Auditory sensory gating and performance on the Delis–Kaplan Executive Function System

Sensory gating is a neurological mechanism that inhibits redundant sensory information. Impaired sensory gating is not uncommon in otherwise healthy individuals, but its relationship with higher level cognitive function is poorly understood. It is plausible that cognitive fragmentation associated with poor sensory gating may affect an individual's higher level executive functioning. Fifty-one participants (Mean age?=?22.02; 24 males) were administered an electroencephalogram with a paired-tone paradigm to measure sensory gating as well as a comprehensive executive functioning battery—the Delis–Kaplan Executive Function System. Overall, better performance on the D-KEFS was related to more effective sensory gating. Also, tasks that measured cognitive flexibility predicted P50 latency as well as P200 amplitude and sensory gating. Understanding the relationship between sensory gating and cognitive processing has implications for healthy individuals and clinical groups alike.     

The sensory nature of knowledge: Sensory priming effects in semantic categorization

The aim of the present study was to show the perceptual nature of conceptual knowledge by using a priming paradigm that excluded an interpretation exclusively in terms of amodal representation. This paradigm was divided into two phases. The first phase consisted in learning a systematic association between a geometrical shape and a white noise. The second phase consisted of a short-term priming paradigm in which a primed shape (either associated or not with a sound in the first phase) preceded a picture of an object, which the participants had to categorize as representing a large or a small object. The objects were chosen in such a way that their principal function either was associated with the production of noise (“noisy” target) or was not typically associated the production of noise (“silent” target). The stimulus onset asynchrony (SOA) between the prime and the target was 100 ms or 500 ms. The results revealed an interference effect with a 100-ms SOA and a facilitatory effect with a 500-ms SOA for the noisy targets only. We interpreted the interference effect obtained at the 100-ms SOA as the result of an overlap between the components reactivated by the sound prime and those activated by the processing of the noisy target. At an SOA of 500 ms, there was no temporal overlap. The observed facilitatory effect was explained by the preactivation of auditory areas by the sound prime, thus facilitating the categorization of the noisy targets only.     

Musical training generalises across modalities and reveals efficient and adaptive mechanisms for reproducing temporal intervals

Expert musicians are able to time their actions accurately and consistently during a musical performance. We investigated how musical expertise influences the ability to reproduce auditory intervals and how this generalises across different techniques and sensory modalities. We first compared various reproduction strategies and interval length, to examine the effects in general and to optimise experimental conditions for testing the effect of music, and found that the effects were robust and consistent across different paradigms. Focussing on a ‘ready-set-go’ paradigm subjects reproduced time intervals drawn from distributions varying in total length (176, 352 or 704 ms) or in the number of discrete intervals within the total length (3, 5, 11 or 21 discrete intervals). Overall, Musicians performed more veridical than Non-Musicians, and all subjects reproduced auditory-defined intervals more accurately than visually-defined intervals. However, Non-Musicians, particularly with visual stimuli, consistently exhibited a substantial and systematic regression towards the mean interval. When subjects judged intervals from distributions of longer total length they tended to regress more towards the mean, while the ability to discriminate between discrete intervals within the distribution had little influence on subject error. These results are consistent with a Bayesian model that minimizes reproduction errors by incorporating a central tendency prior weighted by the subject's own temporal precision relative to the current distribution of intervals. Finally a strong correlation was observed between all durations of formal musical training and total reproduction errors in both modalities (accounting for 30% of the variance). Taken together these results demonstrate that formal musical training improves temporal reproduction, and that this improvement transfers from audition to vision. They further demonstrate the flexibility of sensorimotor mechanisms in adapting to different task conditions to minimise temporal estimation errors.     

About the time-shrinking illusion in the tactile modality

The aim of this study was to examine the occurrence of a so-called time-shrinking illusion in the tactile modality, while it had been tested so far mainly with auditory and visual stimuli. We examined whether the perception of an empty time interval marked by two brief tactile stimuli, S (240 ms), would be influenced by the presence of a preceding time interval, P (160, 240, or 320 ms). Results showed that S was underestimated when P was shorter than S. This underestimation appeared as a kind of perceptual assimilation between P and S, but S was not overestimated when P was longer. The underestimation was rather interpreted as a manifestation of the time-shrinking illusion.     

Temporal reproductions are influenced by an internal reference: Explaining the Vierordt effect

Several findings from duration perception literature suggest that when making decisions about time, participants rely on an internal reference memory for time rather than merely on the current physical stimuli. According to a recent account, such an internal reference is formed by a continuous dynamic updating process that integrates duration information from previous trials and the current trial. In the present work, we show how such a dynamic mechanism can account for the classical yet unresolved Vierordt effect, which refers to the overestimation of relatively short and the underestimation of relatively long temporal intervals. We conducted an experiment to examine this and related predictions by means of a temporal reproduction task. Specifically, participants were presented with two successive time intervals — a standard s with constant duration and a comparison c with variable duration. Instead of performing a comparison judgment, however, the participants were subsequently cued to reproduce one of the two presented stimuli. Reproductions were affected not only by the temporal position of the to-be-reproduced stimulus, but also by the stimuli presented on earlier trials. These results support the notion of a dynamically updated internal reference underlying our judgments about the time elapsed, which might also be the basis of the Vierordt effect.     

Beyond words: Sensory properties of depressive thoughts

Verbal thoughts (such as negative cognitions) and sensory phenomena (such as visual mental imagery) are usually conceptualised as distinct mental experiences. The present study examined to what extent depressive thoughts are accompanied by sensory experiences and how this is associated with symptom severity, insight of illness and quality of life. A large sample of mildly to moderately depressed patients (N = 356) was recruited from multiple sources and asked about sensory properties of their depressive thoughts in an online study. Diagnostic status and symptom severity were established over a telephone interview with trained raters. Sensory properties of negative thoughts were reported by 56.5% of the sample (i.e., sensation in at least one sensory modality). The highest prevalence was seen for bodily (39.6%) followed by auditory (30.6%) and visual (27.2%) sensations. Patients reporting sensory properties of thoughts showed more severe psychopathological symptoms than those who did not. The degree of perceptuality was marginally associated with quality of life. The findings support the notion that depressive thoughts are not only verbal but commonly accompanied by sensory experiences. The perceptuality of depressive thoughts and the resulting sense of authenticity may contribute to the emotional impact and pervasiveness of such thoughts, making them difficult to dismiss for their holder.     

Movement variability near goal equivalent manifolds: Fluctuations,control, and model-based analysis

Fluctuations in the repeated performance of human movements have been the subject of intense scrutiny because they are generally believed to contain important information about the function and health of the neuromotor system. A variety of approaches has been brought to bear to study these fluctuations. However it is frequently difficult to understand how to synthesize different perspectives to give a coherent picture. Here, we describe a conceptual framework for the experimental study of motor variability that helps to unify geometrical methods, which focus on the role of motor redundancy, with dynamical methods that characterize the error-correcting processes regulating the performance of skilled tasks. We describe how goal functions, which mathematically specify the task strategy being employed, together with ideas from the control of redundant systems, allow one to formulate simple, experimentally testable dynamical models of inter-trial fluctuations. After reviewing the basic theory, we present a list of five general hypotheses on the structure of fluctuations that can be expected in repeated trials of goal-directed tasks. We review recent experimental applications of this general approach, and show how it can be used to precisely characterize the error-correcting control used by human subjects.     

Infant long-term memory for associations formed during mere exposure

We previously found that young infants spontaneously associate stimuli that they merely see together. Using a sensory preconditioning paradigm with 6- and 9-month-olds, we asked how long such associations remain latent before being forgotten and what exposure conditions affect their persistence. Groups were preexposed to two puppets for 1 h/day for 2 days, 1 h on 1 day, or 1 h on 1 day in two sessions; 1-27 days later, target actions were modeled on one puppet, and infants were tested with the other puppet 1 day later. The longest delay after which infants imitated the actions on the other puppet defined how long they remembered the association. The data revealed that the preexposure regimen determined retention. Regardless of exposure time, both ages remembered the association longer after two sessions, and younger infants remembered longer than older infants - for 4 weeks - after two 30-min sessions on 1 day.     

Attention and suppression affect tactile perception in reach-to-grasp movements

Reaching with the hand is characterized by a decrease in sensitivity to tactile stimuli presented to the moving hand. Here, we investigated whether tactile suppression can be canceled by attentional orienting. In a first experiment, participants performed a dual-task involving a goal-directed movement paired with the speeded detection of a tactile pulse. The pulse was either delivered to the moving or stationary hand, during movement preparation, execution, or the post-movement phase. Furthermore, stimulation was delivered with equal probability to either hand, or with a higher probability to either the moving or resting hand. The results highlighted faster RTs under conditions of higher probability of stimulation delivery to both moving and resting hands, thus indicating an attentional effect. For the motor preparation period, RTs were faster only at the resting hand under conditions where tactile stimulation was more likely to be delivered there. In a second experiment, a non-speeded perceptual task was used as a secondary task and tactile discrimination thresholds were recorded. Tactile stimulation was delivered concomitantly at both index fingers either in the movement preparation period (both before and after the selection of the movement effector had taken place), in the motor execution period, or, in a control condition, in the time-window of motor execution, but the movement of the hand was restrained. In the preparation period, tactile thresholds were comparable for the two timings of stimulation delivery; i.e., before and after the selection of the movement effector had taken place. These results therefore suggest that shortly prior to, and during, the execution of goal-directed movements, a combined facilitatory and inhibitory influence acts on tactile perception.