Biomedical subjects

Martina Rieger

Publications and source records attributed to Martina Rieger.

8 recordsLinked to original sources

PubMed2006

Target-related coupling in bimanual reaching movements.

While bimanual interference effects can be observed when symbolic cues indicate the parameter values of simultaneous reaching movements, these effects disappear under conditions in which the target locations of two movements are cued directly. The present study investigates the generalizability of these target-location cuing benefits to conditions in which symbolic cues are used to indicate target locations (i.e., the end points of bimanual movements). Participants were asked to move to two of four possible target locations, being located either at the same and different distances (Experiment 1), or in the same and different directions (Experiment 2). Circles and crosses served as symbolic target-location cues and were arranged in a symmetric or non-symmetric fashion over the four target locations. Each trial was preceded by a variable precuing interval. Results revealed faster initiation times for equivalent as compared to non-equivalent target locations (same vs. different cues). Moreover, the time course of prepartion suggests that this effect is in fact due to target-equivalence and not to cue-similarity. Bimanual interference relative to movement parameter values was not observed. These findings suggest that cuing target locations can dominate potential intermanual interference effects during the concurrent programming of different movement parameter values.

Adult↗

PubMed2005

Compensation for and adaptation to changes in the environment.

Human motor behavior is remarkably accurate, even though many everyday skills require flexible adjustments between motor activity and its consequences in extracorporeal space. The present study addressed two questions: first, how do people compensate for unpredictable changes in the environment, and second, how do they adapt to such changes? In Experiment 1, participants repeatedly and continuously drew up and down strokes on a writing pad. After drawing under a base mapping, either (a) a change of target position, or (b) a change of gain, or (c) both occurred. Compensation for gain changes occurred later than compensation for changes in target position. In addition, there were aftereffects of the previous movement in accuracy and movement time. Adaptation to changes occurred in reference to extracorporeal space, with motor constraints as a limiting factor. In Experiment 2 we obtained similar effects when participants had more time to adapt. The view that movements are planned in reference to their goals in extracorporeal space is supported.

Adaptation, Physiological↗

PubMed2005

When hearing turns into playing: movement induction by auditory stimuli in pianists.

In this study, pianists were tested for learned associations between actions (movements on the piano) and their perceivable sensory effects (piano tones). Actions were examined that required the playing of two-tone sequences (intervals) in a four-choice paradigm. In Experiment 1, the intervals to be played were denoted by visual note stimuli. Concurrently with these imperative stimuli, task-irrelevant auditory distractor intervals were presented ("potential" action effects, congruent or incongruent). In Experiment 2, imperative stimuli were coloured squares, in order to exclude possible influences of spatial relationships of notes, responses, and auditory stimuli. In both experiments responses in the incongruent conditions were slower than those in the congruent conditions. Also, heard intervals actually "induced" false responses. The reaction time effects were more pronounced in Experiment 2. In nonmusicians (Experiment 3), no evidence for interference could be observed. Thus, our results show that in expert pianists potential action effects are able to induce corresponding actions, which demonstrates the existence of acquired action-effect associations in pianists.

Adult↗

PubMed2004

Action-effect coupling in pianists.

Recent theories have stressed the role of effect anticipation in action control. Such a mechanism requires the prior acquisition of integrated action-effect associations. The strength of such associations should directly depend on the amount of learning, and therefore be most pronounced in motor experts. Using an interference paradigm, we investigated whether evidence of such representations can be demonstrated in expert pianists. Participants were required to play chords on a keyboard in response to imperative visual stimuli. Concurrently, task-irrelevant auditory stimuli ("potential" action effects) were presented that were congruent or incongruent with the chords to be played. In Experiment 1 we found evidence that expert pianists, compared with non-musicians, have acquired such action-effects representations. Response times were slower when the auditory stimulus was incongruent with the required response. In order to ascertain the locus of interference, we varied imperative stimuli and responses in Experiments 2 and 3. The results indicate that, for the most part, interference occurs on the response level rather than on an abstract level. However, the perception of action effects also evokes processing of abstract features, like the concept of major-minor mode.

Acoustic Stimulation↗

PubMed2004

Automatic keypress activation in skilled typing.

The assumption that letters automatically activate corresponding keypresses in skilled typing was investigated. Participants responded to the color of letters (congruent condition: responding finger was the one usually used to type the letter). Participants skilled in typing showed a congruency effect: unskilled participants did not (Experiment 1). The automatic activation included characteristics of the movement usually performed to type the letters (Experiment 2). Responding with crossed hands on an external response device (Experiment 3) provided evidence for effector-dependent representations only, whereas responding on a keyhoard (Experiment 4) resulted in evidence for effector-dependent and spatial representations. Thus, motoric skill proficiency is accompanied by automatic activation processes that probably contribute to high performance levels.

Automatism↗

PubMed2003

Attention deficits in patients with narcolepsy.

STUDY OBJECTIVES: Although attention problems are presumably responsible for a wide variety of difficulties patients with narcolepsy experience in everyday life, empirical investigation of this issue is scarce. Therefore, we conducted a systematic investigation of different aspects of attention and verbal memory in patients with narcolepsy. DESIGN: Control-group design with comparison of performance in four attention tests--measuring phasic alertness, focused attention, divided attention, and flexible attention--and one verbal memory test. PARTICIPANTS: 19 patients with narcolepsy (NG) and 20 healthy controls (CG) MEASUREMENTS AND RESULTS: The NG showed no deficits in phasic alertness, focused attention, and verbal memory. However, specific deficits occurred in divided and flexible attention. Furthermore, the NG had generally slower and more variable reaction times in all attention tasks. CONCLUSIONS: Our results contradict the hypothesis that attentional impairments in narcolepsy are merely a result of a temporal disturbance of information processing, i.e., deficits can be explained by slowness and variability of performance alone. Rather, deficits in attentional capacity and attentional control also seem to play an important role. Thus, in addition to impairment in the vigilance attention network, results indicate impairment in the executive attention network in patients with narcolepsy.

Adult↗

PubMed2003

Inhibition of ongoing responses following frontal, nonfrontal, and basal ganglia lesions.

The authors investigated the role of the frontal lobes and the basal ganglia in the inhibition of ongoing responses. Seventeen patients with frontal lesions (FG), 20 patients with lesions outside the frontal cortex (NFG), 8 patients with lesions to the basal ganglia (BG), and 20 orthopedic controls (OG) performed the stop-signal task that allows the estimation of the time it takes to inhibit an ongoing reaction (stop signal reaction time [SSRT]). The FG and the BG showed significantly longer SSRTs than the OG. Within the FG, patients with right and bilateral lesions showed significantly longer SSRTs than patients with left lesions. Results provide evidence for a role of the frontal lobes and the basal ganglia in the inhibition of ongoing responses.

Adult↗

PubMed2002

Inhibition of ongoing responses in patients with traumatic brain injury.

In addition to slowness of information processing, it is often assumed that executive functions are deficient in patients with traumatic brain injuries (TBI). The aim of this study was to investigate a specific executive function, the inhibition of ongoing responses in TBI. Twenty-seven patients with TBI and 27 orthopedic patients (OC) performed the stop signal task, which allows the estimation of the time it takes to inhibit an ongoing response. Contrary to expectations, patients with TBI did not perform worse than the OC in the inhibition of ongoing responses. Furthermore, subgroups of the TBI, with frontal and nonfrontal lesions, and with focal versus diffuse damage, did not show any differences in performance. None of the clinical, demographic or neuropsychological data had a significant relationship to inhibition time, apart from age, which showed a significant relationship only in the TBI. It seems likely that deficits in the inhibition of ongoing responses are not very common after TBI.

Adolescent↗