Voluntary Suppression Research Articles

Intrinsic functional connectivity of right dorsolateral prefrontal cortex and hippocampus subregions relates to emotional and sensory-perceptual properties of intrusive trauma memories.

Trauma-related intrusive memories (TR-IMs), unwanted and vivid, are core symptoms of posttraumatic stress disorder (PTSD). Prior research links voluntary TR-IM suppression to inhibitory control of the right dorsolateral prefrontal cortex (dlPFC) over the hippocampus (HPC). However, the potential relevance of tonic resting-state inhibition has not been examined, nor has the functional differentiation of the anterior and posterior hippocampus (aHPC/HPC). This study examined relationships of TR-IM frequency and properties with resting-state negative coupling between the right dlPFC and right aHPC/pHPC in trauma-exposed individuals with PTSD symptoms. Participants (N=109; 88 female) completed two weeks of ecological momentary assessments capturing TR-IM frequency and properties (intrusiveness, emotional intensity, vividness, visual properties, and reliving). Using 3T resting-state magnetic resonance imaging, participant-specific 4-mm spheres were placed at the right dlPFC voxel most anticorrelated with the right aHPC and pHPC. Quasi-Poisson and linear mixed-effects models assessed relationships of TR-IM frequency and properties with right dlPFC-right aHPC and pHPC anticorrelation. TR-IM emotional intensity was positively associated with right dlPFC-aHPC connectivity, while vividness and visual properties were linked to right dlPFC-pHPC connectivity. No significant associations were found between TR-IM frequency, intrusiveness, or reliving, and anticorrelation with either HPC subregion. This study provides novel insights into the neural correlates of TR-IMs, highlighting the relevance of intrinsic negative coupling between the right dlPFC and aHPC/pHPC to their emotional impact and perceptual properties. Further research on inhibitory mechanisms in this circuit could improve understanding of component processes of intrusive reexperiencing, a severe and treatment-refractory PTSD symptom.

Vestibular prepulse inhibition of the human blink reflex

ObjectiveAuditory and somatosensory prepulses are commonly used to assess prepulse inhibition (PPI). The effect of a vestibular prepulse upon blink reflex excitability has not been hitherto assessed. MethodsTwenty-two healthy subjects and two patients with bilateral peripheral vestibular failure took part in the study. Whole body yaw rotation in the dark provided a vestibular inertial prepulse. Blink reflex was electrically evoked after the end of the rotation. The amplitude of R1 and the area-under-the-curve (area) of the blink reflex R2 and R2c responses were recorded and analysed. ResultsA vestibular prepulse inhibited the R2 (p < 0.001) and R2c area (p < 0.05). Increasing the angular acceleration did not increase the R2 and R2c inhibition (p > 0.05). Voluntary suppression of the vestibulo-ocular reflex did not affect the magnitude of inhibition (p > 0.05). Patients with peripheral vestibular failure did not show any inhibition. ConclusionsOur data support a vestibular gating mechanism in humans. SignificanceThe main brainstem nucleus mediating PPI – the pedunculopontine nucleus (PPN) – is heavily vestibular responsive, which is consistent with our findings of a vestibular-mediated PPI. Our technique may be used to interrogate the fidelity of brain circuits mediating vestibular-related PPN functions. Given the PPN’s importance in human postural control, our technique may also provide a neurophysiological biomarker of balance.

Antiferromagnetic artificial neuron modeling of the withdrawal reflex.

Replicating neural responses observed in biological systems using artificial neural networks holds significant promise in the fields of medicine and engineering. In this study, we employ ultra-fast artificial neurons based on antiferromagnetic (AFM) spin Hall oscillators to emulate the biological withdrawal reflex responsible for self-preservation against noxious stimuli, such as pain or temperature. As a result of utilizing the dynamics of AFM neurons, we are able to construct an artificial neural network that can mimic the functionality and organization of the biological neural network responsible for this reflex. The unique features of AFM neurons, such as inhibition that stems from an effective AFM inertia, allow for the creation of biologically realistic neural network components, like the interneurons in the spinal cord and antagonist motor neurons. To showcase the effectiveness of AFM neuron modeling, we conduct simulations of various scenarios that define the withdrawal reflex, including responses to both weak and strong sensory stimuli, as well as voluntary suppression of the reflex.

Observing the suppression of individual aversive memories from conscious awareness.

When reminded of an unpleasant experience, people often try to exclude the unwanted memory from awareness, a process known as retrieval suppression. Here we used multivariate decoding (MVPA) and representational similarity analyses on EEG data to track how suppression unfolds in time and to reveal its impact on item-specific cortical patterns. We presented reminders to aversive scenes and asked people to either suppress or to retrieve the scene. During suppression, mid-frontal theta power within the first 500ms distinguished suppression from passive viewing of the reminder, indicating that suppression rapidly recruited control. During retrieval, we could discern EEG cortical patterns relating to individual memories-initially, based on theta-driven visual perception of the reminders (0 to 500ms) and later, based on alpha-driven reinstatement of the aversive scene (500 to 3000ms). Critically, suppressing retrieval weakened (during 360 to 600ms) and eventually abolished item-specific cortical patterns, a robust effect that persisted until the reminder disappeared (780 to 3000ms). Representational similarity analyses provided converging evidence that retrieval suppression weakened the representation of target scenes during the 500 to 3000ms reinstatement window. Together, rapid top-down control during retrieval suppression abolished cortical patterns of individual memories, and precipitated later forgetting. These findings reveal a precise chronometry on the voluntary suppression of individual memories.

Separate Cue- and Alpha-Related Mechanisms for Distractor Suppression.

Research on selective attention has largely focused on the enhancement of behaviorally important information, with less focus on the suppression of distracting information. Enhancement and suppression can operate through a push-pull relationship attributable to competitive interactions among neural populations. There has been considerable debate, however, regarding (1) whether suppression can be voluntarily deployed, independent of enhancement, and (2) whether voluntary deployment of suppression is associated with neural processes occurring prior to the distractor onset. Here, we investigated the interplay between pre- and post-distractor neural processes, while male and female human subjects performed a visual search task with a cue that indicated the location of an upcoming distractor. We utilized two established EEG markers of suppression: the distractor positivity (PD) and alpha power (∼8-15 Hz). The PD-a component of event-related potentials-has been linked with successful distractor suppression, and increased alpha power has been linked with attenuated sensory processing. Cueing the location of an upcoming distractor speeded responses and led to an earlier PD, consistent with earlier suppression due to strategic use of a spatial cue. In comparison, higher predistractor alpha power contralateral to distractors led to a later PD, consistent with later suppression. Lower alpha power contralateral to distractors instead led to distractor-related attentional capture. Lateralization of alpha power was not linked to the spatial cue. This observation, combined with differences in the timing of suppression-as indexed by earlier and later PD components-demonstrates that cue-related, voluntary suppression can occur separate from alpha-related gating of sensory processing.

Working Mechanisms of Exposure and Response Prevention in the Treatment of Tourette Syndrome and Tic Disorders Revisited: No Evidence for within-Session Habituation to Premonitory Urges.

Exposure and response prevention (ERP) has been shown to be an effective treatment for Tourette syndrome (TS) and chronic tic disorders (CTD). ERP is based on voluntary tic suppression in combination with prolonged exposure to premonitory urges preceding tics. A prevailing hypothesis of the working mechanism underlying ERP in tics is habituation to the premonitory urges as a result of prolonged exposure. However, results so far are equivocal. This study aims to further explore the relation between urges and ERP in tics, by investigating the course of premonitory urges during ERP sessions. Using a data-driven approach, within-session habituation to premonitory urge intensity was investigated. In total, 29 TS patients rated urge intensity at seven timepoints during ten 1 h ERP sessions. Latent growth modeling showed an increase in urge intensity during the first 15 min of each session followed by a plateau in the remaining 45 min of the session. This does not support the idea of within-session habituation to premonitory urges as a working mechanism of ERP. Other potential underlying working mechanisms are discussed and should be tested in future research.

The Supplementary Motor Area and Automatic Cognitive Control: Lack of Evidence from Two Neuromodulation Techniques.

The SMA is fundamental in planning voluntary movements and execution of some cognitive control operations. Specifically, the SMA has been known to play a dominant role in controlling goal-directed actions as well as those that are highly predicted (i.e., automatic). Yet, the essential contribution of SMA in goal-directed or automatic control of behavior is scarce. Our objective was to test the possible direct role of SMA in automatic and voluntary response inhibition. We separately applied two noninvasive brain stimulation (NIBS) inhibitory techniques over SMA: either continuous theta-burst stimulation using repetitive transcranial magnetic stimulation or transcranial static magnetic field stimulation. Each NIBS technique was performed in a randomized, crossover, sham-controlled design. Before applying NIBS, participants practiced a go/no-go learning task where associations between stimulus and stopping behaviors were created (initiation and inhibition). After applying each NIBS, participants performed a go/no-go task with reversed associations (automatic control) and the stop signal task (voluntary control). Learning associations between stimuli and response initiation/inhibition was achieved by participants and therefore automatized during training. However, no significant differences between real and sham NIBS were found in either automatic (go/no-go learning task) or voluntary inhibition (stop signal task), with Bayesian statistics providing moderate evidence of absence. In conclusion, our results are compatible with a nondirect involvement of SMA in automatic control of behavior. Further studies are needed to prove a noncausal link between prior neuroimaging findings relative to SMA controlling functions and the observed behavior.

Modulation of cold-induced shivering activity by intermittent and continuous voluntary suppression.

This investigation assessed the physiological effects of voluntary suppression of shivering thermogenesis in response to whole body cooling. Eleven healthy volunteers underwent passive air cooling (10°C), across three visits: NO_SUP, where participants allowed their body to freely regulate against the cold; FULL_SUP, where participants constantly suppressed shivering; INT_SUP, where participants intermittently suppressed shivering (5 min phases), interspersed with 5 min free regulation. Shivering was assessed via electromyography (EMG), mechanomyography (MMG), and whole body oxygen uptake (V̇o2), whereas body temperature and heat exchange were assessed via skin temperature, rectal temperature, and heat flux sensors. A 29% increase was observed in shivering onset time in the FULL_SUP trial compared with NO_SUP (P = 0.032). Assessing shivering intensity, EMG activity decreased by 29% (P = 0.034), MMG activity decreased by 35% (P = 0.031), whereas no difference was observed in V̇o2 (P = 0.091) in the FULL_SUP trial compared with NO_SUP. Partitioning the no-suppression and suppression phases of the INT_SUP trial, acute voluntary suppression significantly decreased V̇o2 (P = 0.001), EMG (P < 0.001), and MMG (P = 0.012) activity compared with the no-suppression phases. Shivering activity was restored in the no-suppression phases, equivalent to that in the NO_SUP trial (P > 0.3). No difference was observed in thermal metrics between conditions up to 60 min (P > 0.4). Humans can both constantly and periodically suppress shivering activity, leading to a delay in shivering onset and a reduction in shivering intensity. Following suppression, regular shivering is resumed.

EFFECTIVENESS OF ACUPRESSURE PEN WITH ALEXANDER TECHNIQUE IN PARTICIPANTS WITH LOW BACK PAIN AMONG BUS DRIVERS- A RANDOMIZED CONTROLLED TRIAL

Background: Low back pain has a signicant impact on functional capacity, as pain restricts occupational activities and is a major cause of malingering. Acupressure is originated from China basically and it is in use from ages in every disease and disorders to treat participants with manual acupressure and after a time electro acupressure came into introduction. Frederick Matthias Alexander, founder of the Alexander technique and it uses enhanced kinaesthetic awareness and voluntary inhibition to prevent non-benecial movement pattern. Aim:To nd out the effect of acupressure pen with alexander technique in low back pain among bus drivers. Objectives:To decrease pain sensitivity To improve exercise tolerance and endurance To compare the experimental group to the control group Method: Thirty participants were selected based on inclusion and exclusion criteria. They were treated with acupressure pen for three days/week and AT for ve days/week Results:The data was analyzed using SPSS Version22. Parametric test was used. In group A improvement was seen. Conclusions: Acupressure pen along with Alexander technique are effective to reduce low back pain and improve daily life activities among bus drivers.

Voluntary suppression of neck reflexes during passive head-on-trunk rotations: reflex gain control versus proprioceptive feedback.

Normal subjects can completely eliminate resistance upon imposed head-on-trunk rotations when they are asked to relax. It is not, however, clear how neck reflexes to stretch can be voluntarily suppressed. Reflexive responses might be modified by adjusting the gain of the reflex loop through descending control. Theoretically, necessary corrections upon interfering disturbances during coordinated motor performance requiring the interplay of relaxation/activation may be missing if muscle relaxation is taking place exclusively by this mechanism. It has been alternatively proposed that sensory information from the periphery may be allowed to "neutralize" neck reflexes if it is fed back with opposite sign to the structures driving the reflexes. Six healthy subjects were asked to relax while subjected to head-on-trunk rotations generated by a head motor. After any initial resistance had completely subsided, the head was unexpectedly exposed to "ramp-and-hold" perturbations of up to 2° amplitude and 0.7 s duration. Resistance to stretch consistently reappeared thereupon, suggesting that stretch reflex gain had not been set to zero during the previously achieved complete relaxation. Resistance to perturbations under these circumstances was compared with the forces generated when the same ramp-and-hold displacements were delivered unpredictably to the head held stationary. A quantitative model of neck proprioceptive reflexes suppression has been thus constructed. Gain scheduling or "motor set" cannot sufficiently account for the voluntary reflex suppression during slow passive head rotations. Instead, we propose as underlying mechanism, the "neutralization" of the controlling servo by means of continuous feedback tracking displacement and force signals from the periphery.NEW & NOTEWORTHY Head stabilizing neck reflexes can be voluntarily suppressed or activated depending on the task at hand. By applying brief perturbations unexpectedly, both during passive head-on-trunk movements and at rest, we investigated the mechanism of voluntary suppression of resistance to stretch. A physiologically plausible, neuromechanical model of voluntary/reflexive interactions was constructed favoring feedback over reflex gain adjustments. Accordingly, muscle relaxation during imposed head movements is based on sensory feedback similarly to muscle contractions during purposeful movements.

Voluntary suppression of associated activity decreases force steadiness in the active hand.

Unilateral muscle contractions are often accompanied by the activation of the ipsilateral hemisphere, producing associated activity (AA) in the contralateral homologous muscles. However, the functional role of AA is not fully understood. We determined the effects of voluntary suppression of AA in the first dorsal interosseous (FDI), on force steadiness during a constant force isometric contraction of the contralateral FDI. Participants (n = 17, 25.5 years) performed two trials of isometric FDI contractions as steadily as possible. In Trial 1, they did not receive feedback or explicit instructions for suppressing the AA in the contralateral homologous FDI. In Trial 2, participants received feedback and were asked to voluntarily suppress the AA in the contralateral nontarget FDI. During both trials, corticospinal excitability and motor cortical inhibition were measured. The results show that participants effectively suppressed the AA in the nontarget contralateral FDI (-71%), which correlated with reductions in corticospinal excitability (-57%), and the suppression was also accompanied by increases in inhibition (27%) in the ipsilateral motor cortex. The suppression of AA impaired force steadiness, but the decrease in force steadiness did not correlate with the magnitude of suppression. The results show that voluntary suppression of AA decreases force steadiness in the active hand. However, due to the lack of association between suppression and decreased steadiness, we interpret these data to mean that specific elements of the ipsilateral brain activation producing AA in younger adults are neither contributing nor detrimental to unilateral motor control during a steady isometric contraction.

Voluntary Inhibition of Physiological Mirror Activity: An EEG-EMG Study.

Physiological mirror activity (pMA), observed in healthy human adults, describes the involuntary co-activation of contralateral homologous muscles during unilateral limb movements. Here we provide novel evidence, using neuromuscular measurements (electromyography; EMG), that the amplitude of pMA can be voluntarily inhibited during unilateral isometric contractions of intrinsic hand muscles after informing human participants (10 male, 10 female) about its presence and establishing a basic understanding of pMA mechanisms through a standardized protocol. Importantly, significant suppression of pMA was observed immediately after participants were asked to inhibit it, despite the absence of any online feedback during task execution and without special training. Moreover, we observed that the decrease of pMA was specifically accompanied by an increase in relative frontal δ power recorded with electroencephalography (EEG). Correlation analysis further revealed an inverse association between the individual amplitude of pMA and frontal δ power that reached significance once participants started to inhibit. Taken together, these results suggest that δ power in frontal regions might reflect executive processes exerting inhibitory control over unintentional motor output, in this case pMA. Our results provide an initial reference point for the development of therapeutic applications related to the neurorehabilitation of involuntary movements which could be realized through the suppression of pMA observed in the elderly before it would fully manifest in undesirable overt movement patterns.

The Effect of Pain Conditioning on Experimentally Evoked Cough: Evidence of Impaired Endogenous Inhibitory Control Mechanisms in Refractory Chronic Cough.

The pathophysiology of refractory chronic cough (RCC) is unclear. We hypothesised that endogenous inhibitory control mechanisms, such as those activated by noxiousstimuli inducing pain (conditioned pain modulation (CPM)), may be capable of inhibiting coughing and urge to cough evoked by inhaled capsaicin. Furthermore, these mechanisms may be impaired in patients with RCC.The objective was to investigate the effects of pain on cough and urge to cough (UTC) in healthy volunteers (HV) and RCC. HV and RCC patients underwent a randomised, controlled, 4-way cross-over study comparing the effect of 4 interventions on capsaicin evoked coughing and UTC. The interventions comprised immersing a hand in i) noxious cold-water, ii) warm water, iii) warm water but instructed to voluntarily supress coughing and iv) no intervention. The co-primary outcomes were numbers of evoked coughs and UTC scores.Twenty HV (mean age 50.1(±SD14.2), M:F 10:10) and 20 RCC (age 60.1(±7.9), M:F 9:11) participated. Overall, noxious cold water reduced capsaicin evoked UTC scores and cough numbers compared with warm water (1.6 (95% C.I. 1.3-2.0) versus 2.2 (1.8-2.6) p<0.001; 4.8 coughs (3.7-6.2) versus 7.9 coughs (6.7-9.5) p<0.001, respectively). HV and RCC demonstrated similar reductions in the UTC during noxious cold-water immersion, but noxious cold water and voluntary suppression interventions were less effective in RCC than HV in reducing capsaicin evoked cough (p=0.041).Endogenous inhibitory control mechanisms, specifically those activated by pain, can reduce both coughing and the UTC. Impairment of endogenous inhibitory control mechanisms may contribute to excessive coughing in RCC.

Combinational Approach of Genetic SHP-1 Suppression and Voluntary Exercise Promotes Corticospinal Tract Sprouting and Motor Recovery Following Brain Injury

Background. Brain injury often causes severe motor dysfunction, leading to difficulties with living a self-reliant social life. Injured neural circuits must be reconstructed to restore functions, but the adult brain is limited in its ability to restore neuronal connections. The combination of molecular targeting, which enhances neural plasticity, and rehabilitative motor exercise is an important therapeutic approach to promote neuronal rewiring in the spared circuits and motor recovery. Objective. We tested whether genetic reduction of Src homology 2-containing phosphatase-1 (SHP-1), an inhibitor of brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signaling, has synergistic effects with rehabilitative training to promote reorganization of motor circuits and functional recovery in a mouse model of brain injury. Methods. Rewiring of the corticospinal circuit was examined using neuronal tracers following unilateral cortical injury in control mice and in Shp-1 mutant mice subjected to voluntary exercise. Recovery of motor functions was assessed using motor behavior tests. Results. We found that rehabilitative exercise decreased SHP-1 and increased BDNF and TrkB expression in the contralesional motor cortex after the injury. Genetic reduction of SHP-1 and voluntary exercise significantly increased sprouting of corticospinal tract axons and enhanced motor recovery in the impaired forelimb. Conclusions. Our data demonstrate that combining voluntary exercise and SHP-1 suppression promotes motor recovery and neural circuit reorganization after brain injury.

Neurofeedback-Linked Suppression of Cortical β Bursts Speeds Up Movement Initiation in Healthy Motor Control: A Double-Blind Sham-Controlled Study.

Abnormally increased β bursts in cortical-basal ganglia-thalamic circuits are associated with rigidity and bradykinesia in patients with Parkinson's disease. Increased β bursts detected in the motor cortex have also been associated with longer reaction times (RTs) in healthy participants. Here we further hypothesize that suppressing β bursts through neurofeedback training can improve motor performance in healthy subjects. We conducted a double-blind sham-controlled study on 20 human volunteers (10 females) using a sequential neurofeedback-behavior task with the neurofeedback reflecting the occurrence of β bursts over sensorimotor cortex quantified in real time. The results show that neurofeedback training helps healthy participants learn to volitionally suppress β bursts in the sensorimotor cortex, with training being accompanied by reduced RT in subsequent cued movements. These changes were only significant in the real feedback group but not in the sham group, confirming the effect of neurofeedback training over simple motor imagery. In addition, RTs correlated with the rate and accumulated duration of β bursts in the contralateral motor cortex before the go-cue, but not with averaged β power. The reduced RTs induced by neurofeedback training positively correlated with reduced β bursts across all tested hemispheres. These results strengthen the link between the occurrence of β bursts in the sensorimotor cortex before the go-cue and slowed movement initiation in healthy motor control. The results also highlight the potential benefit of neurofeedback training in facilitating voluntary suppression of β bursts to speed up movement initiation.SIGNIFICANCE STATEMENT This double-blind sham-controlled study suggested that neurofeedback training can facilitate volitional suppression of β bursts in sensorimotor cortex in healthy motor control better than sham feedback. The training was accompanied by reduced reaction time (RT) in subsequent cued movements, and the reduced RT positively correlated with the level of reduction in cortical β bursts before the go-cue, but not with average β power. These results provide further evidence of a causal link between sensorimotor β bursts and movement initiation and suggest that neurofeedback training could potentially be used to train participants to speed up movement initiation.

Voluntary tic suppression and the normalization of motor cortical beta power in Gilles de la Tourette syndrome: an EEG study.

Gilles de la Tourette syndrome (GTS) is a neurological condition characterized by motor and vocal tics. Previous studies suggested that this syndrome is associated with abnormal sensorimotor cortex activity at rest, as well as during the execution of voluntary movements. It has been hypothesized that this abnormality might be interpreted as a form of increased tonic inhibition, probably to suppress tics; however, this hypothesis has not been tested so far. The present study was designed to formally test how voluntary tic suppression in GTS influences the activity of the sensorimotor cortex during the execution of a motor task. We used EEG to record neural activity over the contralateral sensorimotor cortex during a finger movement task in adult GTS patients, in both free ticcing and tic suppression conditions; these data were then compared with those collected during the same task in age-matched healthy subjects. We focused on the levels of activity in the beta frequency band, which is typically associated with the activation of the motor system, during three different phases: a pre-movement, a movement, and a post-movement phase. GTS patients showed decreased levels of beta modulation with respect to the healthy controls, during the execution of the task; however, this abnormal pattern returned to be normal when they were explicitly asked to suppress their tics while moving. This is the first demonstration that voluntary tic suppression in GTS operates through the normalization of the EEG rhythm in the beta frequency range during the execution of a voluntary finger movement.

Volitional Suppression of Parkinsonian Resting Tremor.

We have observed in the clinic that a number of patients with Parkinson's disease (PD) can suppress their tremor at will for brief periods, by conscious mental processes. To our knowledge, the ability to consciously diminish one's resting tremor has not yet been reported nor assessed quantitatively. To provide the first detailed systematic investigation of the phenomenon of voluntary tremor suppression in PD. We examined changes in tremor characteristics during voluntary tremor suppression in 37 PD patients (on medication) presenting with rest tremor in their upper limb. We measured tremor oscillations with a triaxis accelerometer on the index finger of the most-affected hand (n = 27). With surface electromyography (EMG), we measured changes in neuromuscular activity of the forearm flexor digitorum superficialis and extensor digitorum muscles (n = 15). Participants completed four 1-minute trials, consisting of alternating consecutive 30-second periods of resting tremor and 30-second periods of attempted tremor suppression. Bayesian multilevel modeling revealed that attempted voluntary tremor suppression did indeed reduce tremor amplitude (peak power) of the acceleration signal and increased tremor frequency of the acceleration and EMG signals. Relative EMG power in the 3- to 8-Hz tremor band was also smaller. Tremor suppression was not by enhanced voluntary contraction of the relevant muscle pairs. We present novel empirical evidence that PD resting tremor can be suppressed by an act of will, as evidenced by significant modulation of key neurophysiological tremor characteristics. These data highlight that it is possible to exert significant conscious control over parkinsonian resting tremor.

Tic Suppression in Children With Recent-Onset Tics Predicts 1-Year Tic Outcome.

Successful voluntary tic suppression is a key component of the behavioral interventions that are used to treat tic disorders. This study aimed to examine tic suppression in children with recent-onset tics and determine whether the capacity to suppress tics predicts future tic severity. We tested 45 children (30 male, mean age 7.74 years) with recent-onset tics (mean 3.47 months prior to the first study visit; baseline) and re-examined each child at the 12-month anniversary of the first recognized tic (follow-up). At the baseline visit, children performed a tic suppression task with several conditions: tic freely, inhibit tics given a verbal request, and inhibit tics in the presence of a reward. At the baseline visit, children with tics for only a few months could suppress their tics, and tic suppression was especially successful when they received an immediate and contingent reward. Additionally, the ability to suppress tics in the presence of a reward predicted tic severity at follow-up. These findings suggest that better inhibitory control of tics within months of tic onset may be an important predictor of future tic symptom outcome.

Oculomotor inhibition of salient distractors: Voluntary inhibition cannot override selection history

ABSTRACTSeveral studies have demonstrated that salient distractors can be proactively inhibited to prevent attentional capture. Traditional theories frame attentional guidance effects such as this in terms of explicit goals. However, several researchers have recently argued that that unconscious factors – such as the features of attended and ignored items on previous trials (called selection history) – play a stronger role in guiding attention and can overpower explicit goals. The current study assessed whether voluntary inhibition can overpower selection history. We directly compared both forms of top-down control by measuring overt eye movements, which offer an unambiguous measure of which location has won the competition for attention. We repeatedly found that selection history overpowered any effects of voluntary goals, such that observers were unable to avoid fixating a salient distractor of a known color if the target had been presented in that color on the previous trial. Moreover, a salient distractor of a particular color captured gaze even when the observer had voluntarily chosen this color to be the distractor color just moments before. Taken together, these experiments suggest that the ability to inhibit a salient color singleton is primarily a result of recent experience and not a result of explicit goals.

P300 in detecting concealed information and deception: A review.

Studies using the P300 ERP in detection of concealed information are reviewed. An overview of the initial findings, methodological issues, and use of bootstrapping methods for data analysis are considered, with various protocols explicated. Applications to forensic issues, employee screening, cognitive deficit malingering, and facial recognition in lineups are outlined. Countermeasures to the original P300-based tests are described, and a possible approach to this problem using a new complex-trial protocol is offered. Applications of this protocol to forensic and antiterror scenarios are then presented, along with its first independent replication. Studies of visual versus auditory stimulus presentation in the complex-trial protocol are evaluated. Findings from attempted voluntary suppression of P300 as a recognition signal are presented, and the effects of motivational manipulations on the P300-based complex-trial protocol are summarized. Limitations of the research are reviewed, and, based on this review, future directions of P300 methods for detection of concealed information and deception are suggested that may guide the development of more precision and reliability of this promising tool.