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Preparation and motor potentials in chronic tic and Tourette syndromes.

Many studies have found that people with tic disorder show more difficulty when inhibiting an automated than a controlled response. Furthermore, although normal motor threshold and excitability are present, but reduced or impaired, motor inhibition seems manifest in patients with tic. In order to localize this inhibition impairment in tic disorder the present study examine two response-locked ERPs: the Bereitschaft (preparation BP) and the motor potentials (MP). The simple tic group showed faster BP latency and smaller amplitude than control and complex tic group and did not show a corresponding change in values with practice or with automated or controlled condition. The MP amplitudes revealed that whereas both controls and complex tic disorder showed a decrease in amplitude during control condition for both blocks, simple tic showed larger amplitude. Our ERP results are in agreement with RT results of a previous study. The explanation could lie with modulation in motor excitation inhibition circuits and seems worse in simple tics where the movements are more automatic and nonvoluntary.

Automatism↗
PubMed1982

Cortical slow potential shifts in tardive dyskinesia.

1. Slow cortical potential shifts such as the late terminal E-wave component of the CNV appear to be determined mainly by the level of motor preparation and as such it was employed to investigate the degree of cortical involvement in schizophrenics exhibiting abnormal motor phenomena induced by prolonged treatment with neuroleptics. 2. The basic experimental task was a constant foreperiod warned reaction time task consisting of a brief warning tone (S1) followed 4 sec later by a light, the imperative stimulus (S2), upon which the subject was instructed to release a response key. The task was presented twice, in a randomized order, under neutral and fast set instructions, to tardive (TD) and non-tardive dyskinesia (NTD) groups. 3. Computer EEG analysis identified and analysed on early O-wave measured as the average amplitude 500-1000 msec post S1, and the latter E-wave measured as the average amplitude 500 msec prior to S2. Two additional epochs of PINV activity were also analysed. 4. The results indicated that the TD group exhibited significantly larger PINV activity, but unlike NTD patients, the TD group failed to exhibit any significant increases in E-wave amplitude concommitant with improved behavioral reaction times. The results are discussed in relation to a disinhibitory theory of tardive dyskinesia.

Adult↗
PubMed2002

The difference in Mismatch negativity between the acute and post-acute phase of schizophrenia.

In order to investigate the trait and state aspects of Mismatch negativity (MMN) amplitude reduction in schizophrenia, auditory MMNs were measured from 13 schizophrenic patients on two occasions, initially when they showed acute exacerbation and later when their symptoms improved. Patients exhibited reduced mean amplitude of the MMN recorded at Fz. There were no significant changes in the amplitude of MMN at Fz between the acute patients and the post-acute patients, despite significant improvement in symptomatology. However, the acute patients showed a significant attenuation of MMN recorded at both mastoids as compared with the post-acute patients. Although the findings of the MMN at Fz support the overall longitudinal stability of MMN deficits in schizophrenia, the acute phase patients showed a modestly altered MMN activity compared with the post-acute phase patients, suggesting that there is some state-dependent modulation of these deficits.

Acoustic Stimulation↗
PubMed2002

Distinguishing neural sources of movement preparation and execution. An electrophysiological analysis.

The present study examined lateralized event-related potentials (L-ERPs) associated with movement preparation and execution. In a response precuing task that involved hand and foot movements a precue conveyed either information about side and effector, side alone, or no information. Advance movement preparation was indicated by RT shortening with increasing amount of precue information. L-ERPs revealed during the preparatory interval an initial parietal activity when movement side was precued. Later in the preparatory interval L-ERPs revealed a polarity inversion for foot versus hand movements when effector and side were specified in advance. This polarity inversion showed up also in execution-related L-ERP waveforms. Comparison of preparation- versus execution-related brain signals yielded topographic differences and dissimilar dipole sources for hand-related L-ERP activity. We take present findings to indicate that brain generators within the parietal lobe and anterior MI are hierarchically related to precue-induced motor preparation, whilst posterior MI is associated with motor execution functions.

Adult↗
PubMed2002

Genetic analysis of IQ, processing speed and stimulus-response incongruency effects.

Psychometric IQ (WAIS-III), onset and peak latency of the lateralized readiness potential (LRP), decision time, and accuracy were assessed during an Eriksen Flanker task in a young (149 families) and in an older (122 families) cohort of twins and their siblings. Stimulus-response incongruency effects were found on all measures of processing speed and accuracy. The effects on the percentages of wrong button presses and too slow (>1,000 ms) responses were larger in the older than in the younger age cohort. Significant heritability was found for processing speed (33-48%), accuracy (41%), and stimulus-response incongruency effects (3-32%). Verbal and performance IQ correlated significantly with stimulus-response incongruency effects on accuracy (-0.22 to -0.39), and this correlation was completely mediated by an underlying set of common genes. It is concluded that measures of the ability to perform well under conditions of stimulus-response incongruency are viable endophenotypes of cognitive ability.

Adult↗
PubMed2003

Which stages of processing are speeded by a warning signal?

This article reviews psychophysiological and behavioral studies that attempt to identify which stages of processing are speeded by a neutral warning signal (WS), that is to say, one that conveys no information about the nature of the imperative stimulus or the required response. Experiments involving the lateralized readiness potential (LRP) provide evidence against the widely held view that warning effects on reaction time (RT) are due to facilitation of low-level motor processes. Studies of modality-specific evoked potentials similarly rule out a locus within sensory-perceptual processing. It is concluded that the speeding of RT by a neutral WS is most likely due to nonspecific motor priming within an early phase of response selection. In addition, fast-guess responses, in which subjects choose a response without fully analyzing the stimulus, are assumed to contribute to warning effects.

Animals↗
PubMed2003

Temporal organization of covert motor processes during response selection and preparation.

Onset of a movement-related brain potential (lateralized readiness potential, LRP) was used to divide reaction time (RT) into two intervals: (1) stimulus onset to LRP onset, and (2) LRP onset to onset of the overt response. Effects on these intervals of advance information about the to-be-signaled response and of the mapping between fingers and response buttons were examined. These effects were used to reach conclusions about the organization of response preparation and about the identity of the processes influenced by advance information. In the absence of advance information, response preparation involved two steps. First, two of the four possible response alternatives were prepared, then one of these two was prepared further. Which pair of responses was prepared during the first step depended on the spatial arrangement of the fingers on the buttons, rather than on any common anatomical feature. Advance information about the upcoming response allowed the first step to be performed prior to the response signal, thus removing its contribution to RT. The second step, however, remained unaffected.

Arousal↗
PubMed2003

Anxiety and error-related brain activity.

Error-related negativity (ERN/Ne) is a component of the event-related brain potential (ERP) associated with monitoring action and detecting errors. It is a sharp negative deflection that generally occurs from 50 to 150 ms following response execution and has been associated with anterior cingulate cortex (ACC) activity. An enhanced ERN has been observed in patients with obsessive-compulsive disorder (OCD)--reflecting abnormal ACC activity hypothesized as part of the pathophysiology of OCD. We recently reported that the ERN is also enhanced in a group of college students with OC characteristics. The present study extended these findings by measuring the ERN in college undergraduates who scored high on either the Penn State Worry Questionnaire (PSWQ) or a combined version of the Snake (SNAQ) and Spider (SPQ) Questionnaires. Results indicate that, like OC subjects, subjects who score high on a measure of general anxiety and worry have enhanced error-related brain activity relative to both phobic and non-anxious control subjects. The enhanced ERN was found to generalize beyond OCD within the anxiety spectrum disorders but also shows some specificity within these disorders.

Anxiety↗
PubMed2003

The late posterior negativity in ERP studies of episodic memory: action monitoring and retrieval of attribute conjunctions.

The focus of the present paper is a late posterior negative slow wave (LPN) that has frequently been reported in event-related potential (ERP) studies of memory. An overview of these studies suggests that two broad classes of experimental conditions tend to elicit this component: (a) item recognition tasks associated with enhanced action monitoring demands arising from response conflict and (b) memory tasks that require the binding of items with contextual information specifying the study episode. A combined stimulus- and response-locked analysis of data from two studies mapping onto these classes allowed a temporal and functional decomposition of the LPN. While only the LPN observed in the item recognition task could be attributed to the involvement of a posteriorly distributed response-locked error-related negativity (or error negativity; ERN/Ne) occurring immediately after the response, the source-memory task was associated with a stimulus-locked negative slow wave occurring prior and during response execution that was evident when data were matched for response latencies. We argue that the presence of the former reflects action monitoring due to high levels of response conflict, whereas the latter reflects retrieval processes that may act to reconstruct the prior study episode when task-relevant attribute conjunctions are not readily recovered or need continued evaluation.

Association Learning↗
PubMed2003

Anatomy of an error: ERP and fMRI.

Successful inhibition of pre-potent responses involves conflict; failed inhibition involves both conflict and errors, complicating the study of errors. Event-related potential (ERP) and functional magnetic resonance imaging (fMRI) data were collected while ten subjects (26-55 years old) performed a Go/NoGo task, with pre-potent responses (88% Go) and inhibition of responses (12% NoGo). We measured error-related negativity (ERN) to false alarms (FA), correct-related negativity (CRN) to hits, NoGo N2 to correct rejections (CR) and Go N2 to hits. ERP difference scores were derived (ERN-CRN; NoGoN2-GoN2) for correlating with fMRI contrasts (FA-hits; CR-hits). Age effects were removed from ERN and N2 difference scores, and conflict effects, reflected in N2 difference scores, were removed from ERN. The resulting ERN correlated with fMRI activations in both caudal and rostral anterior cingulate cortex (ACC), while N2 correlated with fMRI activations in caudal ACC and in executive control regions including dorsolateral prefrontal cortex. Thus, error and conflict monitoring may be dissociable, subserved by both overlapping and distinct ACC regions.

Adult↗
PubMed2003

Implementation of error-processing in the human anterior cingulate cortex: a source analysis of the magnetic equivalent of the error-related negativity.

Recent research has described a component of human electrical brain activity (the ERN or NE) that is associated with error-processing. In the present experiment, we used magneto-encephalographic recordings to provide converging evidence both for the existence of this component and for its putative source in the brain. Six human subjects performed a Go-NoGo task while both magnetoencephalographic and electroencephalographic brain activity were recorded. We found evidence for a magnetic equivalent of the ERN and dipole source analysis suggested that this activity was generated in the anterior cingulate cortex. These data converge with those from electrical recordings in implicating this brain structure in error-processing.

Adult↗
PubMed2003

Effects of alcohol consumption and alcohol susceptibility on cognition: a psychophysiological examination.

The present study sought to examine acute effects of alcohol on cognitive processing and performance within the context of two prominent theories of alcohol's effects; namely, that alcohol restricts the focus of attention (e.g. Steele and Josephs, 1990. Journal of Abnormal Psychology, 97, 196-205) and that alcohol impairs response inhibition (e.g. Fillmore and Vogel-Sprott, 1999. Experimental and Clinical Psychopharmacology, 7, 49-55; Fillmore and Vogel-Sprott, 2000. Journal of Studies on Alcohol, 61, 239-246). Forty-five participants were randomly assigned to receive either a placebo level of alcohol (0.04 g/kg), a moderate dose (0.40 g/kg), or a higher dose (0.80 g/kg). Brain electrical activity (ERPs) and behavioral responses (reaction time and accuracy) were measured while participants performed a modified flanker task, in which a target letter was flanked by response-compatible or response-incompatible letters. Analyses of behavioral data showed that alcohol increased response competition in accuracy but not response times, suggesting that alcohol influences response selection more than attentional processes per se. This finding is in-line with predictions derived from the response inhibition model. ERP latency data provided mixed support for both models. ERP amplitude data showed that the high dose of alcohol primarily influenced a mostly frontal negativity in the ERP, present on both correct and incorrect response trials. Differences in self-reported susceptibility to alcohol were most evident in the amplitude of the P3 component. Findings are discussed in terms of the differential effects of acute dose and susceptibility on information processing.

Adult↗
PubMed1999

The effect of stimulus discriminability on stimulus-preceding negativities prior to instructive and feedback stimuli.

Stimulus-preceding negativity (SPN) was recorded in time estimation tasks that allowed the pre-instruction SPN and the pre-feedback SPN to be compared. In the task in which an acoustic tone was presented 3 s after a voluntary movement, (a) the level of stimulus discriminability (easy and difficult), and (b) the information content of the acoustic tone (feedback and instruction) were manipulated. The pre-instruction SPN over the right hemisphere tended to be larger under the difficult than under the easy level of discriminability, but the difference was only marginally significant. In contrast, the pre-feedback SPN over the right hemisphere was significantly larger under the easy than under the difficult level of discriminability. These findings suggest that the level of stimulus discriminability influences the pre-instruction and the pre-feedback SPN differently, and that it is probable that the pre-feedback and the pre-instruction SPN do not have the same functional significance.

Adult↗
PubMed2001

Human pre-attentive auditory change-detection with single, double, and triple deviations as revealed by mismatch negativity additivity.

The functional nature of the pre-attentive automatic auditory feature analysis was investigated using the mismatch negativity (MMN) component of the auditory event-related brain potential. MMNs to ignored sounds deviating in one, two or three dimensions (duration (D), frequency (F), intensity (I)) were recorded. When the corresponding MMN processes elicited by stimuli simultaneously deviating in multiple features are independent from each other, then the empirically measured MMN elicited by multiple deviants equals the sum of the MMINs elicited by the corresponding single deviants. Indeed, MMNs to double DF- and to double DI-deviants showed additivity for frontocentral as well as for subtemporal sites, whereas MMN to double FI-deviants and MMN to triple DFI-deviants were additive only at subtemporal sites indicating that frontal and temporal MMN generators reveal differential degree of additivity. This finding demonstrates that not all combinations of stimulus dimensions are processed independently from each other.

Acoustic Stimulation↗
PubMed2003

Evidence for the different additivity of the temporal and frontal generators of mismatch negativity: a human auditory event-related potential study.

The auditory sensory-memory mechanisms in the human brain were investigated using the mismatch negativity (MMN) component of the event-related potential. MMNs were recorded to stimuli deviating from the repetitive standard stimuli simultaneously either in one or two features (frequency, intensity). If the processing of these two features is independent of each other, the MMN to the double deviant should equal the sum of the MMNs elicited by the corresponding single deviants. The double-deviant MMNs were found to be additive at the electrode sites below the Sylvian fissure but not at the frontal scalp areas. The results suggest that the temporal subcomponent of MMN is additive whereas the frontal is non-additive. The pattern of results was similar in ignore and attend conditions, suggesting that the components were not attentionally modulated.

Acoustic Stimulation↗
PubMed1997

The mismatch negativity component reveals the sensory memory during REM sleep in humans.

Auditory evoked potentials (AEPs) were recorded during presentation of stimuli of 1000 Hz (standard) and 2000 Hz (deviant) in trains of 10 tone bursts (one deviant per train) in the wake and rapid eye movement (REM) sleep states. The constant inter-stimulus interval (ISI) was 600 ms and the trains were separated by 3 s of silence. The deviant tone occurring at the train start elicited a mismatch negativity component (MMN) in both arousal states, displaying a peak latency between 100 and 150 ms post-stimulation at fronto-central areas. These results suggest the existence of an auditory memory trace (sensory memory) surviving for at least 3 s during REM sleep.

Acoustic Stimulation↗
PubMed1998

Human supplementary motor area is active in preparation for both voluntary muscle relaxation and contraction: subdural recording of Bereitschaftspotential.

Bereitschaftspotentials (BPs) preceding muscle relaxation and contraction were compared by using subdural electrodes which were implanted onto the right medial frontal surface in two patients with supplementary motor area (SMA) seizure. The applied movement paradigm (muscle relaxation and contraction tasks) was completely the same as employed in our previous study [Terada, K., Ikeda, A., Nagamine, T. and Shibasaki, H., Electroenceph. clin. Neurophysiol., 95 (1995) 335-345]. In both patients, either negative or positive BPs were observed in the SMA-proper and supplementary negative motor area (SNMA) starting at 1.2-1.8 prior to both movements. In one patient, BP was more widespread in the relaxation task whereas more restricted to the hand area in the contraction task. In the other patient, the BPs were observed in the cortical area rostral to SNMA (pre-SMA), in addition to the SMA-proper, in both tasks. It is concluded that SMA-proper and SNMA, and probably pre-SMA as well, in humans are similarly active in preparation for both voluntary muscle contraction and relaxation.

Adult↗