Biomedical subjects

Hartmut Leuthold

Publications and source records attributed to Hartmut Leuthold.

14 recordsLinked to original sources

PubMed2006

Electrophysiological evidence for response priming and conflict regulation in the auditory Simon task.

The Simon effect refers to the finding that responses are faster when the task-irrelevant stimulus and response location correspond than when they do not. The present study examined the role of location-based response priming and its regulation by an ancillary monitoring mechanism (AMM) for the auditory Simon effect, manipulating response modality and analyzing event-related brain potentials (ERPs). An auditory Simon effect was obtained for responses with hand, foot, and eyes. Lateralized ERPs revealed a mix of location-based attentional and motor-related activations early on during information processing. The Simon effect in reaction time (RT) was absent or largely reduced when a non-corresponding rather than a corresponding trial preceded, indicating control over location-based response priming. Importantly, RT modulations as a function of the correspondence sequence were mirrored in the amplitude of a negative difference wave (N2c), in accord with the view that response priming is under control of an AMM. In conclusion, both behavioral and electrophysiological measures revealed effect patterns that are consistent with an information-processing model that assumes asynchronous transmission from two separate processing routes to the motor system and top-down control by an AMM over task-irrelevant response priming.

Acoustic Stimulation↗

PubMed2006

Control over speeded actions: a common processing locus for micro- and macro-trade-offs?

Cognitive control processes associated with long- and short-term adjustments of human behaviour have attracted much interest recently. It is still unclear, however, whether the mechanisms underlying these adjustments share a common locus within the chain of stimulus-response processing. In order to address this issue, the present study employed a speed-accuracy instruction producing a macro-trade-off, whereas micro-trade-off was studied by means of posterror slowing in reaction time (RT). Participants performed a spatially compatible or incompatible four-stimuli-to-two-response alternative choice RT task. Reliable variations in micro-and macro-trade-off as well as effects of spatial compatibility were found in RT and error rate. Most importantly, posterror slowing was larger when instruction stressed accuracy rather than speed, an effect being independent of spatial compatibility. Because the influence of speed-accuracy instruction and posterror slowing on performance was strongest for response alternations, together present findings suggest that the mechanisms underlying micro- and macro-trade-offs have one common locus at the level of motor processing. Additional influences of macro-trade-off on premotoric processing are likely.

Adolescent↗

PubMed2006

Motor limitation in dual-task processing under ballistic movement conditions.

The standard bottleneck model of the psychological refractory period (PRP) assumes that the selection of the second response is postponed until the first response has been selected. Accordingly, dual-task interference is attributed to a single central-processing bottleneck involving decision and response selection, but not the execution of the response itself. In order to critically examine the assumption that response execution is not part of this bottleneck, we systematically manipulated the temporal demand for executing the first response in a classical PRP paradigm. Contrary to the assumption of the standard bottleneck model, this manipulation affected the reaction time for Task 2. Specifically, reaction time for Task 2 increased with execution time for Task 1. This carryover effect from Task 1 to Task 2 provides evidence for the notion that response execution can be part of the processing bottleneck.

Decision Making↗

PubMed2005

Response conflict determines sequential effects in serial response time tasks with short response-stimulus intervals.

In serial choice reaction time (RT) tasks, performance in each trial critically depends on the sequence of preceding events. In this study, the authors specifically examined the mechanism underlying RT sequence effects at short response-stimulus intervals (RSIs), in which performance is impaired in the current trial N if events alternate rather than repeat from trial N-2 to trial N-1. Different accounts of this RT pattern in terms of perceptual noise, response-selection monitoring, and response conflict were tested in 4 experiments. Second-order RT costs were caused by the response sequence rather than the stimulus sequence. Manipulation of stimulus contrast, stimulus classification difficulty, and set-level compatibility did not modulate the response-related second-order RT effect, whereas this effect increased when spatially incompatible responses were demanded. These findings support a response conflict account of higher order sequential effects in short-RSI situations.

Adult↗

PubMed2004

The attentional blink is susceptible to concurrent perceptual processing demands.

In a rapid serial visual presentation stream processing of a first target (T1) impairs detection or identification of a second target (T2) that appears within 500 ms after T1. This effect characterizes the so-called attentional blink (AB). To evaluate contemporary information-processing accounts of the AB phenomenon in terms of the underlying processing mechanisms the present study examined the potential influence of Task 1 difficulty on the AB effect. To this end, T1 contrast and T1 response requirements were systematically varied across four experiments. Experiment 1 ruled out a mere sensory basis of the contrast manipulation on T2 performance. When only T2 had to be reported (Experiment 2) an AB effect occurred that was slightly modulated by T1 contrast. When report of both T1 and T2 was required in a standard AB task (Experiment 3), the magnitude of the AB depended to a larger extent on stimulus contrast, and it increased further when speeded T1 choice responses were additionally required (Experiment 4). On the basis of the present impact of Task 1 difficulty on the AB effect we conclude that processing limitations cause the AB phenomenon. We discuss such limitations in terms of perceptual (T1 consolidation) and central (response selection) bottleneck processes.

Adult↗

PubMed2004

Beneficial effects of ambiguous precues: parallel motor preparation or reduced premotoric processing time?

The present study was designed to investigate the mechanisms underlying movement preprogramming in situations where informative but ambiguous precue information is used. In a response precuing task that involved flexion or extension movements with the right or left index finger, a spatially compatible precue conveyed partial information about side, about direction, no parameter information (ambiguous condition), or no information at all. Advance movement preparation was indicated by reaction-time shortening for all informative precue conditions. The analysis of stimulus- and response-locked lateralized readiness potential onsets revealed a clear and exclusive motoric origin of the ambiguous-precue benefit. Additional analyses ruled out a strategic trial by trial choice of just one of the two ambiguous alternatives and provided evidence for a parallel preparation of both response alternatives when information only about direction or ambiguous precue information is provided.

Adult↗

PubMed2003

Control over response priming in visuomotor processing: a lateralized event-related potential study.

In a typical Simon task responses are faster when the task-irrelevant stimulus location corresponds to the response location than when it does not. In the case of noncorrespondence it is assumed that externally triggered and internally selected responses are in conflict. Crucially, such conflict appears to be subject to contextual modulations as induced by the immediately preceding event, i.e., the Simon effect was found to be absent when a conflict trial preceded the current event (Stürmer et al. 2002, JEP:HPP). Here, we examined two possible accounts of this context effect in terms of early suppression of externally triggered S-R coding at a premotoric level versus late suppression at a motoric level. Lateralized event-related brain potentials (L-ERPs) were recorded in a Simon task and analyzed as a function of the correspondence sequence. L-ERP activity started earliest over occipito-parietal brain areas and revealed location-based S-R priming irrespective of the prior correspondence context. By contrast, when a noncorresponding trial preceded, such location-based priming was absent in L-ERP activity over the motor cortex (MC). Thus, in support of the late suppression view L-ERPs suggest a clear dissociation in function between externally triggered visuomotor functions within the dorsal stream and the MC reflecting context-controlled response activation.

Adult↗

PubMed2003

Programming of expected and unexpected movements: effects on the onset of the lateralized readiness potential.

When participants utilize prime information to prepare some or all aspects of the forthcoming movement, reaction time (RT) costs are obtained when the imperative response signal demands an unexpected rather than an expected movement. Longer RT in trials for which primes are invalid rather than valid, i.e., the response validity effect, are taken to reflect prolonged motoric processing time. The present study was designed to test this assumption by using the lateralized readiness potential (LRP) in order to reveal influences of response validity at motoric processes, pre-motoric processes, or both. In two response priming experiments LRP onset latency was examined when valid and invalid advance information about direction (Experiment 1) or about direction and hand (Experiment 2) was provided. RT revealed large response validity effects in both experiments. Analysis of LRP onsets provided strong evidence against the common assumption of a motoric locus of the RT increase in invalid trials. Rather, the present results suggest a pre-motoric locus of the response validity effect within information processing.

Adult↗

PubMed2003

Are fingers special? Evidence about movement preparation from event-related brain potentials.

Ulrich, Leuthold, and Sommer (1998) suggested that movement preparation at the level of the motor cortex, as indexed by the lateralized readiness potential (LRP), proceeds in a strongly hierarchical fashion, where parameters other than response hand are prepared only if all the movement parameters are known. These conclusions were based on an experiment where a precue provided information about response hand, direction of finger movement, and movement force. To assess the generality of these findings, we replaced the force parameter with response finger. LRP indicated that preparation of the required finger is possible even when preliminary information is incomplete. Therefore, movement preparation appears to follow different rules when anatomical relationships (hand and finger) are concerned as compared to functional parameters like movement direction. On the other hand, at a limb-unspecific level, as indicated by the contingent negative variation, we confirmed evidence for parallel programming of all movement parameters.

Adult↗

PubMed2002

Spatiotemporal source localisation reveals involvement of medial premotor areas in movement reprogramming.

Response priming tasks reveal huge reaction time (RT) costs when invalidly prepared movements have to be reprogrammed after the imperative response signal. Yet, possible brain correlates of motor reprogramming have rarely been examined. The present experiments were designed to ascertain the brain correlates associated with motor reprogramming by combining the recording of event-related brain potentials (ERPs) with a spatiotemporal source-localisation approach. In two experiments either valid or invalid advance information about direction (experiment 1) and about direction and response hand (experiment 2) was provided. RTs showed considerable motor reprogramming costs in invalid trials. In both experiments reprogramming effects were reflected in ERP difference waveforms in terms of a centroparietally distributed negative and a frontal positive deviation. Source localisation of these ERP difference waveforms indicated brain activity in medial higher-order motor regions. Present findings accord with the assumption that the human pre-supplementary motor area plays an important role in motor reprogramming.

Adult↗

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

Advance movement preparation of eye, foot, and hand: a comparative study using movement-related brain potentials.

The present study was designed to test the inter-relationship between generalized motor programs (GMPs) and movement preparation by asking participants to perform movements with eye, foot, or hand. In two independent experiments a response precuing task was employed that combined the recording of movement-related brain potentials (MRPs) with dipole source analysis. Behavioral results indicated the utilization of advance information about movement direction and effector. When eye and hand movements were involved (experiment1) partial advance information about response side but not effector induced parallel motor programming of eye and hand at an abstract but not effector-specific level. In contrast, when partial precues specified side of a forthcoming hand or foot movement (experiment 2) foot and hand were prepared in parallel both at abstract and at effector-specific levels of motor programming. Consistent with the GMP view, these results indicate that effector-specific preparation is possible even when the effector is not yet known as long as a common motor program controls the demanded movements. However, because parallel specification of divergent movement pattern (eye, hand) at an abstract level was not predicted by the GMP, we propose a model of advance movement preparation that takes into account neurofunctional considerations.

Adult↗

PubMed2002

Control over location-based response activation in the Simon task: behavioral and electrophysiological evidence.

In 4 Simon experiments the authors examined control over 2 routes of sensorimotor processing: response priming in the unconditional route and response selection via the conditional route. The Simon effect diminished as the frequency of noncorresponding trials increased. Location-based response priming was observed only when the stimulus followed a corresponding event but not after a noncorresponding trial. Therefore, the unconditional route appears to be suppressed whenever the task context indicates priming as potentially disadvantageous. Moreover, the task-irrelevant stimulus location was used for response selection as a function of correspondence probability. Although exact repetitions of stimulus-response sequences caused a marked speed-up of responses, this 3rd mechanism is independent of unconditional route suppression and frequency-based adjustments in the conditional route.

Adult↗

PubMed2002

Stimulus-response compatibility in intensity-force relations.

Romaiguère, Hasbroucq, Possamaï, and Seal (1993) reported a new compatibility effect from a task that required responses of two different target force levels to stimuli of two different intensities. Reaction times were shorter when high and low stimulus intensities were mapped to strong and weak force presses respectively than when this mapping was reversed. We conducted six experiments to refine the interpretation of this effect. Experiments 1 to 4 demonstrated that the compatibility effect is clearly larger for auditory than for visual stimuli. Experiments 5 and 6 generalized this finding to a task where stimulus intensity was irrelevant. This modality difference refines Romaiguère et al.'s (1993) symbolic coding interpretation by showing that modality-specific codes underlie the intensity-force compatibility effect. Possible accounts in terms of differences in the representational mode and action effects are discussed.

Adult↗