Balancing accuracy and speed in the development of inhibitory control

Inhibitory control develops rapidly and nonlinearly, making its accurate assessment challenging. This research investigated the developmental dynamics of accuracy and response latency in inhibitory control assessment of 3- to 6-year-old children in a longitudinal study (N = 431; 212 girls; Mage = 4.86 years, SD = 0.99) and a cross-sectional study (N = 135; 71 girls; Mage = 4.24 years, SD = 0.61). We employed a computerized Stroop task to measure inhibitory control, with fluid intelligence serving as a covariate. A growth curve analysis revealed that children who reached an accuracy threshold of 80% earlier demonstrated faster improvements in response latency. Both the cross-sectional and longitudinal findings demonstrated a positive association between response latency in the inhibitory control task and fluid intelligence, but only when participants had achieved and maintained high accuracy. These results suggest that researchers should consider response latency as an indicator of inhibitory control only in children who manage to respond accurately in an inhibitory control task.

Alternative covariance structures in mixed-effects models: Addressing intra- and inter-individual heterogeneity

Mixed-effects models for repeated measures and longitudinal data include random coefficients that are unique to the individual, and thus permit subject-specific growth trajectories, as well as direct study of how the coefficients of a growth function vary as a function of covariates. Although applications of these models often assume homogeneity of the within-subject residual variance that characterizes within-person variation after accounting for systematic change and the variances of the random coefficients of a growth model that quantify individual differences in aspects of change, alternative covariance structures can be considered. These include allowing for serial correlations between the within-subject residuals to account for dependencies in data that remain after fitting a particular growth model or specifying the within-subject residual variance to be a function of covariates or a random subject effect to address between-subject heterogeneity due to unmeasured influences. Further, the variances of the random coefficients can be functions of covariates to relax the assumption that these variances are constant across subjects and to allow for the study of determinants of these sources of variation. In this paper, we consider combinations of these structures that permit flexibility in how mixed-effects models are specified to understand within- and between-subject variation in repeated measures and longitudinal data. Data from three learning studies are analyzed using these different specifications of mixed-effects models.

Changes in patterns of Early Mother-Child Interaction: A longitudinal study of the first 18 months of life

OBJECTIVE

The main objective of the present longitudinal study is to describe the progression of early adult-child interactions between the first and second years of life. Changes identified in interactions are described, focusing on both the qualitative aspects of maternal responses, as well as maternal response latency to the child's behavior using a microanalytical methodology that collected data on maternal and child behavior in real-time without losing sight of the temporal dimension.

PARTICIPANTS

This study examined 52 mother-child dyads from intact families that presented no psychological, social, or biological risk factors at 6, 12 and 18 months of age.

INSTRUMENT

CITMI-R (early mother-child interaction coding system, revised edition) was used to assess early mother-infant interactions during free play sessions between mother and child the.

RESULTS

The results indicate that some components of maternal sensitivity improve as children progress towards the second year of life, detecting an increase in sensitive maternal behavior and a decrease in intrusive behavior in the evolutive observed period; moreover, regarding latency of maternal response, we observed that mothers of older children give more time for their children to explore, which stimulates autonomy. Finally, the implication of these results for intervention directed to optimizing early adult-child interactions are addressed.

The dynamic role of inhibitory control in language switching during number-word task performance in dominant and balanced bilinguals

Language is one of the fascinating abilities of the human species. The beauty of language becomes intriguing when we examine language processing among bilinguals. This work attempted to study the effects of language dominance among native Hindi speakers who were either Hindi dominant, English dominant, or balanced bilingual in a language switching task. The task required the participants to read aloud the number-words that were presented singly on the computer screen. The findings support the inhibitory control model's predictions as the results were indicative of asymmetrical switch cost for both the Hindi and English dominant bilinguals. In both the language dominance condition, moving back to the dominant language from a non-dominant language required more time than vice versa. The results also indicated overall reduced reaction time in the reading task performance for balanced bilinguals, further demonstrating the benefits of balanced bilingualism.

Medication adversely impacts visually-guided eye movements in Parkinson's disease

OBJECTIVE

We examined whether previous inconsistent findings about the effect of anti-Parkinsonian medication on visually-guided saccades (VGS) were due to the use of different paradigms, which change the timing of fixation offset and target onset, or different target eccentricities.

METHODS

Thirty-three participants with Parkinson's disease (PD) completed the VGS tasks OFF and ON medication, along with 13 healthy controls. Performance on 3 paradigms (gap, step, and overlap) and 2 target eccentricities was recorded. We used mixed models to determine the effect of medication, paradigm, and target eccentricity on saccade latency, gain, and peak velocity.

RESULTS

First, we confirmed known paradigm effects on latency, and target eccentricity effects on gain and peak velocity in participants with PD. Second, latency was positively associated with OFF medication Movement Disorders Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) motor score in PD. Third, medication prolonged latency for the larger target eccentricity across the 3 paradigms, while decreasing gain and peak velocity in the step paradigm across target eccentricities.

CONCLUSIONS

Medication adversely affected and was not therapeutically beneficial for VGS. Previous inconsistencies may have resulted from chosen target eccentricity.

SIGNIFICANCE

The negative medication effect on VGS may be clinically significant, as many activities in daily life require oculomotor control, inhibitory control, and visually-guided shifts of attention.

Temporal vision: measures, mechanisms and meaning

Time is largely a hidden variable in vision. It is the condition for seeing interesting things such as spatial forms and patterns, colours and movements in the external world, and yet is not meant to be noticed in itself. Temporal aspects of visual processing have received comparatively little attention in research. Temporal properties have been made explicit mainly in measurements of resolution and integration in simple tasks such as detection of spatially homogeneous flicker or light pulses of varying duration. Only through a mechanistic understanding of their basis in retinal photoreceptors and circuits can such measures guide modelling of natural vision in different species and illuminate functional and evolutionary trade-offs. Temporal vision research would benefit from bridging traditions that speak different languages. Towards that goal, I here review studies from the fields of human psychophysics, retinal physiology and neuroethology, with a focus on fundamental constraints set by early vision.

Summary: Simple measures of temporal vision such as the critical flicker frequency can be useful for modelling natural vision only if their relationship to photoreceptor responses and retinal processing is understood.

A molecular insight into the dissociable regulation of associative learning and motivation by the synaptic protein neuroligin-1

Background

In a changing environment, a challenge for the brain is to flexibly guide adaptive behavior towards survival. Complex behavior and the underlying neural computations emerge from the structural components of the brain across many levels: circuits, cells, and ultimately the signaling complex of proteins at synapses. In line with this logic, dynamic modification of synaptic strength or synaptic plasticity is widely considered the cellular level implementation for adaptive behavior such as learning and memory. Predominantly expressed at excitatory synapses, the postsynaptic cell-adhesion molecule neuroligin-1 (Nlgn1) forms trans-synaptic complexes with presynaptic neurexins. Extensive evidence supports that Nlgn1 is essential for NMDA receptor transmission and long-term potentiation (LTP), both of which are putative synaptic mechanisms underlying learning and memory. Here, employing a comprehensive battery of touchscreen-based cognitive assays, we asked whether impaired NMDA receptor transmission and LTP in mice lacking Nlgn1 does in fact disrupt decision-making. To this end, we addressed two key decision problems: (i) the ability to learn and exploit the associative structure of the environment and (ii) balancing the trade-off between potential rewards and costs, or positive and negative utilities of available actions.

Results

We found that the capacity to acquire complex associative structures and adjust learned associations was intact. However, loss of Nlgn1 alters motivation leading to a reduced willingness to overcome effort cost for reward and an increased willingness to exert effort to escape an aversive situation. We suggest Nlgn1 may be important for balancing the weighting on positive and negative utilities in reward-cost trade-off.

Conclusions

Our findings update canonical views of this key synaptic molecule in behavior and suggest Nlgn1 may be essential for regulating distinct cognitive processes underlying action selection. Our data demonstrate that learning and motivational computations can be dissociated within the same animal model, from a detailed behavioral dissection. Further, these results highlight the complexities in mapping synaptic mechanisms to their behavioral consequences, and the future challenge to elucidate how complex behavior emerges through different levels of neural hardware.

In or out: Response slowing across housing conditions as a measure of affect in three Western lowland gorillas (Gorilla gorilla gorilla)

Background

Individuals experiencing negative affect have shown response slowing, a longer latency to respond in relation to baseline, when presented with aversive stimuli. We assessed response slowing in three male gorillas housed in a bachelor group as a function of daytime and nighttime housing arrangements.

Methods

In both experiments, three gorillas were rewarded for touching a single image (baseline, non-threatening gorilla or threatening gorilla) on a touchscreen. In Experiment One, they completed 48 50-trial sessions across combinations of three nested daytime and three nighttime conditions. In Experiment Two, they completed eight 50-trial sessions with novel stimuli across two daytime conditions, which were nested within two nighttime conditions. Housing conditions represented different amounts of space and degree of choice. We predicted that the gorillas would show response slowing to threatening stimuli when space and choice were restricted.

Results

We did not observe response slowing in Experiment One, although daytime and nighttime conditions interacted to predict response latencies. The gorillas responded more slowly when they had access to indoors and outdoors overnight compared to when they were in their stalls or together in an indoor habitat, but only if they had been given access to both indoors and outdoors or locked in the indoor habitat the day before. In Experiment Two, the gorillas did show response slowing to threatening stimuli, but this pattern did not interact with housing conditions. Our results, although limited by a small sample, are somewhat consistent with those of a previous study that did not find significant response slowing for apes as a function of aversive testing conditions, although the procedure has been effective in identifying dysregulated fear (high fear in low threat conditions) in macaques. The utility of this paradigm for testing affect in apes awaits further evaluation.

Rituximab in routine care of severe active rheumatoid arthritis : A prospective, non-interventional study in Germany

OBJECTIVE

To assess safety, effectiveness and onset of effect of rituximab (RTX) in routine clinical treatment of severe, active rheumatoid arthritis (RA).

METHODS

Prospective, multi-centre, non-interventional study in rheumatological outpatient clinics or private practices in Germany. RTX-naïve adult patients were to receive RTX according to marketing authorisation and at their physician's discretion. Also according to their physician's discretion, patients could receive a second cycle of RTX (re-treatment = treatment continuation). Major outcome was the change in Disease Activity Score based on 28-joints count and erythrocyte sedimentation rate (DAS28-ESR) over 24 weeks and during 6 months of re-treatment.

RESULTS

Overall, 1653 patients received at least one cycle RTX; 99.2% of these had received disease-modifying antirheumatic drugs (DMARD) pre-treatment and 75.5% anti-tumor necrosis factor(TNF)‑α pre-treatment. After a mean interval of 8.0 months, 820 patients received RTX re-treatment. Mean DAS28-ESR decreased from 5.3 at baseline to 3.8 after 24 weeks (-1.5 [95% confidence interval, CI: -1.6; -1.4]), and from 4.1 at start of cycle 2 to 3.5 at study end (change from baseline: -1.8 [95% CI: -2.0; -1.7]). Improvements in DAS28-ESR and Health Assessment Questionnaire (HAQ) score occurred mainly during the first 12 weeks of RTX treatment, with further DAS28-ESR improvement until week 24 or month 6 of re-treatment. Improvements in DAS28-ESR and EULAR responses were more pronounced in seropositive patients. RF was a predictor of DAS28-ESR change to study end. Safety analysis showed the established profile of RTX.

CONCLUSION

RTX was safe and effective in a real-life setting with rapid and sustained improvement in RA signs and symptoms.

The Neural Basis of Dim-Light Vision in Echolocating Bats

Echolocating bats evolved a sophisticated biosonar imaging system that allows for a life in dim-light habitats. However, especially for far-range operations such as homing, bats can support biosonar by vision. Large eyes and a retina that mainly consists of rods are assumed to be the optical adjustments that enable bats to use visual information at low light levels. In addition to optical mechanisms, many nocturnal animals evolved neural adaptations such as elongated integration times or enlarged spatial sampling areas to further increase the sensitivity of their visual system by temporal or spatial summation of visual information. The neural mechanisms that underlie the visual capabilities of echolocating bats have, however, so far not been investigated. To shed light on spatial and temporal response characteristics of visual neurons in an echolocating bat, Phyllostomus discolor, we recorded extracellular multiunit activity in the retino-recipient superficial layers of the superior colliculus (SC). We discovered that response latencies of these neurons were generally in the mammalian range, whereas neural spatial sampling areas were unusually large compared to those measured in the SC of other mammals. From this we suggest that echolocating bats likely use spatial but not temporal summation of visual input to improve visual performance under dim-light conditions. Furthermore, we hypothesize that bats compensate for the loss of visual spatial precision, which is a byproduct of spatial summation, by integration of spatial information provided by both the visual and the biosonar systems. Given that knowledge about neural adaptations to dim-light vision is mainly based on studies done in non-mammalian species, our novel data provide a valuable contribution to the field and demonstrate the suitability of echolocating bats as a nocturnal animal model to study the neurophysiological aspects of dim-light vision.

Establishing operant conflict tests for the translational study of anxiety in mice

RATIONALE

In conflict-based anxiety tests, rodents decide between actions with simultaneous rewarding and aversive outcomes. In humans, computerised operant conflict tests have identified response choice, latency, and vigour as distinct behavioural components. Animal operant conflict tests for measurement of these components would facilitate translational study.

OBJECTIVES

In C57BL/6 mice, two operant conflict tests for measurement of response choice, latency, and vigour were established, and effects of chlordiazepoxide (CDZ) thereon investigated.

METHODS

Mice were moderately diet-restricted to increase sucrose reward salience. A 1-lever test required responding under medium-effort reward/threat conditions of variable ratio 2-10 resulting in sucrose at p = 0.7 and footshock at p = 0.3. A 2-lever test mandated a choice between low-effort reward/threat with a fixed-ratio (FR) 2 lever yielding sucrose at p = 0.7 and footshock at p = 0.3 versus high-effort reward/no threat with a FR 20 lever yielding sucrose at p = 1.

RESULTS

In the 1-lever test, CDZ (7.5 or 15 mg/kg i.p.) reduced post-trial pause (response latency) following either sucrose or footshock and reduced inter-response interval (increased response vigour) after footshock. In the 2-lever test, mice favoured the FR2 lever and particularly at post-reward trials. CDZ increased choice of FR2 and FR20 responding after footshock, reduced response latency overall, and increased response vigour at the FR2 lever and after footshock specifically.

CONCLUSIONS

Mouse operant conflict tests, especially 2-lever choice, allow for the translational study of distinct anxiety components. CDZ influences each component by ameliorating the impact of both previous punishment and potential future punishment.

Effects of divided attention at encoding and retrieval: Further data

Division of attention (DA) at the time of learning has large detrimental effects on subsequent memory performance, but DA at retrieval has much smaller effects (Baddeley, Lewis, Eldridge, & Thomson, 1984, Journal of Experimental Psychology: General, 113, 518-540; Craik, Govoni, Naveh-Benjamin, & Anderson, 1996, Journal of Experimental Psychology: General, 125, 159-180). Experiment 1 confirmed the relatively small effects of DA on retrieval and also showed that retrieval operations do consume processing resources. The experiment also found that the effect is not attributable to a trade-off in performance with the concurrent task or to recognition decisions made on the basis of familiarity judgments. Participants made levels-of-processing (LOP) judgments during encoding to check whether deeper semantic judgments were differentially vulnerable to the effects of DA. In fact DA did not interact with LOP. Experiment 2 explored reports that the comparatively slight effect of DA on recognition accuracy is accompanied by a compensatory increase in recognition latency (Baddeley et al., 1984). The experiment replicated findings that neither DA nor differential emphasis between recognition and a concurrent continuous reaction time (CRT) task affected recognition accuracy, but also found evidence for a lawful trade-off in decision latencies between recognition and CRT performance. Further analysis showed that the relationship between response rates on the two tasks was well described by a linear function, and that this function was demonstrated by the majority of individual participants. It is concluded that the small effect of DA on recognition performance is attributable to a trade-off within the recognition task itself; accuracy is maintained by a compensatory increase in decision latency.

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.

The effects of stimulus parameters on auditory evoked potentials of Carassius auratus

Whole-brain responses to sound are easily measured through auditory evoked potentials (AEP), but it is unclear how differences in experimental parameters affect these responses. The effect of varying parameters is especially unclear in fish studies, the majority of which use simple sound types and then extrapolate to natural conditions. The current study investigated AEPs in goldfish (Carassius auratus) using sounds of different durations (5, 10, and 20 ms) and frequencies (200, 500, 600 and 700 Hz) to test stimulus effects on latency and thresholds. We quantified differences in latency and threshold in comparison to a 10-ms test tone, a duration often used in AEP fish studies. Both response latency and threshold were significantly affected by stimulus duration, with latency patterning suggesting that AEP fires coincident with a decrease in stimulus strength. Response latency was also significantly affected by presentation frequency. These results show that stimulus type has important effects on AEP measures of hearing and call for clearer standards across different measures of AEP. Duration effects also suggest that AEP measures represent summed responses of duration-detecting neural circuit, but more effort is needed to understand the neural drivers of this commonly used technique.

Reaction time effects in lab- versus Web-based research: Experimental evidence

Although Web-based research is now commonplace, it continues to spur skepticism from reviewers and editors, especially whenever reaction times are of primary interest. Such persistent preconceptions are based on arguments referring to increased variation, the limits of certain software and technologies, and a noteworthy lack of comparisons (between Web and lab) in fully randomized experiments. To provide a critical test, participants were randomly assigned to complete a lexical decision task either (a) in the lab using standard experimental software (E-Prime), (b) in the lab using a browser-based version (written in HTML and JavaScript), or (c) via the Web using the same browser-based version. The classical word frequency effect was typical in size and corresponded to a very large effect in all three conditions. There was no indication that the Web- or browser-based data collection was in any way inferior. In fact, if anything, a larger effect was obtained in the browser-based conditions than in the condition relying on standard experimental software. No differences between Web and lab (within the browser-based conditions) could be observed, thus disconfirming any substantial influence of increased technical or situational variation. In summary, the present experiment contradicts the still common preconception that reaction time effects of only a few hundred milliseconds cannot be detected in Web experiments.

Effects of driver age and experience in abrupt-onset hazards

Novice drivers and older drivers are found to have the highest crash risk among all drivers and this has motivated many research studies into various aspects of novice and older drivers. Although age-related declines were expected, studies did not find older drivers to respond slower to hazards. This study examined the hazard detection and response latencies of 14 young novice drivers, 14 young experienced drivers, and 12 older experienced drivers, to abrupt-onset hazards. Older drivers were found to take longer times before fixating on an abrupt-onset road hazard but appeared to have insignificantly faster reaction times after the initial fixation. Hence, the overall response latency did not suggest any age effects. Older drivers also scanned the roadway less as compared to their younger counterparts. No effects of experience were found. The findings provided insight on age-related declines in hazard detection whose effects have been masked by other components of hazard response.

Equal latency contours and auditory weighting functions for the harbour porpoise (Phocoena phocoena)

Loudness perception by human infants and animals can be studied under the assumption that sounds of equal loudness elicit equal reaction times (RTs). Simple RTs of a harbour porpoise to narrowband frequency-modulated signals were measured using a behavioural method and an RT sensor based on infrared light. Equal latency contours, which connect equal RTs across frequencies, for reference values of 150-200 ms (10 ms intervals) were derived from median RTs to 1 s signals with sound pressure levels (SPLs) of 59-168 dB re. 1 μPa and centre frequencies of 0.5, 1, 2, 4, 16, 31.5, 63, 80 and 125 kHz. The higher the signal level was above the hearing threshold of the harbour porpoise, the quicker the animal responded to the stimulus (median RT 98-522 ms). Equal latency contours roughly paralleled the hearing threshold at relatively low sensation levels (higher RTs). The difference in shape between the hearing threshold and the equal latency contours was more pronounced at higher levels (lower RTs); a flattening of the contours occurred for frequencies below 63 kHz. Relationships of the equal latency contour levels with the hearing threshold were used to create smoothed functions assumed to be representative of equal loudness contours. Auditory weighting functions were derived from these smoothed functions that may be used to predict perceived levels and correlated noise effects in the harbour porpoise, at least until actual equal loudness contours become available.

[Cochlear microphonic latency]

INTRODUCTION AND OBJECTIVE

By using appropriate instrumentation, we have found that cochlear microphonics (CM) advance or delay their appearance, depending on the sound pressure that generates them. This time variation is on the order of microseconds. We have not found any reference to this behaviour, which is why we make the finding known.

MATERIAL AND METHOD

We used the standard instrumentation specified for the study of CM. The method was based on the phase shift function of the CM according to the intensity of the stimulus.

RESULTS

Latency was observed in CM, and we determined that latency time diminishes as the intensity of the stimulus increases.

CONCLUSIONS

From the sound stimulus to the bioelectric potential transduction, there is a time period of microseconds, the shorter the more powerful the stimulus. This suggests that electromechanical transduction is not a simple mechanical process.

Reactivity to fearful expressions of familiar and unfamiliar people in children with autism: an eye-tracking pupillometry study

BACKGROUND

Individuals with autism are often reported to have difficulty with emotion processing. However, clinical and experimental data show that they are sensitive to familiarity; for example, they show normative attachment to familiar people, and have normative brain activity in response to familiar faces. To date, no study has measured their reactivity to the emotions of familiar vs. unfamiliar people. Thus, our aim was to determine whether individuals with autism would show normative reactivity to emotion in familiar people.

METHODS

Participants were 21 children with autism and 21 children with typical development, aged two to five years, matched on age and gender. The children observed videos of familiar people (their child-care teachers) and unfamiliar people expressing fear, whilst their visual attention and pupillary reactions were recorded (the latter as an index of emotional reactivity), using eye tracking technology.

RESULTS

The children with autism showed normative pupillary reactions (peak magnitude) to fear expressed by familiar people, but a reduced response to fear expressed by unfamiliar people. However, across familiarity conditions, the children with autism had longer latency peak responses than the typically developing children. This pattern of findings was independent of cognitive factors or visual attention as visual attention by group was not related to familiarity condition. The children with autism had reduced visual attention to neutral faces; however, on fearful faces there were no group differences. Abnormalities in pupillary reactivity in the autism group were related to less prosocial behaviour and more severe play and communication deficits.

CONCLUSIONS

Children with autism were less atypical in their responses to fearful expressions of people they know, arguing against a pervasive emotional impairment in autism, but rather one that may be mediated by familiarity.