Differences In Response Latencies Research Articles

Gene expression underlying variation in the survival skills of red drum larvae (Sciaenops ocellatus).

Mortality rates of marine fish larvae are incredibly high and can determine year-class strength. The major causes of larval mortality are predation and starvation, and the performance of larvae in survival skills that can mitigate this mortality (predator evasion, foraging) varies among individuals and cohorts, but the causes of the variation are not known. Transcriptomics can link gene expression variation to phenotypic variation at the whole-system level to investigate the molecular basis of behavioural variation. We used tag-based RNA-sequencing to examine the molecular basis of variation in predator evasion and routine swimming (trait related to foraging efficiency) in the larval red drum, Sciaenops ocellatus. We looked for functional gene networks in which interindividual variation would explain variation in larval behavioural performance. We identified co-expressed gene groups ("modules") associated with predator evasion traits and found enrichment of motor, neural and energy metabolism pathways. These functional associations and pattern of correlations between modules and traits suggest that energy availability and allocation were responsible for the magnitude of startle responses, while differential neural and motor activation were associated with differences in response latency.

Preventing Coherence State Side Channel Leaks Using TimeCache

Cache side channel attacks in the presence of shared memory have been used to extract cryptographic keys and enclave data, and are used by Spectre variants for leaking speculatively loaded data. Timing side channels exist in shared caches due to the difference in response latency of cached and uncached data. In prior work, we presented TimeCache, a cache design that prevents side channel exploits from reuse of shared memory. In this work, we extend TimeCache to also defend against attacks that exploit coherence states. TimeCache allows all running applications to use the entire cache, avoiding the need for partitioning in order to effect timing isolation. A per-process caching context prevents cache hits on data filled by another process. A novel bit-serial timestamp-parallel comparison logic allows low-overhead update of stale caching contexts. The defense is suited to all caches levels, and defends against an attacker running on any core. We evaluate TimeCache using the gem5 simulator to show that it is capable of preventing both reuse attacks and an attack based on coherence state leak. The average performance overhead for SPEC2006 is 1.13%, and for PARSEC and SPLASH is 0.46%.

Virtual reality lifeguarding scenarios as a potential training solution for pool lifeguards

BackgroundEnsuring that pool lifeguards develop the skills necessary to detect drowning victims is challenging given that these situations are relatively rare, unpredictable and are difficult to simulate accurately and safely. Virtual reality potentially provides a safe and ecologically valid approach to training since it offers a near-to-real visual experience, together with the opportunity to practice task-related skills and receive feedback. As a prelude to the development of a training intervention, the aim of this research was to establish the construct validity of virtual reality drowning detection tasks. MethodUsing a repeated measures design, a total of 38 qualified lifeguards and 33 non-lifeguards completed 13 min and 23 min simulated drowning detection tasks that were intended to reflect different levels of sustained attention. During the simulated tasks, participants were asked to monitor a virtual pool and identify any drowning targets with accuracy, response latency, and dwell time recorded. ResultsDuring the simulated scenarios, pool lifeguards detected drowning targets more frequently and spent less time than non-lifeguards fixating on the drowning target prior to the drowning onset. No significant differences in response latency were evident between lifeguards and non-lifeguards nor for first fixations on the drowning target. ConclusionThe results provide support for the construct validity of virtual reality lifeguarding scenarios, thereby providing the basis for their development and introduction as a potential training approach for developing and maintaining performance in lifeguarding and drowning detection. ApplicationThis research provides support for the construct validity of virtual reality simulations as a potential training tool, enabling improvements in the fidelity of training solutions to improve pool lifeguard competency in drowning detection.

Spatial and temporal proximity of objects for maximal crowding

Crowding refers to the deleterious visual interaction among nearby objects. Does maximal crowding occur when objects are closest to one another in space and time? We examined how crowding depends on the spatial and temporal proximity, retinally and perceptually, between a target and flankers. Our target was a briefly flashed T-stimulus presented at 10° right of fixation (3-o’clock position). It appeared at different target-onset-to-flanker asynchronies with respect to the instant when a pair of flanking Ts, revolving around the fixation target, reached the 3-o’clock position. Observers judged the orientation of the target-T (the crowding task), or its position relative to the revolving flankers (the flash-lag task). Performance was also measured in the absence of flanker motion: target and flankers were either presented simultaneously (closest retinal temporal proximity) with different angular spatial offsets, or were presented collinearly (closest retinal spatial proximity) with different temporal onset asynchronies. We found that neither retinal nor perceptual spatial or temporal proximity could account for when maximal crowding occurred. Simulations using a model based on feed-forward interactions between sustained and transient channels in static and motion pathways, taking into account the differential response latencies, can explain the crowding functions observed under various spatio-temporal conditions between the target and flankers.

Comparison of volitional opposing and following responses across speakers with different vocal histories

Research has shown that people who are instructed to volitionally respond to pitch-shifted feedback either produce responses that follow the shift direction with a short latency of 100-200 ms or oppose the shift direction with longer latencies of 300-400 ms. This difference in response latencies prompted a comparison of three groups of vocalists with differing abilities, non-trained English-speaking subjects, non-trained Mandarin-speaking subjects, and trained English-speaking singers. All subjects produced short latency following responses and long latency opposing responses, and in most cases the opposing responses were preceded by a shorter latency following response. Across groups, the magnitudes of the opposing and following responses were largest for the Mandarin speakers. Singers produced the smallest opposing response magnitudes, suggesting differences in the pitch goals of the two groups. Opposing response latencies were longest for the English and Mandarin speaking subjects and shortest for the trained singers, demonstrating that musical training increases the speed of producing the opposing responses. The presence of similar latencies of small following responses preceding larger opposing responses in all groups suggests that the tendency to mimic changes in sounds to which a person is attending are not influenced by vocal training or experience.

Speed Gaps: Exploring Differences in Response Latencies Among Groups

AbstractThere is much discussion about and many policies to address achievement gaps in education among groups of students. The focus here is on a different gap and it is argued that it also should be of concern. Speed gaps are differences in how quickly different groups of students answer the questions on academic assessments. To investigate some speed gaps, response times from approximately 75,000 untimed online assessments were compared by English language learning proficiency, student gender, and ethnicity. Also examined were the relationships between response time and accuracy for these groups. The differences observed lead to recommendations for assessment accommodations and teaching strategies for taking assessments.

Recognition times for 62 thousand English words: Data from the English Crowdsourcing Project.

We present a new dataset of English word recognition times for a total of 62 thousand words, called the English Crowdsourcing Project. The data were collected via an internet vocabulary test in which more than one million people participated. The present dataset is limited to native English speakers. Participants were asked to indicate which words they knew. Their response times were registered, although at no point were the participants asked to respond as quickly as possible. Still, the response times correlate around .75 with the response times of the English Lexicon Project for the shared words. Also, the results of virtual experiments indicate that the new response times are a valid addition to the English Lexicon Project. This not only means that we have useful response times for some 35 thousand extra words, but we now also have data on differences in response latencies as a function of education and age.

Recognition Times for 54 Thousand Dutch Words: Data from the Dutch Crowdsourcing Project.

We present a new database of Dutch word recognition times for a total of 54 thousand words, called the Dutch Crowdsourcing Project. The data were collected with an internet vocabulary test. The database is limited to native Dutch speakers. Participants were asked to indicate which words they knew. Their response times were registered, even though the participants were not asked to respond as fast as possible. Still, the response times correlate around .7 with the response times of the Dutch Lexicon Projects for shared words. Also results of virtual experiments indicate that the new response times are a valid addition to the Dutch Lexicon Projects. This not only means that we have useful response times for some 20 thousand extra words, but we now also have data on differences in response latencies as a function of education and age. The new data correspond better to word use in the Netherlands.

Nonverbal Markers of Lying During Children’s Collective Interviewing with Friends

To examine nonverbal behaviors that may differentiate between lie- and truth-tellers, recent studies have relied on collective interviews (e.g., Vrij and Granhag in Appl Cognit Psychol 28(6):936–944, 2014. https://doi.org/10.1002/acp.3071 ), where participants were solicited to fake their responses about an unexperienced event. In this study, we made participants experience actual events that involved a potential rule violation, and later interviewed them collectively and unanticipatedly about these previously experienced events. Ninety same-sex preschool dyads were observed in a temptation resistance paradigm, where an adult experimenter proscribed touching of attractive toys and left the children alone. The dyads of children were later interviewed by the experimenter about how they handled this rule. Nonverbal behaviors were coded during the entire interview phase where they could lie by withholding transgression (i.e., lying by omission) and right after a target question where children chose to lie or tell the truth (i.e., lying by commission). Truth-tellers and lie-tellers showed (1) differences in response latency, looking at friend, and use of gestures right after the target question, but were (2) similar in their interactive nonverbal behaviors during the entire interview (i.e., speech transition, looking at friend, and utterance rate). This is the first study showing that nonverbal behaviors accompanying lie-telling behavior are different when a collective interview is carried out in a spontaneous deceptive context as opposed to planned deceptive contexts.

Examination of the Effects of Auditory and Textual Stimuli on Response Accuracy and Latency during a Math Task and Tangram Puzzle.

Although Skinner (1957) provided a behavioral account of verbal thinking, additional research is needed to evaluate stimuli that may influence covert verbal behavior that occurs between the onset of a verbal stimulus and the emission of a response during an episode of verbal thinking. The present investigation examined the effects of auditory distractors and/or textual stimuli during arithmetic problems and tangram puzzles on the participants' response latency and accuracy. In addition, we measured and categorized occurrences of vocal verbal behavior during the response interval. In Experiments 1 and 2, the experimenter played auditory distractors during a proportion of arithmetic problems. In Experiment 2, the experimenter also presented a textual stimulus of the arithmetic problem. In Experiment 3, the experimenter played auditory distractors during a proportion of tangram puzzles. Results showed that auditory distractors led to longer response latencies and reduced accuracy in Experiment 1. The addition of the textual stimulus during trials in Experiment 2 improved accuracy and reduced differences in response latency when the auditory distractors were and were not present during the response interval. The auditory distractors during tangram puzzles in Experiment 3 produced no differential effects on accuracy or latency to respond.

Emotion Recognition Biases in Alcohol Use Disorder.

Alcohol use disorder (AUD) has been associated with impairments in cognitive and emotional function, including difficulty identifying emotional facial expressions. However, it is unclear whether these deficits are associated with alcohol consumption or related anxious and depressive symptoms. We compared the recognition of emotional faces expressing happiness, surprise, sadness, fear, anger, and disgust in 19 AUD participants and 19 healthy volunteers using the Cambridge Neuropsychological Test Automated Battery Emotion Recognition Task. We analyzed group differences in response latency, accuracy, and misidentification patterns (as defined by the tendency to mislabel facial expressions as exhibiting specific emotions). To assess whether misidentification patterns were associated with drinking severity, we also examined associations with alcohol consumption over the past 90days. There were no differences in response latency or accuracy between groups. However, there were group differences in misidentification patterns. While controls tended to misidentify emotional expressions as happy, those with AUD tended to misidentify expressions as angry or disgusted. In AUD participants, the degree to which individuals were biased toward anger or disgust was positively correlated with the number of drinks they consumed in the past 90days but was not associated with depression or anxiety scores. Our findings suggest that individuals with AUD have a bias toward misidentifying emotional facial expressions as hostile, which is not mediated by associated mood changes. This provides further evidence of disrupted social cognition in AUD.

Combining the Implicit Relational Assessment Procedure and the Recording of Event Related Potentials in the Analysis of Racial Bias: a Preliminary Study

The current study examined racial bias among White individuals residing in Ireland using the Implicit Relational Assessment Procedure (IRAP). In addition, neural activity, measured with electroencephalograms (EEGs), was recorded while participants completed the IRAP. On some blocks of trials, participants were required to respond quickly and accurately in a pro-White and anti-Black manner, whereas on other blocks they were required to respond in the opposite manner (anti-White or pro-Black). The difference in response latencies between these two types of trials provided an index of racial bias, and event-related potentials (ERPs), derived from the EEG signals, provided a simultaneous measure of brain activity during these responses. Results revealed anti-Black and pro-White biased responding on the IRAP in terms of differential response latencies. In addition, greater positivity in the ERP signals located in the frontal sites was recorded when participants responded in a pro-Black or anti-White pattern relative to a pro-White or anti-Black pattern. These results are broadly consistent with those of previous literature in the area and suggest that the IRAP is a potentially useful methodology for research in the field of affective neuroscience.

Mismatch Negativity as an Indicator of Cognitive Sub-Domain Dysfunction in Amyotrophic Lateral Sclerosis.

To evaluate the utility of mismatch negativity (MMN), a neurophysiologic marker of non-motor cognitive processing, in amyotrophic lateral sclerosis (ALS). 89 patients, stratified into 4 different phenotypic presentations of ALS (67 spinal-onset, 15 bulbar-onset, 7 ALS-FTD, 7 C9ORF72 gene careers), and 19 matched controls underwent 128-channel EEG data recording. Subjects were presented with standard auditory tones interleaved with pitch-deviant tones in three recording blocks. The MMN response was quantified by peak amplitude, peak delay, average amplitude, and average delay, 100-300 ms after stimuli. 64 patients underwent cognitive screening using the Edinburgh Cognitive and Behavioural ALS Screen (ECAS), and 38 participants underwent contemporaneous cognitive assessment using the Stroop Color-Word Interference test (CWIT), which measures attention shift, inhibitory control, and error monitoring. The MMN response was observed in frontal and frontocentral regions of patient and control groups. Compared to controls, waveforms were attenuated in early onset, and the average delay was significantly increased in all of the ALS subgroups, with no significant difference between subgroups. Comparing with the control response, the ALS MMN response clustered into four new subgroups characterized by differences in response latency. The increased average delay correlated with changes in the Stroop CWIT; however, it did not show a direct relationship with age, gender, traditional phenotypes, revised ALS Functional Rating Scale, or ECAS scores. The MMN response in ALS patients reflects the cognitive dysfunction in specific sub-domains, as the new patient subgroups, identified by cluster analysis, do not segregate with existing clinical or cognitive classifications. Event-related potentials can provide additional quantitative neurophysiologic measures of impairment in specific cognitive sub-domains from which it may be possible to generate novel biologically relevant subgroups of ALS.

Using Neural Response Telemetry to Monitor Physiological Responses to Acoustic Stimulation in Hybrid Cochlear Implant Users.

This report describes the results of a series of experiments where we use the neural response telemetry (NRT) system of the Nucleus cochlear implant (CI) to measure the response of the peripheral auditory system to acoustic stimulation in Nucleus Hybrid CI users. The objectives of this study were to determine whether they could separate responses from hair cells and neurons and to evaluate the stability of these measures over time. Forty-four CI users participated. They all had residual acoustic hearing and used a Nucleus Hybrid S8, S12, or L24 CI or the standard lateral wall CI422 implant. The NRT system of the CI was used to trigger an acoustic stimulus (500-Hz tone burst or click), which was presented at a low stimulation rate (10, 15, or 50 per second) to the implanted ear via an insert earphone and to record the cochlear microphonic, the auditory nerve neurophonic and the compound action potential (CAP) from an apical intracochlear electrode. To record acoustically evoked responses, a longer time window than is available with the commercial NRT software is required. This limitation was circumvented by making multiple recordings for each stimulus using different time delays between the onset of stimulation and the onset of averaging. These recordings were then concatenated off-line. Matched recordings elicited using positive and negative polarity stimuli were added off-line to emphasize neural potentials (SUM) and subtracted off-line to emphasize potentials primarily generated by cochlear hair cells (DIF). These assumptions regarding the origin of the SUM and DIF components were tested by comparing the magnitude of these derived responses recorded using various stimulation rates. Magnitudes of the SUM and DIF components were compared with each other and with behavioral thresholds. SUM and DIF components were identified for most subjects, consistent with both hair cell and neural responses to acoustic stimulation. For a subset of the study participants, the DIF components grew as stimulus level was increased, but little or no SUM components were identified. Latency of the CAPs in response to click stimuli was long relative to reports in the literature of recordings obtained using extracochlear electrodes. This difference in response latency and general morphology of the CAPs recorded was likely due to differences across subjects in hearing loss configuration. The use of high stimulation rates tended to decrease SUM and CAP components more than DIF components. We suggest this effect reflects neural adaptation. In some individuals, repeated measures were made over intervals as long as 9 months. Changes over time in DIF, SUM, and CAP thresholds mirrored changes in audiometric threshold for the subjects who experienced loss of acoustic hearing in the implanted ear. The Nucleus NRT software can be used to record peripheral responses to acoustic stimulation at threshold and suprathreshold levels, providing a window into the status of the auditory hair cells and the primary afferent nerve fibers. These acoustically evoked responses are sensitive to changes in hearing status and consequently could be useful in characterizing the specific pathophysiology of the hearing loss experienced by this population of CI users.

N450 and LPC Event-Related Potential Correlates of an Emotional Stroop Task with Words Differing in Valence and Emotional Origin.

Affective meaning of verbal stimuli was found to influence cognitive control as expressed in the Emotional Stroop Task (EST). Behavioral studies have shown that factors such as valence, arousal, and emotional origin of reaction to stimuli associated with words can lead to lengthening of reaction latencies in EST. Moreover, electrophysiological studies have revealed that affective meaning altered amplitude of some components of evoked potentials recorded during EST, and that this alteration correlated with the performance in EST. The emotional origin was defined as processing based on automatic vs. reflective mechanisms, that underlines formation of emotional reactions to words. The aim of the current study was to investigate, within the framework of EST, correlates of processing of words differing in valence and origin levels, but matched in arousal, concreteness, frequency of appearance and length. We found no behavioral differences in response latencies. When controlling for origin, we found no effects of valence. We found the effect of origin on ERP in two time windows: 290–570 and 570–800 ms. The earlier effect can be attributed to cognitive control while the latter is rather the manifestation of explicit processing of words. In each case, reflective originated stimuli evoked more positive amplitudes compared to automatic originated words.

Exploring Racial Bias in a European Country with a Recent History of Immigration of Black Africans

The present study examined levels of racial bias among black and white individuals residing in Ireland using the Implicit Relational Assessment Procedure (IRAP) and a range of questionnaire measures. The IRAP required participants to respond quickly and accurately on a computer-based task. On some blocks of trials participants were required to respond in a pro-white and anti-black manner, whereas on other blocks responding in the opposite direction was required (anti-white/pro-black). The difference in response latencies between these two types of trials provided an index of racial bias. Performance on the IRAP (i) revealed in-group/out-group bias for the white but not the black participants; (ii) substantively increased the predictive validity of a range of questionnaire-based measures; and (iii) provided the best prediction of racial group. The results support the utility of the IRAP as a measure of racial bias, and indicate that this bias differed between black and white Irish residents.

SU92. Implicit Socioemotional Modulation of Working Memory Brain Activity in Schizophrenia

Author(s): Bolden, Khalima Alicia | Advisor(s): Brown, Gregory G | Abstract: The neural substrate of interactions of working memory (WM) with socio-emotional processing is poorly understood in schizophrenia. This study builds on published papers using a delayed match to sample design to study the interaction of WM load with type of distracter (socially relevant faces vs. socially irrelevant geometric designs [FvG]) presented briefly during the WM maintenance period. Based on previously published findings, we hypothesize: (1) The FvG difference in brain activity in the dorsolateral prefrontal cortex (DLPFC) in the task maintenance period will be largest at the highest WM load. (2) Among schizophrenia/ schizoaffective patients and healthy controls the magnitude of the face vs. geometric design (FvG) contrast in brain activity in the amygdala during the task maintenance period will follow a quadratic pattern across WM load when averaged over face type. (3) Among schizophrenia patients, the magnitude of the FvG contrast in brain activity in the amygdala and DLPFC at the greatest WM load will be correlated with negative symptoms. Individuals between the ages of 18-55 diagnosed with schizophrenia/schizoaffective disorder (N = 12) and non-psychiatric controls (N = 20) matched with the patients on age, gender, paternal education and paternal socioeconomic status underwent structural and functional magnetic resonance imaging (fMRI). To assess the effect of implicit socioemotional modulation on brain activity during WM, the effect of facial distraction on brain activation was assessed for WM of pseudowords at three syllable loads (1, 2, and 3) across several face valence types and contrasted with the effect of a geometric distracter. Results: Although patients performed significantly above chance, they were less accurate than controls with no difference in response latency. When the FvG contrast was tested for response latency, we observed a significant quadratic effect of WM load in healthy controls (F[1,19] = 6.108, p = .023, η2 = .24) but a linear effect among patients (F[1,10] = 4.012, p = .073, η2 = .29). Similar patterns were found for response accuracy but were not statistically significant. With regard to neural activity, we found a significant bilateral linear trend of percent signal change on WM load for the FvG contrast in the DLPFC (F[1,19] = 5.818, p = .026, MSE = .077, η2 = .23). among controls, with brain activation to faces greater than activation to designs only at the highest WM load. In the amygdala we observed a significant bilateral quadratic effect of percent signal change on WM load for the FvG contrast in the control group (F[1,19] = 10.423, p = .004, MSE = .121, η2 = .35). We observed a significant difference in neural activation patterns in patients compared to controls in the DLPFC and the amygdala. Specifically, in patients, we observed a quadratic instead of a linear trend in the DLPFC but only in the right hemisphere (hemisphere x quadratic: F[1,11] = 9.362, p = .011, η2 = .40). In the amygdala, the patients displayed a quadratic trend also only in the right hemisphere, (hemisphere x quadratic: F[1,11] = 10.442 p = .008, η2 = .49). In neither controls nor patients did individual differences in the quadratic effect of brain activity in the amygdala correlate with the quadratic effect in response time or accuracy. Although the correlation between the magnitude of the quadratic trend in the right amygdala at the highest WM load with general psychopathology was moderately large in patients, neither this effect nor any other brain activation effects were significantly correlated with psychopathology. Confirming hypothesis one, controls showed the largest difference in brain activity of the FvG contrast in the DLPFC during the maintenance period at the highest WM load. However, in patients we saw significantly decreased percent signal change in DLPFC at the highest WM load on the FvG contrast in the maintenance period. For hypothesis two we observed a quadratic pattern of WM load on the FvG contrast in the maintenance period for both controls and patients, although this effect was only present in the right hemisphere of patients. Furthermore, contrary to hypothesis 3 we did not observe significant correlations between symptom severity and the magnitude of the FvG contrast in brain activity in the amygdala and DLPFC at the greatest WM load. These results suggest a separate process of social-discrimination is taking place in controls. However, this process appears to be impaired in individuals with schizophrenia. This disruption may be due to poor integration of different brain areas and interhemispheric communication.

P171 Impact of a novel high-definition tDCS set-up on cognitive control

Question High-definition transcranial direct current stimulation (HD-tDCS) allows for more focal current delivery than conventional-tDCS. However, very few studies have assessed potential cognitive effects and regional specificity of HD-tDCS. Objectives This study assessed the impact and specificity of a novel HD-tDCS montage on cognitive control during a visual flanker task. Methods 120 healthy young participants were recruited and randomly assigned to four stimulation conditions: left or right dorsolateral prefrontal cortex (DLPFC) or primary motor cortex (M1) HD-tDCS (N = 30 per condition). Each group underwent both active- and sham HD-tDCS in cross-over, double-blind designs. tDCS was administered using a one-channel DC-stimulator and two concentric round rubber electrodes mimicking the frequently used “4 × 1” HD-tDCS set-up. Our analyses focused on conflict adaptation (CA), a hallmark effect of adaptive cognitive control. Conflict adaptation in the flanker paradigm is reflected by the finding that the flanker effect (i.e., differences in response latency between incongruent and congruent trials in the flanker task) is smaller following trials with high vs. low response conflict. Results We obtained a sizeable CA effect which was influenced by region-specific active HD-tDCS, as indicated by a significant four-way interaction between region, stimulation, current congruency and previous congruency (p Conclusions Our results confirm the potential of this novel HD-tDCS set-up to modulate behavioural performance in a regionally specific manner. Selectively improved conflict adaptation during DLPFC stimulation supports the theory that left and right DLPFC play a critical role in behavioral adaptation following conflict detection.

It does exist! A left-to-right spatial-numerical association of response codes (SNARC) effect among native Hebrew speakers.

Several studies, starting with Dehaene, Bossini, and Giraux (1993), have reported that, in parity-judgment tasks, the difference in response latencies generated by the right and left hand are negatively correlated with number magnitudes. This SNARC (spatial-numerical association of response codes) effect is in line with the notion that the "mental number line" extends from left to right. The SNARC effect has been found mainly in native speakers of Germanic/Romanic languages; it has been suggested that the SNARC effect may derive from the experience of reading from left to right. To date, there is no evidence that the SNARC (or reverse SNARC) effect exists in parity judgments in native speakers of Hebrew readers. Here we provide the first demonstration of a horizontal, left-to-right SNARC effect in native speakers of Hebrew performing the parity task. Although we found no SNARC effect using the standard parity task, a reliable SNARC effect was found when we succeeded in reducing the MARC (markedness association of response codes) effect. We succeeded in reducing the MARC effect by implementing the parity task in 2 sessions, on 2 different days, each time using a different mapping of the parity-to-response side. (PsycINFO Database Record

Rapid and Objective Assessment of Neural Function in Autism Spectrum Disorder Using Transient Visual Evoked Potentials.

ObjectiveThere is a critical need to identify biomarkers and objective outcome measures that can be used to understand underlying neural mechanisms in autism spectrum disorder (ASD). Visual evoked potentials (VEPs) offer a noninvasive technique to evaluate the functional integrity of neural mechanisms, specifically visual pathways, while probing for disease pathophysiology.MethodsTransient VEPs (tVEPs) were obtained from 96 unmedicated children, including 37 children with ASD, 36 typically developing (TD) children, and 23 unaffected siblings (SIBS). A conventional contrast-reversing checkerboard condition was compared to a novel short-duration condition, which was developed to enable objective data collection from severely affected populations who are often excluded from electroencephalographic (EEG) studies.ResultsChildren with ASD showed significantly smaller amplitudes compared to TD children at two of the earliest critical VEP components, P60-N75 and N75-P100. SIBS showed intermediate responses relative to ASD and TD groups. There were no group differences in response latency. Frequency band analyses indicated significantly weaker responses for the ASD group in bands encompassing gamma-wave activity. Ninety-two percent of children with ASD were able to complete the short-duration condition compared to 68% for the standard condition.ConclusionsThe current study establishes the utility of a short-duration tVEP test for use in children at varying levels of functioning and describes neural abnormalities in children with idiopathic ASD. Implications for excitatory/inhibitory balance as well as the potential application of VEP for use in clinical trials are discussed.