Response Inhibition Processes Research Articles

Effects of ISI and stimulus probability on event-related go/nogo potentials after somatosensory stimulation

The present study investigated the characteristics of the middle-latency negative potential of event-related potentials (ERPs) using somatosensory go/nogo tasks. We manipulated interstimulus interval (ISI) in Experiment 1 and stimulus probability in Experiment 2 and analyzed the subtracted difference waveform resulting from subtraction of the ERP evoked by the go stimulation from that evoked by the nogo stimulation. In Experiment 1, the peak latency of negativity became significantly longer as the ISI increased, but the peak amplitude was unchanged. The reaction time (RT) was longer with increasing ISI. In Experiment 2, manipulation of the stimulus probability yielded an increase in peak amplitude with decreasing probability of the nogo stimulus, but did not affect the latency. The RT increased as the probability of a nogo stimulus rose. Because manipulation of the ISI and stimulus probability elicited different brain activities, we hypothesized that manipulation of the ISI elicited a delay of the stimulus evaluation process including response inhibition, and that stimulus probability significantly affected the strength of the response inhibition process.

Impacto de la gravedad del consumo de drogas de abuso sobre distintos componentes de la función ejecutiva

A number of neuropsychological studies have shown the relationship between severity of drug abuse and the executive functioning of substance abusers, along with its negative impact on treatment results. The aim of this study is to examine the relationship between severity of consumption of alcohol, cannabis, cocaine, heroin, amphetamines and ecstasy on the executive processes of fluency, working memory, response inhibition, concept formation and decision-making. Forty poly-substance abusers participated in this study. In a series of setwise regression analyses we introduced the standardized scores of a severity index as predictor variables, and the raw scores of five indexes sensitive to executive functioning as dependent variables: the Ruff Figural Fluency Test (RFFT), the Letter Number Sequencing subtest (LyN), the 5 Digit Test (5DT), the Category Test (TC) and the Gambling Task (GT). Best subsets of predictors for each dependent variable were included in multiple regression models. We obtained significant relationships between severity of heroin and ecstasy abuse and RFFT performance; between severity of alcohol, cocaine, heroin and amphetamines and LyN performance; between severity of alcohol, cannabis, cocaine, heroin and ecstasy and 5DT performance; and between severity of heroin and amphetamines and TC performance. These results show the significant influence of severity of drug abuse on executive impairment, which may have a negative impact on treatment results.

AD/HD児における反応抑制とエラー認知機能の評価-CPT課題におけるERPを指標として-

本研究では, 注意欠陥・多動性障害児 (AD/HD) における反応抑制とエラー処理の2つの心理生理的過程に焦点を当てた検討を行った.AD/HD児17名, 健常児8名, 健常成人13名を対象にしてcontinuous performance test時におけるNOGO電位とエラー関連陰性電位 (ERN) を記録し, AD/HD児においては, それらの生理指標を行動指標による心理特性分類に従って評価した.AD/HD児におけるNOGO電位は健常児と同様に, 健常成人に比べると高振幅で, 潜時が遅かった.このことは, AD/HD児の問題が反応抑制の欠損というよりも行動調整機能の成熟途中であることを示唆している.また, NOGO電位の潜時は年齢と負の相関が認められ, 直線的な潜時の短縮を示した.このことから前頭機能は前頭前野の成熟によって発達することを示唆している.一方で, 衝動性の高いAD/HD児においてはERN潜時が遅いことから行動調整の速度の遅さが指摘され, 低い標的ヒット率を示す不注意性のAD/HD児においても, ERNの惹起が認められることから, エラー認知といった認知機能を維持している持続的注意に問題があることが示唆された.

ERP components associated with successful and unsuccessful stopping in a stop-signal task.

The primary aim of this study was to examine how response inhibition is reflected in components of the event-related potential (ERP), using the stop-signal paradigm as a tool to manipulate response inhibition processes. Stop signals elicited a sequence of N2/P3 components that partly overlapped with ERP components elicited by the reaction stimulus. N2/P3 components were more pronounced on stop-signal trials than on no-stop-signal trials. At Cz, the stop-signal P3 peaked earlier on successful than on unsuccessful stop trials. This finding extends the horse race model by demonstrating that the internal response to the stop signal (as reflected in stop-signal P3) is not constant, but terminates at different moments in time on successful and unsuccessful stop trials. In addition, topographical distributions and dipole analysis of high density EEG recordings indicated that different cortical generators were involved in P3s elicited on successful and unsuccessful stop-signal trials. The latter results suggest that P3 on successful stop-signal trials not only reflects stop-signal processing per se, but also efficiency of inhibitory control.

Inhibition of subliminally primed responses is mediated by the caudate and thalamus: evidence from functional MRI and Huntington's disease.

Masked prime tasks have shown that sensory information that has not been consciously perceived can nevertheless trigger the preactivation of a motor response. Automatic inhibitory control processes prevent such response tendencies from interfering with behaviour. The present study investigated the possibility that these inhibitory control processes are mediated by a cortico-striatal-pallidal-thalamic pathway by using a masked prime task with Huntington's disease patients (Experiment 1) and with healthy volunteers in a functional MRI (fMRI) study (Experiment 2). In the masked prime task, clearly visible left- or right-pointing target arrows are preceded by briefly presented and subsequently masked prime arrows. Participants respond quickly with a left or right key-press to each target. Trials are either compatible (prime and target pointing in the same direction) or incompatible (prime and target pointing in different directions). Prior behavioural and electrophysiological results show that automatic inhibition of the initially primed response tendency is reflected in a 'negative compatibility effect' (faster reaction times for incompatible trials than for compatible trials), and is shown to consist of three distinct processes (prime activation, response inhibition and response conflict) occurring within 300 ms. Experiment 1 tested the hypothesis that lesions of the striatum would interrupt automatic inhibitory control by studying early-stage Huntington's disease patients. Findings supported the hypothesis: there was a bimodal distribution for patients, with one-third (choreic) showing disinhibition, manifested as an absent negative compatibility effect, and two-thirds (non-choreic) showing excessive inhibition, manifested as a significantly greater negative compatibility effect than that in controls. Experiment 2 used fMRI and a region of interest (ROI) template-based method to further test the hypothesis that structures of the striatal-pallidal-thalamic pathway mediate one or more of the processes of automatic inhibitory control. Neither prime activation nor response conflict significantly engaged any ROIs, but the response inhibition process led to significant modulation of both the caudate and thalamus. Taken together, these experiments indicate a causal role for the caudate nucleus and thalamus in automatic inhibitory motor control, and the results are consistent with performance of the task requiring both direct and indirect striatal-pallidal-thalamic pathways. The finding that Huntington's disease patients with greater chorea were disinhibited is consistent with the theory that chorea arises from selective degeneration of striatal projections to the lateral globus pallidus, while the exaggerated inhibitory effect for patients with little or no chorea may be due to additional degeneration of projections to the medial globus pallidus.

Frontal lobe contribution to response inhibition process—an ERP study and aging effect

Objectives: The aim of this study was to clarify activation areas during a Go/NoGo task using event-related brain potentials (ERPs), and to examine aging effects on the ERP components. Methods: Twenty-seven healthy volunteers were investigated with 128 channel recordings during a cued continuous performance test. The peak latency, amplitude, topographic distribution and neural sources of each ERP component were estimated with the low-resolution electromagnetic tomography (LORETA) on the grand average waveforms and ERPs from individual subjects. Results: Interpolated voltage maps over the scalp surface and LORETA images showed that the source of the P3 component for the Go condition was located at the bilateral parietal lobes. On the other hand, the NoGo-P3 source was observed mainly in the inferior anterior cingulate cortex and lateral orbitofrontal area. The source of the N2 component was located in the medial orbitofrontal area. The activities of the Go-P3, NoGo-P3 and NoGo-N2 in the old group showed relatively longer latencies and smaller amplitudes than the young group. Conclusions: Both the NoGo-P3 and NoGo-N2 have main electrical sources in the frontal lobe. The orbitofrontal area and the anterior cingulate cortex are the most important regions for the inhibitory control of behaviors. The activities of the Go-P3, NoGo-P3 and NoGo-N2 sources were decreased with age.

Cognitive impairment in amyotrophic lateral sclerosis: evidence from neuropsychological investigation and event-related potentials

The presence of subclinical cognitive impairment in patients with amyotrophic lateral sclerosis (ALS) is investigated using neuropsychological assessment and event-related potential recordings (ERP). An extensive battery of neuropsychological tests assessing the domains of attention, memory, language, visuo-spatial and executive functions were administered to 20 non-demented patients with sporadic ALS and 13 age- and education-matched healthy control subjects. Mismatch negativity (MMN), P3b, P3a (novelty P300) and contingent negative variation (CNV) were recorded. ALS patients were significantly impaired in tests of working memory, sustained attention, response inhibition, naming, verbal fluency and complex visuo-spatial processing. The memory impairment seemed to be secondary to deficits in forming learning strategies and retrieval. In ERP recordings, P3a and P3b amplitudes of ALS patients were lower compared with the controls, P3a latencies were significantly longer and mean CNV amplitudes were higher. These results indicate subclinical impairment of cognitive functions in patients with ALS. The pattern of cognitive impairment suggests the dysfunction of the frontal network.

The Functional Anatomy of Inhibition Processes Investigated with the Hayling Task

The cortical areas involved in inhibition processes were examined with positron emission tomography (PET). The tasks administered to subjects were an adaptation of the Hayling test. In the first condition (response initiation), subjects had to complete sentences with a word clearly suggested by the context, whereas in the second condition (response inhibition), subjects had to produce a word that made no sense in the context of the sentence. Results indicated that the response initiation processes were associated to increases of activity in the left inferior frontal gyrus (BA 45/47), whereas response inhibition processes led to increases in a network of left prefrontal areas, including the middle (BA 9 and BA 10) and inferior (BA 45) frontal areas.

Neural activation during response competition.

The flanker task, introduced by Eriksen and Eriksen [Eriksen, B. A., & Eriksen, C. W. (1974). Effects of noise letters upon the identification of a target letter in a nonsearch task. Perception & Psychophysics, 16, 143--149], provides a means to selectively manipulate the presence or absence of response competition while keeping other task demands constant. We measured brain activity using functional magnetic resonance imaging (fMRI) during performance of the flanker task. In accordance with previous behavioral studies, trials in which the flanking stimuli indicated a different response than the central stimulus were performed significantly more slowly than trials in which all the stimuli indicated the same response. This reaction time effect was accompanied by increases in activity in four regions: the right ventrolateral prefrontal cortex, the supplementary motor area, the left superior parietal lobe, and the left anterior parietal cortex. The increases were not due to changes in stimulus complexity or the need to overcome previously learned associations between stimuli and responses. Correspondences between this study and other experiments manipulating response interference suggest that the frontal foci may be related to response inhibition processes whereas the posterior foci may be related to the activation of representations of the inappropriate responses.

Children's Serial Recall Errors: Implications for Theories of Short-Term Memory Development

Three experiments examined developmental changes in serial recall of lists of 6 letters, with errors classified as movements, omissions, intrusions, or repetitions. In Experiments 1 and 2, developmental differences between groups of children aged from 7 to 11 years and adults were found in the pattern of serial recall errors. The errors of older participants were more likely to be movements than were those of younger participants, who made more intrusions and omissions. The number of repetition errors did not change with age, and this finding is interpreted in terms of a developmentally invariant postoutput response inhibition process. This interpretation was supported by the findings of Experiment 3, which measured levels of response inhibition in 7-, 9-, and 11-year-olds by comparing recall of lists with and without repeated items. Response inhibition remained developmentally invariant, although older children showed greater response facilitation (improved correct recall of adjacent repeated items). Group differences in the patterns of other errors are accounted for in terms of developmental changes in levels of output forgetting and changes in the efficiency of temporal encoding processes.

ERP correlates of response inhibition to elemental and configural stimuli in a negative patterning task

Objective: The present experiment examined the ERP correlates of response inhibition to elemental and configural Nogo stimuli in a Go/Nogo task.Design and Methods: Event-related potentials (ERPs) were recorded while 8 subjects completed a visual Go/Nogo task. Nogo stimuli required the inhibition of a response to stimuli that differed from Go stimuli (A+, B+) either on the basis of each of two physical features (elemental Nogo stimuli; CD−) or on the basis of the conjunction of features represented in the Go stimuli (configural Nogo stimuli; AB−). Behavioural data and ERP component measures (amplitude and latency) were analysed using analysis of variance.Results: An enhanced N2 component and an enhanced fronto-centrally distributed P3 component were elicited following elemental Nogo stimuli relative to Go stimuli, consistent with a number of studies examining ERPs during Go/Nogo tasks. In contrast, an enhanced late frontal negative/parietal positive slow wave was elicited following configural Nogo stimuli relative to Go stimuli.Conclusions: These results cast doubt on the interpretation of the N2 enhancement as reflecting response inhibition processes per se. The pattern of results was interpreted as providing support for the unique cue model of learning rather than the configural model of learning and was discussed in the context of a recent model of executive functioning.

An electrophysiological study of the insertion of overt response choice.

Using electrophysiological measures, the authors studied changes in prestimulus state, stimulus identification, and response-related processing when, in a go/no-go task, forced choice between 2 overt go responses was inserted. The authors observed decreased prestimulus motor preparation (electromyogram), no change in stimulus identification time (selection negativity), a minor increase in response selection time (lateralized readiness potential), a large increase in response preparation time (lateralized readiness potential), a minor effect on response execution time (electromyogram), and a decrease in the activation of a response-inhibition process on no-go trials (frontal event-related potential). The existence of the response-inhibition process was verified by the presence of inverted lateralized readiness potentials on no-go trials. Pure insertion of response choice in a task seems impossible because the choice between activation and inhibition (go/no-go) always seems already present.

Visual attention task performance in Wistar and Lister Hooded rats: response inhibition deficits after medial prefrontal cortex lesions

The prefrontal cortex has traditionally been implicated in a variety of cognitive processes, including memory, attention and decision making. The detection of effects of prefrontal cortex lesions on attention has been shown to depend on the procedure used to assess the attentional process. We therefore investigated the effects of lesions of the prefrontal cortex in two different visual attention tasks, i.e. a three-choice serial reaction time task involving sustained and divided attention processes and a visual timing task involving sustained attention and response inhibition processes. In two rat strains that are frequently used in behavioural analysis, i.e. albino Wistar rats and pigmented Lister Hooded rats, lesions of the medial prefrontal cortex caused a deterioration of performance in both tasks, although the effect lasted much longer in the visual timing task. This latter task proved to be especially sensitive to detect the consequences of medial prefrontal cortex lesions, consisting of a loss of both attention control and response inhibition. In both attention tasks, Wistar rats performed less accurate and made more anticipatory responses than Listers. Strain differences could not entirely be attributed to possible visual deficits in albinos, which was also evident when locomotor activity in an open field and food-motivated behaviour in a hoarding paradigm were assessed. Due to slower habituation rates, Lister rats were more active and displayed little food hoarding behaviour. In Wistar rats, hoarding was disrupted by medial prefrontal cortex lesions, showing the effectiveness of the lesion. The results indicate that, although different rat strains provide different baseline levels of behaviour for testing lesion- or drug-induced behavioural changes, lesions of the medial prefrontal cortex do not only disrupt sustained attention processes, but also induce a strong impairment in response inhibition in both Wistar and Lister rats.

Effects of early postnatal gonadal steroids on extinction of a continuously food-rewarded running response

In the present work the existence of sex differences (Experiment 1) on the acquisition and extinction of a continuously reinforced response in a short and narrow runway (100 × 9 × 10 cm) were investigated. In addition to the investigation of the basic sex differences in Experiment 1, the effect of postpuberal gonadectomy of male and female rats and the role of the early postnatal gonadal steroids on these situations were also examined in Experiments 2 and 3, respectively. In all experiments, no sex differences were found in acquisition. However, males extinguished faster than female rats. Gonadectomy of both sexes in adulthood, although it increases their latencies in acquisition, did not affect the differences between sexes during extinction. In contrast, in Experiment 3 female androgenization and male orchidectomy on day one after birth reversed the direction of sex differences found between control rats in the extinction period. Our findings suggests that the observed sex differences in extinction may be due to an underlying sexual dimorphism in the response inhibition process.

In search of the point of no return: The control of response processes.

Control processes underlying response inhibition were examined. Six Ss performed a visual choice reaction task and were occasionally presented with a tone that told them to withhold the response. Reaction time results were in agreement with a model that assumes a race between response activation and response inhibition processes. Event-related brain potentials, electromyogram, and continuous response measures showed that responses could be interrupted at any time. Evidence was obtained for two inhibitory mechanisms: inhibition of central activation processes and inhibition of transmission of motor commands from central to peripheral structures. Results have implications for the distinction between controlled and ballistic processes.

Effects of dexamethasone on discriminative fear conditioning in pigs

Eight pigs were trained in a shuttle-box to avoid electric shocks according to a continuous avoidance schedule. After stabilisation of the response rate they were submitted to a discriminative Pavlovian fear conditioning. In a subsequent test session, presentation of the CS+ increased the avoidance response rat at a greater extent than the CS−. Dexamethasone (0.2 mg/kg) administered before Pavlovian conditioning and before test sessions enhanced the increase in avoidance response rate to both CS presentation, irrespective of its type. Results are interpreted in terms of DX effects on response inhibition processes.