should generate a bias in perceptual selection that depends on predictive context. To manipulate predictive context, we developed a novel binocular rivalry paradigm in which rivalrous test images were immediately preceded by a sequence of context images presented identically to the two eyes. One of the test images was consistent with the preceding image sequence (it was the expected next image in the series), and the other was inconsistent (non-predicted). We found that human observers were more likely to perceive the consistent image at the onset of rivalry, suggesting that predictive context biased selection in favor of the predicted percept. This prediction effect was distinct from the effects of adaptation to stimuli presented before the binocular rivalry test. In addition, perceptual reports were speeded for predicted percepts relative to non-predicted percepts. These results suggest that predictive signals related to visual stimulus history exist at neural sites that can bias conscious perception during binocular rivalry. Our paradigm provides a new way to study how prior information and incoming sensory information combine to generate visual percepts. PMID:22180741

Denison, Rachel N.; Piazza, Elise A.; Silver, Michael A.

2011-01-01

193

Modeling Recognition Memory Using the Similarity Structure of Natural Input  

ERIC Educational Resources Information Center

The natural input memory (NAM) model is a new model for recognition memory that operates on natural visual input. A biologically informed perceptual preprocessing method takes local samples (eye fixations) from a natural image and translates these into a feature-vector representation. During recognition, the model compares incoming preprocessed…

Lacroix, Joyca P. W.; Murre, Jaap M. J.; Postma, Eric O.; van den Herik, H. Jaap

2006-01-01

194

Embodied Memory Judgments: A Case of Motor Fluency  

ERIC Educational Resources Information Center

It is well known that perceptual and conceptual fluency can influence episodic memory judgments. Here, the authors asked whether fluency arising from the motor system also impacts recognition memory. Past research has shown that the perception of letters automatically activates motor programs of typing actions in skilled typists. In this study,…

Yang, Shu-Ju; Gallo, David A.; Beilock, Sian L.

2009-01-01

195

Sex differences in sleep-dependent perceptual learning Elizabeth A. McDevitt a,b,1,2  

E-print Network

17 October 2013 Keywords: Perceptual learning REM sleep Napping Memory consolidation Specificity found that rapid eye movement (REM) sleep facilitates consolidation of PL but that the pattern of specificity in the REM condition differed between men and women. PL for men whose naps contained REM sleep

Whitney, David

196

How "Central" Is Central Coherence?: Preliminary Evidence on the Link between Conceptual and Perceptual Processing in Children with Autism  

ERIC Educational Resources Information Center

This study aimed to test the assumption drawn from weak central coherence theory that a central cognitive mechanism is responsible for integrating information at both conceptual and perceptual levels. A visual semantic memory task and a face recognition task measuring use of holistic information were administered to 15 children with autism and 16…

Lopez, Beatriz; Leekam, Susan R.; Arts, Gerda R. J.

2008-01-01

197

Premotor cortex mediates perceptual performance.  

PubMed

Articulatory goals have long been proposed to mediate perception. Examples include direct realist and constructivist (analysis by synthesis) theories of speech perception. Although the activity in brain regions involved with action production has been shown to be present during action observation (Mirror Neuron System), the relationship of this activity to perceptual performance has not been clearly demonstrated at the event level. To this end we used functional magnetic resonance imaging fMRI and magnetoencephalography MEG to measure brain activity for correct and incorrect trials of an auditory phonetic identification in noise task. FMRI analysis revealed activity in the premotor cortex including the neighboring frontal opercular part of Broca's area (PMC/Broca's) for both perception and production tasks involving the same phonetic stimuli (potential mirror system site) that was significantly greater for correct over incorrect perceptual identification trials. Time-frequency analysis of single trials conducted over MEG current localized to PMC/Broca's using a hierarchical variational Bayesian source analysis technique revealed significantly greater event-related synchronization ERS and desynchronization ERD for correct over incorrect trials in the alpha, beta, and gamma frequency range prior to and after stimulus presentation. Together, these fMRI and MEG results are consistent with the hypothesis that articulatory processes serve to facilitate perceptual performance, while further dispelling concerns that activity found in ventral PMC/Broca's (mirror system) is merely a product of covert production of the perceived action. The finding of performance predictive activity prior to stimulus onset as well as activity related to task difficulty instead of information available in stimulation are consistent with constructivist and contrary to direct realist theories of perception. PMID:20184959

Callan, Daniel; Callan, Akiko; Gamez, Mario; Sato, Masa-aki; Kawato, Mitsuo

2010-06-01

198

Distinguishing the Functional Roles of Multiple Regions in Distributed Neural Systems for Visual Working Memory  

Microsoft Academic Search

We have investigated the human neural systems for visual working memory using functional magnetic resonance imaging to distinguish sustained activity during memory delays from transient responses related to perceptual and motor operations. These studies have identified six distinct frontal regions that demonstrate sustained activity during memory delays. These regions could be distinguished from brain regions in extrastriate cortex that participate

James V. Haxby; Laurent Petit; Leslie G. Ungerleider; Susan M. Courtney

2000-01-01

199

Distinguishing the Functional Roles of Multiple Regions in Distributed Neural Systems for Visual Working Memory1  

Microsoft Academic Search

We have investigated the human neural systems for visual working memory using functional magnetic res- onance imaging to distinguish sustained activity dur- ing memory delays from transient responses related to perceptual and motor operations. These studies have identified six distinct frontal regions that demonstrate sustained activity during memory delays. These re- gions could be distinguished from brain regions in extrastriate

James V. Haxby; Laurent Petit; Leslie G. Ungerleider; Susan M. Courtney

200

Action Control: Independent Effects of Memory and Monocular Viewing on Reaching Accuracy  

ERIC Educational Resources Information Center

Evidence suggests that perceptual networks in the ventral visual pathway are necessary for action control when targets are viewed with only one eye, or when the target must be stored in memory. We tested whether memory-linked (i.e., open-loop versus memory-guided actions) and monocular-linked effects (i.e., binocular versus monocular actions) on…

Westwood, D.A.; Robertson, C.; Heath, M.

2005-01-01

201

Transient and sustained activity in a distributed neural system for human working memory  

Microsoft Academic Search

Working memory involves the short-term maintenance of an active representation of information so that it is available for further processing. Visual working memory tasks, in which subjects retain the memory of a stimulus over brief delays, require both the perceptual encoding of the stimulus and the subsequent maintenance of its representation after the stimulus is removed from view. Such tasks

Susan M. Courtney; Leslie G. Ungerleider; Katrina Keil; James V. Haxby

1997-01-01

202

Perceptual development and auditory backward recognition masking  

Microsoft Academic Search

Three amplitude-discrimination experiments within a backward masking task were carried out to study whether young children have a slower rate of perceptual processing than do adults. Rate of processing was defined within an explicit model of perceptual performance that allows the investi- gator to determine if rate is responsible for developmental differences in auditory discrimination. A developmental difference in discrimination

Dominic W. Massaro; Deborah Burke

1991-01-01

203

Continuity and Discontinuity of Perceptual Development.  

ERIC Educational Resources Information Center

Despite external changes such as those of magnitudes, the functional properties of the visual system also improve with increased age. According to Jean Piaget's centration/decentration theory, the process of perceptual development might continue until adulthood and even after. However, perceptual development should not be understood in all of its…

Fischer, Hardi

204

Three Dimensional Video: Perceptual and Aesthetic Drawbacks.  

ERIC Educational Resources Information Center

The revolution brought about by computerized technology, in general, and television imagery, in particular, challenges the perceptual habits and alters the television viewer's means of expressing appreciation of the aesthetic merits of such television images. This study speculates on several perceptual and aesthetic drawbacks of future massive…

Metallinos, Nikos

205

Task Specific Devices and the Perceptual Bottleneck*  

E-print Network

-segment system, the muscular system, the circulatory system, and the nervous system. A methodological dilemma properties of four subsystems of the human action system are described. The subsystems are the link. The characteristics of the human perceptual system lead to the perceptual bottleneck. Information about the dynamics

206

Block Mean Value Based Image Perceptual Hashing  

Microsoft Academic Search

Image perceptual hashing has been proposed to identify or authenticate image contents in a robust way against distortions caused by compression, noise, common signal processing and geometrical modifications, while still holding a good discriminability for different ones in sense of human perception. We propose and compare four normalized block mean value based image perceptual hashing algorithms which demonstrate higher performances

Bian Yang; Fan Gu; Xiamu Niu

2006-01-01

207

Perceptual Differences between Hippies and College Students  

ERIC Educational Resources Information Center

Perceptual differences were investigated between 50 college students who were non-drug users and 50 hippies who used LSD. The major hypothesis predicted was that hippies would score differently from college students in a specific direction on each of the perceptual tasks. (Author)

Brothers, Robert; Gaines, Rosslyn

1973-01-01

208

Repetition blindness has a perceptual locus: evidence from online processing of targets in RSVP streams  

NASA Technical Reports Server (NTRS)

Four experiments tested whether repetition blindness (RB; reduced accuracy reporting repetitions of briefly displayed items) is a perceptual or a memory-recall phenomenon. RB was measured in rapid serial visual presentation (RSVP) streams, with the task altered to reduce memory demands. In Experiment 1 only the number of targets (1 vs. 2) was reported, eliminating the need to remember target identities. Experiment 2 segregated repeated and nonrepeated targets into separate blocks to reduce bias against repeated targets. Experiments 3 and 4 required immediate "online" buttonpress responses to targets as they occurred. All 4 experiments showed very strong RB. Furthermore, the online response data showed clearly that the 2nd of the repeated targets is the one missed. The present results show that in the RSVP paradigm, RB occurs online during initial stimulus encoding and decision making. The authors argue that RB is indeed a perceptual phenomenon.

Johnston, James C.; Hochhaus, Larry; Ruthruff, Eric

2002-01-01

209

Neocortical Connectivity during Episodic Memory Formation  

Microsoft Academic Search

During the formation of new episodic memories, a rich array of perceptual information is bound together for long-term storage. However, the brain mechanisms by which sensory representations (such as colors, objects, or individuals) are selected for episodic encoding are currently unknown. We describe a functional magnetic resonance imaging experiment in which participants encoded the association between two classes of visual

Christopher Summerfield; Matthew Greene; Tor Wager; Tobias Egner; Joy Hirsch; Jennifer Mangels

2006-01-01

210

Perceptual estimation obeys Occam's razor.  

PubMed

Theoretical models of unsupervised category learning postulate that humans "invent" categories to accommodate new patterns, but tend to group stimuli into a small number of categories. This "Occam's razor" principle is motivated by normative rules of statistical inference. If categories influence perception, then one should find effects of category invention on simple perceptual estimation. In a series of experiments, we tested this prediction by asking participants to estimate the number of colored circles on a computer screen, with the number of circles drawn from a color-specific distribution. When the distributions associated with each color overlapped substantially, participants' estimates were biased toward values intermediate between the two means, indicating that subjects ignored the color of the circles and grouped different-colored stimuli into one perceptual category. These data suggest that humans favor simpler explanations of sensory inputs. In contrast, when the distributions associated with each color overlapped minimally, the bias was reduced (i.e., the estimates for each color were closer to the true means), indicating that sensory evidence for more complex explanations can override the simplicity bias. We present a rational analysis of our task, showing how these qualitative patterns can arise from Bayesian computations. PMID:24137136

Gershman, Samuel J; Niv, Yael

2013-01-01

211

Collapse models and perceptual processes  

NASA Astrophysics Data System (ADS)

Theories including a collapse mechanism have been presented various years ago. They are based on a modification of standard quantum mechanics in which nonlinear and stochastic terms are added to the evolution equation. Their principal merits derive from the fact that they are mathematically precise schemes accounting, on the basis of a unique universal dynamical principle, both for the quantum behavior of microscopic systems as well as for the reduction associated to measurement processes and for the classical behavior of macroscopic objects. Since such theories qualify themselves not as new interpretations but as modifications of the standard theory they can be, in principle, tested against quantum mechanics. Recently, various investigations identifying possible crucial test have been discussed. In spite of the extreme difficulty to perform such tests it seems that recent technological developments allow at least to put precise limits on the parameters characterizing the modifications of the evolution equation. Here we will simply mention some of the recent investigations in this direction, while we will mainly concentrate our attention to the way in which collapse theories account for definite perceptual process. The differences between the case of reductions induced by perceptions and those related to measurement procedures by means of standard macroscopic devices will be discussed. On this basis, we suggest a precise experimental test of collapse theories involving conscious observers. We make plausible, by discussing in detail a toy model, that the modified dynamics can give rise to quite small but systematic errors in the visual perceptual process.

Carlo Ghirardi, Gian; Romano, Raffaele

2014-04-01

212

Broad-based visual benefits from training with an integrated perceptual-learning video game.  

PubMed

Perception is the window through which we understand all information about our environment, and therefore deficits in perception due to disease, injury, stroke or aging can have significant negative impacts on individuals' lives. Research in the field of perceptual learning has demonstrated that vision can be improved in both normally seeing and visually impaired individuals, however, a limitation of most perceptual learning approaches is their emphasis on isolating particular mechanisms. In the current study, we adopted an integrative approach where the goal is not to achieve highly specific learning but instead to achieve general improvements to vision. We combined multiple perceptual learning approaches that have individually contributed to increasing the speed, magnitude and generality of learning into a perceptual-learning based video-game. Our results demonstrate broad-based benefits of vision in a healthy adult population. Transfer from the game includes; improvements in acuity (measured with self-paced standard eye-charts), improvement along the full contrast sensitivity function, and improvements in peripheral acuity and contrast thresholds. The use of this type of this custom video game framework built up from psychophysical approaches takes advantage of the benefits found from video game training while maintaining a tight link to psychophysical designs that enable understanding of mechanisms of perceptual learning and has great potential both as a scientific tool and as therapy to help improve vision. PMID:24406157

Deveau, Jenni; Lovcik, Gary; Seitz, Aaron R

2014-06-01

213

Where do we store the memory representations that guide attention?  

PubMed Central

During the last decade one of the most contentious and heavily studied topics in the attention literature has been the role that working memory representations play in controlling perceptual selection. The hypothesis has been advanced that to have attention select a certain perceptual input from the environment, we only need to represent that item in working memory. Here we summarize the work indicating that the relationship between what representations are maintained in working memory and what perceptual inputs are selected is not so simple. First, it appears that attentional selection is also determined by high-level task goals that mediate the relationship between working memory storage and attentional selection. Second, much of the recent work from our laboratory has focused on the role of long-term memory in controlling attentional selection. We review recent evidence supporting the proposal that working memory representations are critical during the initial configuration of attentional control settings, but that after those settings are established long-term memory representations play an important role in controlling which perceptual inputs are selected by mechanisms of attention. PMID:23444390

Woodman, Geoffrey F.; Carlisle, Nancy B.; Reinhart, Robert M. G.

2013-01-01

214

Perceptual and oculomotor evidence of limitations on processing accelerating motion.  

PubMed

Psychophysical studies have demonstrated that humans are less sensitive to image acceleration than to image speed (e.g., Gottsdanker, 1956; Werkhoven, Snippe, & Toet, 1992). Because there is evidence that a common motion-processing stage subserves perception and pursuit (e.g., Watamaniuk & Heinen, 1999), either pursuit should be similarly impaired in discriminating acceleration or it must receive input from a system different from the one that processes visual motion for perception. We assessed the sensitivity of pursuit to acceleration or speed, and compared the results with those obtained in perceptual experiments done with similar stimuli and tasks. Specifically, observers pursued or made psychophysical judgments of targets that moved at randomly selected base speeds and subsequent accelerations. Oculomotor and psychophysical discrimination were compared by analyzing performance for the entire stimulus set sorted by either target acceleration or speed. Thresholds for pursuit and perception were higher for target acceleration than speed, further evidence that a common motion-processing stage limits the performance of both systems. PMID:14765954

Watamaniuk, Scott N J; Heinen, Stephen J

2003-01-01

215

Visual working memory for simple and complex visual stimuli  

Microsoft Academic Search

Does the magical number four characterize our visual working memory (VWM) capacity for all kinds of objects, or is the capacity\\u000a of VWM inversely related to the perceptual complexity of those objects? To find out how perceptual complexity affects VWM,\\u000a we used a change detection task to measure VWM capacity for six types of stimuli of different complexity: colors, letters,

Hing Yee Eng; Diyu Chen; Yuhong Jiang

2005-01-01

216

Using Virtual Reality to Characterize Episodic Memory Profiles in Amnestic Mild Cognitive Impairment and Alzheimer's Disease: Influence of Active and Passive Encoding  

ERIC Educational Resources Information Center

Most neuropsychological assessments of episodic memory bear little similarity to the events that patients actually experience as memories in daily life. The first aim of this study was to use a virtual environment to characterize episodic memory profiles in an ecological fashion, which includes memory for central and perceptual details,…

Plancher, G.; Tirard, A.; Gyselinck, V.; Nicolas, S.; Piolino, P.

2012-01-01

217

Neural mechanisms of speed perception: transparent motion  

PubMed Central

Visual motion on the macaque retina is processed by direction- and speed-selective neurons in extrastriate middle temporal cortex (MT). There is strong evidence for a link between the activity of these neurons and direction perception. However, there is conflicting evidence for a link between speed selectivity of MT neurons and speed perception. Here we study this relationship by using a strong perceptual illusion in speed perception: when two transparently superimposed dot patterns move in opposite directions, their apparent speed is much larger than the perceived speed of a single pattern moving at that physical speed. Moreover, the sensitivity for speed discrimination is reduced for such bidirectional patterns. We first confirmed these behavioral findings in human subjects and extended them to a monkey subject. Second, we determined speed tuning curves of MT neurons to bidirectional motion and compared these to speed tuning curves for unidirectional motion. Consistent with previous reports, the response to bidirectional motion was often reduced compared with unidirectional motion at the preferred speed. In addition, we found that tuning curves for bidirectional motion were shifted to lower preferred speeds. As a consequence, bidirectional motion of some speeds typically evoked larger responses than unidirectional motion. Third, we showed that these changes in neural responses could explain changes in speed perception with a simple labeled line decoder. These data provide new insight into the encoding of transparent motion patterns and provide support for the hypothesis that MT activity can be decoded for speed perception with a labeled line model. PMID:23926031

van Wezel, Richard J. A.

2013-01-01

218

Distortions in memory for visual displays  

NASA Technical Reports Server (NTRS)

Systematic errors in perception and memory present a challenge to theories of perception and memory and to applied psychologists interested in overcoming them as well. A number of systematic errors in memory for maps and graphs are reviewed, and they are accounted for by an analysis of the perceptual processing presumed to occur in comprehension of maps and graphs. Visual stimuli, like verbal stimuli, are organized in comprehension and memory. For visual stimuli, the organization is a consequence of perceptual processing, which is bottom-up or data-driven in its earlier stages, but top-down and affected by conceptual knowledge later on. Segregation of figure from ground is an early process, and figure recognition later; for both, symmetry is a rapidly detected and ecologically valid cue. Once isolated, figures are organized relative to one another and relative to a frame of reference. Both perceptual (e.g., salience) and conceptual factors (e.g., significance) seem likely to affect selection of a reference frame. Consistent with the analysis, subjects perceived and remembered curves in graphs and rivers in maps as more symmetric than they actually were. Symmetry, useful for detecting and recognizing figures, distorts map and graph figures alike. Top-down processes also seem to operate in that calling attention to the symmetry vs. asymmetry of a slightly asymmetric curve yielded memory errors in the direction of the description. Conceptual frame of reference effects were demonstrated in memory for lines embedded in graphs. In earlier work, the orientation of map figures was distorted in memory toward horizontal or vertical. In recent work, graph lines, but not map lines, were remembered as closer to an imaginary 45 deg line than they had been. Reference frames are determined by both perceptual and conceptual factors, leading to selection of the canonical axes as a reference frame in maps, but selection of the imaginary 45 deg as a reference frame in graphs.

Tversky, Barbara

1989-01-01

219

Development of Auditory-Vocal Perceptual Skills in Songbirds  

PubMed Central

Songbirds are one of the few groups of animals that learn the sounds used for vocal communication during development. Like humans, songbirds memorize vocal sounds based on auditory experience with vocalizations of adult “tutors”, and then use auditory feedback of self-produced vocalizations to gradually match their motor output to the memory of tutor sounds. In humans, investigations of early vocal learning have focused mainly on perceptual skills of infants, whereas studies of songbirds have focused on measures of vocal production. In order to fully exploit songbirds as a model for human speech, understand the neural basis of learned vocal behavior, and investigate links between vocal perception and production, studies of songbirds must examine both behavioral measures of perception and neural measures of discrimination during development. Here we used behavioral and electrophysiological assays of the ability of songbirds to distinguish vocal calls of varying frequencies at different stages of vocal learning. The results show that neural tuning in auditory cortex mirrors behavioral improvements in the ability to make perceptual distinctions of vocal calls as birds are engaged in vocal learning. Thus, separate measures of neural discrimination and behavioral perception yielded highly similar trends during the course of vocal development. The timing of this improvement in the ability to distinguish vocal sounds correlates with our previous work showing substantial refinement of axonal connectivity in cortico-basal ganglia pathways necessary for vocal learning. PMID:23285011

Miller-Sims, Vanessa C.; Bottjer, Sarah W.

2012-01-01

220

Defensive engagement and perceptual enhancement  

PubMed Central

We tested whether visual cortical sensitivity to external cues in the context of an acute defensive reaction is heightened or attenuated. A strong cardiac defense (fear) response was elicited by presenting an abrupt, loud acoustic stimulus following a 10-minute period of quiescence. Electrocortical responses to aversive and neutral pictures following defensive stimulus onset were measured using dense-array EEG. Pictures were flickered at 12.5 Hz to evoke steady-state visual evoked potentials (ssVEP), which can be reliably extracted on the basis of single trials. Visual cortical activity indexing perceptual processing was substantially heightened when pictures were shown in temporal proximity to (i.e., 5 second after) the defense stimulus. Replicating previous studies, aversive visual stimuli were associated with enhanced ssVEP amplitude, compared to neutral stimuli. Acute defense facilitates visual perception of external cues and preserves accurate discrimination between threatening and safe cues. PMID:20713075

Keil, Andreas; Bradley, Margaret M.; Ihssen, Niklas; Heim, Sabine; Vila, Jaime; Guerra, Pedro; Lang, Peter J.

2010-01-01

221

A New Differential-Amplifier-Based Offset-Cancellation Sense Amplifier for Speed-Improvement of High-Density Static Random Access Memories in Scaled-Down Complementary Metal-Oxide-Semiconductor Technology  

NASA Astrophysics Data System (ADS)

A new differential-amplifier-based offset-cancellation sense amplifier (DOCSA) is proposed in order to improve operation speed of high-density, six-transistor-cell static random access memories (SRAMs) in scaled-down complementary metal-oxide-semiconductor (CMOS) technology. 40-nm node CMOS test chips were fabricated and measured to demonstrate the successful operation and performance of DOCSA. Simulated offset voltage of DOCSA was 60% compared to that of a conventional latch-type sense amplifier with the same input capacitance, and the bit-line delay in an SRAM is expected to be 60% by using DOCSA. The standard deviation of measured offset voltage in DOCSA agreed well with that of the simulated one. Combination of CMOS scaling and deviation-relief circuit technology becomes important in advanced LSI technology.

Hidetoshi Ikeda,; Koichi Takeda,; Masahiro Nomura,; Yoshihiro Hayashi,

2010-04-01

222

Interdisciplinary Adventures in Perceptual Ecology  

NASA Astrophysics Data System (ADS)

A portfolio dissertation that began as acoustic ecology and matured into perceptual ecology, centered on ecomusicology, bioacoustics, and translational audio-based media works with environmental perspectives. The place of music in Western eco-cosmology through time provides a basis for structuring an environmental history of human sound perception. That history suggests that music may stabilize human mental activity, and that an increased musical practice may be essential for the human project. An overview of recent antecedents preceding the emergence of acoustic ecology reveals structural foundations from 20th century culture that underpin modern sound studies. The contextual role that Aldo Leopold, Jacob von Uexkull, John Cage, Marshall McLuhan, and others played in anticipating the development of acoustic ecology as an interdiscipline is detailed. This interdisciplinary aspect of acoustic ecology is defined and defended, while new developments like soundscape ecology are addressed, though ultimately sound studies will need to embrace a broader concept of full-spectrum "sensory" or "perceptual" ecology. The bioacoustic fieldwork done on spawning sturgeon emphasized this necessity. That study yielded scientific recordings and spectrographic analyses of spawning sounds produced by lake sturgeon, Acipenser fulvescens, during reproduction in natural habitats in the Lake Winnebago watershed in Wisconsin. Recordings were made on the Wolf and Embarrass River during the 2011-2013 spawning seasons. Several specimens were dissected to investigate possible sound production mechanisms; no sonic musculature was found. Drumming sounds, ranging from 5 to 7 Hz fundamental frequency, verified the infrasonic nature of previously undocumented "sturgeon thunder". Other characteristic noises of sturgeon spawning including low-frequency rumbles and hydrodynamic sounds were identified. Intriguingly, high-frequency signals resembling electric organ discharges were discovered. These sounds create a distinctive acoustic signature of sturgeon spawning. Media files include concert performance video, sturgeon audio samples, podcasts, radio pieces, music recordings, sound design, and a time-lapse soundscape reconstructed from Aldo Leopold's notes.

Bocast, Christopher S.

223

Memory Processes in Learning Disability Subtypes of Children Born Preterm  

PubMed Central

The purpose of this study was to evaluate immediate auditory and visual memory processes in learning disability subtypes of 40 children born preterm. Three subgroups of children were examined: (a) primary language disability group (n = 13), (b) perceptual-motor disability group (n = 14), and (c) no learning disability diagnosis group without identified language or perceptual-motor learning disability (n = 13). Between-group comparisons indicate no significant differences in immediate auditory or visual memory performances between language and perceptual-motor learning disability groups. Within-group comparisons revealed that both learning disability groups performed significantly lower on a task of immediate memory when the mode of stimulus presentation and mode of response were visual. PMID:22375897

McCoy, Thomasin E.; Conrad, Amy L.; Richman, Lynn C.; Nopoulos, Peg C.; Bell, Edward F.

2014-01-01

224

Perceptual Evaluation of Video-Realistic Speech  

E-print Network

abstract With many visual speech animation techniques now available, there is a clear need for systematic perceptual evaluation schemes. We describe here our scheme and its application to a new video-realistic ...

Geiger, Gadi

2003-02-28

225

Robot Partners: Collaborative Perceptual Robotic Systems  

E-print Network

Robot Partners: Collaborative Perceptual Robotic Systems Working paper Cooperative Distributed robotic systems, including remote-brained soccer players, visually guided mobile robots, and visual been supported by the the Networks of Centres of Excellence Institute for Robotics and Intelligent

Little, Jim

226

Studying real-world perceptual expertise  

PubMed Central

Significant insights into visual cognition have come from studying real-world perceptual expertise. Many have previously reviewed empirical findings and theoretical developments from this work. Here we instead provide a brief perspective on approaches, considerations, and challenges to studying real-world perceptual expertise. We discuss factors like choosing to use real-world versus artificial object domains of expertise, selecting a target domain of real-world perceptual expertise, recruiting experts, evaluating their level of expertise, and experimentally testing experts in the lab and online. Throughout our perspective, we highlight expert birding (also called birdwatching) as an example, as it has been used as a target domain for over two decades in the perceptual expertise literature. PMID:25147533

Shen, Jianhong; Mack, Michael L.; Palmeri, Thomas J.

2014-01-01

227

Emergence and perceptual guidance of prehensile action   

E-print Network

Successful coordination of prehensile action depends upon the selection and control of appropriate reach and grasp movements. This thesis explores how prehensile actions are shaped and regulated by perceptual information. ...

Smith, Joanne

2009-01-01

228

From perceptual to language-mediated categorization.  

PubMed

From at least two months onwards, infants can form perceptual categories. During the first year of life, object knowledge develops from the ability to represent individual object features to representing correlations between attributes and to integrate information from different sources. At the end of the first year, these representations are shaped by labels, opening the way to conceptual knowledge. Here, we review the development of object knowledge and object categorization over the first year of life. We then present an artificial neural network model that models the transition from early perceptual categorization to categories mediated by labels. The model informs a current debate on the role of labels in object categorization by suggesting that although labels do not act as object features they nevertheless affect perceived similarity of perceptually distinct objects sharing the same label. The model presents the first step of an integrated account from early perceptual categorization to language-based concept learning. PMID:24324235

Westermann, Gert; Mareschal, Denis

2014-01-01

229

From perceptual to language-mediated categorization  

PubMed Central

From at least two months onwards, infants can form perceptual categories. During the first year of life, object knowledge develops from the ability to represent individual object features to representing correlations between attributes and to integrate information from different sources. At the end of the first year, these representations are shaped by labels, opening the way to conceptual knowledge. Here, we review the development of object knowledge and object categorization over the first year of life. We then present an artificial neural network model that models the transition from early perceptual categorization to categories mediated by labels. The model informs a current debate on the role of labels in object categorization by suggesting that although labels do not act as object features they nevertheless affect perceived similarity of perceptually distinct objects sharing the same label. The model presents the first step of an integrated account from early perceptual categorization to language-based concept learning. PMID:24324235

Westermann, Gert; Mareschal, Denis

2014-01-01

230

Perceptual Factors Influence Visual Search for Meaningful Symbols in Individuals with Intellectual Disabilities and Down Syndrome or Autism Spectrum Disorders  

ERIC Educational Resources Information Center

Augmentative and alternative communication (AAC) systems often supplement oral communication for individuals with intellectual and communication disabilities. Research with preschoolers without disabilities has demonstrated that two visual--perceptual factors influence speed and/or accuracy of finding a target: the internal color and spatial…

Wilkinson, Krista M.; McIlvane, William J.

2013-01-01

231

Short-Term Memory Affects Color Perception in Context  

PubMed Central

Color-based object selection — for instance, looking for ripe tomatoes in the market — places demands on both perceptual and memory processes: it is necessary to form a stable perceptual estimate of surface color from a variable visual signal, as well as to retain multiple perceptual estimates in memory while comparing objects. Nevertheless, perceptual and memory processes in the color domain are generally studied in separate research programs with the assumption that they are independent. Here, we demonstrate a strong failure of independence between color perception and memory: the effect of context on color appearance is substantially weakened by a short retention interval between a reference and test stimulus. This somewhat counterintuitive result is consistent with Bayesian estimation: as the precision of the representation of the reference surface and its context decays in memory, prior information gains more weight, causing the retained percepts to be drawn toward prior information about surface and context color. This interaction implies that to fully understand information processing in real-world color tasks, perception and memory need to be considered jointly. PMID:24475131

Olkkonen, Maria; Allred, Sarah R.

2014-01-01

232

Shared-Memory Multiprocessors Using Optical SMART Interconnects Group  

E-print Network

Shared-Memory Multiprocessors Using Optical SMART Interconnects Group Electrical Engineering and Background · Conclusions and Future Work · SPEED DMON Performance #12;Introduction Shared-memory multiprocessors: Centralized shared-memory: UMA (uniform memory access) Distributed shared-memory: NUMA (non

Pinkston, Timothy M.

233

Motor and perceptual factors in pseudoneglect  

Microsoft Academic Search

An important variant of the traditional line bisection task has involved a mechanical device invented by Bisiach and his colleagues (Bisiach et al. Perceptual and premotor factors of unilateral neglect. Neurology 1990;40:1278–81 [3]). This tool was devised to dissociate motor from perceptual factors in hemi-spatial neglect, by means of a mid-line indicator which moved congruently or non-congruently with the direction

Mairi S MacLeod; Oliver H Turnbull

1999-01-01

234

Enhancement of programming speed on gate-all-around poly-silicon nanowire nonvolatile memory using self-aligned NiSi Schottky barrier source/drain  

NASA Astrophysics Data System (ADS)

The programming characteristics of gate-all-around silicon-oxide-nitride-oxide silicon (SONOS) nonvolatile memories are presented using NiSi/poly-Si nanowires (SiNW) Schottky barrier (SB) heterojunctions. The non-uniform thermal stress distribution on SiNW channels due to joule heating affected the carrier transport behavior. Under a high drain voltage, impact ionization was found as a large lateral field enhances carrier velocity. As gate voltage (Vg) increased, the difference in the drain current within a range of various temperature conditions can be mitigated because a high gate field lowers the SB height of a NiSi source/SiNW/NiSi drain junction to ensure efficient hot-carrier generation. By applying the Fowler-Nordheim programming voltage to the SONOS nanowire memory, the SB height (?n = 0.34 eV) could be reduced by image force; thus, hot electrons could be injected from SB source/drain electrodes into the SiN storage node. To compare both SiNW and Si nanocrystal SONOS devices, the SB SiNW SONOS device was characterized experimentally to propose a wider threshold-voltage window, exhibiting efficient programming characteristics.

Ho, Ching-Yuan; Chang, Yaw-Jen; Chiou, Y. L.

2013-08-01

235

The therapeutic benefits of perceptual learning  

PubMed Central

The modern field of perceptual learning addresses improvements of sensory and perceptual functioning in adult observers and provides powerful tools to ameliorate the effects of neurological conditions that involve a sensory or attentional deficit. While the sensory systems were once thought to be plastic only during early development, modern research demonstrates a great deal of plasticity in the adult brain. Here we discuss the value of perceptual learning as a method to improve sensory and attentional function, with a brief overview of the current approaches in the field, including how perceptual learning can be highly specific to the training set, and also how new training approaches can overcome this specificity and transfer learning effects to untrained tasks. We discuss these in the context of extant applications of perceptual learning as a treatment for neurological conditions and how new knowledge mechanisms (including attention, exposure based learning, reinforcement learning and multisensory facilitation) that allow or restrict learning in the visual system can lead to enhanced treatment approaches. We suggest new approaches that integrate multiple mechanisms of perceptual learning that promise greater learning and more generalization to real world conditions.

Deveau, Jenni; Lovcik, Gary; Seitz, Aaron R.

2014-01-01

236

Enhanced memory ability: Insights from synaesthesia.  

PubMed

People with synaesthesia show an enhanced memory relative to demographically matched controls. The most obvious explanation for this is that the 'extra' perceptual experiences lead to richer encoding and retrieval opportunities of stimuli which induce synaesthesia (typically verbal stimuli). Although there is some evidence for this, it is unlikely to be the whole explanation. For instance, not all stimuli which trigger synaesthesia are better remembered (e.g., digit span) and some stimuli which do not trigger synaesthesia are better remembered. In fact, synaesthetes tend to have better visual memory than verbal memory. We suggest that enhanced memory in synaesthesia is linked to wider changes in cognitive systems at the interface of perception and memory and link this to recent findings in the neuroscience of memory. PMID:22634573

Rothen, Nicolas; Meier, Beat; Ward, Jamie

2012-09-01

237

Main Memory Database Systems: An Overview  

Microsoft Academic Search

Abstract-Memory resident database systems (MMDB’s) store their data,in main physical memory and provide very high-speed access. Conventional database systems are optimized for the particular,characteristics,of disk,storage,mechanisms.,Memory resident systems, on the other hand, use different optimizations to structure and organize data, as well as to make it reliable. This paper,surveys,the major memory residence optimizations and briefly discusses some of the memory resident

Hector Garcia-molina; Kenneth Salem

1992-01-01

238

High Speed Six-Transistor Static Random Access Memory Cells Using Single Grain Thin Film Transistors Fabricated at Low Temperature Process  

NASA Astrophysics Data System (ADS)

In this paper we will report successfully fabricated six transistor static random access memory (6T SRAM) cells using single-grain thin film transistors (TFTs). SRAM cells have been designed by analytical calculations and verified by DC and transient simulations. TFTs are fabricated by ?-Czochralski process that consists of making grain filter and Excimer laser crystallization at temperatures below 550 °C. The gate length of transistors are 2 ?m. Fabricated SRAM cells based on single grain TFTs, show good read and write static noise margin (SNM and WNM) equal to 0.55 and 0.75 V at 3.3 V power supply, respectively. Finally, excellent read and write access times equal to 13 and 8 ns in 87 MHz worldline frequency were obtained.

Negin Golshani,; Jaber Derakhshandeh,; Ryoichi Ishihara,; Cees I. M. Beenakker,

2010-03-01

239

High Speed Six-Transistor Static Random Access Memory Cells Using Single Grain Thin Film Transistors Fabricated at Low Temperature Process  

NASA Astrophysics Data System (ADS)

In this paper we will report successfully fabricated six transistor static random access memory (6T SRAM) cells using single-grain thin film transistors (TFTs). SRAM cells have been designed by analytical calculations and verified by DC and transient simulations. TFTs are fabricated by µ-Czochralski process that consists of making grain filter and Excimer laser crystallization at temperatures below 550 °C. The gate length of transistors are 2 µm. Fabricated SRAM cells based on single grain TFTs, show good read and write static noise margin (SNM and WNM) equal to 0.55 and 0.75 V at 3.3 V power supply, respectively. Finally, excellent read and write access times equal to 13 and 8 ns in 87 MHz worldline frequency were obtained.

Golshani, Negin; Derakhshandeh, Jaber; Ishihara, Ryoichi; Beenakker, Cees I. M.

2010-03-01

240

Changes across the psychometric function following perceptual learning of an RSVP reading task  

PubMed Central

Several recent studies have shown that perceptual learning can result in improvements in reading speed for people with macular disease (e.g., Chung, 2011; Tarita-Nistor et al., 2014). The improvements were reported as an increase in reading speed defined by specific criteria; however, little is known about how other properties of the reading performance or the participants' perceptual responses change as a consequence of learning. In this paper, we performed detailed analyses of data following perceptual learning using an RSVP (rapid serial visual presentation) reading task, looking beyond the change in reading speed defined by the threshold at a given accuracy on a psychometric function relating response accuracy with word exposure duration. Specifically, we explored the statistical characteristics of the response data to address two specific questions: was there a change in the slope of the psychometric function and did the improvements in performance occur consistently across different word exposure durations? Our results show that there is a general steepening of the slope of the psychometric function, leading to non-uniform improvements across stimulus levels.

Coates, Daniel R.; Chung, Susana T. L.

2014-01-01

241

It does not look odd to me: Perceptual impairments and eye movements in amnesic patients with medial temporal lobe damage  

PubMed Central

Studies of people with memory impairments have shown that a specific set of brain structures in the medial temporal lobe (MTL) is vital for memory function. However, whether these structures have a role outside of memory remains contentious. Recent studies of amnesic patients with damage to two structures within the MTL, the hippocampus and the perirhinal cortex, indicated that these patients also performed poorly on perceptual tasks. More specifically, they performed worse than controls when discriminating between objects, faces and scenes with overlapping features. In order to investigate whether these perceptual deficits are reflected in their viewing strategies, we tested a group of amnesic patients with MTL damage that included the hippocampus and perirhinal cortex on a series of oddity discrimination tasks in which they had to select an odd item from a visual array. Participants' eye movements were monitored throughout the experiment. Results revealed that patients were impaired on tasks that required them to discriminate between items that shared many features, and tasks that required processing items from different viewpoints. An analysis of their eye movements revealed that they exhibited a similar viewing pattern as controls: they fixated more on the target item on trials answered correctly, but not on trials answered incorrectly. In addition, their impaired performance was not explained by an abnormal viewing-strategy that assessed their use of working memory. These results suggest that the perceptual deficits in the MTL patients are not a consequence of abnormal viewing patterns of the objects and scenes, but instead, could involve an inability to bind information gathered from several fixations into a cohesive percept. These data also support the view that MTL structures are important not only for long-term memory, but are also involved in perceptual tasks. PMID:23154380

Erez, Jonathan; Lee, Andy C.H.; Barense, Morgan D.

2013-01-01

242

Memory loss  

MedlinePLUS

Forgetfulness; Amnesia; Impaired memory; Loss of memory; Amnestic syndrome; Dementia - memory loss ... or severe illness, including brain surgery Transient global amnesia (sudden, temporary loss of memory) of unclear cause ...

243

Mapping the perceptual grain of the human retina.  

PubMed

In humans, experimental access to single sensory receptors is difficult to achieve, yet it is crucial for learning how the signals arising from each receptor are transformed into perception. By combining adaptive optics microstimulation with high-speed eye tracking, we show that retinal function can be probed at the level of the individual cone photoreceptor in living eyes. Classical psychometric functions were obtained from cone-sized microstimuli targeted to single photoreceptors. Revealed psychophysically, the cone mosaic also manifests a variable sensitivity to light across its surface that accords with a simple model of cone light capture. Because this microscopic grain of vision could be detected on the perceptual level, it suggests that photoreceptors can act individually to shape perception, if the normally suboptimal relay of light by the eye's optics is corrected. Thus the precise arrangement of cones and the exact placement of stimuli onto those cones create the initial retinal limits on signals mediating spatial vision. PMID:24741057

Harmening, Wolf M; Tuten, William S; Roorda, Austin; Sincich, Lawrence C

2014-04-16

244

Mapping the Perceptual Grain of the Human Retina  

PubMed Central

In humans, experimental access to single sensory receptors is difficult to achieve, yet it is crucial for learning how the signals arising from each receptor are transformed into perception. By combining adaptive optics microstimulation with high-speed eye tracking, we show that retinal function can be probed at the level of the individual cone photoreceptor in living eyes. Classical psychometric functions were obtained from cone-sized microstimuli targeted to single photoreceptors. Revealed psychophysically, the cone mosaic also manifests a variable sensitivity to light across its surface that accords with a simple model of cone light capture. Because this microscopic grain of vision could be detected on the perceptual level, it suggests that photoreceptors can act individually to shape perception, if the normally suboptimal relay of light by the eye's optics is corrected. Thus the precise arrangement of cones and the exact placement of stimuli onto those cones create the initial retinal limits on signals mediating spatial vision. PMID:24741057

Tuten, William S.; Roorda, Austin; Sincich, Lawrence C.

2014-01-01

245

Mechanical memory  

DOEpatents

A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

Gilkey, Jeffrey C. (Albuquerque, NM); Duesterhaus, Michelle A. (Albuquerque, NM); Peter, Frank J. (Albuquerque, NM); Renn, Rosemarie A. (Albuquerque, NM); Baker, Michael S. (Albuquerque, NM)

2006-05-16

246

Mechanical memory  

DOEpatents

A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

Gilkey, Jeffrey C. (Albuquerque, NM); Duesterhaus, Michelle A. (Albuquerque, NM); Peter, Frank J. (Albuquerque, NM); Renn, Rosemarie A. (Alburquerque, NM); Baker, Michael S. (Albuquerque, NM)

2006-08-15

247

Influence of near threshold visual distractors on perceptual detection and reaching movements.  

PubMed

Providing evidence against a dissociation between conscious vision for perception and unconscious vision for action, recent studies have suggested that perceptual and motor decisions are based on a unique signal but distinct decisional thresholds. The aim of the present study was to provide a direct test of this assumption in a perceptual-motor dual task involving arm movements. In 300 trials, 10 participants performed speeded pointing movements toward a highly visible target located at 10° from the fixation point and ± 45° from the body midline. The target was preceded by one or two close to threshold distractor(s) (80 ms stimulus onset asynchrony) presented ± 30° according to the target location. After each pointing movement, participants judged whether the distractor was present or not on either side of the target. Results showed a robust reaction time facilitation effect and a deviation toward the distractor when the distractor was both present and consciously perceived (Hit). A small reaction time facilitation was also observed when two distractors were physically present but undetected (double-miss)--this facilitation being highly correlated with the physical contrast of the distractors. These results are compatible with the theory proposing that perceptual and motor decisions are based on a common signal but emerge from a contrast dependent fixed threshold for motor responses and a variable context dependent criterion for perceptual responses. This paper thus extends to arm movement control previous findings related to oculomotor control. PMID:20702742

Deplancke, A; Madelain, L; Chauvin, A; Cardoso-Leite, P; Gorea, A; Coello, Y

2010-10-01

248

Perceptual Contrast Enhancement with Dynamic Range Adjustment  

PubMed Central

Recent years, although great efforts have been made to improve its performance, few Histogram equalization (HE) methods take human visual perception (HVP) into account explicitly. The human visual system (HVS) is more sensitive to edges than brightness. This paper proposes to take use of this nature intuitively and develops a perceptual contrast enhancement approach with dynamic range adjustment through histogram modification. The use of perceptual contrast connects the image enhancement problem with the HVS. To pre-condition the input image before the HE procedure is implemented, a perceptual contrast map (PCM) is constructed based on the modified Difference of Gaussian (DOG) algorithm. As a result, the contrast of the image is sharpened and high frequency noise is suppressed. A modified Clipped Histogram Equalization (CHE) is also developed which improves visual quality by automatically detecting the dynamic range of the image with improved perceptual contrast. Experimental results show that the new HE algorithm outperforms several state-of-the-art algorithms in improving perceptual contrast and enhancing details. In addition, the new algorithm is simple to implement, making it suitable for real-time applications. PMID:24339452

Zhang, Hong; Li, Yuecheng; Chen, Hao; Yuan, Ding; Sun, Mingui

2013-01-01

249

The Neurobiology of Semantic Memory  

PubMed Central

Semantic memory includes all acquired knowledge about the world and is the basis for nearly all human activity, yet its neurobiological foundation is only now becoming clear. Recent neuroimaging studies demonstrate two striking results: the participation of modality-specific sensory, motor, and emotion systems in language comprehension, and the existence of large brain regions that participate in comprehension tasks but are not modality-specific. These latter regions, which include the inferior parietal lobe and much of the temporal lobe, lie at convergences of multiple perceptual processing streams. These convergences enable increasingly abstract, supramodal representations of perceptual experience that support a variety of conceptual functions including object recognition, social cognition, language, and the remarkable human capacity to remember the past and imagine the future. PMID:22001867

Binder, Jeffrey R.; Desai, Rutvik H.

2011-01-01

250

Cultural Differences in Perceptual Reorganization in US and Pirahã Adults  

E-print Network

Visual illusions and other perceptual phenomena can be used as tools to uncover the otherwise hidden constructive processes that give rise to perception. Although many perceptual processes are assumed to be universal, ...

Yoon, Jennifer M. D.

251

Conceptual and perceptual encoding instructions differently affect event recall.  

PubMed

When recalling an event, people usually retrieve the main facts and a reduced proportion of specific details. The objective of this experiment was to study the effects of conceptually and perceptually driven encoding in the recall of conceptual and perceptual information of an event. The materials selected for the experiment were two movie trailers. To enhance the encoding instructions, after watching the first trailer participants answered conceptual or perceptual questions about the event, while a control group answered general knowledge questions. After watching the second trailer, all of the participants completed a closed-ended recall task consisting of conceptual and perceptual items. Conceptual information was better recalled than perceptual details and participants made more perceptual than conceptual commission errors. Conceptually driven processing enhanced the recall of conceptual information, while perceptually driven processing not only did not improve the recall of descriptive details, but also damaged the standard conceptual/perceptual recall relationship. PMID:24718934

García-Bajos, Elvira; Migueles, Malen; Aizpurua, Alaitz

2014-11-01

252

Perceptual Image Compression in Telemedicine  

NASA Technical Reports Server (NTRS)

The next era of space exploration, especially the "Mission to Planet Earth" will generate immense quantities of image data. For example, the Earth Observing System (EOS) is expected to generate in excess of one terabyte/day. NASA confronts a major technical challenge in managing this great flow of imagery: in collection, pre-processing, transmission to earth, archiving, and distribution to scientists at remote locations. Expected requirements in most of these areas clearly exceed current technology. Part of the solution to this problem lies in efficient image compression techniques. For much of this imagery, the ultimate consumer is the human eye. In this case image compression should be designed to match the visual capacities of the human observer. We have developed three techniques for optimizing image compression for the human viewer. The first consists of a formula, developed jointly with IBM and based on psychophysical measurements, that computes a DCT quantization matrix for any specified combination of viewing distance, display resolution, and display brightness. This DCT quantization matrix is used in most recent standards for digital image compression (JPEG, MPEG, CCITT H.261). The second technique optimizes the DCT quantization matrix for each individual image, based on the contents of the image. This is accomplished by means of a model of visual sensitivity to compression artifacts. The third technique extends the first two techniques to the realm of wavelet compression. Together these two techniques will allow systematic perceptual optimization of image compression in NASA imaging systems. Many of the image management challenges faced by NASA are mirrored in the field of telemedicine. Here too there are severe demands for transmission and archiving of large image databases, and the imagery is ultimately used primarily by human observers, such as radiologists. In this presentation I will describe some of our preliminary explorations of the applications of our technology to the special problems of telemedicine.

Watson, Andrew B.; Ahumada, Albert J., Jr.; Eckstein, Miguel; Null, Cynthia H. (Technical Monitor)

1996-01-01

253

How embodied is perceptual decision making? Evidence for separate processing of perceptual and motor decisions.  

PubMed

The extent to which different cognitive processes are "embodied" is widely debated. Previous studies have implicated sensorimotor regions such as lateral intraparietal (LIP) area in perceptual decision making. This has led to the view that perceptual decisions are embodied in the same sensorimotor networks that guide body movements. We use event-related fMRI and effective connectivity analysis to investigate whether the human sensorimotor system implements perceptual decisions. We show that when eye and hand motor preparation is disentangled from perceptual decisions, sensorimotor areas are not involved in accumulating sensory evidence toward a perceptual decision. Instead, inferior frontal cortex increases its effective connectivity with sensory regions representing the evidence, is modulated by the amount of evidence, and shows greater task-positive BOLD responses during the perceptual decision stage. Once eye movement planning can begin, however, an intraparietal sulcus (IPS) area, putative LIP, participates in motor decisions. Moreover, sensory evidence levels modulate decision and motor preparation stages differently in different IPS regions, suggesting functional heterogeneity of the IPS. This suggests that different systems implement perceptual versus motor decisions, using different neural signatures. PMID:23365248

Filimon, Flavia; Philiastides, Marios G; Nelson, Jonathan D; Kloosterman, Niels A; Heekeren, Hauke R

2013-01-30

254

Perceived visual speed constrained by image segmentation  

NASA Technical Reports Server (NTRS)

Little is known about how or where the visual system parses the visual scene into objects or surfaces. However, it is generally assumed that the segmentation and grouping of pieces of the image into discrete entities is due to 'later' processing stages, after the 'early' processing of the visual image by local mechanisms selective for attributes such as colour, orientation, depth, and motion. Speed perception is also thought to be mediated by early mechanisms tuned for speed. Here we show that manipulating the way in which an image is parsed changes the way in which local speed information is processed. Manipulations that cause multiple stimuli to appear as parts of a single patch degrade speed discrimination, whereas manipulations that perceptually divide a single large stimulus into parts improve discrimination. These results indicate that processes as early as speed perception may be constrained by the parsing of the visual image into discrete entities.

Verghese, P.; Stone, L. S.

1996-01-01

255

Perceptually-Based Adaptive JPEG Coding  

NASA Technical Reports Server (NTRS)

An extension to the JPEG standard (ISO/IEC DIS 10918-3) allows spatial adaptive coding of still images. As with baseline JPEG coding, one quantization matrix applies to an entire image channel, but in addition the user may specify a multiplier for each 8 x 8 block, which multiplies the quantization matrix, yielding the new matrix for the block. MPEG 1 and 2 use much the same scheme, except there the multiplier changes only on macroblock boundaries. We propose a method for perceptual optimization of the set of multipliers. We compute the perceptual error for each block based upon DCT quantization error adjusted according to contrast sensitivity, light adaptation, and contrast masking, and pick the set of multipliers which yield maximally flat perceptual error over the blocks of the image. We investigate the bitrate savings due to this adaptive coding scheme and the relative importance of the different sorts of masking on adaptive coding.

Watson, Andrew B.; Rosenholtz, Ruth; Null, Cynthia H. (Technical Monitor)

1996-01-01

256

Perceptual and neural pliability of odor objects.  

PubMed

A key function of the sense of smell is to guide organisms towards rewards and away from dangers. However, because relatively few volatile chemicals in the environment carry intrinsic biological value, the meaning of an odor often needs to be acquired through learning and experience. The tremendous perceptual and neural plasticity of the olfactory system provides a design that is ideal for the establishment of links between odor cues and behaviorally relevant events, promoting appropriate adaptive responses to foods, friends, foes, and mates. This article describes recent human neuroimaging data showing the dynamic effects of olfactory perceptual learning and aversive conditioning on the behavioral discrimination of odor objects, with parallel plasticity and reorganization in the posterior piriform and orbitofrontal cortices. The findings presented here highlight the important role of experience in shaping odor object perception and in ensuring the human sense of smell achieves its full perceptual potential. PMID:19686155

Gottfried, Jay A; Wu, Keng Nei

2009-07-01

257

Action-specific disruption of perceptual confidence.  

PubMed

Theoretical models of perception assume that confidence is related to the quality or strength of sensory processing. Counter to this intuitive view, we showed in the present research that the motor system also contributes to judgments of perceptual confidence. In two experiments, we used transcranial magnetic stimulation (TMS) to manipulate response-specific representations in the premotor cortex, selectively disrupting postresponse confidence in visual discrimination judgments. Specifically, stimulation of the motor representation associated with the unchosen response reduced confidence in correct responses, thereby reducing metacognitive capacity without changing visual discrimination performance. Effects of TMS on confidence were observed when stimulation was applied both before and after the response occurred, which suggests that confidence depends on late-stage metacognitive processes. These results place constraints on models of perceptual confidence and metacognition by revealing that action-specific information in the premotor cortex contributes to perceptual confidence. PMID:25425059

Fleming, Stephen M; Maniscalco, Brian; Ko, Yoshiaki; Amendi, Namema; Ro, Tony; Lau, Hakwan

2015-01-01

258

Quantum-Computation for Perceptual Control Architecture  

NASA Astrophysics Data System (ADS)

In this Chapter, we propose a quantum-dynamical modeling approach to Perceptual Control Architecture, using large networks of Josephson Junctions and their category-theoretic generalizations with fuzzy associative functors Our approach provides the basis for composing modular multi-layered perceptual control architectures using Josephson Junction Networks, employing intuitively appealing category-theoretic abstractions to hide the algebraic details from the designer while nonetheless being able to rigorously ensure functional composition correctness. That is, our approach ensures that Josephson Junction Networks, as a modeling primitive, can be composed into formally correct multi-layered perceptual control architectures, while hiding the underlying algebraic systems of equations from the designer under a blanket of category-theoretic abstraction.

Ivancevic, Vladimir G.; Reid, Darryn J.

2015-11-01

259

Healthy Older Observers Show Equivalent Perceptual-Cognitive Training Benefits to Young Adults for Multiple Object Tracking  

PubMed Central

The capacity to process complex dynamic scenes is of critical importance in real life. For instance, traveling through a crowd while avoiding collisions and maintaining orientation and good motor control requires fluent and continuous perceptual-cognitive processing. It is well documented that effects of healthy aging can influence perceptual-cognitive processes (Faubert, 2002) and that the efficiency of such processes can improve with training even for older adults (Richards et al., 2006). Here we assess the capacity of older participants to improve their tracking speed thresholds in a dynamic, virtual reality environment. Results show that this capacity is significantly affected by healthy aging but that perceptual-cognitive training can significantly reduce age-related effects in older individuals, who show an identical learning function to younger healthy adults. Data support the notion that learning in healthy older persons is maintained for processing complex dynamic scenes. PMID:23761025

Legault, Isabelle; Allard, Rémy; Faubert, Jocelyn

2013-01-01

260

Conceptual Distinctiveness Supports Detailed Visual Long-Term Memory for Real-World Objects  

ERIC Educational Resources Information Center

Humans have a massive capacity to store detailed information in visual long-term memory. The present studies explored the fidelity of these visual long-term memory representations and examined how conceptual and perceptual features of object categories support this capacity. Observers viewed 2,800 object images with a different number of exemplars…

Konkle, Talia; Brady, Timothy F.; Alvarez, George A.; Oliva, Aude

2010-01-01

261

Working memory for visual objects: Complementary roles of inferior temporal, medial temporal, and prefrontal cortex  

Microsoft Academic Search

Humans have an extraordinary ability to maintain and manipulate visual image information in the absence of perceptual stimulation. The neural substrates of visual working memory have been extensively researched, but there have been few attempts to integrate these findings into a model of how different cortical areas interact to form and maintain visual memories. In this paper, I review findings

C. Ranganath

2006-01-01

262

Effects of Aging on True and False Memory Formation: An fMRI Study  

ERIC Educational Resources Information Center

Compared to young, older adults are more likely to forget events that occurred in the past as well as remember events that never happened. Previous studies examining false memories and aging have shown that these memories are more likely to occur when new items share perceptual or semantic similarities with those presented during encoding. It is…

Dennis, Nancy A.; Kim, Hongkeun; Cabeza, Roberto

2007-01-01

263

Perceptual Learning for Speech: Is There a Return to Normal?  

ERIC Educational Resources Information Center

Recent work on perceptual learning shows that listeners' phonemic representations dynamically adjust to reflect the speech they hear (Norris, McQueen, & Cutler, 2003). We investigate how the perceptual system makes such adjustments, and what (if anything) causes the representations to return to their pre-perceptual learning settings. Listeners are…

Kraljic, Tanya; Samuel, Arthur G.

2005-01-01

264

Static Energy Reduction in Cache Memories Using Data Compression  

Microsoft Academic Search

Cache memory is effective in bridging a growing speed gap between a processor and relatively slow external main memory. However, the energy consumption in the cache memory would approach or exceed 50% of the total consumption by the processor, which leads to a serious problem in terms of allowable temperature and high-speed processing. In the near future, static (leakage) energy

Kiyofumi Tanaka; Aiko Matsuda

2006-01-01

265

Image data compression having minimum perceptual error  

NASA Technical Reports Server (NTRS)

A method for performing image compression that eliminates redundant and invisible image components is described. The image compression uses a Discrete Cosine Transform (DCT) and each DCT coefficient yielded by the transform is quantized by an entry in a quantization matrix which determines the perceived image quality and the bit rate of the image being compressed. The present invention adapts or customizes the quantization matrix to the image being compressed. The quantization matrix comprises visual masking by luminance and contrast techniques and by an error pooling technique all resulting in a minimum perceptual error for any given bit rate, or minimum bit rate for a given perceptual error.

Watson, Andrew B. (inventor)

1995-01-01

266

Image Data Compression Having Minimum Perceptual Error  

NASA Technical Reports Server (NTRS)

A method is presented for performing color or grayscale image compression that eliminates redundant and invisible image components. The image compression uses a Discrete Cosine Transform (DCT) and each DCT coefficient yielded by the transform is quantized by an entry in a quantization matrix which determines the perceived image quality and the bit rate of the image being compressed. The quantization matrix comprises visual masking by luminance and contrast technique all resulting in a minimum perceptual error for any given bit rate, or minimum bit rate for a given perceptual error.

Watson, Andrew B. (Inventor)

1997-01-01

267

A perceptual account of symbolic reasoning  

PubMed Central

People can be taught to manipulate symbols according to formal mathematical and logical rules. Cognitive scientists have traditionally viewed this capacity—the capacity for symbolic reasoning—as grounded in the ability to internally represent numbers, logical relationships, and mathematical rules in an abstract, amodal fashion. We present an alternative view, portraying symbolic reasoning as a special kind of embodied reasoning in which arithmetic and logical formulae, externally represented as notations, serve as targets for powerful perceptual and sensorimotor systems. Although symbolic reasoning often conforms to abstract mathematical principles, it is typically implemented by perceptual and sensorimotor engagement with concrete environmental structures. PMID:24795662

Landy, David; Allen, Colin; Zednik, Carlos

2014-01-01

268

Influence of early attentional modulation on working memory  

PubMed Central

It is now established that attention influences working memory (WM) at multiple processing stages. This liaison between attention and WM poses several interesting empirical questions. Notably, does attention impact WM via its influences on early perceptual processing? If so, what are the critical factors at play in this attention-perception-WM interaction. I review recent data from our laboratory utilizing a variety of techniques (electroencephalography (EEG), functional MRI (fMRI) and transcranial magnetic stimulation (TMS)), stimuli (features and complex objects), novel experimental paradigms, and research populations (younger and older adults), which converge to support the conclusion that top-down modulation of visual cortical activity at early perceptual processing stages (100–200 ms after stimulus onset) impacts subsequent WM performance. Factors that affect attentional control at this stage include cognitive load, task practice, perceptual training, and aging. These developments highlight the complex and dynamic relationships among perception, attention, and memory. PMID:21184764

Gazzaley, Adam

2011-01-01

269

Dazzle camouflage affects speed perception.  

PubMed

Movement is the enemy of camouflage: most attempts at concealment are disrupted by motion of the target. Faced with this problem, navies in both World Wars in the twentieth century painted their warships with high contrast geometric patterns: so-called "dazzle camouflage". Rather than attempting to hide individual units, it was claimed that this patterning would disrupt the perception of their range, heading, size, shape and speed, and hence reduce losses from, in particular, torpedo attacks by submarines. Similar arguments had been advanced earlier for biological camouflage. Whilst there are good reasons to believe that most of these perceptual distortions may have occurred, there is no evidence for the last claim: changing perceived speed. Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds. The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles. In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle. PMID:21673797

Scott-Samuel, Nicholas E; Baddeley, Roland; Palmer, Chloe E; Cuthill, Innes C

2011-01-01

270

Dazzle Camouflage Affects Speed Perception  

PubMed Central

Movement is the enemy of camouflage: most attempts at concealment are disrupted by motion of the target. Faced with this problem, navies in both World Wars in the twentieth century painted their warships with high contrast geometric patterns: so-called “dazzle camouflage”. Rather than attempting to hide individual units, it was claimed that this patterning would disrupt the perception of their range, heading, size, shape and speed, and hence reduce losses from, in particular, torpedo attacks by submarines. Similar arguments had been advanced earlier for biological camouflage. Whilst there are good reasons to believe that most of these perceptual distortions may have occurred, there is no evidence for the last claim: changing perceived speed. Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds. The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles. In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle. PMID:21673797

Scott-Samuel, Nicholas E.; Baddeley, Roland; Palmer, Chloe E.; Cuthill, Innes C.

2011-01-01

271

Memory Hierarchy Hardware-Software Co-design in Embedded Systems  

E-print Network

The memory hierarchy is the main bottleneck in modern computer systems as the gap between the speed of the processor and the memory continues to grow larger. The situation in embedded systems is even worse. The memory ...

Ge, Zhiguo

272

Uncovering Camouflage: Amygdala Activation Predicts Long-Term Memory  

E-print Network

Neuron Article Uncovering Camouflage: Amygdala Activation Predicts Long-Term Memory of Induced (``camouflage''), followed by brief exposures to the original images (``solution''), which led to induced as ``remembered'' if detailed perceptual knowledge was elicited from the camouflage image alone. During encoding

Rubin, Nava

273

Intersensory Redundancy Enhances Memory in Bobwhite Quail Embryos  

ERIC Educational Resources Information Center

Information presented concurrently and redundantly to 2 or more senses (intersensory redundancy) has been shown to recruit attention and promote perceptual learning of amodal stimulus properties in animal embryos and human infants. This study examined whether the facilitative effect of intersensory redundancy also extends to the domain of memory.…

Lickliter, Robert; Bahrick, Lorraine E.; Honeycutt, Hunter

2004-01-01

274

Developmental Changes in the Interface between Perception and Memory Retrieval.  

ERIC Educational Resources Information Center

Four experiments examined how perception affects delayed recognition, visual pop out, and memory reactivation (priming) in six month olds. Infants discriminated cues differing in spatial arrangement or number of primitive perceptual units (textons) in a delayed recognition task and exhibited adultlike visual pop-out effects in a priming task. (MDM)

Bhatt, Ramesh S.; And Others

1994-01-01

275

FEBAM: A Feature-Extracting Bidirectional Associative Memory  

Microsoft Academic Search

In this paper, a new model that can ultimately create its own set of perceptual features is proposed. Using a bidirectional associative memory (BAM)-inspired architecture, the resulting model inherits properties such as attractor-like behavior and successful processing of noisy inputs, while being able to achieve principal component analysis (PCA) tasks such as feature extraction and dimensionality reduction. The model is

Sylvain Chartier; Gyslain Giguère; Patrice Renaud; Jean-marc Lina; Robert Proulx

2007-01-01

276

Improving Perceptual Skills with 3-Dimensional Animations.  

ERIC Educational Resources Information Center

Describes three-dimensional computer aided design (CAD) models for every component in a representative mechanical system; the CAD models made it easy to generate 3-D animations that are ideal for teaching perceptual skills in multimedia computer-based technical training. Fifteen illustrations are provided. (AEF)

Johns, Janet Faye; Brander, Julianne Marie

1998-01-01

277

Improved perceptual-motor performance measurement system  

NASA Technical Reports Server (NTRS)

Battery of tests determines the primary dimensions of perceptual-motor performance. Eighteen basic measures range from simple tests to sophisticated electronic devices. Improved system has one unit for the subject containing test display and response elements, and one for the experimenter where test setups, programming, and scoring are accomplished.

Parker, J. F., Jr.; Reilly, R. E.

1969-01-01

278

The Mirage of the Perceptually Handicapped Syndrome  

ERIC Educational Resources Information Center

Emphasize the importance of a positive diagnosis of perceptual handicap, rather than a wastebasket" diagnosis. The tendency to separate the child's handicap from his feelings about it is reflected in the treatment process. There exists little concern with the totality of the child's development in his total environment. (Author)

West, Malcolm

1970-01-01

279

Perceptual speech modeling for noisy speech recognition  

Microsoft Academic Search

This paper proposes a perceptual modeling approach with a two-stage recognition to deal with the issues of recognition degradation in noisy environment. The auditory masking effect is used for speech enhancement and acoustic modeling in order to overcome the model inconsistencies between training speech and noisy input. In the two-stage recognition, the maximum a posteriori (MAP) based adaptation algorithm is

Chung-Hsien Wu; Yu-Hsien Chiu; Huigan Lim

2002-01-01

280

Generalization of Perceptual Learning of Vocoded Speech  

ERIC Educational Resources Information Center

Recent work demonstrates that learning to understand noise-vocoded (NV) speech alters sublexical perceptual processes but is enhanced by the simultaneous provision of higher-level, phonological, but not lexical content (Hervais-Adelman, Davis, Johnsrude, & Carlyon, 2008), consistent with top-down learning (Davis, Johnsrude, Hervais-Adelman,…

Hervais-Adelman, Alexis G.; Davis, Matthew H.; Johnsrude, Ingrid S.; Taylor, Karen J.; Carlyon, Robert P.

2011-01-01

281

Sex, Aspiration Level, and Perceptual Discrimination  

ERIC Educational Resources Information Center

This study investigated some of the differences in a perceptual discrimination performance task due to: (1) sex and (2) level of aspiration of each group of subjects. It was found that there is an interaction effect between femaleness, maleness, and aspiration level. (Author)

Peretti, Peter O.

1974-01-01

282

Auditory Brainstem Correlates of Perceptual Timing Deficits  

E-print Network

Auditory Brainstem Correlates of Perceptual Timing Deficits Krista L. Johnson, Trent G. Nicol. Speech-evoked brainstem responses were analyzed across groups to measure the neural integrity of stimulus in structures as early as the auditory brainstem. Thus, speech- evoked brainstem responses are a biological

283

Infants Experience Perceptual Narrowing for Nonprimate Faces  

ERIC Educational Resources Information Center

Perceptual narrowing--a phenomenon in which perception is broad from birth, but narrows as a function of experience--has previously been tested with primate faces. In the first 6 months of life, infants can discriminate among individual human and monkey faces. Though the ability to discriminate monkey faces is lost after about 9 months, infants…

Simpson, Elizabeth A.; Varga, Krisztina; Frick, Janet E.; Fragaszy, Dorothy

2011-01-01

284

Predicting Odor Perceptual Similarity from Odor Structure  

PubMed Central

To understand the brain mechanisms of olfaction we must understand the rules that govern the link between odorant structure and odorant perception. Natural odors are in fact mixtures made of many molecules, and there is currently no method to look at the molecular structure of such odorant-mixtures and predict their smell. In three separate experiments, we asked 139 subjects to rate the pairwise perceptual similarity of 64 odorant-mixtures ranging in size from 4 to 43 mono-molecular components. We then tested alternative models to link odorant-mixture structure to odorant-mixture perceptual similarity. Whereas a model that considered each mono-molecular component of a mixture separately provided a poor prediction of mixture similarity, a model that represented the mixture as a single structural vector provided consistent correlations between predicted and actual perceptual similarity (r?0.49, p<0.001). An optimized version of this model yielded a correlation of r?=?0.85 (p<0.001) between predicted and actual mixture similarity. In other words, we developed an algorithm that can look at the molecular structure of two novel odorant-mixtures, and predict their ensuing perceptual similarity. That this goal was attained using a model that considers the mixtures as a single vector is consistent with a synthetic rather than analytical brain processing mechanism in olfaction. PMID:24068899

Weiss, Tali; Frumin, Idan; Khan, Rehan M.; Sobel, Noam

2013-01-01

285

Perceptual Modeling for Behavioral Animation of Fishes  

E-print Network

Perceptual Modeling for Behavioral Animation of Fishes Xiaoyuan Tu Demetri Terzopoulos Department of animal behavior by autonomous animate agents re­ quires that the agents able to perceive their virtual by the animator. Simple autonomous models emerged as researchers began to introduce behavioral components

Toronto, University of

286

Towards perceptual quality evaluation of dynamic meshes  

Microsoft Academic Search

In practical applications, it is common that a 3D mesh undergoes some lossy operations (e.g. simplification, watermarking, compression, noise contamination, etc.). Since the end users of 3D meshes are often human beings, it is thus important to derive metrics that can faithfully assess the perceptual distortions induced by these operations. The derived metrics can be used, for instance, to benchmark

Fakhri Torkhani; Kai Wang; Annick Montanvert

2011-01-01

287

Perceptual watermarks for digital images and video  

Microsoft Academic Search

The growth of new imaging technologies has created a need for techniques that can be used for copyright protection of digital images and video. One approach for copyright protection is to introduce an invisible signal, known as a digital watermark, into an image or video sequence. In this paper, we describe digital watermarking techniques, known as perceptually based watermarks, that

Raymond B. Wolfgang; Christine I. Podilchuk; Edward J. Delp

1999-01-01

288

Perceptual Learning During Action Video Game Playing  

Microsoft Academic Search

Action video games have been shown to enhance behavioral performance on a wide variety of perceptual tasks, from those that require effective allocation of attentional resources across the visual scene, to those that demand the successful identification of fleetingly presented stimuli. Importantly, these effects have not only been shown in expert action video game players, but a causative link has

C. Shawn Green; Renjie Li; Daphne Bavelierb

2009-01-01

289

Using body size to predict perceptual range  

Microsoft Academic Search

We examined the relationship between body size and perceptual range (the distance at which an animal can perceive landscape elements) for a group of forest-dwelling rodents. We used previously published data on orientation ability at various distances for three sciurid species (gray squirrel, fox squirrel and chipmunk) and one murid species (white-footed mouse) to build a predictive model. We found

Stephen G. Mech; Patrick A. Zollner

2002-01-01

290

Perceptually grounded meaning Artificial Intelligence Laboratory  

E-print Network

Perceptually grounded meaning creation. Luc Steels Artificial Intelligence Laboratory Vrije systems mechanisms such as self­organisation, co­evolution, and level formation [5]. This paper focuses on the meaning creation process. A theoretical model is proposed to explain how an autonomous agent may originate

Steels, Luc

291

Perceptual crossing: the simplest online paradigm  

PubMed Central

Researchers in social cognition increasingly realize that many phenomena cannot be understood by investigating offline situations only, focusing on individual mechanisms and an observer perspective. There are processes of dynamic emergence specific to online situations, when two or more persons are engaged in a real-time interaction that are more than just the sum of the individual capacities or behaviors, and these require the study of online social interaction. Auvray et al.'s (2009) perceptual crossing paradigm offers possibly the simplest paradigm for studying such online interactions: two persons, a one-dimensional space, one bit of information, and a yes/no answer. This study has provoked a lot of resonance in different areas of research, including experimental psychology, computer/robot modeling, philosophy, psychopathology, and even in the field of design. In this article, we review and critically assess this body of literature. We give an overview of both behavioral experimental research and simulated agent modeling done using the perceptual crossing paradigm. We discuss different contexts in which work on perceptual crossing has been cited. This includes the controversy about the possible constitutive role of perceptual crossing for social cognition. We conclude with an outlook on future research possibilities, in particular those that could elucidate the link between online interaction dynamics and individual social cognition. PMID:22723776

Auvray, Malika; Rohde, Marieke

2012-01-01

292

Optimal reward harvesting in complex perceptual environments  

E-print Network

Optimal reward harvesting in complex perceptual environments Vidhya Navalpakkama,1 , Christof Kocha value or saliency on choice; thus, it is not known how the brain combines these two variables during, and (iii) subjects behave as an ideal Baye- sian observer who combines both factors to maximize

Koch, Christof

293

A coarse-grained analysis of the functional brain connectivity from EEG recordings of a visuo-perceptual discrimination task  

NASA Astrophysics Data System (ADS)

We report the emergent functional connectivity of cortical areas during a visuo-perceptual discrimination task with or without the retention in memory of the location of visual targets using EEG. The networks were computed using multivariate Granger causality on groups of electrodes reflecting coarse-grained brain areas. The analysis showed that at alpha band (8-12Hz) there are no significant differences. In contrast, in beta and gamma band, we identified a top-down information flow pattern which was evident for the task that required the activation of the working memory mechanism.

Protopapa, Foteini; Mylonas, Dimitris; Smyrnis, Nikolaos; Siettos, Constantinos

2013-10-01

294

Birth of projection neurons in adult avian brain may be related to perceptual or motor learning  

SciTech Connect

Projection neurons that form part of the motor pathway for song control continue to be produced and to replace older projection neurons in adult canaries and zebra finches. This is shown by combining (3H)thymidine, a cell birth marker, and fluorogold, a retrogradely transported tracer of neuronal connectivity. Species and seasonal comparisons suggest that this process is related to the acquisition of perceptual or motor memories. The ability of an adult brain to produce and replace projection neurons should influence our thinking on brain repair.

Alvarez-Buylla, A.; Kirn, J.R.; Nottebohm, F. (Rockefeller Univ. Field Research Center, Millbrook, NY (USA))

1990-09-21

295

[Memory and brain--neurobiological correlates of memory disturbances].  

PubMed

A differentiation of memory is possible on the basis of chronological and contents-related aspects. Furthermore, it is possible to make process-specific subdivisions (encoding, transfer, consolidation, retrieval). The time-related division on the one hand refers to the general differentiation into short-term and long-term memory, and, on the other, to that between anterograde and retrograde memory ("new" and "old memory"; measured from a given time point, usually that when brain damage occurred). Anterograde memory means the successful encoding and storing of new information; retrograde the ability to retrieve successfully acquired and/or stored information. On the contents-based level, memory can be divided into five basic long-term systems--episodic memory, the knowledge system, perceptual, procedural and the priming form of memory. Neural correlates for these divisions are discussed with special emphasis of the episodic and the knowledge systems, based both on normal individuals and brain-damaged subjects. It is argued that structures of the limbic system are important for encoding of information and for its transfer into long-term memory. For this, two independent, but interacting memory circuits are proposed--one of them controlling and integrating primarily the emotional, and the other primarily the cognitive components of newly incoming information. For information storage principally neocortical structures are regarded as important and for the recall of information from the episodic and semantic memory systems the combined action of portions of prefrontal and anterior temporal regions is regarded as essential. Within this fronto-temporal agglomerate, a moderate hemispheric-specificity is assumed to exist with the right-hemispheric combination being mainly engaged in episodic memory retrieval and the left-hemispheric in that of semantic information. Evidence for this specialization comes from the results from focally brain-damaged patients as well as from that functional brain imaging in normal human subjects. Comparing results from imaging studies in memory disturbed patients with brain damage and from patients with a psychiatric diagnosis (e. g., psychogenic amnesia) revealed that both patient groups demonstrate comparable metabolic changes on the brain level. It can therefore be concluded that in neurological patients distinct, identifiable tissue damage is existent, while in psychiatric patients changes in the brain's biochemistry (release of stress hormones, and transmitters) constitute the physiological bases for the memory disturbances. PMID:12677555

Calabrese, P; Markowitsch, H J

2003-04-01

296

Stimulus Roving and Flankers Affect Perceptual Learning of Contrast Discrimination in Macaca mulatta  

PubMed Central

‘Stimulus roving’ refers to a paradigm in which the properties of the stimuli to be discriminated vary from trial to trial, rather than being kept constant throughout a block of trials. Rhesus monkeys have previously been shown to improve their contrast discrimination performance on a non-roving task, in which they had to report the contrast of a test stimulus relative to that of a fixed-contrast sample stimulus. Human psychophysics studies indicate that roving stimuli yield little or no perceptual learning. Here, we investigate how stimulus roving influences perceptual learning in macaque monkeys and how the addition of flankers alters performance under roving conditions. Animals were initially trained on a contrast discrimination task under non-roving conditions until their performance levels stabilized. The introduction of roving contrast conditions resulted in a pronounced drop in performance, which suggested that subjects initially failed to heed the sample contrast and performed the task using an internal memory reference. With training, significant improvements occurred, demonstrating that learning is possible under roving conditions. To investigate the notion of flanker-induced perceptual learning, flanker stimuli (30% fixed-contrast iso-oriented collinear gratings) were presented jointly with central (roving) stimuli. Presentation of flanker stimuli yielded substantial performance improvements in one subject, but deteriorations in the other. Finally, after the removal of flankers, performance levels returned to their pre-flanker state in both subjects, indicating that the flanker-induced changes were contingent upon the continued presentation of flankers. PMID:25340335

Thiele, Alexander

2014-01-01

297

Tangential Speed  

NSDL National Science Digital Library

This lab is purely a thought experiment. Although students are given an introduction to angular speed and tangential speed, they will discover the relationship between the two in this activity. The lab is an inquiry activity in that students do not know t

Horton, Michael

2009-05-30

298

Memory bandwidth and machine balance in current high performance computers  

Microsoft Academic Search

The ratio of cpu speed to memory speed in current high-performance computers is growing rapidly, with significant implications for the design and implementation of algorithms in scientific computing. I present the results of a broad survey of memory bandwidth and machine balance for a large variety current computers, including uniprocessors, vector processors, shared-memory systems, and distributed-memory systems. The results are

J. D. Mccalpin

1995-01-01

299

Speed and Intelligence in Old Age  

Microsoft Academic Search

Past research suggest that age differences in measures of cognitive speed contribute to differences in intellectual functioning between young and old adults. To investigate whether speed also predicts age-related differences in intellectual performance beyond age 70 years, tests indicating 5 intellectual abilities—speed, reasoning, memory, knowledge, and fluency—were administered to a close-to-representative, age-stratified sample of old and very old adults. Age

Ulman Lindenberger; Ulrich Mayr; Reinhold Kliegl

1993-01-01

300

Perceptual color image coding with JPEG2000.  

PubMed

A perceptual color image coder (PCIC) is presented for the YC(b)C(r) color space within the framework of JPEG2000. This coder employs a vision model based perceptual distortion metric (PDM) to approximate perceived error for rate-distortion (R-D) optimization in order to maximize the visual quality of coded images. The vision model employed in the PCIC is structurally based on an existing monochromatic multichannel vision model, which is extended for color image coding. Subjective tests with 30 viewers show that the PCIC provides superior picture quality at low to intermediate bitrates in comparison with a JPEG2000 compliant coder employing the mean squared error (MSE) and the visual distortion metric (Cvis) as distortion measures, respectively. PMID:20083452

Tan, D M; Tan, C S; Wu, H R

2010-02-01

301

Perceptual Spaces: Mathematical Structures to Neural Mechanisms  

PubMed Central

A central goal of neuroscience is to understand how populations of neurons build and manipulate representations of percepts that provide useful information about the environment. This symposium explores the fundamental properties of these representations and the perceptual spaces in which they are organized. Spanning the domains of color, visual texture, environmental sound, music, tactile quality, and odor, we show how the geometric structures of perceptual spaces can be determined experimentally and how these structures provide insights into the principles of neural coding and the neural mechanisms that generate the codes, and into the neural processing of complex sensory stimuli. The diversity of the neural architecture in these different sensory systems provides an opportunity to compare their different solutions to common problems: the need for dimensionality reduction, strategies for topographic or nontopographic mapping, the utility of the higher-order statistical structure inherent in natural sensory stimuli, and the constraints of neural hardware. PMID:24198350

Victor, Jonathan; McDermott, Josh; Geffen, Maria; Bensmaia, Sliman; Cleland, Thomas A.

2013-01-01

302

Perceptual spaces: mathematical structures to neural mechanisms.  

PubMed

A central goal of neuroscience is to understand how populations of neurons build and manipulate representations of percepts that provide useful information about the environment. This symposium explores the fundamental properties of these representations and the perceptual spaces in which they are organized. Spanning the domains of color, visual texture, environmental sound, music, tactile quality, and odor, we show how the geometric structures of perceptual spaces can be determined experimentally and how these structures provide insights into the principles of neural coding and the neural mechanisms that generate the codes, and into the neural processing of complex sensory stimuli. The diversity of the neural architecture in these different sensory systems provides an opportunity to compare their different solutions to common problems: the need for dimensionality reduction, strategies for topographic or nontopographic mapping, the utility of the higher-order statistical structure inherent in natural sensory stimuli, and the constraints of neural hardware. PMID:24198350

Zaidi, Qasim; Victor, Jonathan; McDermott, Josh; Geffen, Maria; Bensmaia, Sliman; Cleland, Thomas A

2013-11-01

303

Statistical and perceptual updating: correlated impairments in right brain injury.  

PubMed

It has been hypothesized that many of the cognitive impairments commonly seen after right brain damage (RBD) can be characterized as a failure to build or update mental models. We (Danckert et al. in Neglect as a disorder of representational updating. NOVA Open Access, New York, 2012a; Cereb Cortex 22:2745-2760, 2012b) were the first to directly assess the association between RBD and updating and found that RBD patients were unable to exploit a strongly biased play strategy in their opponent in the children's game rock, paper, scissors. Given that this game required many other cognitive capacities (i.e., working memory, sustained attention, reward processing), RBD patients could have failed this task for various reasons other than a failure to update. To assess the generality of updating deficits after RBD, we had RBD, left brain-damaged (LBD) patients and healthy controls (HCs) describe line drawings that evolved gradually from one figure (e.g., rabbit) to another (e.g., duck) in addition to the RPS updating task. RBD patients took significantly longer to alter their perceptual report from the initial object to the final object than did LBD patients and HCs. Although both patient groups performed poorly on the RPS task, only the RBD patients showed a significant correlation between the two, very different, updating tasks. We suggest these data indicate a general deficiency in the ability to update mental representations following RBD. PMID:24615155

Stöttinger, Elisabeth; Filipowicz, Alex; Marandi, Elahe; Quehl, Nadine; Danckert, James; Anderson, Britt

2014-06-01

304

Posttraining Sleep Enhances Automaticity in Perceptual Discrimination  

Microsoft Academic Search

Perceptual learning can develop over extended periods, with slow, at times sleep-dependent, improvement seen several days after training. As a result, performance can become more automatic, that is, less dependent on voluntary attention. This study investigates whether the brain correlates of this enhancement of automaticity are sleep-dependent. Event-related potentials produced in response to complex auditory stimuli were recorded while subjects'

Mercedes Atienza; Jose L. Cantero; Robert Stickgold

2004-01-01

305

Perceptual challenges to computer-aided diagnosis  

NASA Astrophysics Data System (ADS)

We review the motivation and development of computer-aided diagnosis (CAD) in diagnostic medical imaging, particularly in breast cancer screening. After briefly describe in generic terms of typical CAD methods, we focus on the question of whether CAD helps improve diagnostic accuracy. We review both studies that support the notion that CAD helps improve diagnostic accuracy and studies that do not. We further identify difficulties in conducting this type of evaluation studies and suggest areas of perceptual challenges to applications of CAD.

Jiang, Yulei

2012-03-01

306

Perceptual adaptation to non-native speech  

Microsoft Academic Search

This study investigated talker-dependent and talker-independent perceptual adaptation to foreign-accent English. Experiment 1 investigated talker-dependent adaptation by comparing native English listeners’ recognition accuracy for Chinese-accented English across single and multiple talker presentation conditions. Results showed that the native listeners adapted to the foreign-accented speech over the course of the single talker presentation condition with some variation in the rate and

Ann R. Bradlow; Tessa Bent

2008-01-01

307

Perceptual uniformity of commonly used color spaces  

NASA Astrophysics Data System (ADS)

Use of color images in medical imaging has increased significantly the last few years. Color information is essential for applications such as ophthalmology, dermatology and clinical photography. Use of color at least brings benefits for other applications such as endoscopy, laparoscopy and digital pathology. Remarkably, as of today, there is no agreed standard on how color information needs to be visualized for medical applications. This lack of standardization results in large variability of how color images are visualized and it makes quality assurance a challenge. For this reason FDA and ICC recently organized a joint summit on color in medical imaging (CMI). At this summit, one of the suggestions was that modalities such as digital pathology could benefit from using a perceptually uniform color space (T. Kimpe, "Color Behavior of Medical Displays," CMI presentation, May 2013). Perceptually uniform spaces have already been used for many years in the radiology community where the DICOM GSDF standard provides linearity in luminance but not in color behavior. In this paper we quantify perceptual uniformity, using CIE's ?E2000 as a color distance metric, of several color spaces that are typically used for medical applications. We applied our method to theoretical color spaces Gamma 1.8, 2.0, & 2.2, standard sRGB, and DICOM (correction LUT for gray applied to all primaries). In addition, we also measured color spaces (i.e., native behavior) of a high-end medical display (Barco Coronis Fusion 6MP DL, MDCC-6130), and a consumer display (Dell 1907FP). Our results indicate that sRGB & the native color space on the Barco Coronis Fusion exhibit the least non-uniformity within their group. However, the remaining degree of perceptual non-uniformity is still significant and there is room for improvement.

Avanaki, Ali; Espig, Kathryn; Kimpe, Tom; Xthona, Albert; Marchessoux, Cedric; Rostang, Johan; Piepers, Bastian

2014-03-01

308

Perceptual Centering Effects in Body Orientation  

Microsoft Academic Search

This study mathematically characterizes the results of DiZio and Lackner (Percept Psychphys 39(1): 39–46) on the perception\\u000a of self-orientation during circular vection induced by an optokinetic stimulus. Using the hypothesis of perceptual centering,\\u000a it is shown that five basic centering transformations can logically account for the full range of illusions reported by the\\u000a subjects. All five of these transformations center

D. A. Hanes

2006-01-01

309

Acoustic and perceptual correlates of syllable weight  

NASA Astrophysics Data System (ADS)

Differences between languages in the stress-attracting properties of various syllable types (syllable weight) are associated with phonetic differences. Certain languages that preferentially stress CVC syllables (i.e., treat CVC as heavy) fail to display substantial vowel shortening in CVC, unlike languages that treat CVC as non-stress-attracting or light [Broselow et al. (1997)]. Furthermore, CVC has greater energy (intensity integrated over time) in languages in which it is heavy relative to languages with light CVC [Gordon (2002)]. This paper compares multiple potential acoustic and perceptual correlates of syllable weight. A representative cross section of syllable types in words uttered by speakers of four languages was recorded. In two languages (Arabic, Hindi), CVC is heavy; in two languages (Mongolian, Malayalam), CVC is light. Three measurements were taken: duration of the syllable rime, acoustic intensity integrated over the rime, and a measure of perceptual energy of the rime incorporating various factors (e.g., temporal integration and adaptation, bandpass filtering). Results thus far indicate that a measure of prominence factoring in both intensity and duration better distinguishes languages on the basis of weight criterion than a simple measure of duration. The perceptual energy measure provides a slightly better fit than acoustic energy. [Work supported by NSF.

Gordon, Matthew; Jany, Carmen; Nash, Carlos

2005-09-01

310

Perceptual consequences of "hidden" hearing loss.  

PubMed

Dramatic results from recent animal experiments show that noise exposure can cause a selective loss of high-threshold auditory nerve fibers without affecting absolute sensitivity permanently. This cochlear neuropathy has been described as hidden hearing loss, as it is not thought to be detectable using standard measures of audiometric threshold. It is possible that hidden hearing loss is a common condition in humans and may underlie some of the perceptual deficits experienced by people with clinically normal hearing. There is some evidence that a history of noise exposure is associated with difficulties in speech discrimination and temporal processing, even in the absence of any audiometric loss. There is also evidence that the tinnitus experienced by listeners with clinically normal hearing is associated with cochlear neuropathy, as measured using Wave I of the auditory brainstem response. To date, however, there has been no direct link made between noise exposure, cochlear neuropathy, and perceptual difficulties. Animal experiments also reveal that the aging process itself, in the absence of significant noise exposure, is associated with loss of auditory nerve fibers. Evidence from human temporal bone studies and auditory brainstem response measures suggests that this form of hidden loss is common in humans and may have perceptual consequences, in particular, regarding the coding of the temporal aspects of sounds. Hidden hearing loss is potentially a major health issue, and investigations are ongoing to identify the causes and consequences of this troubling condition. PMID:25204468

Plack, Christopher J; Barker, Daphne; Prendergast, Garreth

2014-01-01

311

Self-stimulatory behavior and perceptual reinforcement.  

PubMed Central

Self-stimulatory behavior is repetitive, stereotyped, functionally autonomous behavior seen in both normal and developmentally disabled populations, yet no satisfactory theory of its development and major characteristics has previously been offered. We present here a detailed hypothesis of the acquisition and maintenance of self-stimulatory behavior, proposing that the behaviors are operant responses whose reinforcers are automatically produced interoceptive and exteroceptive perceptual consequences. The concept of perceptual stimuli and reinforcers, the durability of self-stimulatory behaviors, the sensory extinction effect, the inverse relationship between self-stimulatory and other behaviors, the blocking effect of self-stimulatory behavior on new learning, and response substitution effects are discussed in terms of the hypothesis. Support for the hypothesis from the areas of sensory reinforcement and sensory deprivation is also reviewed. Limitations of major alternative theories are discussed, along with implications of the perceptual reinforcement hypothesis for the treatment of excessive self-stimulatory behavior and for theoretical conceptualizations of functionally related normal and pathological behaviors. PMID:3583964

Lovaas, I; Newsom, C; Hickman, C

1987-01-01

312

Generalized perceptual features for animal vocalization classification  

NASA Astrophysics Data System (ADS)

Two sets of generalized, perceptual-based features are investigated for use in classifying animal vocalizations. Since many species, especially mammals, share similar physical sound perception mechanisms which vary in size, two features sets commonly used in human speech processing, mel-frequency cepstral coefficients (MFCCs) and perceptual linear prediction (PLP) analysis, are modified for use in other species. One modification made to the feature extraction process is incorporating the frequency range of hearing and length of the basilar membrane of the animal in order to correctly determine the width and location of the critical band filters used for signal processing. Experimentally determined critical bands (equivalent rectangular bandwidth) and equal loudness curves (audiograms) can also be incorporated directly into the feature extraction process. Experiments are performed on African elephant (Loxodonta africana) vocalizations using a hidden Markov model (HMM) based classifier showing increased classification accuracy when using features sets based on the specific animals perceptual abilities compared to the original human perception-based feature sets.

Clemins, Patrick J.; Johnson, Michael T.

2001-05-01

313

Effects of Ketamine on Thought Disorder, Working Memory, and Semantic Memory in Healthy Volunteers  

Microsoft Academic Search

Background: The N-methyl-d-aspartate receptor antagonist, ketamine, produces a clinical syndrome of thought disorder, perceptual distortion, and cognitive impairment.Methods: We have administered ketamine to healthy volunteers to characterize the formal thought disorder and specific memory dysfunction associated with ketamine. Ten healthy volunteers underwent a double-blind, placebo-controlled, ketamine infusion (0.12 mg\\/kg bolus and 0.65 mg\\/kg\\/hour). Thought disorder was evaluated with the Scale

Caleb M. Adler; Terry E. Goldberg; Anil K. Malhotra; David Pickar; Alan Breier

1998-01-01

314

Causal role of dorsolateral prefrontal cortex in human perceptual decision making.  

PubMed

The way that we interpret and interact with the world entails making decisions on the basis of available sensory evidence. Recent primate neurophysiology [1-6], human neuroimaging [7-13], and modeling experiments [14-19] have demonstrated that perceptual decisions are based on an integrative process in which sensory evidence accumulates over time until an internal decision bound is reached. Here we used repetitive transcranial magnetic stimulation (rTMS) to provide causal support for the role of the dorsolateral prefrontal cortex (DLPFC) in this integrative process. Specifically, we used a speeded perceptual categorization task designed to induce a time-dependent accumulation of sensory evidence through rapidly updating dynamic stimuli and found that disruption of the left DLPFC with low-frequency rTMS reduced accuracy and increased response times relative to a sham condition. Importantly, using the drift-diffusion model, we show that these behavioral effects correspond to a decrease in drift rate, a parameter describing the rate and thereby the efficiency of the sensory evidence integration in the decision process. These results provide causal evidence linking the DLPFC to the mechanism of evidence accumulation during perceptual decision making. PMID:21620706

Philiastides, Marios G; Auksztulewicz, Ryszard; Heekeren, Hauke R; Blankenburg, Felix

2011-06-01

315

When more equals less: overtraining inhibits perceptual learning owing to lack of wakeful consolidation.  

PubMed

Performance on perceptual tasks usually improves with training. However, too much consecutive training can be detrimental. Repeated within-day testing or overtraining demonstrates the detrimental effects this has on perceptual learning. Consolidation of learnt information during sleep has the power to prevent such deficits in learning. However, little is known regarding the role of wakeful consolidation in preventing the effects of overtraining. Here, we report that perceptual deterioration may result from the disruption of early wakeful consolidation processes. Three groups were tested on day 1 and again 24 h later, on a motion discrimination task. Participants who had a 1 h break between the two training sessions on the first day displayed improved accuracy on the second day (i.e. learning). Subjects who only completed the first training session on day 1 also exhibited learning. However, individuals who completed two blocks without a break ('overtraining') showed no improvement in accuracy on day 2. Interestingly, changes in reaction times were not susceptible to the effects of overtraining, but instead speeded up as a function of total performed trials. These data suggest that effects of overtraining might be due to disruption of wakeful consolidation processes. PMID:22896650

Ashley, Soren; Pearson, Joel

2012-10-22

316

Drawing from Memory: Hand-Eye Coordination at Multiple Scales  

PubMed Central

Eyes move to gather visual information for the purpose of guiding behavior. This guidance takes the form of perceptual-motor interactions on short timescales for behaviors like locomotion and hand-eye coordination. More complex behaviors require perceptual-motor interactions on longer timescales mediated by memory, such as navigation, or designing and building artifacts. In the present study, the task of sketching images of natural scenes from memory was used to examine and compare perceptual-motor interactions on shorter and longer timescales. Eye and pen trajectories were found to be coordinated in time on shorter timescales during drawing, and also on longer timescales spanning study and drawing periods. The latter type of coordination was found by developing a purely spatial analysis that yielded measures of similarity between images, eye trajectories, and pen trajectories. These results challenge the notion that coordination only unfolds on short timescales. Rather, the task of drawing from memory evokes perceptual-motor encodings of visual images that preserve coarse-grained spatial information over relatively long timescales as well. PMID:23554894

Spivey, Michael J.

2013-01-01

317

Drawing from memory: hand-eye coordination at multiple scales.  

PubMed

Eyes move to gather visual information for the purpose of guiding behavior. This guidance takes the form of perceptual-motor interactions on short timescales for behaviors like locomotion and hand-eye coordination. More complex behaviors require perceptual-motor interactions on longer timescales mediated by memory, such as navigation, or designing and building artifacts. In the present study, the task of sketching images of natural scenes from memory was used to examine and compare perceptual-motor interactions on shorter and longer timescales. Eye and pen trajectories were found to be coordinated in time on shorter timescales during drawing, and also on longer timescales spanning study and drawing periods. The latter type of coordination was found by developing a purely spatial analysis that yielded measures of similarity between images, eye trajectories, and pen trajectories. These results challenge the notion that coordination only unfolds on short timescales. Rather, the task of drawing from memory evokes perceptual-motor encodings of visual images that preserve coarse-grained spatial information over relatively long timescales as well. PMID:23554894

Huette, Stephanie; Kello, Christopher T; Rhodes, Theo; Spivey, Michael J

2013-01-01

318

Competition explains limited attention and perceptual resources: implications for perceptual load and dilution theories  

PubMed Central

Both perceptual load theory and dilution theory purport to explain when and why task-irrelevant information, or so-called distractors are processed. Central to both explanations is the notion of limited resources, although the theories differ in the precise way in which those limitations affect distractor processing. We have recently proposed a neurally plausible explanation of limited resources in which neural competition among stimuli hinders their representation in the brain. This view of limited capacity can also explain distractor processing, whereby the competitive interactions and bias imposed to resolve the competition determine the extent to which a distractor is processed. This idea is compatible with aspects of both perceptual load and dilution models of distractor processing, but also serves to highlight their differences. Here we review the evidence in favor of a biased competition view of limited resources and relate these ideas to both classic perceptual load theory and dilution theory. PMID:23717289

Scalf, Paige E.; Torralbo, Ana; Tapia, Evelina; Beck, Diane M.

2013-01-01

319

The Effect of Set Size on the Relation Between Saccadic and Perceptual Decisions During Search  

NASA Technical Reports Server (NTRS)

We have shown that when searching for a disk in noise at one of 10 locations, the accuracy of the I st saccade is similar to that of the perceptual decision at the time of saccadic programming. The present study has two goals: 1) to test whether this linden - extends to a contrast-discrimination task without noise, and 2) to measure the effect of set size on the relation between saccadic and perceptual decisions. Methods: Three observers searched over a grey background (34.5 cd/sq m) for a bright disk (63.2 cd/sq m) among dim disks (54.1 cd/sq m) along the circumference of a circle (r = 5.9 deg.) centered on a fixation cress. Four set sizes (2, 4, 6, 12) were used. In the 1st condition, stimuli were presented for 1 sec. and observers used natural eye movements. We then measured the accuracy of the first saccade (% correct using a shortest-distance criterion). In the 2nd condition, observers fixated a central cross at all times and the stimulus duration was approx. 70 as less than the median latency of the first saccade in the 1st condition (saccadic programming time). We then recorded perceptual performance and discarded trials in which observers broke fixation. Results: For set sizes of 2, 4, 8, and 12, the mean d' across observers for the perceptual decision was 2.03, 1.96, 1.94, 1.71, respectively, while the mean d' of the first saccade was only 0.73, 1.40, 1.23, 1.17. Conclusions: Unlike detection of a disk in noise, for all observers and set-sizes, the perceptual accuracy at the time of saccadic programming is better than that of the lst saccade. For set-sizes of 4, 6, and 12, the amount of information available to the perceptual system relative to that available to the saccadic system is approximately constant (fixed do ratio). For these higher set sizes, the constancy in do across set size for both perception and saccadic decisions is consistent with a simple signal detection theory (SDT) model that processes noisy signals in parallel. However, for 2 observers, at a set-size of 2, saccadic targeting appears to be worse than the SDT model prediction, perhaps due to speed-accuracy trade-off.

Eckstein, M. P.; Beutter, B. R.; Stone, L. S.; Wenzel, Beth (Technical Monitor)

1998-01-01

320

The Role of Textured Material in Supporting Perceptual-Motor Functions  

PubMed Central

Simple deformation of the skin surface with textured materials can improve human perceptual-motor performance. The implications of these findings are inexpensive, adaptable and easily integrated clothing, equipment and tools for improving perceptual-motor functionality. However, some clarification is needed because mixed results have been reported in the literature, highlighting positive, absent and/or negative effects of added texture on measures of perceptual-motor performance. Therefore the aim of this study was to evaluate the efficacy of textured materials for enhancing perceptual-motor functionality. The systematic review uncovered two variables suitable for sub-group analysis within and between studies: participant age (groupings were 18–51 years and 64.7–79.4 years) and experimental task (upright balance and walking). Evaluation of studies that observed texture effects during upright balance tasks, uncovered two additional candidate sub-groups for future work: vision (eyes open and eyes closed) and stability (stable and unstable). Meta-analysis (random effects) revealed that young participants improve performance by a small to moderate amount in upright balance tasks with added texture (SMD?=?0.28, 95%CI?=?0.46–0.09, Z?=?2.99, P?=?0.001; Tau2?=?0.02; Chi2?=?9.87, df?=?6, P?=?0.13; I2?=?39.22). Significant heterogeneity was found in, the overall effect of texture: Tau2?=?0.13; Chi2?=?130.71, df?=?26, P<0.0001; I2?=?85.98%, pooled samples in upright balance tasks: Tau2?=?0.09; Chi2?=?101.57, df?=?13, P<0.001; I2?=?72.67%, and in elderly in upright balance tasks: Tau2?=?0.16; Chi2?=?39.42, df?=?5, P<0.001; I2?=?83.05%. No effect was shown for walking tasks: Tau2?=?0.00; Chi2?=?3.45, df?=?4, P?=?0.27, I2?=?22.99%. Data provides unequivocal support for utilizing textured materials in young healthy populations for improving perceptual-motor performance. Future research is needed in young healthy populations under conditions where visual and proprioceptive information is challenged, as in high-speed movements, or where use of equipment mediates the performer-environment interaction or where dysfunctional information sources ‘compete’ for attention. In elderly and ailing populations data suggests further research is required to better understand contexts where texture can facilitate improved perceptual-motor performance. PMID:23565232

Orth, Dominic; Davids, Keith; Wheat, Jon; Seifert, Ludovic; Liukkonen, Jarmo; Jaakkola, Timo; Ashford, Derek; Kerr, Graham

2013-01-01

321

High-Speed Scanning in Human Memory  

Microsoft Academic Search

When subjects judge whether a test symbol is contained in a short memorized sequence of symbols, their mean reaction-time increases linearly with the length of the sequence. The linearity and slope of the function imply the existence of an internal serial-comparison process whose average rate is between 25 and 30 symbols per second.

Saul Sternberg

1966-01-01

322

Perceptual load corresponds with factors known to influence visual search  

PubMed Central

One account of the early versus late selection debate in attention proposes that perceptual load determines the locus of selection. Attention selects stimuli at a late processing level under low-load conditions but selects stimuli at an early level under high-load conditions. Despite the successes of perceptual load theory, a non-circular definition of perceptual load remains elusive. We investigated the factors that influence perceptual load by using manipulations that have been studied extensively in visual search, namely target-distractor similarity and distractor-distractor similarity. Consistent with previous work, search was most efficient when targets and distractors were dissimilar and the displays contained homogeneous distractors; search became less efficient when target-distractor similarity increased irrespective of display heterogeneity. Importantly, we used these same stimuli in a typical perceptual load task that measured attentional spill-over to a task-irrelevant flanker. We found a strong correspondence between search efficiency and perceptual load; stimuli that generated efficient searches produced flanker interference effects, suggesting that such displays involved low perceptual load. Flanker interference effects were reduced in displays that produced less efficient searches. Furthermore, our results demonstrate that search difficulty, as measured by search intercept, has little bearing on perceptual load. These results suggest that perceptual load might be defined in part by well-characterized, continuous factors that influence visual search. PMID:23398258

Roper, Zachary J. J.; Cosman, Joshua D.; Vecera, Shaun P.

2014-01-01

323

Speeding up local correlation methods  

NASA Astrophysics Data System (ADS)

We present two techniques that can substantially speed up the local correlation methods. The first one allows one to avoid the expensive transformation of the electron-repulsion integrals from atomic orbitals to virtual space. The second one introduces an algorithm for the residual equations in the local perturbative treatment that, in contrast to the standard scheme, does not require holding the amplitudes or residuals in memory. It is shown that even an interpreter-based implementation of the proposed algorithm in the context of local MP2 method is faster and requires less memory than the highly optimized variants of conventional algorithms.

Kats, Daniel

2014-12-01

324

Unifying Memory and Database Transactions  

NASA Astrophysics Data System (ADS)

Software Transactional Memory is a concurrency control technique gaining increasing popularity, as it provides high-level concurrency control constructs and eases the development of highly multi-threaded applications. But this easiness comes at the expense of restricting the operations that can be executed within a memory transaction, and operations such as terminal and file I/O are either not allowed or incur in serious performance penalties. Database I/O is another example of operations that usually are not allowed within a memory transaction. This paper proposes to combine memory and database transactions in a single unified model, benefiting from the ACID properties of the database transactions and from the speed of main memory data processing. The new unified model covers, without differentiating, both memory and database operations. Thus, the users are allowed to freely intertwine memory and database accesses within the same transaction, knowing that the memory and database contents will always remain consistent and that the transaction will atomically abort or commit the operations in both memory and database. This approach allows to increase the granularity of the in-memory atomic actions and hence, simplifies the reasoning about them.

Dias, Ricardo J.; Lourenço, João M.

325

Flexible memory retrieval in bilingual 6-month-old infants.  

PubMed

Memory flexibility is a hallmark of the human memory system. As indexed by generalization between perceptually dissimilar objects, memory flexibility develops gradually during infancy. A recent study has found a bilingual advantage in memory generalization at 18 months of age [Brito and Barr [2012] Developmental Science, 15, 812-816], and the present study examines when this advantage may first emerge. In the current study, bilingual 6-month-olds were more likely than monolinguals to generalize to a puppet that differed in two features (shape and color) than monolingual 6-month-olds. When challenged with a less complex change, two puppets that differed only in one feature--color, monolingual 6-month-olds were also able to generalize. These findings demonstrate early emerging differences in memory generalization in bilingual infants, and have important implications for our understanding of how early environmental variations shape the trajectory of memory development. PMID:24318980

Brito, Natalie; Barr, Rachel

2014-07-01

326

Auditory Perceptual Learning for Speech Perception Can be Enhanced by Audiovisual Training  

PubMed Central

Speech perception under audiovisual (AV) conditions is well known to confer benefits to perception such as increased speed and accuracy. Here, we investigated how AV training might benefit or impede auditory perceptual learning of speech degraded by vocoding. In Experiments 1 and 3, participants learned paired associations between vocoded spoken nonsense words and nonsense pictures. In Experiment 1, paired-associates (PA) AV training of one group of participants was compared with audio-only (AO) training of another group. When tested under AO conditions, the AV-trained group was significantly more accurate than the AO-trained group. In addition, pre- and post-training AO forced-choice consonant identification with untrained nonsense words showed that AV-trained participants had learned significantly more than AO participants. The pattern of results pointed to their having learned at the level of the auditory phonetic features of the vocoded stimuli. Experiment 2, a no-training control with testing and re-testing on the AO consonant identification, showed that the controls were as accurate as the AO-trained participants in Experiment 1 but less accurate than the AV-trained participants. In Experiment 3, PA training alternated AV and AO conditions on a list-by-list basis within participants, and training was to criterion (92% correct). PA training with AO stimuli was reliably more effective than training with AV stimuli. We explain these discrepant results in terms of the so-called “reverse hierarchy theory” of perceptual learning and in terms of the diverse multisensory and unisensory processing resources available to speech perception. We propose that early AV speech integration can potentially impede auditory perceptual learning; but visual top-down access to relevant auditory features can promote auditory perceptual learning. PMID:23515520

Bernstein, Lynne E.; Auer, Edward T.; Eberhardt, Silvio P.; Jiang, Jintao

2013-01-01

327

Motor impairments screened by the movement assessment battery for children-2 are related to the visual-perceptual deficits in children with developmental coordination disorder.  

PubMed

This study was to examine to what extent the motor deficits of children with Developmental Coordination Disorder (DCD) verified by the Movement Assessment Battery for Children-2 (MABC-2) are linked to their visual-perceptual abilities. Seventeen children with DCD and seventeen typically developing children (TD) aged 5-10 years screened from a total of 250 children were recruited. The assessments included MABC-2, traditional test of visual perceptual skills (TVPS-R), and computerized test for sequential coupling of eye and hand as well as motion coherence. The results indicated that children with DCD scored lower than TD in MABC-2, and their total scores were highly correlated with manual dexterity component scores. DCD group also showed poor visual-perceptual abilities in various aspects. The visual discrimination and visual sequential memory from the TVPS-R, the sequential coupling of eye and hand, and the motion coherence demonstrated a moderate or strong correlation with the MABC-2 in the DCD rather than the TD group. It was concluded that the motor problems screened by MABC-2 were significantly related to the visual-perceptual deficits of children with DCD. MABC-2 is suggested to be a prescreening tool to identify the visual-perceptual related motor deficits. PMID:24915646

Cheng, Chih-Hsiu; Ju, Yan-Ying; Chang, Hsin-Wen; Chen, Chia-Ling; Pei, Yu-Cheng; Tseng, Kevin C; Cheng, Hsin-Yi Kathy

2014-09-01

328

Perceptual study of the impact of varying frame rate on motion imagery interpretability  

NASA Astrophysics Data System (ADS)

The development of a motion imagery (MI) quality scale, akin to the National Image Interpretibility Rating Scale (NIIRS) for still imagery, would have great value to designers and users of surveillance and other MI systems. A multiphase study has adopted a perceptual approach to identifying the main MI attributes that affect interpretibility. The current perceptual study measured frame rate effects for simple motion imagery interpretation tasks of detecting and identifying a known target. By using synthetic imagery, there was full control of the contrast and speed of moving objects, motion complexity, the number of confusers, and the noise structure. To explore the detectibility threshold, the contrast between the darker moving objects and the background was set at 5%, 2%, and 1%. Nine viewers were to detect or identify a moving synthetic "bug" in each of 288 10-second clip. We found that frame rate, contrast, and confusers had a statistically significant effect on image interpretibility (at the 95% level), while the speed and background showed no significant effect. Generally, there was a significant loss in correct detection and identification for frame rates below 10 F/s. Increasing the contrast improved detection and at high contrast, confusers did not affect detection. Confusers reduced detection of higher speed objects. Higher speed improved detection, but complicated identification, although this effect was small. Higher speed made detection harder at 1 Frame/s, but improved detection at 30 F/s. The low loss of quality at moderately lower frame rates may have implications for bandwidth limited systems. A study is underway to confirm, with live action imagery, the results reported here with synthetic.

Fenimore, Charles; Irvine, John; Cannon, David; Roberts, John; Aviles, Ivelisse; Isreal, Steven; Brennan, Michelle; Simon, Larry; Miller, James; Haverkamp, Donna; Tighe, Paul F.; Gross, Michael

2006-02-01

329

Ongoing behavior predicts perceptual report of interval duration  

PubMed Central

The ability to estimate the passage of time is essential for adaptive behavior in complex environments. Yet, it is not known how the brain encodes time over the durations necessary to explain animal behavior. Under temporally structured reinforcement schedules, animals tend to develop temporally structured behavior, and interval timing has been suggested to be accomplished by learning sequences of behavioral states. If this is true, trial to trial fluctuations in behavioral sequences should be predictive of fluctuations in time estimation. We trained rodents in an duration categorization task while continuously monitoring their behavior with a high speed camera. Animals developed highly reproducible behavioral sequences during the interval being timed. Moreover, those sequences were often predictive of perceptual report from early in the trial, providing support to the idea that animals may use learned behavioral patterns to estimate the duration of time intervals. To better resolve the issue, we propose that continuous and simultaneous behavioral and neural monitoring will enable identification of neural activity related to time perception that is not explained by ongoing behavior. PMID:24672473

Gouvêa, Thiago S.; Monteiro, Tiago; Soares, Sofia; Atallah, Bassam V.; Paton, Joseph J.

2014-01-01

330

Perceptual constancy in auditory perception of distance to railway tracks.  

PubMed

Distance to a sound source can be accurately estimated solely from auditory information. With a sound source such as a train that is passing by at a relatively large distance, the most important auditory information for the listener for estimating its distance consists of the intensity of the sound, spectral changes in the sound caused by air absorption, and the motion-induced rate of change of intensity. However, these cues are relative because prior information/experience of the sound source-its source power, its spectrum and the typical speed at which it moves-is required for such distance estimates. This paper describes two listening experiments that allow investigation of further prior contextual information taken into account by listeners-viz., whether they are indoors or outdoors. Asked to estimate the distance to the track of a railway, it is shown that listeners assessing sounds heard inside the dwelling based their distance estimates on the expected train passby sound level outdoors rather than on the passby sound level actually experienced indoors. This form of perceptual constancy may have consequences for the assessment of annoyance caused by railway noise. PMID:23862822

De Coensel, Bert; Nilsson, Mats E; Berglund, Birgitta; Brown, A L

2013-07-01

331

Evidence Accumulation in Obsessive-Compulsive Disorder: the Role of Uncertainty and Monetary Reward on Perceptual Decision-Making Thresholds.  

PubMed

The compulsive behaviour underlying Obsessive-Compulsive Disorder (OCD) may be related to abnormalities in decision-making. The inability to commit to ultimate decisions, e.g. patients unable to decide whether their hands are sufficiently clean, may reflect failures in accumulating sufficient evidence prior to a decision. Here we investigate the process of evidence accumulation in OCD in perceptual discrimination, hypothesizing enhanced evidence accumulation relative to healthy volunteers. Twenty-eight OCD patients and 35 controls were tested with a low-level visual perceptual task (random-dot-motion task, RDMT) and two response conflict control tasks. Regression analysis across different motion coherence levels and hierarchical drift diffusion modelling (HDDM) were used to characterize response strategies between groups in the RDMT. Patients required more evidence under high uncertainty perceptual contexts, as indexed by longer response time and higher decision boundaries. HDDM, which defines a decision when accumulated noisy evidence reaches a decision boundary, further showed slower drift rate towards the decision boundary reflecting poorer quality of evidence entering the decision process in patients under low uncertainty. With monetary incentives emphasizing speed, patients decreased the decision thresholds relative to controls, accumulating less evidence in low uncertainty. These findings were unrelated to visual perceptual deficits and response conflict. This study provides evidence for impaired decision-formation processes in OCD, with a differential influence of high and low uncertainty contexts on evidence accumulation (decision threshold) and on the quality of evidence gathered (drift rates). It further emphasizes that OCD patients are sensitive to monetary incentives heightening speed in the speed-accuracy tradeoff, improving evidence accumulation.Neuropsychopharmacology accepted article preview online, 26 November 2014. doi:10.1038/npp.2014.303. PMID:25425323

Banca, Paula; Vestergaard, Martin D; Rankov, Vladan; Baek, Kwangyeol; Mitchell, Simon; Lapa, Tatyana; Castelo-Branco, Miguel; Voon, Valerie

2014-11-26

332

Perceptual learning and perceptual search are altered in male university students with higher Autism Quotient scores  

Microsoft Academic Search

Two experiments investigated the validity of the Autism Quotient (AQ) scale for measuring traits associated with Autism Spectrum Disorders (ASD) in a population of male university students. Both studies found evidence that individuals who scored higher on the AQ questionnaire performed in a similar way to individuals with ASD on tasks with a perceptual component. Experiment 1 demonstrated a difference

Phil Reed; Caroline Lowe; Rhiannan Everett

2011-01-01

333

Hierarchical Traces for Reduced NSM Memory Requirements  

NASA Astrophysics Data System (ADS)

This paper presents work on using hierarchical long term memory to reduce the memory requirements of nearest sequence memory (NSM) learning, a previously published, instance-based reinforcement learning algorithm. A hierarchical memory representation reduces the memory requirements by allowing traces to share common sub-sequences. We present moderated mechanisms for estimating discounted future rewards and for dealing with hidden state using hierarchical memory. We also present an experimental analysis of how the sub-sequence length affects the memory compression achieved and show that the reduced memory requirements do not effect the speed of learning. Finally, we analyse and discuss the persistence of the sub-sequences independent of specific trace instances.

Dahl, Torbjørn S.

334

Features of autobiographical memory: theoretical and empirical issues in the measurement of flashbulb memory.  

PubMed

Flashbulb memories (FBMs) were defined by R. Brown and J. Kulik (1977) as vivid, detailed, and long-lasting memories for attributes of the reception context of public news. Unlike ordinary autobiographical memories, they are conceived as autobiographical formations that noticeably integrate specific perceptual details. The authors aimed to test a measurement model for FBMs as compared with event memory (EM) by hypothesizing that a categorical, rather than dimensional, approach would be more appropriate to account for FBM data. They submitted FBM and EM recollections from U.S. and European citizens concerning the terrorist attacks of September 11, 2001 to latent-trait model (LTM) and latent-class model (LCM) analyses. Results revealed that FBM data could be appropriately modeled through LCM, whereas for EM, LTM and LCM exhibited some inadequacy. The authors discuss implications for a theoretical account of FBMs. PMID:19350832

Curci, Antonietta; Lanciano, Tiziana

2009-04-01

335

Cognitive memory.  

PubMed

Regarding the workings of the human mind, memory and pattern recognition seem to be intertwined. You generally do not have one without the other. Taking inspiration from life experience, a new form of computer memory has been devised. Certain conjectures about human memory are keys to the central idea. The design of a practical and useful "cognitive" memory system is contemplated, a memory system that may also serve as a model for many aspects of human memory. The new memory does not function like a computer memory where specific data is stored in specific numbered registers and retrieval is done by reading the contents of the specified memory register, or done by matching key words as with a document search. Incoming sensory data would be stored at the next available empty memory location, and indeed could be stored redundantly at several empty locations. The stored sensory data would neither have key words nor would it be located in known or specified memory locations. Sensory inputs concerning a single object or subject are stored together as patterns in a single "file folder" or "memory folder". When the contents of the folder are retrieved, sights, sounds, tactile feel, smell, etc., are obtained all at the same time. Retrieval would be initiated by a query or a prompt signal from a current set of sensory inputs or patterns. A search through the memory would be made to locate stored data that correlates with or relates to the prompt input. The search would be done by a retrieval system whose first stage makes use of autoassociative artificial neural networks and whose second stage relies on exhaustive search. Applications of cognitive memory systems have been made to visual aircraft identification, aircraft navigation, and human facial recognition. Concerning human memory, reasons are given why it is unlikely that long-term memory is stored in the synapses of the brain's neural networks. Reasons are given suggesting that long-term memory is stored in DNA or RNA. Neural networks are an important component of the human memory system, and their purpose is for information retrieval, not for information storage. The brain's neural networks are analog devices, subject to drift and unplanned change. Only with constant training is reliable action possible. Good training time is during sleep and while awake and making use of one's memory. A cognitive memory is a learning system. Learning involves storage of patterns or data in a cognitive memory. The learning process for cognitive memory is unsupervised, i.e. autonomous. PMID:23453302

Widrow, Bernard; Aragon, Juan Carlos

2013-05-01

336

A Guide for Perceptual-Motor Training Activities.  

ERIC Educational Resources Information Center

This document has been prepared as part of a kindergarten perceptual-training program of the South Euclid-Lyndhurst City School District near Cleveland, Ohio. The guide contains information on training and procedures related to perceptual-motor learning. This information is structured primarily into 150 lesson plans, devised as 30-minute sessions…

South Euclid - Lyndhurst City Schools, Lyndhurst, OH.

337

Teaching social perceptual skills to students with learning disabilities  

Microsoft Academic Search

We investigated the effects of descriptive feedback and reinforcement on the acquisition and exhibition of social perceptual skills in three students with identified learning disabilities and social perceptual deficits. The students rated their teacher's affect based on six emotions, and received feedback regarding the accuracy of their ratings plus reinforcement for accurate ratings. Descriptive feedback and reinforcement resulted in a

Andrew B. Sandier; Jane Y. Murdock; Elizabeth Dofny; Paul J. Gerber

1991-01-01

338

The role of perceptual laws in the Rorschach test.  

PubMed

The purpose of this study is twofold: to ascertain the perceptual deficits in schizophrenic subjects and to test the assumption that the Rorschach is mainly a perceptual task. Forty-eight subjects participated in the study, distributed in six groups of eight subjects each: normals, affective disorders, and four groups of schizophrenics (chronic paranoid, chronic nonparanoid, acute paranoid, and acute nonparanoid). They were given a perceptual test developed by Fernández-Trespalacios, Bermudez, and Luna (1979). Contrary to previous findings, no differences in the perceptual test were found among the groups. In the second part of the study, a group of schizophrenic subjects was given the Rorschach and the perceptual test in a balanced order. Subsequently, subjects in the experimental group were trained in the perceptual laws they had failed. Comparison of the Rorschach protocols obtained before and after this training failed to show any significant differences in the expected direction, thus questioning the perceptual nature of this test. Interestingly, an increase in negative categories of the Rorschach subsequent to the perceptual training was observed. PMID:3572712

Vizcarro-Guarch, C; Fernández-Ballesteros, R; Fernández-Trespalacios, J L

1987-01-01

339

Estimating the Growth of Internal Evidence Guiding Perceptual Decisions  

ERIC Educational Resources Information Center

Perceptual decision-making is thought to involve a gradual accrual of noisy evidence. Temporal integration of the evidence reduces the relative contribution of dynamic internal noise to the decision variable, thereby boosting its signal-to-noise ratio. We aimed to estimate the internal evidence guiding perceptual decisions over time, using a novel…

Ludwig, Casimir J. H.; Davies, J. Rhys

2011-01-01

340

Psychophysical indices of perceptual functioning in dyslexia: A psychometric analysis  

E-print Network

Psychophysical indices of perceptual functioning in dyslexia: A psychometric analysis Steve M dyslexia to visual and/or auditory perceptual deficits. This theory derives from group differences between individuals with dyslexia and controls on a range of psychophysical tasks, but there is substantial variation

Nottingham, University of

341

Perceptual Learning: 12-Month-Olds' Discrimination of Monkey Faces  

ERIC Educational Resources Information Center

Six-month-olds reliably discriminate different monkey and human faces whereas 9-month-olds only discriminate different human faces. It is often falsely assumed that perceptual narrowing reflects a permanent change in perceptual abilities. In 3 experiments, ninety-six 12-month-olds' discrimination of unfamiliar monkey faces was examined. Following…

Fair, Joseph; Flom, Ross; Jones, Jacob; Martin, Justin

2012-01-01

342

Bayesian Face Recognition and Perceptual Narrowing in Face-Space  

ERIC Educational Resources Information Center

During the first year of life, infants' face recognition abilities are subject to "perceptual narrowing", the end result of which is that observers lose the ability to distinguish previously discriminable faces (e.g. other-race faces) from one another. Perceptual narrowing has been reported for faces of different species and different races, in…

Balas, Benjamin

2012-01-01

343

Pupil-linked arousal determines variability in perceptual decision making  

E-print Network

1 Pupil-linked arousal determines variability in perceptual decision making Peter R. Murphy1) ­ 527 3874 E: p.murphy@fsw.leidenuniv.nl #12;2 Abstract Decision making between several alternatives determinant of variability in perceptual decision making. We measured pupil size, a highly sensitive index

Nieuwenhuis, Sander

344

A Perceptual Study of Approximated Cantonese Tone Contours  

Microsoft Academic Search

This paper describes a perceptual study on approximated Cantonese tone contours. It is found that Cantonese tone contours and tone transitions can be approximated by a limited number of linear movements, without creating any noticeable perceptual difference. The slopes of these linear movements are analyzed. They are found to be related with two thresholds of pitch movement perception. The results

Yujia Li; Tan Lee

2008-01-01

345

Better discrimination for illusory than for occluded perceptual completions  

E-print Network

Better discrimination for illusory than for occluded perceptual completions School of Life Sciences Liu We applied the thin­fat Kanizsa shape discrimination task invented by D. L. Ringach and R. Shapley (1996) to study perceptual completion by measuring whether the discrimination was more accurate

Zhou, Yi-Feng

346

Perceptual Optimization of DCT Color Quantization Matrices  

NASA Technical Reports Server (NTRS)

Many image compression schemes employ a block Discrete Cosine Transform (DCT) and uniform quantization. Acceptable rate/distortion performance depends upon proper design of the quantization matrix. In previous work, we showed how to use a model of the visibility of DCT basis functions to design quantization matrices for arbitrary display resolutions and color spaces. Subsequently, we showed how to optimize greyscale quantization matrices for individual images, for optimal rate/perceptual distortion performance. Here we describe extensions of this optimization algorithm to color images.

Watson, Andrew B.; Statler, Irving C. (Technical Monitor)

1994-01-01

347

Advances in visual perceptual learning and plasticity  

PubMed Central

Visual perceptual learning (VPL) is defined as a long-term improvement in performance on a visual task. In recent years, the idea that conscious effort is necessary for VPL to occur has been challenged by research suggesting the involvement of more implicit processing mechanisms, such as reinforcement-driven processing and consolidation. In addition, we have learnt much about the neural substrates of VPL and it has become evident that changes in visual areas and regions beyond the visual cortex can take place during VPL. PMID:19953104

Sasaki, Yuka; Nanez, Jose E.; Watanabe, Takeo

2010-01-01

348

Virtual Memory  

Microsoft Academic Search

\\\\The need for automatic storage allocation arises from desires for program modularity, machine independence, and resource sharing. Virtual memory is an elegant way of achieving these objectives. In a virtual memory, the addresses a program may use to identify information are distinguished from the addresses the memory system uses to identify physical storage sites, and program-generated addresses are translated automatically

Peter J. Denning

1970-01-01

349

Working Memory  

Microsoft Academic Search

The term working memory refers to a brain system that provides temporary storage and manipulation of the information necessary for such complex cognitive tasks as language comprehension, learning, and reasoning. This definition has evolved from the concept of a unitary short-term memory system. Working memory has been found to require the simultaneous storage and processing of information. It can be

Alan Baddeley

1992-01-01

350

System-Level Integration of Mass Memory  

NASA Technical Reports Server (NTRS)

A report discusses integrating multiple memory modules on the high-speed serial interconnect (IEEE 1393) that is used by a spacecraft?s inter-module communications in order to ease data congestion and provide for a scalable, strong, flexible system that can meet new system-level mass memory requirements.

Cox, Brian; Mellstrom, Jeffrey; Wysocky, Terry

2008-01-01

351

Is Statistical Learning Constrained by Lower Level Perceptual Organization?  

PubMed Central

In order for statistical information to aid in complex developmental processes such as language acquisition, learning from higher-order statistics (e.g. across successive syllables in a speech stream to support segmentation) must be possible while perceptual abilities (e.g. speech categorization) are still developing. The current study examines how perceptual organization interacts with statistical learning. Adult participants were presented with multiple exemplars from novel, complex sound categories designed to reflect some of the spectral complexity and variability of speech. These categories were organized into sequential pairs and presented such that higher-order statistics, defined based on sound categories, could support stream segmentation. Perceptual similarity judgments and multi-dimensional scaling revealed that participants only perceived three perceptual clusters of sounds and thus did not distinguish the four experimenter-defined categories, creating a tension between lower level perceptual organization and higher-order statistical information. We examined whether the resulting pattern of learning is more consistent with statistical learning being “bottom-up,” constrained by the lower levels of organization, or “top-down,” such that higher-order statistical information of the stimulus stream takes priority over the perceptual organization, and perhaps influences perceptual organization. We consistently find evidence that learning is constrained by perceptual organization. Moreover, participants generalize their learning to novel sounds that occupy a similar perceptual space, suggesting that statistical learning occurs based on regions of or clusters in perceptual space. Overall, these results reveal a constraint on learning of sound sequences, such that statistical information is determined based on lower level organization. These findings have important implications for the role of statistical learning in language acquisition. PMID:23618755

Emberson, Lauren L.; Liu, Ran; Zevin, Jason D.

2013-01-01

352

The Effect of Perceptually Oriented Physical Education on Perceptual Motor Ability and Academic Ability of Kindergarten and First Grade Children.  

ERIC Educational Resources Information Center

The effects of a perceptually oriented physical education program (PPE) on perceptual-motor ability and academic ability were studied using kindergarten and first-grade children. The four groups of kindergarten children varied the number of periods of PPE per week which then met--0, 1, 2, and 3 times per week. The four groups of first-grade…

Davis, Robert G.

353

Memory for motion and spatial location is mediated by contralateral and ipsilateral motion processing cortex.  

PubMed

Memory and perception have been associated with common sensory cortical activity. However, previous studies have only investigated memory and perception effects associated with a single feature (i.e., spatial location or color). The aim of the present functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) study was to assess whether memory for multiple (two) features would produce sensory cortical activity that mirrored perceptual processing of the same features. During encoding, moving or stationary abstract shapes were presented to the right or left of fixation. During retrieval, shapes were presented at fixation and participants classified each item as previously in motion or stationary within the right or left visual field. Memory for items in motion, regardless of spatial location, produced fMRI activity in perceptual motion processing region MT+. Memory for motion and spatial location produced contralateral and ipsilateral fMRI activity in perceptual motion processing sub-region MT. Following TMS to MT, memory for motion was impaired, but performance did not differ between the contralateral and ipsilateral visual fields. The present results are consistent with previous findings in that memory for motion produced fMRI activity in MT+ and was impaired following TMS to MT. However, memory for motion and spatial location produced contralateral and ipsilateral fMRI and TMS effects, deviating from the primarily contralateral perceptual processing organization of MT. The present evidence suggests that during memory for motion and spatial location only motion information is coded in motion processing cortex, while previous findings suggest spatial location information is coded in earlier extrastriate cortex. PMID:21134469

Slotnick, Scott D; Thakral, Preston P

2011-03-15

354

Perceptual learning: Toward a comprehensive theory  

PubMed Central

Visual perceptual learning (VPL) is long-term performance increase resulting from visual perceptual experience. Task-relevant VPL of a feature results from training of a task on the feature relevant to the task. Task-irrelevant VPL arises as a result of exposure to the feature irrelevant to the trained task. There are at least two serious problems. First, which stage of information processing is changed in association with task-relevant VPL is controversial. Second, no model has ever explained both task-relevant and task-irrelevant VPL. Here we propose a dual plasticity model, in which there are feature-based plasticity that is a change in a representation of the learned feature and task-based plasticity that is a change in processing of the trained task. While the two types of plasticity underlie task-relevant VPL, only feature-based plasticity lies under task-irrelevant VPL. This model provides a new comprehensive framework in which apparently contradictory results could be explained. PMID:25251494

Watanabe, Takeo; Sasaki, Yuka

2014-01-01

355

Memory protection  

NASA Technical Reports Server (NTRS)

Accidental overwriting of files or of memory regions belonging to other programs, browsing of personal files by superusers, Trojan horses, and viruses are examples of breakdowns in workstations and personal computers that would be significantly reduced by memory protection. Memory protection is the capability of an operating system and supporting hardware to delimit segments of memory, to control whether segments can be read from or written into, and to confine accesses of a program to its segments alone. The absence of memory protection in many operating systems today is the result of a bias toward a narrow definition of performance as maximum instruction-execution rate. A broader definition, including the time to get the job done, makes clear that cost of recovery from memory interference errors reduces expected performance. The mechanisms of memory protection are well understood, powerful, efficient, and elegant. They add to performance in the broad sense without reducing instruction execution rate.

Denning, Peter J.

1988-01-01

356

Light Speed!  

NSDL National Science Digital Library

Light Speed! is an OpenGL-based program developed to illustrate the effects of special relativity on the appearance of moving objects. In particular, the program allows users to see the manner in which an object is distorted based upon the viewpoint from which it is observed. In particular, Lorentz contraction, Doppler shift, the headlight effect, and optical aberration issues are highlighted at relativistic velocities.

Daniel, Richard

2009-06-10

357

Computing Speed  

NSDL National Science Digital Library

This lesson should take one day of class time. The purpose of this lesson is to develop an understanding of quadratic functions. We use the linear relation between distance, constant speed and time and the quadratic relation between the vertical distance of a falling object and time. From these, students will develop two new quadratic functions. The graph of one of these provides a picture of the physical phenomenon they have viewed.

2011-01-01

358

Probing short-term face memory in developmental prosopagnosia.  

PubMed

It has recently been proposed that the face recognition deficits seen in neurodevelopmental disorders may reflect impaired short-term face memory (STFM). For example, introducing a brief delay between the presentation of target and test faces seems to disproportionately impair matching or recognition performance in individuals with Autism Spectrum Disorders. The present study sought to determine whether deficits of STFM contribute to impaired face recognition seen in Developmental Prosopagnosia. To determine whether developmental prosopagnosics exhibit impaired STFM, the present study used a six-alternative-forced-choice match-to-sample procedure. Memory demand was manipulated by employing a short or long delay between the presentation of the target face, and the six test faces. Crucially, the perceptual demands were identical in both conditions, thereby allowing the independent contribution of STFM to be assessed. Prosopagnosics showed clear evidence of a category-specific impairment for face-matching in both conditions; they were both slower and less accurate than matched controls. Crucially, however, the prosopagnosics showed no evidence of disproportionate face recognition impairment in the long-interval condition. While individuals with DP may have problems with the perceptual encoding of faces, it appears that their representations are stable over short durations. These results suggest that the face recognition difficulties seen in DP and autism may be qualitatively different, attributable to deficits of perceptual encoding and perceptual maintenance, respectively. PMID:25461712

Shah, Punit; Gaule, Anne; Gaigg, Sebastian B; Bird, Geoffrey; Cook, Richard

2014-10-24

359

Cognit activation: a mechanism enabling temporal integration in working memory  

PubMed Central

Working memory is critical to the integration of information across time in goal-directed behavior, reasoning and language, yet its neural substrate is unknown. Based on recent research, we propose a mechanism by which the brain can retain working memory for prospective use, thereby bridging time in the perception/action cycle. The essence of the mechanism is the activation of cognits, which consist of distributed, overlapping and interactive cortical networks that in the aggregate encode the long-term memory of the subject. Working memory depends on the excitatory reentry between perceptual and executive cognits of posterior and frontal cortices, respectively. Given the pervasive role of working memory in the structuring of purposeful cognitive sequences, its mechanism looms essential to the foundation of behavior, reasoning and language. PMID:22440831

Fuster, Joaquín M.; Bressler, Steven L.

2012-01-01

360

Perceptual accuracy and conflicting effects of certainty on risk-taking behaviour  

E-print Network

LETTERS Perceptual accuracy and conflicting effects of certainty on risk-taking behaviour Sharoni by perceptual noise and that the certainty effect can be restored experimentally by reducing perceptual accuracy perceptual accuracy in experience- based tasks, both the certainty and the reversed certainty effects can

Indiana University

361

Evidence of Schizophrenia Patients' Reduced Perceptual Biases in Response to Emotion Chimera  

Microsoft Academic Search

The goal of the study was to determine whether dextral individuals with schizophrenia display atypical perceptual biases in response to faces in general, or whether they display atypical perceptual biases in response to emotional facial cues. To this end, we assessed perceptual processing in schizophrenia patients with four types of free-vision chimeric stimuli. Perceptual biases were evaluated in 45 schizophrenia

Diane C. Gooding; Karen E. Luh; Kathleen A. Tallent

2001-01-01

362

Runtime and Programming Support for Memory Adaptation in Scientific Applications via Local Disk and Remote Memory  

SciTech Connect

The ever increasing memory demands of many scientific applications and the complexity of today's shared computational resources still require the occasional use of virtual memory, network memory, or even out-of-core implementations, with well known drawbacks in performance and usability. In Mills et al. (Adapting to memory pressure from within scientific applications on multiprogrammed COWS. In: International Parallel and Distributed Processing Symposium, IPDPS, Santa Fe, NM, 2004), we introduced a basic framework for a runtime, user-level library, MMlib, in which DRAM is treated as a dynamic size cache for large memory objects residing on local disk. Application developers can specify and access these objects through MMlib, enabling their application to execute optimally under variable memory availability, using as much DRAM as fluctuating memory levels will allow. In this paper, we first extend our earlier MMlib prototype from a proof of concept to a usable, robust, and flexible library. We present a general framework that enables fully customizable memory malleability in a wide variety of scientific applications. We provide several necessary enhancements to the environment sensing capabilities of MMlib, and introduce a remote memory capability, based on MPI communication of cached memory blocks between 'compute nodes' and designated memory servers. The increasing speed of interconnection networks makes a remote memory approach attractive, especially at the large granularity present in large scientific applications. We show experimental results from three important scientific applications that require the general MMlib framework. The memory-adaptive versions perform nearly optimally under constant memory pressure and execute harmoniously with other applications competing for memory, without thrashing the memory system. Under constant memory pressure, we observe execution time improvements of factors between three and five over relying solely on the virtual memory system. With remote memory employed, these factors are even larger and significantly better than other, system-level remote memory implementations.

Mills, Richard T [ORNL; Yue, Chuan [College of William and Mary, Williamsburg, VA; Andreas, Stathopoulos [College of William and Mary, Williamsburg, VA; Nikolopoulos, Dimitrios S [Virginia Polytechnic Institute and State University (Virginia Tech)

2007-01-01

363

Perceptual Factors Influence Visual Search for Meaningful Symbols In Individuals with Intellectual Disabilities and Down Syndrome or Autism Spectrum Disorders  

PubMed Central

Augmentative and alternative communication (AAC) systems often supplement oral communication of individuals with intellectual and communication disabilities. Research with nondisabled preschoolers has demonstrated that two visual perceptual factors influence speed and/or accuracy of finding a target - the internal color and spatial organization of symbols. Twelve participants with Down syndrome and 12 with ASD underwent two search tasks. In one, the symbols were clustered by internal color; in the other the identical symbols had no arrangement cue. Visual search was superior in participants with ASD compared to those with Down syndrome. In both groups, responses were significantly faster when the symbols were clustered by internal color. Construction of aided AAC displays may benefit from attention to their physical/perceptual features. PMID:24245729

Wilkinson, Krista M.; McIlvane, William J.

2013-01-01

364

Quantum memory Quantum memory  

NASA Astrophysics Data System (ADS)

Interaction of quantum radiation with multi-particle ensembles has sparked off intense research efforts during the past decade. Emblematic of this field is the quantum memory scheme, where a quantum state of light is mapped onto an ensemble of atoms and then recovered in its original shape. While opening new access to the basics of light-atom interaction, quantum memory also appears as a key element for information processing applications, such as linear optics quantum computation and long-distance quantum communication via quantum repeaters. Not surprisingly, it is far from trivial to practically recover a stored quantum state of light and, although impressive progress has already been accomplished, researchers are still struggling to reach this ambitious objective. This special issue provides an account of the state-of-the-art in a fast-moving research area that makes physicists, engineers and chemists work together at the forefront of their discipline, involving quantum fields and atoms in different media, magnetic resonance techniques and material science. Various strategies have been considered to store and retrieve quantum light. The explored designs belong to three main—while still overlapping—classes. In architectures derived from photon echo, information is mapped over the spectral components of inhomogeneously broadened absorption bands, such as those encountered in rare earth ion doped crystals and atomic gases in external gradient magnetic field. Protocols based on electromagnetic induced transparency also rely on resonant excitation and are ideally suited to the homogeneous absorption lines offered by laser cooled atomic clouds or ion Coulomb crystals. Finally off-resonance approaches are illustrated by Faraday and Raman processes. Coupling with an optical cavity may enhance the storage process, even for negligibly small atom number. Multiple scattering is also proposed as a way to enlarge the quantum interaction distance of light with matter. The quest for higher efficiency, better fidelity, broader bandwidth, multimode capacity and longer storage lifetime is pursued in all those approaches, as shown in this special issue. The improvement of quantum memory operation specifically requires in-depth study and control of numerous physical processes leading to atomic decoherence. The present issue reflects the development of rare earth ion doped matrices offering long lifetime superposition states, either as bulk crystals or as optical waveguides. The need for quantum sources and high efficiency detectors at the single photon level is also illustrated. Several papers address the networking of quantum memories either in long-haul cryptography or in the prospect of quantum processing. In this context, much attention has been paid recently to interfacing quantum light with superconducting qubits and with nitrogen-vacancy centers in diamond. Finally, the quantum interfacing of light with matter raises questions on entanglement. The last two papers are devoted to the generation of entanglement by dissipative processes. It is shown that long lifetime entanglement may be built in this way. We hope this special issue will help readers to become familiar with the exciting field of ensemble-based quantum memories and will stimulate them to bring deeper insights and new ideas to this area.

Le Gouët, Jean-Louis; Moiseev, Sergey

2012-06-01

365

Location-specific cortical activation changes during sleep after training for perceptual learning  

PubMed Central

SUMMARY Visual perceptual learning is defined as performance enhancement on a sensory task and is distinguished from other types of learning and memory in that it is highly specific for location of the trained stimulus. The location specificity has been shown to be paralleled by changes in neural activity in V1 or V4 of monkeys [1, 2] and enhancement in functional magnetic resonance imaging (fMRI) signal in the trained region of the primary visual cortex (V1) [3–5] after visual training. Although recently the role of sleep in strengthening visual perceptual learning has attracted much attention, its underlying neural mechanism has yet to be clarified. Here, for the first time, fMRI activation of early visual cortex was measured and compared during sleep with and without preceding visual perceptual learning training. The fMRI measurement was conducted concurrently with polysomnogram, which indicates a subject’s sleep/wake status. As a result of predetermined region-of-interest (ROI) analysis of the human primary cortex (V1), activation enhancement during non rapid eye movement sleep after training was observed specifically in the trained region of V1. Furthermore, improvement of task-performance measured subsequently to the post-training sleep session was significantly correlated with the amount of the trained-region-specific fMRI activation in V1 during sleep. These results suggest that as far as V1 is concerned, only the trained region is involved in improving task performance after sleep. PMID:19576772

Yotsumoto, Yuko; Sasaki, Yuka; Chan, Patrick; Vasios, Christos E.; Bonmassar, Giorgio; Ito, Nozomi; Náñez, José E.; Shimojo, Shinsuke; Watanabe, Takeo

2009-01-01

366

Overview of emerging nonvolatile memory technologies.  

PubMed

Nonvolatile memory technologies in Si-based electronics date back to the 1990s. Ferroelectric field-effect transistor (FeFET) was one of the most promising devices replacing the conventional Flash memory facing physical scaling limitations at those times. A variant of charge storage memory referred to as Flash memory is widely used in consumer electronic products such as cell phones and music players while NAND Flash-based solid-state disks (SSDs) are increasingly displacing hard disk drives as the primary storage device in laptops, desktops, and even data centers. The integration limit of Flash memories is approaching, and many new types of memory to replace conventional Flash memories have been proposed. Emerging memory technologies promise new memories to store more data at less cost than the expensive-to-build silicon chips used by popular consumer gadgets including digital cameras, cell phones and portable music players. They are being investigated and lead to the future as potential alternatives to existing memories in future computing systems. Emerging nonvolatile memory technologies such as magnetic random-access memory (MRAM), spin-transfer torque random-access memory (STT-RAM), ferroelectric random-access memory (FeRAM), phase-change memory (PCM), and resistive random-access memory (RRAM) combine the speed of static random-access memory (SRAM), the density of dynamic random-access memory (DRAM), and the nonvolatility of Flash memory and so become very attractive as another possibility for future memory hierarchies. Many other new classes of emerging memory technologies such as transparent and plastic, three-dimensional (3-D), and quantum dot memory technologies have also gained tremendous popularity in recent years. Subsequently, not an exaggeration to say that computer memory could soon earn the ultimate commercial validation for commercial scale-up and production the cheap plastic knockoff. Therefore, this review is devoted to the rapidly developing new class of memory technologies and scaling of scientific procedures based on an investigation of recent progress in advanced Flash memory devices. PMID:25278820

Meena, Jagan Singh; Sze, Simon Min; Chand, Umesh; Tseng, Tseung-Yuen

2014-01-01

367

The Neural Basis of Implicit Perceptual Sequence Learning  

PubMed Central

The present fMRI study investigated the neural areas involved in implicit perceptual sequence learning. To obtain more insight in the functional contributions of the brain areas, we tracked both the behavioral and neural time course of the learning process, using a perceptual serial color matching task. Next, to investigate whether the neural time course was specific for perceptual information, imaging results were compared to the results of implicit motor sequence learning, previously investigated using an identical serial color matching task (Gheysen et al., 2010). Results indicated that implicit sequences can be acquired by at least two neural systems: the caudate nucleus and the hippocampus, having different operating principles. The caudate nucleus contributed to the implicit sequence learning process for perceptual as well as motor information in a similar and gradual way. The hippocampus, on the other hand, was engaged in a much faster learning process which was more pronounced for the motor compared to the perceptual task. Interestingly, the perceptual and motor learning process occurred on a comparable implicit level, suggesting that consciousness is not the main determinant factor dissociating the hippocampal from the caudate learning system. This study is not only the first to successfully and unambiguously compare brain activation between perceptual and motor levels of implicit sequence learning, it also provides new insights into the specific hippocampal and caudate learning function. PMID:22087090

Gheysen, Freja; Van Opstal, Filip; Roggeman, Chantal; Van Waelvelde, Hilde; Fias, Wim

2011-01-01

368

Auditory-perceptual learning improves speech motor adaptation in children.  

PubMed

Auditory feedback plays an important role in children's speech development by providing the child with information about speech outcomes that is used to learn and fine-tune speech motor plans. The use of auditory feedback in speech motor learning has been extensively studied in adults by examining oral motor responses to manipulations of auditory feedback during speech production. Children are also capable of adapting speech motor patterns to perceived changes in auditory feedback; however, it is not known whether their capacity for motor learning is limited by immature auditory-perceptual abilities. Here, the link between speech perceptual ability and the capacity for motor learning was explored in two groups of 5- to 7-year-old children who underwent a period of auditory perceptual training followed by tests of speech motor adaptation to altered auditory feedback. One group received perceptual training on a speech acoustic property relevant to the motor task while a control group received perceptual training on an irrelevant speech contrast. Learned perceptual improvements led to an enhancement in speech motor adaptation (proportional to the perceptual change) only for the experimental group. The results indicate that children's ability to perceive relevant speech acoustic properties has a direct influence on their capacity for sensory-based speech motor adaptation. PMID:24842067

Shiller, Douglas M; Rochon, Marie-Lyne

2014-08-01

369

Accurate expectancies diminish perceptual distraction during visual search  

PubMed Central

The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively “spills-over” to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, functional magnetic resonance imaging, and electrophysiology. Expectations were generated using a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean blood oxygenation level dependent responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information. PMID:24904374

Sy, Jocelyn L.; Guerin, Scott A.; Stegman, Anna; Giesbrecht, Barry

2014-01-01

370

Detecting perceptual groupings in textures by continuity considerations  

NASA Technical Reports Server (NTRS)

A generalization is presented for the second derivative of a Gaussian D(sup 2)G operator to apply to problems of perceptual organization involving textures. Extensions to other problems of perceptual organization are evident and a new research direction can be established. The technique presented is theoretically pleasing since it has the potential of unifying the entire area of image segmentation under the mathematical notion of continuity and presents a single algorithm to form perceptual groupings where many algorithms existed previously. The eventual impact on both the approach and technique of image processing segmentation operations could be significant.

Greene, Richard J.

1990-01-01

371

The Processing Speed of Humans on Various Visual Tasks: An Analysis of Relationships. Final Report.  

ERIC Educational Resources Information Center

The purpose of this study was to examine the relationship between the various techniques used to estimate the time required by the human to process a visual stimuli, i.e., recognize a stimulus input into the visual perceptual system. Sixteen tests of visual processing speed were administered to 110 undergraduate students. In summary, scores tended…

Bosco, James J.

372

Perceptual and contextual awareness: methodological considerations in the search for the neural correlates of consciousness  

PubMed Central

In the last decades, the neural correlates of consciousness (NCCs) have been explored using both invasive and non-invasive recordings by comparing the brain activity elicited by seen versus unseen visual stimuli (i.e., the contrastive analysis). Here, we review a selection of these studies and discuss a set of considerations to improve the search for the NCCs using the contrastive analysis. In particular, we first argue in favor of implementing paradigms where different perceptual outputs are obtained using identical visual inputs. Second, we propose that the large disagreement in the field -in terms of the dissimilar neural patterns proposed as NCCs- is partially explained by the fact that different studies report the neural correlates of different conscious processes in the brain. More specifically, we distinguish between the perceptual awareness of a visual stimulus, associated to a boost in object-selective neural assemblies, and a more elaborate process (contextual awareness) that we argue is reflected in the firing of concept neurons in the medial temporal lobe, triggering a rich representation of the context, associations, and memories linked to the specific stimulus. PMID:25221537

Navajas, Joaquin; Rey, Hernan G.; Quian Quiroga, Rodrigo

2014-01-01

373

Corresponding delay-dependent biases in spatial language and spatial memory  

Microsoft Academic Search

The present study addresses the relationship between linguistic and non-linguistic spatial representations. In three experiments\\u000a we probe spatial language and spatial memory at the same time points in the task sequence. Experiments 1 and 2 show analogous\\u000a delay-dependent biases in spatial language and spatial memory. Experiment 3 extends this correspondence, showing that additional\\u000a perceptual structure along the vertical axis reduces

John Lipinski; John P. Spencer; Larissa K. Samuelson

2010-01-01

374

Conceptual Distinctiveness Supports Detailed Visual Long-Term Memory for Real-World Objects  

Microsoft Academic Search

Humans have a massive capacity to store detailed information in visual long-term memory. The present studies explored the fidelity of these visual long-term memory representations and examined how conceptual and perceptual features of object categories support this capacity. Observers viewed 2,800 object images with a different number of exemplars presented from each category. At test, observers indicated which of 2

Talia Konkle; Timothy F. Brady; George A. Alvarez; Aude Oliva

2010-01-01

375

Representation Sharpening Can Explain Perceptual Priming  

PubMed Central

Perceiving and identifying an object is improved by prior exposure to the object. This perceptual priming phenomenon is accompanied by reduced neural activity. But whether suppression of neuronal activity with priming is responsible for the improvement in perception is unclear. To address this problem, we developed a rate-based network model of visual processing. In the model, decreased neural activity following priming was due to stimulus-specific sharpening of representations taking place in the early visual areas. Representation sharpening led to decreased interference of representations in higher visual areas that facilitated selection of one of the competing representations, thereby improving recognition. The model explained a wide range of psychophysical and physiological data observed in priming experiments, including antipriming phenomena, and predicted two functionally distinct stages of visual processing. PMID:20028230

Moldakarimov, Samat; Bazhenov, Maxim; Sejnowski, Terrence J.

2010-01-01

376

Representation sharpening can explain perceptual priming.  

PubMed

Perceiving and identifying an object is improved by prior exposure to the object. This perceptual priming phenomenon is accompanied by reduced neural activity. But whether suppression of neuronal activity with priming is responsible for the improvement in perception is unclear. To address this problem, we developed a rate-based network model of visual processing. In the model, decreased neural activity following priming was due to stimulus-specific sharpening of representations taking place in the early visual areas. Representation sharpening led to decreased interference of representations in higher visual areas that facilitated selection of one of the competing representations, thereby improving recognition. The model explained a wide range of psychophysical and physiological data observed in priming experiments, including antipriming phenomena, and predicted two functionally distinct stages of visual processing. PMID:20028230

Moldakarimov, Samat; Bazhenov, Maxim; Sejnowski, Terrence J

2010-05-01

377

Perceptually motivated time-frequency analysis.  

PubMed

This paper describes the design of a bilinear time-frequency distribution which is a joint model of temporal and spectral masking. The distribution is used to generate temporally evolving excitation patterns of nonstationary signals and systems and is conceived as a tool for acousticians and engineers for perceptual time-frequency analysis. Distribution time and frequency resolutions are controlled by a separable kernel consisting of a set of low-pass time and frequency smoothing windows. These windows are designed by adapting existing psychoacoustic models of auditory resolution, rather than using mathematical window functions. Cross-term interference and windowing clutter are highly suppressed for the distribution, ensuring resolution accuracy over a dynamic range sufficient to encompass that of the auditory system (in excess of 100 dB). Application to the analysis of a synthetic and two real signals are included to demonstrate the approach. PMID:15704418

O'Donovan, Jonathan J; Furlong, Dermot J

2005-01-01

378

Selective Interference on the Holistic Processing of Faces in Working Memory  

ERIC Educational Resources Information Center

Faces and objects of expertise compete for early perceptual processes and holistic processing resources (Gauthier, Curran, Curby, & Collins, 2003). Here, we examined the nature of interference on holistic face processing in working memory by comparing how various types of loads affect selective attention to parts of face composites. In dual tasks,…

Cheung, Olivia S.; Gauthier, Isabel

2010-01-01

379

Stepping into a Map: Initial Heading Direction Influences Spatial Memory Flexibility  

ERIC Educational Resources Information Center

Learning a novel environment involves integrating first-person perceptual and motoric experiences with developing knowledge about the overall structure of the surroundings. The present experiments provide insights into the parallel development of these egocentric and allocentric memories by intentionally conflicting body- and world-centered frames…

Gagnon, Stephanie A.; Brunyé, Tad T.; Gardony, Aaron; Noordzij, Matthijs L.; Mahoney, Caroline R.; Taylor, Holly A.

2014-01-01

380

When Spatial and Temporal Contiguities Help the Integration in Working Memory: "A Multimedia Learning" Approach  

ERIC Educational Resources Information Center

Two experiments examined the effects of spatial and temporal contiguities in a working memory binding task that required participants to remember coloured objects. In Experiment 1, a black and white drawing and a corresponding phrase that indicated its colour perceptually were either near or far (spatial study condition), while in Experiment 2,…

Mammarella, Nicola; Fairfield, Beth; Di Domenico, Alberto

2013-01-01

381

Virtual memory  

NASA Technical Reports Server (NTRS)

Virtual memory was conceived as a way to automate overlaying of program segments. Modern computers have very large main memories, but need automatic solutions to the relocation and protection problems. Virtual memory serves this need as well and is thus useful in computers of all sizes. The history of the idea is traced, showing how it has become a widespread, little noticed feature of computers today.

Denning, P. J.

1986-01-01

382

Recognition and Memory for Briefly Presented Scenes  

PubMed Central

Three times per second, our eyes make a new fixation that generates a new bottom-up analysis in the visual system. How much is extracted from each glimpse? For how long and in what form is that information remembered? To answer these questions, investigators have mimicked the effect of continual shifts of fixation by using rapid serial visual presentation of sequences of unrelated pictures. Experiments in which viewers detect specified target pictures show that detection on the basis of meaning is possible at presentation durations as brief as 13?ms, suggesting that understanding may be based on feedforward processing, without feedback. In contrast, memory for what was just seen is poor unless the viewer has about 500?ms to think about the scene: the scene does not need to remain in view. Initial memory loss after brief presentations occurs over several seconds, suggesting that at least some of the information from the previous few fixations persists long enough to support a coherent representation of the current environment. In contrast to marked memory loss shortly after brief presentations, memory for pictures viewed for 1?s or more is excellent. Although some specific visual information persists, the form and content of the perceptual and memory representations of pictures over time indicate that conceptual information is extracted early and determines most of what remains in longer-term memory. PMID:22371707

Potter, Mary C.

2012-01-01

383

Perceptual and motor learning underlies human stick-balancing skill.  

PubMed

We investigated the acquisition of skill in balancing a stick (52 cm, 34 g) on the fingertip in nine participants using three-dimensional motion analysis. After 3.5 h of practice over 6 wk, the participants could more consistently balance the stick for longer durations with greatly reduced magnitude and speed of stick and finger movements. Irrespective of level of skill, the balanced stick behaved like a normal noninverted pendulum oscillating under greater-than-gravity torque with simple harmonic motion about a virtual pivot located at the radius of gyration above the center of mass. The control input parameter was the magnitude ratio between the torque applied on the stick by the participant and the torque due to gravity. The participants utilized only a narrow range of this parameter, which did not change with practice, to rotate the stick like a linear mass-spring system. With increased skill, the stick therefore maintained the same period of oscillation but showed marked reductions in magnitude of both oscillation and horizontal translation. Better balancing was associated with 1) more accurate visual localization of the stick and proprioceptive localization of the finger and 2) reduced cross-coupling errors between finger and stick movements in orthogonal directions; i.e., finger movements in the anteroposterior plane became less coupled with stick tip movements in the mediolateral plane, and vice versa. Development of this fine motor skill therefore depended on perceptual and motor learning to provide improved estimation of sensorimotor state and precision of motor commands to an unchanging internal model of the rotational dynamics. PMID:25298388

Lee, Kwee-Yum; O'Dwyer, Nicholas; Halaki, Mark; Smith, Richard

2015-01-01

384

Increased gamma-band synchrony precedes switching of conscious perceptual objects in binocular rivalry.  

PubMed

Gamma-band neural synchrony has been proposed as a correlate of consciousness and as a solution for the binding problem. Research on visual working memory and the perception of coherent images in ambiguous figures supports this view. To test the relationship between perceptual consciousness and gamma synchrony, we recorded electroencephalogram activity while participants were presented with rivalling visual images to each eye. Participants pressed buttons to indicate which image they were perceiving, and response-locked phase-locking values (6-60 Hz) were calculated from the electroencephalogram time series. Results revealed transient bursts of increased global phase synchrony in the gamma-band peaking approximately 425 and approximately 260 ms preresponse. This suggests that global gamma synchrony is associated with the emergence of a coherent conscious percept. PMID:16012336

Doesburg, Sam M; Kitajo, Keiichi; Ward, Lawrence M

2005-08-01

385

Imaging early consolidation of perceptual learning with face stimuli during rest.  

PubMed

Studies investigating visual perceptual learning (VPL) have traditionally used simple visual tasks and focused on assessing the active (online) processes of learning and memory: encoding and retrieval. The assessment of complex stimuli and the passive (offline) process of consolidation is, however, necessary for a full understanding of the development of VPL and has received little direct analysis. In the current study, 30 young adults completed a VPL task with face stimuli while undergoing an fMRI scan. Activity was assessed within offline rest breaks both during and after the learning task. Changes in baseline activity within functionally-relevant regions were identified during these rest periods. Furthermore, differences in consolidation-related resting activity were evident between individuals who performed well on the active task, and those who performed less well. These findings provide preliminary evidence that activity during offline rest breaks, which immediately follow the active task, is associated with consolidation and learning, in VPL. PMID:24394347

Vilsten, J S; Mundy, M E

2014-03-01

386

Task contingencies and perceptual strategies shape behavioral effects on neuronal response profiles  

PubMed Central

We presented optic flow simulating eight directions of self-movement in the ground plane, while monkeys performed delayed match-to-sample tasks, and we recorded dorsal medial superior temporal (MSTd) neuronal activity. Randomly selected sample headings yield smaller test responses to the neuron's preferred heading when it is near the sample's heading direction and larger test responses to the preferred heading when it is far from the sample's heading. Limiting test stimuli to matching or opposite headings suppresses responses to preferred stimuli in both test conditions, whereas focusing on each neuron's preferred vs. antipreferred stimuli enhances responses to the antipreferred stimulus. Match vs. opposite paradigms create bimodal heading profiles shaped by interactions with late delay-period activity. We conclude that task contingencies, determining the prior probabilities of specific stimuli, interact with the monkeys' perceptual strategy for optic flow analysis. These influences shape attentional and working memory effects on the heading direction selectivities and preferences of MSTd neurons. PMID:23100141

Sato, Nobuya; Page, William K.

2013-01-01

387

Missing the Memory Wall: The Case for Processor\\/Memory Integration  

Microsoft Academic Search

Current high performance computer systems use complex, large superscalar CPUs that interface to the main memory through a hierarchy of caches and interconnect systems. These CPU-centric designs invest a lot of power and chip area to bridge the widening gap between CPU and main memory speeds. Yet, many large applications do not operate well on these systems and are limited

Ashley Saulsbury; Fong Pong; Andreas Nowatzyk

1996-01-01

388

Perceptual tools for quality-aware video networks  

NASA Astrophysics Data System (ADS)

Monitoring and controlling the quality of the viewing experience of videos transmitted over increasingly congested networks (especially wireless networks) is a pressing problem owing to rapid advances in video-centric mobile communication and display devices that are straining the capacity of the network infrastructure. New developments in automatic perceptual video quality models offer tools that have the potential to be used to perceptually optimize wireless video, leading to more efficient video data delivery and better received quality. In this talk I will review key perceptual principles that are, or could be used to create effective video quality prediction models, and leading quality prediction models that utilize these principles. The goal is to be able to monitor and perceptually optimize video networks by making them "quality-aware."

Bovik, A. C.

2014-01-01

389

Creating a Virtual Reality as a Perceptual Equivalence for Training.  

ERIC Educational Resources Information Center

Explores the relationship between virtual reality (VR) stimulation and perceptual equivalence. Topics include perceived realism; creating a virtual illusion; displayed realism; and VR as an instructional technology. (Author/AEF)

Bailey, Sandra S.

1994-01-01

390

Phonetic knowledge, phonotactics and perceptual validation for automatic language identification  

E-print Network

Phonetic knowledge, phonotactics and perceptual validation for automatic language identification- tribute to human language identification: among the most important are acoustics, phonetics, phonotactics for automatic LId. Acoustic-phonetic and phonotactic modelling benefit from many decades of research first

Boula de Mareüil, Philippe

391

Perceptual data mining : bootstrapping visual intelligence from tracking behavior  

E-print Network

One common characteristic of all intelligent life is continuous perceptual input. A decade ago, simply recording and storing a a few minutes of full frame-rate NTSC video required special hardware. Today, an inexpensive ...

Stauffer, Christopher P. (Christopher Paul), 1971-

2002-01-01

392

COGNITIVE NEUROSCIENCE A perceptual representation in the frontal eye field  

E-print Network

COGNITIVE NEUROSCIENCE A perceptual representation in the frontal eye field during covert visual selective processes, the selection of which stimulus to act upon and the selection of which action to make

Zhou, Yi-Feng

393

Cultural Differences in Perceptual Reorganization in US and Pirahã Adults  

PubMed Central

Visual illusions and other perceptual phenomena can be used as tools to uncover the otherwise hidden constructive processes that give rise to perception. Although many perceptual processes are assumed to be universal, variable susceptibility to certain illusions and perceptual effects across populations suggests a role for factors that vary culturally. One striking phenomenon is seen with two-tone images—photos reduced to two tones: black and white. Deficient recognition is observed in young children under conditions that trigger automatic recognition in adults. Here we show a similar lack of cue-triggered perceptual reorganization in the Pirahã, a hunter-gatherer tribe with limited exposure to modern visual media, suggesting such recognition is experience- and culture-specific. PMID:25411970

Yoon, Jennifer M. D.; Witthoft, Nathan; Winawer, Jonathan; Frank, Michael C.; Everett, Daniel L.; Gibson, Edward

2014-01-01

394

The perceptual basis of long-distance laryngeal restrictions  

E-print Network

The two main arguments in this dissertation are 1. That laryngeal co-occurrence restrictions are restrictions on the perceptual strength of contrasts between roots, as opposed to restrictions on laryngeal configurations ...

Gallagher, Gillian Elizabeth Scott

2010-01-01

395

Perceptual Learning: Cortical Changes When Cats Learn a New Trick  

PubMed Central

A new study has found that the tuning properties of neurons in the primary visual cortex of cats change as they learn an orientation-discrimination task, casting new light on the neuronal basis of perceptual learning. PMID:20619806

Sasaki, Yuka; Gold, Joshua; Watanabe, Takeo

2013-01-01

396

An ecological perceptual aid for precision vertical landings  

E-print Network

Pilots of vertical landing vehicles face numerous control challenges which often involve the loss of outside visual perceptual cues or the control of flight parameters within tight constraints. These challenges are often ...

Smith, Cristin Anne

2006-01-01

397

Variance misperception explains illusions of confidence in simple perceptual decisions.  

PubMed

Confidence in a perceptual decision is a judgment about the quality of the sensory evidence. The quality of the evidence depends not only on its strength ('signal') but critically on its reliability ('noise'), but the separate contribution of these quantities to the formation of confidence judgments has not been investigated before in the context of perceptual decisions. We studied subjective confidence reports in a multi-element perceptual task where evidence strength and reliability could be manipulated independently. Our results reveal a confidence paradox: confidence is higher for stimuli of lower reliability that are associated with a lower accuracy. We show that the subjects' overconfidence in trials with unreliable evidence is caused by a reduced sensitivity to stimulus variability. Our results bridge between the investigation of miss-attributions of confidence in behavioral economics and the domain of simple perceptual decisions amenable to neuroscience research. PMID:24951943

Zylberberg, Ariel; Roelfsema, Pieter R; Sigman, Mariano

2014-07-01

398

Inferring Perceptual Saliency Fields from Viewpoint-Dependent Recognition Data  

Microsoft Academic Search

We present an algorithm for computing the relative perceptual saliencies of the features of a three-dimensional object using either goodness-of- view scores measured at several viewpoints or perceptual similarities among several object views. This technique addresses the inverse, ill- posed version of the direct problem of predicting goodness-of-view scores or viewpoint similarities when the object features are known. On the

Florin Cutzu; Michael J. Tarr

1999-01-01

399

Teacher Expectations: Self-Fulfilling Prophecies, Perceptual Biases, and Accuracy  

Microsoft Academic Search

Students' performance may confirm teachers' expectations because teacher expectations create self-fulfilling prophecies, create perceptual biases, or accurately predict, without influencing, student performance. Longitudinal data obtained from 27 teachers and 429 students in 6th-grade math classes assessed the extent of self-fulfilling prophecies, perceptual biases, and accuracy. Results revealed modest self-fulfilling-prophecy effects on student achievement and motivation, modest biasing effects on the

Lee Jussim

1989-01-01

400

Consolidating memories.  

PubMed

Our own experiences, as well as the findings of many studies, suggest that emotionally arousing experiences can create lasting memories. This autobiographical article provides a brief summary of the author's research investigating neurobiological systems responsible for the influence of emotional arousal on the consolidation of lasting memories. The research began with the finding that stimulant drugs enhanced memory in rats when administered shortly after training. Those findings suggested the possibility that endogenous systems activated by arousal might influence neural processes underlying memory consolidation. Subsequent findings that adrenal stress hormones activated by learning experiences enhance memory consolidation provided strong evidence supporting this hypothesis. Other findings suggest that the enhancement is induced by stress hormone activation of the amygdala. The findings also suggest that the basolateral amygdala modulates memory consolidation via its projections to brain regions involved in processing different aspects and forms of memory. This emotional-arousal-activated neurobiological system thus seems to play an important adaptive role in insuring that the strength of our memories will reflect their emotional significance. PMID:25559113

McGaugh, James L

2015-01-01

401

Collaging Memories  

ERIC Educational Resources Information Center

Even middle school students can have memories of their childhoods, of an earlier time. The art of Romare Bearden and the writings of Paul Auster can be used to introduce ideas about time and memory to students and inspire works of their own. Bearden is an exceptional role model for young artists, not only because of his astounding art, but also…

Wallach, Michele

2011-01-01

402

Consensus Paper: The Role of the Cerebellum in Perceptual Processes.  

PubMed

Various lines of evidence accumulated over the past 30 years indicate that the cerebellum, long recognized as essential for motor control, also has considerable influence on perceptual processes. In this paper, we bring together experts from psychology and neuroscience, with the aim of providing a succinct but comprehensive overview of key findings related to the involvement of the cerebellum in sensory perception. The contributions cover such topics as anatomical and functional connectivity, evolutionary and comparative perspectives, visual and auditory processing, biological motion perception, nociception, self-motion, timing, predictive processing, and perceptual sequencing. While no single explanation has yet emerged concerning the role of the cerebellum in perceptual processes, this consensus paper summarizes the impressive empirical evidence on this problem and highlights diversities as well as commonalities between existing hypotheses. In addition to work with healthy individuals and patients with cerebellar disorders, it is also apparent that several neurological conditions in which perceptual disturbances occur, including autism and schizophrenia, are associated with cerebellar pathology. A better understanding of the involvement of the cerebellum in perceptual processes will thus likely be important for identifying and treating perceptual deficits that may at present go unnoticed and untreated. This paper provides a useful framework for further debate and empirical investigations into the influence of the cerebellum on sensory perception. PMID:25479821

Baumann, Oliver; Borra, Ronald J; Bower, James M; Cullen, Kathleen E; Habas, Christophe; Ivry, Richard B; Leggio, Maria; Mattingley, Jason B; Molinari, Marco; Moulton, Eric A; Paulin, Michael G; Pavlova, Marina A; Schmahmann, Jeremy D; Sokolov, Arseny A

2014-12-01

403

COMMENTARY Episodic Memory, Semantic Memory, and Amnesia  

Microsoft Academic Search

Episodic memory and semantic memory are two types of declarative memory. There have been two principal views about how this distinction might be reflected in the organization of memory functions in the brain. One view, that episodic memory and semantic memory are both dependent on the integrity of medial temporal lobe and midline dience- phalic structures, predicts that amnesic patients

Larry R. Squire; Stuart M. Zola

404

Visual search for category sets: Tradeoffs between exploration and memory  

PubMed Central

Limitations of working memory force a reliance on motor exploration to retrieve forgotten features of the visual array. A category search task was devised to study tradeoffs between exploration and memory in the face of significant cognitive and motor demands. The task required search through arrays of hidden, multi-featured objects to find three belonging to the same category. Location contents were revealed briefly by either a: (1) mouseclick, or (2) saccadic eye movement with or without delays between saccade offset and object appearance. As the complexity of the category rule increased, search favored exploration, with more visits and revisits needed to find the set. As motor costs increased (mouseclick search or oculomotor search with delays) search favored reliance on memory. Application of the model of J. Epelboim and P. Suppes (2001) to the revisits produced an estimate of immediate memory span (M) of about 4–6 objects. Variation in estimates of M across category rules suggested that search was also driven by strategies of transforming the category rule into concrete perceptual hypotheses. The results show that tradeoffs between memory and exploration in a cognitively demanding task are determined by continual and effective monitoring of perceptual load, cognitive demand, decision strategies and motor effort. PMID:21421747

Kibbe, Melissa M.; Kowler, Eileen

2012-01-01

405

(perceptual, motivational, learning, motor, etc.) Behavioral capacities  

E-print Network

Retrieval Response selection Physiological activation Behavioral activation Associativelearning #12;Classes term? ·Working memory General Specific ·Human language ·Song learning ·Imprinting #12;ASSOCIATIVE Freezing Fear conditioning (rats) #12;Kick Light Tendon hit (1) Early in training (2) Late in training

Cooper, Brenton G.

406

Physiological and perceptual responses to backward and forward treadmill walking in water.  

PubMed

We compared physiological and perceptual responses, and stride characteristics while walking backward in water with those of walking forward in water. Eight males walked on an underwater treadmill, immersed to their xiphoid process level. Oxygen uptake ((.)V(O2)), respiratory exchange ratio (R), heart rate (HR), minute ventilation ((.)V(E)), blood lactate concentration (BLa), ratings of perceived exertion (RPE: for breathing and legs, RPE-Br and RPE-Legs, respectively), blood pressure (for systolic and diastolic pressures, SBP and DBP, respectively), and step frequency (SF) were measured. In addition, step length (SL) was calculated. (.)V(O2), R, HR, V (E), BLa, RPE-Br, RPE-Legs, and SBP were significantly higher while walking backward in water than when walking forward in water (P<0.05). Furthermore, SF was significantly higher (P<0.001) and SL was significantly lower (P<0.001) while walking backward in water, compared to walking forward in water. These results indicate that walking backward in water elicits higher physiological and perceptual responses than those produced when walking forward in water at the same speed. PMID:18829319

Masumoto, Kenji; Hamada, Ayako; Tomonaga, Hiro-Omi; Kodama, Kana; Amamoto, Yuko; Nishizaki, Yoshiko; Hotta, Noboru

2009-02-01

407

Assessment of the influence of cognition and cognitive processing speed on three tests of olfaction  

Microsoft Academic Search

The extent to which measures of working memory, cognitive speed, and verbal retrieval are associated with performance on tests of olfaction was evaluated in a sample of 138 older adults. Structural equation modeling techniques indicated that verbal retrieval difficulties significantly affect performance on the University of Pennsylvania Smell Identification Test (UPSIT). Further, poor working memory and slow cognitive speed significantly

Mario F. Dulay; Robert C. Gesteland; Paula K. Shear; P. Neal Ritchey; Robert A. Frank

2008-01-01

408

SPEED: Stand-alone programmable ethernet enabled devices  

Microsoft Academic Search

In this paper we present the design and synthesis of Standalone Programmable Ethernet Enabled Devices (SPEED) as a low cost and power consumption embedded system, which also include an Electrical Erasable Programmable Read Only Memory controller for configurable address assignments.The main function of SPEED is to eliminate the operating system processing of network protocol stack running by personal computer processor

Omar S. Elkeelany; Ghulam Chaudhry

2004-01-01

409

Raman Quantum Memory of Photonic Polarised Entanglement  

E-print Network

Quantum entanglement of particles is regarded as a fundamental character in quantum information, in which quantum state should be given for whole system instead of independently describing single particle. Constructing quantum memory of photonic entanglement is essential for realizing quantum networks, which had been performed previously by many memory protocols. Of which Raman quantum memory gives advantages in broadband and high-speed properties, resulting in huge potential in quantum network and quantum computation. However, Raman quantum memory of photonic polarised entanglement is a challenge work and still missing. Here, we report two Raman quantum memories based on gas atomic ensembles: 1. Heralded Raman quantum memory of hybrid entanglement of path and polarization of single photon. 2. Raman storage of two-particle photonic polarised entangled state. Our experimental performances of these two different Raman quantum storages of photonic entanglement show a very promising prospective in quantum information science.

Dong-Sheng Ding; Wei Zhang; Zhi-Yuan Zhou; Shuai Shi; Bao-Sen Shi; Guang-Can Guo

2014-10-27

410

Memory reconsolidation.  

PubMed

The formation, storage and use of memories is critical for normal adaptive functioning, including the execution of goal-directed behavior, thinking, problem solving and decision-making, and is at the center of a variety of cognitive, addictive, mood, anxiety, and developmental disorders. Memory also significantly contributes to the shaping of human personality and character, and to social interactions. Hence, understanding how memories are formed, stored, retrieved, modified, updated and used potentially impacts many areas in human life, including mental health. PMID:24028957

Alberini, Cristina M; Ledoux, Joseph E

2013-09-01

411

High speed quantitative digital microscopy  

NASA Technical Reports Server (NTRS)

Modern digital image processing hardware makes possible quantitative analysis of microscope images at high speed. This paper describes an application to automatic screening for cervical cancer. The system uses twelve MC6809 microprocessors arranged in a pipeline multiprocessor configuration. Each processor executes one part of the algorithm on each cell image as it passes through the pipeline. Each processor communicates with its upstream and downstream neighbors via shared two-port memory. Thus no time is devoted to input-output operations as such. This configuration is expected to be at least ten times faster than previous systems.

Castleman, K. R.; Price, K. H.; Eskenazi, R.; Ovadya, M. M.; Navon, M. A.

1984-01-01

412

Perceptually controlled doping for audio source separation  

NASA Astrophysics Data System (ADS)

The separation of an underdetermined audio mixture can be performed through sparse component analysis (SCA) that relies however on the strong hypothesis that source signals are sparse in some domain. To overcome this difficulty in the case where the original sources are available before the mixing process, the informed source separation (ISS) embeds in the mixture a watermark, which information can help a further separation. Though powerful, this technique is generally specific to a particular mixing setup and may be compromised by an additional bitrate compression stage. Thus, instead of watermarking, we propose a `doping' method that makes the time-frequency representation of each source more sparse, while preserving its audio quality. This method is based on an iterative decrease of the distance between the distribution of the signal and a target sparse distribution, under a perceptual constraint. We aim to show that the proposed approach is robust to audio coding and that the use of the sparsified signals improves the source separation, in comparison with the original sources. In this work, the analysis is made only in instantaneous mixtures and focused on voice sources.

Mahé, Gaël; Nadalin, Everton Z.; Suyama, Ricardo; Romano, João MT

2014-12-01

413

Perceptual prothesis in native Spanish speakers  

NASA Astrophysics Data System (ADS)

Previous research suggests a perceptual bias exists for native phonotactics [D. Massaro and M. Cohen, Percept. Psychophys. 34, 338-348 (1983)] such that listeners report nonexistent segments when listening to stimuli that violate native phonotactics [E. Dupoux, K. Kakehi, Y. Hirose, C. Pallier, and J. Mehler, J. Exp. Psychol.: Human Percept. Perform. 25, 1568-1578 (1999)]. This study investigated how native-language experience affects second language processing, focusing on how native Spanish speakers perceive the English clusters /st/, /sp/, and /sk/, which represent phonotactically illegal forms in Spanish. To preserve native phonotactics, Spanish speakers often produce prothetic vowels before English words beginning with /s/ clusters. Is the influence of native phonotactics also present in the perception of illegal clusters? A stimuli continuum ranging from no vowel (e.g., ``sku'') to a full vowel (e.g., ``esku'') before the cluster was used. Four final vowel contexts were used for each cluster, resulting in 12 sCV and 12 VsCV nonword endpoints. English and Spanish listeners were asked to discriminate between pairs differing in vowel duration and to identify the presence or absence of a vowel before the cluster. Results will be discussed in terms of implications for theories of second language speech perception.

Theodore, Rachel M.; Schmidt, Anna M.

2003-04-01

414

Issues in the measurement of perceptual assimilation  

NASA Astrophysics Data System (ADS)

This study examined the effect of methodological variables on the fit between predicted discrimination scores based on identification data and actual discrimination data in cross-language speech perception experiments. Such variables include (1) single versus multiple talkers in discrimination test trials; (2) different discrimination test types (e.g., AX, AXB, oddity); and (3) identification tests in which stimuli are presented individually versus stimuli being presented in the same context as they appear in discrimination tests. The optimal pair of identification and discrimination tests, yielding the best match between predicted and actual discrimination scores, can be used in subsequent studies examining perceptual category structure. These methodological variables were examined by presenting American English speakers with two Hindi contrasts, [b]-[p] and breathy voiced dental-retroflex, both in initial position and in an [i], [a], or [u] context. The stimuli appeared in a range of categorial discrimination and identification tests. Early results examining the third variable listed above demonstrate that identification tests that present stimuli in the same context as they appear in corresponding discrimination test trials correlate more strongly with discrimination scores (r=0.72, p<0.05) than identification tests that present stimuli in isolation (r=0.58, p<0.05).

Harnsberger, James; Wayland, Ratree

2001-05-01

415

Perceptual basis of evolving Western musical styles.  

PubMed

The brain processes temporal statistics to predict future events and to categorize perceptual objects. These statistics, called expectancies, are found in music perception, and they span a variety of different features and time scales. Specifically, there is evidence that music perception involves strong expectancies regarding the distribution of a melodic interval, namely, the distance between two consecutive notes within the context of another. The recent availability of a large Western music dataset, consisting of the historical record condensed as melodic interval counts, has opened new possibilities for data-driven analysis of musical perception. In this context, we present an analytical approach that, based on cognitive theories of music expectation and machine learning techniques, recovers a set of factors that accurately identifies historical trends and stylistic transitions between the Baroque, Classical, Romantic, and Post-Romantic periods. We also offer a plausible musicological and cognitive interpretation of these factors, allowing us to propose them as data-driven principles of melodic expectation. PMID:23716669

Rodriguez Zivic, Pablo H; Shifres, Favio; Cecchi, Guillermo A

2013-06-11

416

The perceptual basis of common photographic practice  

PubMed Central

Photographers, cinematographers, and computer-graphics engineers use certain techniques to create striking pictorial effects. By using lenses of different focal lengths, they can make a scene look compressed or expanded in depth, make a familiar object look natural or distorted, or make a person look smarter, more attractive, or more neurotic. We asked why pictures taken with a certain focal length look natural, while those taken with other focal lengths look distorted. We found that people’s preferred viewing distance when looking at pictures leads them to view long-focal-length pictures from too near and short-focal-length pictures from too far. Perceptual distortions occur because people do not take their incorrect viewing distances into account. By following the rule of thumb of using a 50-mm lens, photographers greatly increase the odds of a viewer looking at a photograph from the correct distance, where the percept will be undistorted. Our theory leads to new guidelines for creating pictorial effects that are more effective than conventional guidelines. PMID:22637709

Cooper, Emily A.; Piazza, Elise A.; Banks, Martin S.

2012-01-01

417

Speed Isn't Everything: Complex Processing Speed Measures Mask Individual Differences and Developmental Changes in Executive Control  

ERIC Educational Resources Information Center

The rate at which people process information appears to influence many aspects of cognition across the lifespan. However, many commonly accepted measures of "processing speed" may require goal maintenance, manipulation of information in working memory, and decision-making, blurring the distinction between processing speed and executive control and…

Cepeda, Nicholas J.; Blackwell, Katharine A.; Munakata, Yuko

2013-01-01

418

Dynamic interactions between visual working memory and saccade target selection.  

PubMed

Recent psychophysical experiments have shown that working memory for visual surface features interacts with saccadic motor planning, even in tasks where the saccade target is unambiguously specified by spatial cues. Specifically, a match between a memorized color and the color of either the designated target or a distractor stimulus influences saccade target selection, saccade amplitudes, and latencies in a systematic fashion. To elucidate these effects, we present a dynamic neural field model in combination with new experimental data. The model captures the neural processes underlying visual perception, working memory, and saccade planning relevant to the psychophysical experiment. It consists of a low-level visual sensory representation that interacts with two separate pathways: a spatial pathway implementing spatial attention and saccade generation, and a surface feature pathway implementing color working memory and feature attention. Due to bidirectional coupling between visual working memory and feature attention in the model, the working memory content can indirectly exert an effect on perceptual processing in the low-level sensory representation. This in turn biases saccadic movement planning in the spatial pathway, allowing the model to quantitatively reproduce the observed interaction effects. The continuous coupling between representations in the model also implies that modulation should be bidirectional, and model simulations provide specific predictions for complementary effects of saccade target selection on visual working memory. These predictions were empirically confirmed in a new experiment: Memory for a sample color was biased toward the color of a task-irrelevant saccade target object, demonstrating the bidirectional coupling between visual working memory and perceptual processing. PMID:25228628

Schneegans, Sebastian; Spencer, John P; Schöner, Gregor; Hwang, Seongmin; Hollingworth, Andrew

2014-01-01

419

Dynamic interactions between visual working memory and saccade target selection  

PubMed Central

Recent psychophysical experiments have shown that working memory for visual surface features interacts with saccadic motor planning, even in tasks where the saccade target is unambiguously specified by spatial cues. Specifically, a match between a memorized color and the color of either the designated target or a distractor stimulus influences saccade target selection, saccade amplitudes, and latencies in a systematic fashion. To elucidate these effects, we present a dynamic neural field model in combination with new experimental data. The model captures the neural processes underlying visual perception, working memory, and saccade planning relevant to the psychophysical experiment. It consists of a low-level visual sensory representation that interacts with two separate pathways: a spatial pathway implementing spatial attention and saccade generation, and a surface feature pathway implementing color working memory and feature attention. Due to bidirectional coupling between visual working memory and feature attention in the model, the working memory content can indirectly exert an effect on perceptual processing in the low-level sensory representation. This in turn biases saccadic movement planning in the spatial pathway, allowing the model to quantitatively reproduce the observed interaction effects. The continuous coupling between representations in the model also implies that modulation should be bidirectional, and model simulations provide specific predictions for complementary effects of saccade target selection on visual working memory. These predictions were empirically confirmed in a new experiment: Memory for a sample color was biased toward the color of a task-irrelevant saccade target object, demonstrating the bidirectional coupling between visual working memory and perceptual processing. PMID:25228628

Schneegans, Sebastian; Spencer, John P.; Schöner, Gregor; Hwang, Seongmin; Hollingworth, Andrew

2014-01-01

420

Component processes of memory in alcoholism: pattern of compromise and neural substrates.  

PubMed

Initially, alcohol-related memory deficits were considered only through the prism of Korsakoff's syndrome (KS). It is now clear, however, that chronic alcohol consumption results in memory disorders in alcoholics without ostensible neurologic complications, such as Wernicke's encephalopathy and KS. Most of the principal memory components are affected, including working memory, episodic memory, semantic memory, perceptual memory, and procedural memory. The extent of those cognitive impairments depends on several factors, such as age, gender, nutritional status, and psychiatric comorbidity. While memory disorders, especially episodic memory deficits, are largely definitive in patients with KS, recovery of memory abilities has been described with abstinence in uncomplicated alcoholics. Neuropsychologic impairments, and especially memory disorders, must be evaluated at alcohol treatment entry because they could impede patients from benefiting fully from cognitive and behavioral treatment approaches for alcohol dependence. Screening of memory deficits could also enable clinicians to detect, among alcoholics without ostensible neurologic complications, those at risk of developing permanent and debilitating amnesia that features KS. PMID:25307577

Pitel, Anne-Lise; Eustache, Francis; Beaunieux, Helene

2014-01-01

421

Dopamine receptor 4 promoter polymorphism modulates memory and neuronal responses to salience.  

PubMed

Animal models and human functional imaging data implicate the dopamine system in mediating enhanced encoding of novel stimuli into human memory. A separate line of investigation suggests an association between a functional polymorphism in the promoter region for the human dopamine 4 receptor gene (DRD4) and sensitivity to novelty. We demonstrate, in two independent samples, that the -521C>T DRD4 promoter polymorphism determines the magnitude of human memory enhancement for contextually novel, perceptual oddball stimuli in an allele dose-dependent manner. The genotype-dependent memory enhancement conferred by the C allele is associated with increased neuronal responses during successful encoding of perceptual oddballs in the ventral striatum, an effect which is again allele dose-dependent. Furthermore, with repeated presentations of oddball stimuli, this memory advantage decreases, an effect mirrored by adaptation of activation in the hippocampus and substantia nigra/ventral tegmental area in C carriers only. Thus, a dynamic modulation of human memory enhancement for perceptually salient stimuli is associated with activation of a dopaminergic-hippocampal system, which is critically dependent on a functional polymorphism in the DRD4 promoter region. PMID:24099848

Strange, B A; Gartmann, N; Brenninkmeyer, J; Haaker, J; Reif, A; Kalisch, R; Büchel, C

2014-01-01

422

Learning, Memory, & Attention Instructor  

E-print Network

1 COGS 101B: Learning, Memory, & Attention · Welcome! · Instructor ­ Dr. Coulson ­ Email: coulson Attention ­ Divided Attention ­ Automaticity ­ Attentional Capture · Immediate Memory ­ Sensory Memory ­ Short-Term Memory ­ Working Memory · Long-Term Memory ­ Levels of Processing ­ Memory Systems

Coulson, Seana

423

Is conceptual implicit memory impaired in schizophrenia? Evidence from lexical decision and category verification.  

PubMed

Introduction. Implicit memory tasks differ along two orthogonal dimensions, tapping the relative involvement of perceptual/conceptual and identification/production processes. Previous studies have documented a dissociation between perceptual (spared) and conceptual (impaired) implicit memory, using in the latter case a production task (category exemplar generation), in which there is high response competition during the retrieval phase. The present study sought to determine whether the perceptual/conceptual dissociation held when comparing two identification tasks, in which there is no response competition at retrieval. Methods. In two experiments, repetition priming was assessed in 44 schizophrenic patients and 46 healthy controls in lexical decision (a test based on perceptual identification processes) and category verification (a test based on conceptual identification processes). Results. Schizophrenic patients achieved a priming as high as that of controls in the lexical decision task. In contrast, only controls exhibited significant priming in the category verification task. Conclusions. It is concluded that schizophrenia is associated with a specific deficit in conceptual implicit memory, irrespective of the degree of response competition in the test phase. PMID:25255844

Marques, Valéria R S; Spataro, Pietro; Cestari, Vincenzo; Sciarretta, Antonio; Iannarelli, Francesca; Rossi-Arnaud, Clelia

2015-01-01

424

POW Memory  

NSDL National Science Digital Library

Most people think eyewitness testimony is the best possible evidence against an alleged criminal -- especially when that testimony comes from the victim. But people who survive terrifying situations may actually have surprisingly unreliable memories of who or what caused them.

Science Update;

2004-07-12

425

Acoustic and perceptual similarity of Japanese and American English vowels.  

PubMed

Acoustic and perceptual similarities between Japanese and American English (AE) vowels were investigated in two studies. In study 1, a series of discriminant analyses were performed to determine acoustic similarities between Japanese and AE vowels, each spoken by four native male speakers using F1, F2, and vocalic duration as input parameters. In study 2, the Japanese vowels were presented to native AE listeners in a perceptual assimilation task, in which the listeners categorized each Japanese vowel token as most similar to an AE category and rated its goodness as an exemplar of the chosen AE category. Results showed that the majority of AE listeners assimilated all Japanese vowels into long AE categories, apparently ignoring temporal differences between 1- and 2-mora Japanese vowels. In addition, not all perceptual assimilation patterns reflected context-specific spectral similarity patterns established by discriminant analysis. It was hypothesized that this incongruity between acoustic and perceptual similarity may be due to differences in distributional characteristics of native and non-native vowel categories that affect the listeners' perceptual judgments. PMID:18647000

Nishi, Kanae; Strange, Winifred; Akahane-Yamada, Reiko; Kubo, Rieko; Trent-Brown, Sonja A

2008-07-01

426

Perceptual learning for speech: Is there a return to normal?  

PubMed

Recent work on perceptual learning shows that listeners' phonemic representations dynamically adjust to reflect the speech they hear (Norris, McQueen, & Cutler, 2003). We investigate how the perceptual system makes such adjustments, and what (if anything) causes the representations to return to their pre-perceptual learning settings. Listeners are exposed to a speaker whose pronunciation of a particular sound (either /s/ or /integral/) is ambiguous (e.g., halfway between /s/ and /integral/). After exposure, participants are tested for perceptual learning on two continua that range from /s/ to /integral/, one in the Same voice they heard during exposure, and one in a Different voice. To assess how representations revert to their prior settings, half of Experiment 1's participants were tested immediately after exposure; the other half performed a 25-min silent intervening task. The perceptual learning effect was actually larger after such a delay, indicating that simply allowing time to pass does not cause learning to fade. The remaining experiments investigate different ways that the system might unlearn a person's pronunciations: listeners hear the Same or a Different speaker for 25 min with either: no relevant (i.e., 'good') /s/ or /integral/ input (Experiment 2), one of the relevant inputs (Experiment 3), or both relevant inputs (Experiment 4). The results support a view of phonemic representations as dynamic and flexible, and suggest that they interact with both higher- (e.g., lexical) and lower-level (e.g., acoustic) information in important ways. PMID:16095588

Kraljic, Tanya; Samuel, Arthur G

2005-09-01

427

Perceptual decision-making in patients with Parkinson's disease.  

PubMed

Impulsive choice and poor information sampling have been found to be key behavioural mechanisms linked to impulse control disorders (ICDs) in Parkinson's disease (PD). Perceptual decision-making is intimately related to information sampling. Therefore, we wanted to determine whether dopaminergic medication or ICDs influence perceptual decision-making in PD. All participants performed two tasks. One was a simple reaction time task, where subjects needed to respond as quickly as possible. The second was a perceptual decision-making task, in which participants had to estimate whether a stimulus contained either more red or more blue pixels. We tested three groups of patients, one treated with levodopa monotherapy, one additionally treated with dopamine agonists, and a third group had ICDs. Results were compared to healthy controls. We found that all patients made more errors than controls. Further, patients with ICDs responded fastest on the reaction time task and also in incorrect trials on the perceptual decision-making task. Similarly, patients with dopamine agonists responded faster than those on levodopa monotherapy and controls. Our results demonstrate that all patients have deficits in perceptual decision-making. However, patients treated with dopamine agonists closely resembled patients with ICDs. PMID:25237123

Djamshidian, Atbin; O'Sullivan, Sean S; Lawrence, Andrew D; Foltynie, Thomas; Aviles-Olmos, Iciar; Magdalinou, Nadia; Tomassini, Alessandro; Warner, Thomas T; Lees, Andrew J; Averbeck, Bruno B

2014-12-01

428

Importance of perceptual representation in the visual control of action  

NASA Astrophysics Data System (ADS)

In recent years, many experiments have demonstrated that optic flow is sufficient for visually controlled action, with the suggestion that perceptual representations of 3-D space are superfluous. In contrast, recent research in our lab indicates that some visually controlled actions, including some thought to be based on optic flow, are indeed mediated by perceptual representations. For example, we have demonstrated that people are able to perform complex spatial behaviors, like walking, driving, and object interception, in virtual environments which are rendered visible solely by cyclopean stimulation (random-dot cinematograms). In such situations, the absence of any retinal optic flow that is correlated with the objects and surfaces within the virtual environment means that people are using stereo-based perceptual representations to perform the behavior. The fact that people can perform such behaviors without training suggests that the perceptual representations are likely the same as those used when retinal optic flow is present. Other research indicates that optic flow, whether retinal or a more abstract property of the perceptual representation, is not the basis for postural control, because postural instability is related to perceived relative motion between self and the visual surroundings rather than to optic flow, even in the abstract sense.

Loomis, Jack M.; Beall, Andrew C.; Kelly, Jonathan W.; Macuga, Kristen L.

2005-03-01

429

Effects of Perceptual and Contextual Enrichment on Visual Confrontation Naming in Adult Aging  

PubMed Central

Purpose The purpose of this study was to determine the effects of enriching line drawings with color/texture and environmental context as a facilitator of naming speed and accuracy in older adults. Method Twenty young and 23 older adults named high-frequency picture stimuli from the Boston Naming Test (Kaplan, Goodglass, & Weintraub, 2001) under three conditions: (a) black-and-white items, (b) colorized-texturized items, and (c) scene-primed colored items (e.g., “hammock” preceded 1,000 ms by a backyard scene). Results With respect to speeded naming latencies, mixed-model analyses of variance revealed that young adults did not benefit from colorization-texturization but did show scene-priming effects. In contrast, older adults failed to show facilitation effects from either colorized-texturized or scene-primed items. Moreover, older adults were consistently slower to initiate naming than were their younger counterparts across all conditions. Conclusions Perceptual and contextual enrichment of sparse line drawings does not appear to facilitate visual confrontation naming in older adults, whereas younger adults do tend to show benefits of scene priming. We interpret these findings as generally supportive of a processing speed account of age-related object picture-naming difficulty. PMID:21498581

Rogalski, Yvonne; Peelle, Jonathan E.; Reilly, Jamie

2013-01-01

430

A plastic corticostriatal circuit model of adaptation in perceptual decision making  

PubMed Central

The ability to optimize decisions and adapt them to changing environments is a crucial brain function that increase survivability. Although much has been learned about the neuronal activity in various brain regions that are associated with decision making, and about how the nervous systems may learn to achieve optimization, the underlying neuronal mechanisms of how the nervous systems optimize decision strategies with preference given to speed or accuracy, and how the systems adapt to changes in the environment, remain unclear. Based on extensive empirical observations, we addressed the question by extending a previously described cortico-basal ganglia circuit model of perceptual decisions with the inclusion of a dynamic dopamine (DA) system that modulates spike-timing dependent plasticity (STDP). We found that, once an optimal model setting that maximized the reward rate was selected, the same setting automatically optimized decisions across different task environments through dynamic balancing between the facilitating and depressing components of the DA dynamics. Interestingly, other model parameters were also optimal if we considered the reward rate that was weighted by the subject's preferences for speed or accuracy. Specifically, the circuit model favored speed if we increased the phasic DA response to the reward prediction error, whereas the model favored accuracy if we reduced the tonic DA activity or the phasic DA responses to the estimated reward probability. The proposed model provides insight into the roles of different components of DA responses in decision adaptation and optimization in a changing environment. PMID:24339814

Hsiao, Pao-Yueh; Lo, Chung-Chuan

2013-01-01

431

Contributions of area Te2 to rat recognition memory  

PubMed Central

Ablations and local intracerebral infusions were used to determine the role of rat temporal association cortex (area Te2) in object recognition memory, so that this role might be compared with that of the adjacent perirhinal cortex (PRH). Bilateral lesions of Te2 impaired recognition memory measured by preferential exploration of a novel rather than a familiar object at delays ?20 min but not after a 5-min delay. Local infusion bilaterally into Te2 of (1) CNQX to block AMPA/kainate receptors or (2) lidocaine to block axonal transmission or (3) AP5, an NMDA receptor antagonist, impaired recognition memory after a 24-h but not a 20-min delay. In PRH all these manipulations impair recognition memory after a 20-min as well as a 24-h delay. UBP302, a GluK1 kainate receptor antagonist, impaired recognition memory after a 24-h but not a 20-min delay, contrasting with its action in PRH where it impairs only shorter-term (20 min) recognition memory. Also in contrast to PRH, infusion of the muscarinic receptor antagonist scopolamine was without effect. The Te2 impairments could not readily be ascribed to perceptual deficits. Hence, Te2 is essential for object recognition memory at delays >5 or 20 min. Thus, at long delays both area Te2 and PRH are necessary for object recognition memory. PMID:21700715

Ho, Jonathan Weng-Thim; Narduzzo, Katherine Elizabeth; Outram, Alexandra; Tinsley, Christopher John; Henley, Jeremy Martin; Warburton, Elizabeth Clea; Brown, Malcolm Watson

2011-01-01

432

The cognitive neuroscience of memory: perspectives from neuroimaging research.  

PubMed Central

Cognitive neuroscience approaches to memory attempt to elucidate the brain processes and systems that are involved in different forms of memory and learning. This paper examines recent research from brain-damaged patients and neuroimaging studies that bears on the distinction between explicit and implicit forms of memory. Explicit memory refers to conscious recollection of previous experiences, whereas implicit memory refers to the non-conscious effects of past experiences on subsequent performance and behaviour. Converging evidence suggests that an implicit form of memory known as priming is associated with changes in posterior cortical regions that are involved in perceptual processing; some of the same regions may contribute to explicit memory. The hippocampal formation and prefrontal cortex also play important roles in explicit memory. Evidence is presented from recent PET scanning studies that suggests that frontal regions are associated with intentional strategic efforts to retrieve recent experiences, whereas the hippocampal formation is associated with some aspect of the actual recollection of an event. PMID:9415920

Schacter, D L

1997-01-01

433

Evaluation of a theoretical model of perceptual accuracy and self-management behavior in pediatric diabetes  

E-print Network

This study evaluated a model of perceptual accuracy and self-management behavior in pediatric diabetes. Participants were 169 children and adolescents (10-18 years) attending diabetes summer camps. Error grid analysis quantified global perceptual...

Lane, Mariella Marie

2005-11-01

434

Music Lessons Improve Auditory Perceptual and Cognitive Performance in Deaf Children  

PubMed Central

Despite advanced technologies in auditory rehabilitation of profound deafness, deaf children often exhibit delayed cognitive and linguistic development and auditory training remains a crucial element of their education. In the present cross-sectional study, we assess whether music would be a relevant tool for deaf children rehabilitation. In normal-hearing children, music lessons have been shown to improve cognitive and linguistic-related abilities, such as phonetic discrimination and reading. We compared auditory perception, auditory cognition, and phonetic discrimination between 14 profoundly deaf children who completed weekly music lessons for a period of 1.5–4?years and 14 deaf children who did not receive musical instruction. Children were assessed on perceptual and cognitive auditory tasks using environmental sounds: discrimination, identification, auditory scene analysis, auditory working memory. Transfer to the linguistic domain was tested with a phonetic discrimination task. Musically trained children showed better performance in auditory scene analysis, auditory working memory and phonetic discrimination tasks, and multiple regressions showed that success on these tasks was at least partly driven by music lessons. We propose that musical education contributes to development of general processes such as auditory attention and perception, which, in turn, facilitate auditory-related cognitive and linguistic processes. PMID:25071518

Rochette, Françoise; Moussard, Aline; Bigand, Emmanuel

2014-01-01

435

Effects of Internal Clock and Memory Disorders on Duration Reproductions and Duration Productions in Patients with Parkinson's Disease  

ERIC Educational Resources Information Center

Patients with Parkinson's disease (PD) exhibit deficits in perceptual and motor timing as well as impairments in memory and attentional processes that are related to dysfunction of dopaminergic systems in the basal ganglia. The aim of the present study was to assess the relationships existing between impaired duration judgments and defective…

Perbal, S.; Deweer, B.; Pillon, B.; Vidailhet, M.; Dubois, B.; Pouthas, V.

2005-01-01

436

Towards Terabit Memories  

NASA Astrophysics Data System (ADS)

Memories have been the major yardstick for the continuing validity of Moore's law. In single-transistor-per-Bit dynamic random-access memories (DRAM), the number of bits per chip pretty much gives us the number of transistors. For decades, DRAM's have offered the largest storage capacity per chip. However, DRAM does not scale any longer, both in density and voltage, severely limiting its power efficiency to 10 fJ/b. A differential DRAM would gain four-times in density and eight-times in energy. Static CMOS RAM (SRAM) with its six transistors/cell is gaining in reputation because it scales well in cell size and operating voltage so that its fundamental advantage of speed, non-destructive read-out and low-power standby could lead to just 2.5 electrons/bit in standby and to a dynamic power efficiency of 2aJ/b. With a projected 2020 density of 16 Gb/cm², the SRAM would be as dense as normal DRAM and vastly better in power efficiency, which would mean a major change in the architecture and market scenario for DRAM versus SRAM. Non-volatile Flash memory have seen two quantum jumps in density well beyond the roadmap: Multi-Bit storage per transistor and high-density TSV (through-silicon via) technology. The number of electrons required per Bit on the storage gate has been reduced since their first realization in 1996 by more than an order of magnitude to 400 electrons/Bit in 2010 for a complexity of 32Gbit per chip at the 32 nm node. Chip stacking of eight chips with TSV has produced a 32GByte solid-state drive (SSD). A stack of 32 chips with 2 b/cell at the 16 nm node will reach a density of 2.5 Terabit/cm². Non-volatile memory with a density of 10 × 10 nm²/Bit is the target for widespread development. Phase-change memory (PCM) and resistive memory (RRAM) lead in cell density, and they will reach 20 Gb/cm² in 2D and higher with 3D chip stacking. This is still almost an order-of-magnitude less than Flash. However, their read-out speed is ~10-times faster, with as yet little data on their energy/b. As a read-out memory with unparalleled retention and lifetime, the ROM with electron-beam direct-write-lithography (Chap. 8) should be considered for its projected 2D density of 250 Gb/cm², a very small read energy of 0.1 ?W/Gb/s. The lithography write-speed 10 ms/Terabit makes this ROM a serious contentender for the optimum in non-volatile, tamper-proof storage.

Hoefflinger, Bernd

437

Up-down Asymmetries in Speed Perception  

NASA Technical Reports Server (NTRS)

We compared speed matches for pairs of stimuli that moved in opposite directions (upward and downward). Stimuli were elliptical patches (2 deg horizontally by 1 deg vertically) of horizontal sinusoidal gratings of spatial. frequency 2 cycles/deg. Two sequential 380 msec reveal presentations were compared. One of each pair of gratings (the standard) moved at 4 Hz (2 deg/sec), the other (the test) moved at a rate determined by a simple up-down staircase. The point of subjectively equal speed was calculated from the average of the last eight reversals. The task was to fixate a central point and to determine which one of the pair appeared to move faster. Eight of 10 observers perceived the upward drifting grating as moving faster than a grating moving downward but otherwise identical. on average (N = 10), when the standard moved downward, it was matched by a test moving upward at 94.7+/-1.7(SE)% of the standard speed, and when the standard moved upward it was matched by a test moving downward at 105.1+/-2.3(SE)% of the standard speed. Extending this paradigm over a range of spatial (1.5 to 13.5 c/d) and temporal (1.5 to 13.5 Hz) frequencies, preliminary results (N = 4) suggest that, under the conditions of our experiment, upward matter is seen as faster than downward for speeds greater than approx.1 deg/sec, but the effect appears to reverse at speeds below approx.1 deg/sec with downward motion perceived as faster. Given that an up-down asymmetry has been observed for the optokinetic response, both perceptual and oculomotor contributions to this phenomenon deserve exploration.

Thompson, Peter; Stone, Leland S.

1997-01-01

438

DCTune Perceptual Optimization of Compressed Dental X-Rays  

NASA Technical Reports Server (NTRS)

In current dental practice, x-rays of completed dental work are often sent to the insurer for verification. It is faster and cheaper to transmit instead digital scans of the x-rays. Further economies result if the images are sent in compressed form. DCtune is a technology for optimizing DCT quantization matrices to yield maximum perceptual quality for a given bit-rate, or minimum bit-rate for a given perceptual quality. In addition, the technology provides a means of setting the perceptual quality of compressed imagery in a systematic way. The purpose of this research was, with respect to dental x-rays: (1) to verify the advantage of DCTune over standard JPEG; (2) to verify the quality control feature of DCTune; and (3) to discover regularities in the optimized matrices of a set of images. Additional information is contained in the original extended abstract.

Watson, Andrew B.; Null, Cynthia H. (Technical Monitor)

1997-01-01

439

Perceptual compression of magnitude-detected synthetic aperture radar imagery  

NASA Technical Reports Server (NTRS)

A perceptually-based approach for compressing synthetic aperture radar (SAR) imagery is presented. Key components of the approach are a multiresolution wavelet transform, a bit allocation mask based on an empirical human visual system (HVS) model, and hybrid scalar/vector quantization. Specifically, wavelet shrinkage techniques are used to segregate wavelet transform coefficients into three components: local means, edges, and texture. Each of these three components is then quantized separately according to a perceptually-based bit allocation scheme. Wavelet coefficients associated with local means and edges are quantized using high-rate scalar quantization while texture information is quantized using low-rate vector quantization. The impact of the perceptually-based multiresolution compression algorithm on visual image quality, impulse response, and texture properties is assessed for fine-resolution magnitude-detected SAR imagery; excellent image quality is found at bit rates at or above 1 bpp along with graceful performance degradation at rates below 1 bpp.

Gorman, John D.; Werness, Susan A.

1994-01-01

440

Automatic Perceptual Color Map Generation for Realistic Volume Visualization  

PubMed Central

Advances in computed tomography imaging technology and inexpensive high performance computer graphics hardware are making high-resolution, full color (24-bit) volume visualizations commonplace. However, many of the color maps used in volume rendering provide questionable value in knowledge representation and are non-perceptual thus biasing data analysis or even obscuring information. These drawbacks, coupled with our need for realistic anatomical volume rendering for teaching and surgical planning, has motivated us to explore the auto-generation of color maps that combine natural colorization with the perceptual discriminating capacity of grayscale. As evidenced by the examples shown that have been created by the algorithm described, the merging of perceptually accurate and realistically colorized virtual anatomy appears to insightfully interpret and impartially enhance volume rendered patient data. PMID:18430609

Silverstein, Jonathan C.; Parsad, Nigel M.; Tsirline, Victor

2008-01-01

441

Enhancing recognition of lesions in radiographic images using perceptual feedback  

NASA Astrophysics Data System (ADS)

When radiologists search a medical x-ray image for an abnormality, their eyes often fixate and refixate the true target, dwelling on it for prolonged times, often without recognizing that they have discovered the object of search. Monitoring the eye position of the radiologist provides the x andy coordinates of the dwelling location. This location can be superimposed on the image and dynamically fed back to the radiologist for reevaluation. When this is done, the probability of recognizing and reporting an abnormality is shown to be enhanced significantly. An increase of 20 percent in observer performance is observed for radiologists searching chest images for tumors after receiving perceptual feedback compared to a second look without perceptual feedback. The true-positive rate increased and the false- positive rate decreased. Perceptual feedback represents a potentially significant technique for enhancing lesion recognition in radiology.

Krupinski, Elizabeth A.; Nodine, Calvin F.; Kundel, Harold L.

1998-03-01

442

Language, Perceptual Categories and their Interaction: Insights from Computational Modelling  

NASA Astrophysics Data System (ADS)

How do humans acquire perceptual categories? This question is far from being resolved. Specifically the balance between the influence of nature and nurture on perceptual categories remains the topic of heated debate. We present a computational model and take as case study colour categories to study two issues in perceptual category acquisition. The first issue is the effect of linguistic communication on categories during their acquisition: we demonstrate how categories can become coordinated under the influence of language. The second issue concerns the amount of coordination needed between the categories of individuals in order to achieve unambiguous communication. We show that, depending on how strictly linguistic utterances are interpreted, coordination of the individuals' categories is not always a prerequisite for successful communication.

Belpaeme, Tony; Bleys, Joris

443

Naval Research Laboratory Memorandum Report, 2003 Perceptual and Ergonomic Issues in  

E-print Network

Naval Research Laboratory Memorandum Report, 2003 1 Perceptual and Ergonomic Issues in Mobile paradigm, the field needs a much better understanding of the fundamental perceptual and ergonomic issues aimed at both understanding the fundamental perceptual and ergonomic issues in AR display

Swan II, J. Edward

444

Effects of Perceptual Learning Style Preferences on L2 Lexical Inferencing  

ERIC Educational Resources Information Center

The purpose of this pilot study was to examine the effects of perceptual learning style preferences on L2 lexical inferencing and whether learners with certain perceptual learning styles benefited more from an explicitly instructional program. Joy Reid's (1995) Perceptual Learning Style Preferences (PLSP) Inventory and a lexical inferencing test…

Shen, Ming-yueh

2010-01-01

445

Strength of Perceptual Experience Predicts Word Processing Performance Better than Concreteness or Imageability  

ERIC Educational Resources Information Center

Abstract concepts are traditionally thought to differ from concrete concepts by their lack of perceptual information, which causes them to be processed more slowly and less accurately than perceptually-based concrete concepts. In two studies, we examined this assumption by comparing concreteness and imageability ratings to a set of perceptual

Connell, Louise; Lynott, Dermot

2012-01-01

446

The Development of Perceptual Grouping Biases in Infancy: A Japanese-English Cross-Linguistic Study  

ERIC Educational Resources Information Center

Perceptual grouping has traditionally been thought to be governed by innate, universal principles. However, recent work has found differences in Japanese and English speakers' non-linguistic perceptual grouping, implicating language in non-linguistic perceptual processes (Iversen, Patel, & Ohgushi, 2008). Two experiments test Japanese- and…

Yoshida, Katherine A.; Iversen, John R.; Patel, Aniruddh D.; Mazuka, Reiko; Nito, Hiromi; Gervain, Judit; Werker, Janet F.

2010-01-01

447

Capturing Human Body Motion from Video for Perceptual Interfaces by Sequential Variational MAP  

E-print Network

Capturing Human Body Motion from Video for Perceptual Interfaces by Sequential Variational MAP Gang human body motion from video for perceptual interfaces. Most probabilistic methods for visual tracking for articulated human body tracking, and its applicability to vision based perceptual interfaces. 1 Introduction

Wu, Ying

448

Perceptual and Cognitive Load Interact to Control the Spatial Focus of Attention  

ERIC Educational Resources Information Center

Caparos and Linnell (2009, 2010) used a variable-separation flanker paradigm to show that (a) when cognitive load is low, increasing perceptual load causes spatial attention to focus and (b) when perceptual load is high, decreasing cognitive load causes spatial attention to focus. Here, we tested whether the effects of perceptual and cognitive…

Linnell, Karina J.; Caparos, Serge

2011-01-01

449

Comparing thelandscape level perceptual abilities of forest sciurids in fragmented agricultural landscapes* I  

Microsoft Academic Search

• Abstract • Perceptual range is the maximum distance from which an animal can perceive the presence of remote landscape ' . elements such as patches of habitat. Such perceptual abilities are of interest because they influence the probability that an animal will successfully disperse to a new patch in a landscape. Furthermore, understanding how perceptual range differs between species

Patrick A. Zollner

450

Comparing the landscape level perceptual abilities of forest sciurids in fragmented agricultural landscapes  

Microsoft Academic Search

Perceptual range is the maximum distance from which an animal can perceive the presence of remote landscape elements such as patches of habitat. Such perceptual abilities are of interest because they influence the probability that an animal will successfully disperse to a new patch in a landscape. Furthermore, understanding how perceptual range differs between species may help to explain differential

Patrick A. Zollner

2000-01-01

451

Colour within an internalist framework: The role of 'colour' in the structure of the perceptual system  

Microsoft Academic Search

Colour is, according to prevailing orthodoxy in perceptual psychology, a kind of autonomous and unitary attribute. It is regarded as unitary or homogeneous by assuming that its core properties do not depend on the type of 'perceptual object' to which it pertains and that 'colour per se' constitutes a natural attribute in the functional architecture of the perceptual system. It

Rainer Mausfeld

452

Human Perceptual Performance With Nonliteral Imagery: Region Recognition and Texture-Based Segmentation  

ERIC Educational Resources Information Center

In this study the authors address the issue of how the perceptual usefulness of nonliteral imagery should be evaluated. Perceptual performance with nonliteral imagery of natural scenes obtained at night from infrared and image-intensified sensors and from multisensor fusion methods was assessed to relate performance on 2 basic perceptual tasks to…

Essock, Edward A.; Sinai, Michael J.; DeFord, Kevin; Hansen, Bruce C.; Srinivasan, Narayanan

2004-01-01

453

Investigation of fast initialization of spacecraft bubble memory systems  

NASA Technical Reports Server (NTRS)

Bubble domain technology offers significant improvement in reliability and functionality for spacecraft onboard memory applications. In considering potential memory systems organizations, minimization of power in high capacity bubble memory systems necessitates the activation of only the desired portions of the memory. In power strobing arbitrary memory segments, a capability of fast turn on is required. Bubble device architectures, which provide redundant loop coding in the bubble devices, limit the initialization speed. Alternate initialization techniques are investigated to overcome this design limitation. An initialization technique using a small amount of external storage is demonstrated.

Looney, K. T.; Nichols, C. D.; Hayes, P. J.

1984-01-01

454

Random noise stimulation improves neuroplasticity in perceptual learning.  

PubMed

Perceptual learning is considered a manifestation of neural plasticity in the human brain. We investigated brain plasticity mechanisms in a learning task using noninvasive transcranial electrical stimulation (tES). We hypothesized that different types of tES would have varying actions on the nervous system, which would result in different efficacies of neural plasticity modulation. Thus, the principal goal of the present study was to verify the possibility of inducing differential plasticity effects using two tES approaches [i.e., direct current stimulation (tDCS) and random noise stimulation (tRNS)] during the execution of a visual perceptual learning task. PMID:22031888

Fertonani, Anna; Pirulli, Cornelia; Miniussi, Carlo

2011-10-26

455

Profiles of visual perceptual functions in Down syndrome.  

PubMed

The primary purpose of this study was to investigate the visual perceptual functions measured by the Test of Visual Perceptual Skill-Third Edition (TVPS-3) in Down syndrome (DS). Seventy individuals with DS, seventy with typical development (TD), and forty mental-age-matched participants with intellectual disabilities (ID) were recruited for the assessment session. Significant between-group differences in TVPS-3 were observed between either DS or ID and TD groups. There was no significant difference on TVPS-3 between DS and ID groups. Implications for clinical professionals and recommendations for further research are discussed. PMID:25460225

Wan, Yi-Ting; Chiang, Ching-Sui; Chen, Sharon Chia-Ju; Wang, Chih-Chung; Wuang, Yee-Pay

2015-02-01

456

Systems implications of new memory developments: memoria ex machina  

Microsoft Academic Search

Computer design has historically been limited by, and even largely determined by, available memory capability: speed, size, cost, and operational characteristics. Just as Edgar Allen Poe could create the entire complicated plot and counterplot of Dickens's \\

Sullivan G. Campbell

1963-01-01

457

Episodic memory, semantic memory, and amnesia  

Microsoft Academic Search

ABSTRACT: Episodic memory,and semantic memory,are two types of declarative memory. There have been two principal views about how this distinction might be reflected in the organization of memory,functions in the brain. One view, that episodic memory and semantic memory are both dependent on the integrity of medial temporal lobe and midline dience- phalic structures, predicts that amnesic patients with medial

Larry R. Squire; Stuart M. Zola

1998-01-01

458

Gigabit Networking: High-Speed Routing and Switching Sadikin Djumin, djumin.1@osu.edu  

E-print Network

refer to the list of acronyms), fast memory, and high-speed buses in desktop computers, workstationsGigabit Networking: High-Speed Routing and Switching Sadikin Djumin, djumin.1@osu.edu The focus on high-speed switching and routing, and current gigab