Impulsive responses in children with conduct disorder and borderline intellectual functioning.

The study is designed to investigate response inhibition in children with conduct disorder and borderline intellectual functioning. To this end, children are compared to a normal peer control group using the Alertness test. The test has two conditions. In one condition, children are instructed to push a response button after a visual "go" signal is presented on the screen. In a second condition the "go" signal is preceded by an auditory signal, telling the child that a target stimulus will occur soon. Compared to the control group, the group carrying the dual diagnosis made many preliminary responses (responses before the presentation of the "go" signal), especially in the condition with an auditory signal. This impulsive response style was controlled for attention deficit/hyperactivity disorder characteristics of the children.     

Impulsive Responses In Children with Conduct Disorder and Borderline Intellectual Functioning

The study is designed to investigate response inhibition in children with conduct disorder and borderline intellectual functioning. To this end, children are compared to a normal peer control group using the Alertness test. The test has two conditions. In one condition, children are instructed to push a response button after a visual “go” signal is presented on the screen. In a second condition the “go” signal is preceded by an auditory signal, telling the child that a target stimulus will occur soon. Compared to the control group, the group carrying the dual diagnosis made many preliminary responses (responses before the presentation of the “go” signal), especially in the condition with an auditory signal. This impulsive response style was controlled for attention deficit/hyperactivity disorder characteristics of the children.     

Deficit in Response Inhibition in Children with Attention Deficit/Hyperactivity Disorder (ADHD): Impact of Motivation?

To date, neuropsychological and psycho-physiological studies have revealed inconsistent results regarding an executive or motivational deficit explaining the response inhibition deficit in children with attention deficit/hyperactivity disorder (ADHD). Research on differentiating neuropsychological processes in ADHD subtypes is still scarce. Therefore, the motivational impact on response inhibition among boys with ADHD was examined in this study. In the first study, 19 boys with ADHD-combined type (ADHD-C) and 19 age-matched healthy control subjects performed a modified Go/No-Go task with the following experimental conditions: neutral, auditory feedback, reward, response cost, and reward/response cost. Performance and physiological data (heart rate and skin conductance responses) were recorded. In a second study with the modified Go/No-Go task, data for six children with ADHD-C, six with ADHD-inattentive subtype (ADHD-I), and six healthy control subjects were compared. Neither of the two studies revealed group by condition interactions. In study 1, boys with ADHD-C generally made more commissions and omissions compared to the control group. However, feedback significantly improved the response inhibition in all children. The heart rate of all children was increased in the two conditions of reward and reward/response cost. Study 2 revealed that children with ADHD-I responded more slowly and showed increased reaction time variability compared to both other groups. The present study supports an executive rather than a motivational deficit in the response inhibition among children with ADHD-C, though further results also indicate the role of auditory feedback on response inhibition. Additionally, the findings support the differentiation of ADHD-C and ADHD-I, suggesting that ADHD-I children are characterized by a sluggish cognitive tempo.     

Training and transfer effects of response inhibition training in children and adults

Response inhibition is crucial for mental and physical health but studies assessing the trainability of this type of inhibition are rare. Thirty‐nine children aged 10‐12 years and 46 adults aged 18‐24 years were assigned to an adaptive go/no‐go inhibition training condition or an active control condition. Transfer of training effects to performance on tasks assessing response inhibition, interference control, working memory updating, task‐switching, and non‐verbal fluid intelligence were assessed during 3‐ and 6‐month follow‐up sessions and/or an immediate post‐training session. Significant training improvements and positive transfer effects to a similar response inhibition task with other stimuli were observed for both children and adults. Reliable albeit short‐lived transfer effects were only found for the children, specifically to working memory updating and task switching. These results suggest some potential for response‐inhibition training programs to enhance aspects of cognitive functioning in children but not adults.     

The effect of reinforcement variables on inhibition in children with ADHD.

Behavioral inhibition, often cited as a central deficit in children with ADHD, has been shown to change in response to reinforcement. In this preliminary investigation, children with ADHD (n= 20) and matched controls (ages 7 to 12) completed a new version of the stop signal paradigm, the Fire Fighter Game, a measure of inhibition of a prepotent motor response, under three conditions: (1) no reinforcement; (2) immediate reinforcement; and (3) delayed reinforcement. In all conditions, the stop signal reaction time (SSRT) of children with ADHD was consistently longer than controls. Both groups improved significantly with reinforcement, and there was no strong evidence that immediate reinforcement was more effective than delayed reinforcement. However, it appeared that the reason for the changes in SSRT in response to reinforcement differed between the groups. Children in the control group responded faster on go trials, whereas children with ADHD improved their ability to inhibit responding with shorter stop delays. The relevance of these findings is discussed in terms of current theories of ADHD.     

激活水平对两亚型ADHD儿童反应执行与抑制能力的影响

研究选取了混合型ADHD儿童14名,注意缺陷型ADHD儿童16名以及正常儿童18名,考察了在不同激活水平下,两亚型ADHD儿童之间,及其与正常儿童之间的反应执行能力与抑制能力的异同。采用传统的go/no-go任务,并将刺激间的时间间隔设置为1秒、4秒、8秒三种条件,分别对应高、中、低三种激活水平。结果发现,(1)与正常儿童相比,ADHD儿童的反应执行能力更容易受到激活水平的影响,且两亚型ADHD儿童受到的影响模式基本一致。具体而言:在高激活水平下,ADHD儿童与正常儿童差异最小;在中、低激活水平下,ADHD儿童与正常儿童差异增大,表明ADHD儿童状态调节能力落后。(2)两亚型ADHD儿童的功能缺损模式不同,混合型儿童在状态调节和反应抑制两方面都存在缺损,且其反应抑制缺陷不受激活水平影响;注意缺陷型儿童仅在状态调节方面受损。     

Underlying processes in the poor response inhibition of children with Attention-Deficit/Hyperactivity Disorder

This study evaluated the effects of reward, punishment, and reward + punishment on the impulsive responses of ADHD children. The impulsive responses of ADHD and normal control boys (30 per group) were compared during performance of a go/no-go task, administered under reward-only, punishment-only, and reward + punishment conditions. When differences in aggression, anxiety, and IQ between these groups were controlled for, results indicated that the impulsivity levels of the ADHD group were higher than the control group in all three reinforcement conditions. Also, the ADHD group was more impulsive in the reward + punishment condition, compared to the reward-only and punishment-only conditions, and there was no difference between the reward-only and punishment-only conditions. The control groups showed no difference across the three reinforcement conditions. These findings raise the possibility that the poor response inhibition of ADHD children may be related to both a generalized inhibitory deficit and a response modulation deficit.     

Restraint and Cancellation: Multiple Inhibition Deficits in Attention Deficit Hyperactivity Disorder

We used variations of the stop signal task to study two components of motor response inhibition—the ability to withhold a strong response tendency (restraint) and the ability to cancel an ongoing action (cancellation)—in children with a diagnosis of attention deficit hyperactivity disorder (ADHD) and in non-ADHD controls of similar age (ages 7–14 years). The goal was to determine if restraint and cancellation were related and if both were deficient in ADHD. The stop signal task involved a choice reaction time task (go task) which required a rapid response. The demand for inhibitory control was invoked through the presentation of a stop signal on a subset of go trials which required that the ongoing response be suspended. The stop signal was presented either concurrently with the go signal (restraint version) or after a variable delay (cancellation version). In Study 1, we compared ADHD and control children on the cancellation version of the stop task; in Study 2, we compared ADHD and controls on the restraint version. In Study 3, a subset of ADHD and control participants completed both tasks so that we could examine convergence of these dimensions of inhibition. Compared to control participants, ADHD participants showed a deficit both in the ability to cancel and to restrain a speeded motor response. Performance on the restraint version was significantly correlated with performance on the cancellation version in controls, but not in ADHD participants. We conclude that ADHD is associated with deficits in both restraint and cancellation subcomponents of inhibition.     

Very Low Birth Weight and Attention Deficit/Hyperactivity Disorder

It is well recognized that reaction time performance of term-born children with a normal birth weight (NBW > 2500 g) who fulfill the DSM-IV criteria for attention deficit/hyperactivity disorder (ADHD) in the primary school age is sensitive for the presentation rate of stimuli. They have been found to perform more poorly in conditions of relatively slow event rates as compared with fast event rates. The purpose of the current study was to explore whether reaction time performance of children with very low birth weight (VLBW < 1500 g) with or without ADHD showed the same sensitivity for the factor presentation rate of stimuli compared to children with a normal birth weight plus ADHD. To this end, reaction time performance of four groups of children was compared on a Go/No-Go test with a fast presentation rate of 1 second and a slow presentation rate of 6 seconds. Groups were: children with VLBW plus ADHD, children with VLBW only, children born full term with normal birth weight (NBW >2500 g) plus ADHD, and children born full term without ADHD (the control group). Findings indicated that, compared to the non-ADHD groups, the groups with ADHD (NBW and VLBW) showed a more dramatic decline in their reaction time performance in the slow condition: a state regulation deficit. In addition, both groups showed a response inhibition deficit. No difference was found in reaction time performance between the groups of children with VLBW only and the control group.     

Differential effects of social and non‐social reward on response inhibition in children and adolescents

An important issue in the field of clinical and developmental psychopathology is whether cognitive control processes, such as response inhibition, can be specifically enhanced by motivation. To determine whether non‐social (i.e. monetary) and social (i.e. positive facial expressions) rewards are able to differentially improve response inhibition accuracy in typically developing children and adolescents, an ‘incentive’ go/no‐go task was applied with reward contingencies for successful inhibition. In addition, the impact of children's personality traits (such as reward seeking and empathy) on monetary and social reward responsiveness was assessed in 65 boys, ages 8 to 12 years. All subjects were tested twice: At baseline, inhibitory control was assessed without reward, and then subjects were pseudorandomly assigned to one of four experimental conditions, including (1) social reward only, (2) monetary reward only, (3) mixed social and monetary reward, or (4) a retest condition without reward. Both social and non‐social reward significantly improved task performance, although larger effects were observed for monetary reward. The higher the children scored on reward seeking scales, the larger was their improvement in response inhibition, but only if monetary reward was used. In addition, there was a tendency for an association between empathic skills and benefits from social reward. These data suggest that social incentives do not have an equally strong reinforcing value as compared to financial incentives. However, different personality traits seem to determine to what extent a child profits from different types of reward. Clinical implications regarding probable hyposensitivity to social reward in subjects with autism and dysregulated reward‐seeking behaviour in children with attention‐deficit/hyperactivity disorder (ADHD) are discussed.     

Evidence for an Error Monitoring Deficit in Attention Deficit Hyperactivity Disorder

We studied error monitoring in ADHD and control children in a task requiring inhibition of a motor response. The extent of slowing following successful (stopped) and failed (nonstopped) inhibition was compared across groups. We also measured the time required to inhibit a response (stop signal reaction time, SSRT). Compared to controls, ADHD participants slowed less following nonstopped responses. Slowing did not vary with comorbid reading, oppositional, conduct or anxiety disorder, sex or ADHD subtype. Slowing after nonstopped responses was marginally, although significantly correlated with total ADHD symptoms and with age. ADHD participants had significantly longer SSRT than controls, but SSRT was not significantly correlated with slowing. The apparent deficit in error monitoring in ADHD and its independence from the inhibition deficit observed in ADHD has implications for executive control models of ADHD, performance problems associated with the disorder and for component theories of executive control.     

Response inhibition and interference control: Effects of schizophrenia,genetic risk,and schizotypy

The ability to inhibit inappropriate responses and suppress irrelevant information is a core feature of executive control. In this study, we provide a detailed analysis of prepotent response inhibition and interference in patients with schizophrenia. To further test the role of genetic factors and subclinical schizophrenia‐like traits, we additionally studied clinically unaffected, first‐degree relatives of schizophrenia patients and assessed dimensions of schizotypy in both relatives and healthy controls. Inhibition and interference control were assessed using a battery comprising the antisaccade, Stroop, stop signal, go/no‐go, flanker, and Simon tasks. Schizophrenia patients differed from both relatives and controls in making more errors on the antisaccade task and having longer response times on the Stroop task, especially the incongruent condition. Patients also had general, that is, condition independent, increases in reaction times on the go/no‐go and flanker tasks and made more errors on the flanker and Simon tasks, suggesting general performance impairments independent of inhibitory demand. Relatives were characterized by hypometric antisaccade amplitude gain despite normal prosaccades, suggesting a selective deficit in non‐standard sensorimotor transformations. Schizotypy was correlated with inhibitory performance across a number of tasks in both relatives and controls. Generally, these effects were independent of verbal intelligence levels. Overall, the findings point to rather selective impairments of inhibitory control in the schizophrenia spectrum and confirm a previously observed deficit in antisaccade spatial accuracy as an endophenotype of schizophrenia.     

Hot and Cool Aspects of Cognitive Control in Children with ADHD: Decision-Making and Inhibition

This study investigated hot and cool aspects of cognitive control in children with Attention Deficit Hyperactivity Disorder (ADHD). The study aimed to: (1) replicate the postulated response inhibition deficit of children with ADHD; (2) explore whether children with ADHD choose disadvantageously in a decision-making task and to explore the mechanisms underlying the expected response pattern; and (3) study whether performance on a combination of hot and cool executive control measures has predictive value for an ADHD diagnosis. The sample consisted of 20 children with ADHD and 22 normal developing children (NC, 8 to 12 years) matched on age, FSIQ, and gender. Two paradigms have been applied: (1) the stop signal paradigm, and (2) the adapted children's version of the IOWA Gambling task. There were no group differences for both paradigms. Both groups chose in a reward-oriented manner and seemed to develop the ability to take future consequences into account in making decisions. Moreover, feedback resulted in direct behavioral changes. Children with ADHD did not have a specific response inhibition deficit or a decision-making deficit.     

奖惩对行为抑制及程序阶段中自主生理反应的影响

采用停止信号任务探讨奖惩条件对行为抑制和程序阶段中自主生理反应的影响。结果显示：(1)奖惩组的反应时显著高于控制组, 抑制失败率则显著低于控制组; (2)奖励组与其它两组相比表现出心率显著增加和皮肤电活动显著降低; (3)各生理指标在准备、工作和奖惩阶段中的奖惩差异性显著(4)奖惩条件下皮肤电活动呈现出一致性程序阶段变化。结果表明：奖惩条件均对行为具有抑制作用, 但在自主生理反应上则有显著差异; 各生理指标在准备、工作和奖惩阶段的情绪效价显著; 皮肤电活动的程序阶段变化显著, 但其奖惩效价较为稳定, 很少接受程序阶段变化的影响。     

Stimulus-response incompatibility effects on event-related potentials in children with attention-deficit hyperactivity disorder

In order to test the hypothesis of a response choice deficit in attention-deficit hyperactivity disorder (ADHD) children, event-related potentials (ERPs) were recorded from 30 scalp electrodes in 21 ADHD and 21 normal boys during a spatial stimulus-response compatibility (SRC) task. ADHD children made fewer correct responses than control children, but did not show a larger incompatibility effect on response speed and accuracy. In ERPs, ADHD children had longer N1 latency and larger condition effect on the frontal N2, which would reflect a greater frontal involvement for the correct responses. The ADHD group who performed the SRC task first showed a larger condition effect on an early occipital P3 only, while the ADHD group who performed the SRC task second showed a larger condition effect on a later central P650 component and on a late parietal NSW, as compared with normal controls. These results suggest strategic differences in information processing in ADHD children, rather than a specific deficit.     

奖惩对行为抑制能力和自主生理活动影响的时效性

将45名被试随机分配为奖励组、惩罚组和对照组, 实验进程按时间发展过程被分为五阶段, 采用停止信号任务探讨奖惩刺激对行为抑制能力和自主生理活动影响的时效性。结果显示：奖惩刺激对行为反应时和抑制失败率影响仅在第二、三阶段差异显著, 对心率影响的显著差异在第三阶段结束、而对皮电和指温影响的显著差异仍持续到第五阶段。结果表明：奖惩刺激对行为的抑制作用具有时效性, 有效时间内表现为仅奖励能提高行为抑制能力; 奖惩刺激对心率的影响具有时效性, 但对其它生理指标的影响则未显示出时效性。     

Mood and the DRM paradigm: An investigation of the effects of valence and arousal on false memory

Recent studies regarding the effect of mood on the DRM (Deese–Roediger–McDermott) illusion have not been able to clearly establish yet whether valence or arousal is most critical in determining susceptibility to false memories, nor what the underlying processes are. In three experiments, both the valence and the level of arousal of participants' mood were manipulated. Six conditions were used: positive mood with high/low arousal, negative mood with high/low arousal, neutral mood, and a control condition. Memory was tested by means of immediate and delayed recognition and immediate free recall. The mood induction procedure was effective. For recognition memory, there was an effect of arousal on the endorsement of critical lures. Low-arousal moods elicited more false recognition than high-arousal moods, regardless of valence. Based on signal detection analyses, the effect was attributed to more liberal response criteria with low arousal, in combination with a tendency towards improved item-specific memory with high arousal.     

高功能自闭症儿童不同常规度转喻加工的发展：来自ERP的证据

采用ERP技术考察了6~11岁高功能自闭症（HFA）儿童常规和新奇转喻的认知加工过程及发展轨迹。结果显示,6~8岁HFA组和典型发展（TD）组加工常规和新奇转喻的N400波幅无差异,未出现常规度效应,其波幅与错误句也无差异。9~11岁HFA组对新奇转喻N400波幅负于常规转喻,出现常规度效应,常规转喻N400波幅异于错误句,9~11岁TD组常规和新奇转喻均异于错误句。6~8岁HFA组对常规转喻N400差异波负于9~11岁,6~8岁TD组对常规和新奇转喻均负于9~11岁。HFA组转喻N400波幅均负于TD组。结论：HFA儿童常规和新奇转喻的加工较TD儿童存在缺陷。从6岁到11岁,HFA儿童常规转喻加工随年龄增长显著提高,新奇转喻则未出现明显变化,较之常规转喻,新奇转喻的加工尤为困难。     

A Simple Measure of Interviewer and Interviewee Speech Durations

A hypothesis that peer pressure affects delay-of-gratification behavior was tested by comparing the private vs. public responses of Cree children to the offer of an immediate reward or a larger delayed reward. One group of children was twice tested in private. Another group was first tested in private and then in public. In both testings approximately 65% of the control group chose an immediate reward. The experimental group, however, although preferring an immediate reward in private, in public elected to go along with the choices of their classmates, many reversing themselves and choosing a delayed rather than immediate reward.     

Response monitoring, the error-related negativity, and differences in social behavior in autism

Children with autism not only display social impairments but also significant individual differences in social development. Understanding the source of these differences, as well as the nature of social impairments, is important for improved diagnosis and treatments for these children. Current theory and research suggests that individual differences in response monitoring, a specific function of the anterior cingulate cortex (ACC), may contribute to social-emotional and social-cognitive impairments and individual differences in autism. To examine this hypothesis, we used a modified flanker task to assess an ERP index of response monitoring, the error-related negativity (ERN), in a sample of higher function children with autism (HFA) and an IQ-matched control sample. The results revealed a significant Diagnostic group by Verbal IQ interaction on ERN amplitude indicating that the most verbally capable HFA children displayed significantly larger ERN amplitudes than did the control children. Within the HFA sample, greater ERN amplitude was also related to parent reports of fewer symptoms of social interaction impairments, fewer internalizing problems, but more externalizing problems, although these associations were reduced to nonsignificance when medication status was controlled. The latter results complement previous observations from imaging studies of a significant association between ACC activity and social symptoms and impairments in autism. The implications of these results for future research on brain-behavior relations, as well as treatment related research with children with autism are discussed.