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Kai Lutz

Publications and source records attributed to Kai Lutz.

11 recordsLinked to original sources
PubMed2006

How finger tapping practice enhances efficiency of motor control.

Maximum-speed movements have been suggested to put maximum neural control demands on the primary motor cortex; hence, we are asking how primary motor cortex function changes to enable enhanced maximum movement rates induced by long-lasting practice. Cortical function was assessed by recording task-related spectral electroencephalogram alpha-power. Low-resolution brain electromagnetic tomography was used to localize intracortical neuronal sources. The main result is a decrease in neural activity in the left hemisphere (ipsilateral to trained hand) from pretraining to posttraining, whereas right hemispheric activity remained constant across training. This likely reflects the initially limited capacity of the right hemisphere to control demanding left-hand movements, but also highlights its ability to become more efficient with training, indicated by reduced involvement of the left primary motor cortex after training.

Adult↗
PubMed2006

Neural control of playing a reversed piano: empirical evidence for an unusual cortical organization of musical functions.

Using functional magnetic imaging techniques and neuropsychological tests, we studied a young male musician (C.S.) who performs at a professional level both on a regular piano keyboard and on a reverse keyboard (reversed right to left). The participant was left-handed, had left dominance for language but, remarkably, right dominance for the control of piano playing on both keyboards. With respect to music perception, C.S. showed left-sided activation dominance within the left superior temporal sulcus, which is normally associated with higher order auditory processing and right-sided activations in the secondary sensory cortex extending into the supramarginal gyrus. We suggest that C.S.'s pattern of functional asymmetry, characterized by audio-motor control using a right-sided network, could be a factor in his exceptional piano-playing ability on both the standard and reversed keyboard.

Adult↗
PubMed2006

The emotional power of music: how music enhances the feeling of affective pictures.

Music is an intriguing stimulus widely used in movies to increase the emotional experience. However, no brain imaging study has to date examined this enhancement effect using emotional pictures (the modality mostly used in emotion research) and musical excerpts. Therefore, we designed this functional magnetic resonance imaging study to explore how musical stimuli enhance the feeling of affective pictures. In a classical block design carefully controlling for habituation and order effects, we presented fearful and sad pictures (mostly taken from the IAPS) either alone or combined with congruent emotional musical excerpts (classical pieces). Subjective ratings clearly indicated that the emotional experience was markedly increased in the combined relative to the picture condition. Furthermore, using a second-level analysis and regions of interest approach, we observed a clear functional and structural dissociation between the combined and the picture condition. Besides increased activation in brain areas known to be involved in auditory as well as in neutral and emotional visual-auditory integration processes, the combined condition showed increased activation in many structures known to be involved in emotion processing (including for example amygdala, hippocampus, parahippocampus, insula, striatum, medial ventral frontal cortex, cerebellum, fusiform gyrus). In contrast, the picture condition only showed an activation increase in the cognitive part of the prefrontal cortex, mainly in the right dorsolateral prefrontal cortex. Based on these findings, we suggest that emotional pictures evoke a more cognitive mode of emotion perception, whereas congruent presentations of emotional visual and musical stimuli rather automatically evoke strong emotional feelings and experiences.

Acoustic Stimulation↗
PubMed2006

Neuronal modifications during visuomotor association learning assessed by electric brain tomography.

In everyday life specific situations need specific reactions. Through repetitive practice, such stimulus-response associations can be learned and performed automatically. The aim of the present EEG study was the illustration of learning dependent modifications in neuronal pathways during short-term practice of visuomotor associations. Participants performed a visuomotor association task including four visual stimuli, which should be associated with four keys, learned by trial and error. We assumed that distinct cognitive processes might be dominant during early learning e.g., visual perception and decision making. Advanced learning, however, might be indicated by increased neuronal activation in integration- and memory-related regions. For assessment of learning progress, visual- and movement-related brain potentials were measured and compared between three learning stages (early, intermediate, and late). The results have revealed significant differences between the learning stages during distinct time intervals. Related to visual stimulus presentation, Low Resolution Electromagnetic Brain Tomography (LORETA) revealed strong neuronal activation in a parieto-prefrontal network in time intervals between 100-400 ms post event and during early learning. In relation to the motor response neuronal activation was significantly increased during intermediate compared to early learning. Prior to the motor response (120-360 ms pre event), neuronal activation was detected in the cingulate motor area and the right dorsal premotor cortex. Subsequent to the motor response (68-430 ms post event) there was an increase in neuronal activation in visuomotor- and memory-related areas including parietal cortex, SMA, premotor, dorsolateral prefrontal, and parahippocampal cortex. The present study has shown specific time elements of a visuomotor-memory-related network, which might support learning progress during visuomotor association learning.

Adult↗
PubMed2006

Converging evidence of ERD/ERS and BOLD responses in motor control research.

In this chapter we summarize findings of our group in which we studied the neural underpinnings of finger tapping control using different methods (functional magnetic resonance imaging: fMRI, electroencephalography: EEG, transcranial magnetic stimulation: TMS, and behavioural experiments). First, we found that maximum finger tapping speed is a matter of training as shown for professional musicians. Secondly, we demonstrated that different finger tapping speeds are accompanied by different hemodynamic responses in the primary hand motor area (M1), the cerebellum and partly in pre-motor areas. With increasing tapping speed there is an increase of hemodynamic response in these areas (rate effect). Thirdly, the effect measured with fMRI is substantiated by rate effects measured by means of task-related power decreases in the upper alpha-band (10-12 Hz) over the primary motor cortex. In case of sequential finger movement learning, we observed decreases in task-related alpha-power in lateral PMC (event-related desynchronization: ERD) and simultaneous alpha-power increases in SMA (event-related synchronization: ERS) that came along with training-induced increases in movement rate. This pattern is discussed in relation to the "focal ERD/surround ERS" phenomenon suggested by Pfurtscheller and Lopes da Silva. Finally, we demonstrated that finger tapping speed was slowed by selectively inhibiting the primary hand motor area using TMS. Taken together, these studies demonstrate on the basis of converging evidence that the primary hand motor area is the basic control centre for controlling the movement parameter tapping speed. However, the neural efficiency to control finger tapping speed (as measured with hemodynamic responses or ERD/ERS patterns) is a matter of training.

Animals↗
PubMed2005

Effects of long-term potentiation in the human visual cortex: a functional magnetic resonance imaging study.

Applying functional magnetic resonance imaging techniques, hemodynamic responses elicited by slowly flashing checkerboards (0.25 Hz) were measured both before and after a block of rapidly presented checkerboards (9 Hz -- a 'photic tetanus') was delivered. It has been shown previously, using electroencephalography, that this photic tetanus potentiates components of the visual-evoked potential. In the present study, hemodynamic responses in the extrastriate visual cortex were significantly increased to checkerboards presented at a low frequency after the administration of the photic tetanus. These results support the idea that long-term potentiation can be demonstrated non-invasively within the human visual cortex and provide evidence that the plastic changes are localized within the secondary visual cortex.

Brain Mapping↗
PubMed2005

The role of the right dorsal premotor cortex in visuomotor learning: a transcranial magnetic stimulation study.

To study the role of the right dorsal premotor cortex in visuomotor association learning (association of four visual stimuli to four buttons), transcranial magnetic stimulation was applied to this area to interfere with the ongoing learning processes. Two transcranial magnetic stimulation pulses to the right dorsal premotor cortex at 150 and 200 ms after onset of the imperative stimulus resulted in the abolishing of reaction time decreases during learning. Transcranial magnetic stimulation applied to a control region revealed no influence on reaction time decreases. During both conditions, however, there were similar increases of accuracy scores. We conclude that the right dorsal premotor cortex is not directly involved in associating visual with motor cues. We suggest that this area is intimately involved in selection and preparation of forthcoming movements.

Adult↗
PubMed2005

Scanning silence: mental imagery of complex sounds.

In this functional magnetic resonance imaging (fMRI) study, we investigated the neural basis of mental auditory imagery of familiar complex sounds that did not contain language or music. In the first condition (perception), the subjects watched familiar scenes and listened to the corresponding sounds that were presented simultaneously. In the second condition (imagery), the same scenes were presented silently and the subjects had to mentally imagine the appropriate sounds. During the third condition (control), the participants watched a scrambled version of the scenes without sound. To overcome the disadvantages of the stray acoustic scanner noise in auditory fMRI experiments, we applied sparse temporal sampling technique with five functional clusters that were acquired at the end of each movie presentation. Compared to the control condition, we found bilateral activations in the primary and secondary auditory cortices (including Heschl's gyrus and planum temporale) during perception of complex sounds. In contrast, the imagery condition elicited bilateral hemodynamic responses only in the secondary auditory cortex (including the planum temporale). No significant activity was observed in the primary auditory cortex. The results show that imagery and perception of complex sounds that do not contain language or music rely on overlapping neural correlates of the secondary but not primary auditory cortex.

Acoustic Stimulation↗
PubMed2004

Long-term training affects cerebellar processing in skilled keyboard players.

We studied cerebellar hemodynamic responses in highly skilled keyboard players and control subjects during complex tasks requiring unimanual and bimanual finger movements. Both groups showed strong hemodynamic responses in the cerebellum during the task conditions. However, non-musicians showed generally stronger hemodynamic responses in the cerebellum than keyboard players. We conclude that, due to long-term motor practice a different cortical activation pattern can be visualized in keyboard players. For the same movements fewer neurons need to be recruited. The different volume of the activated cortical areas might therefore reflect the different effort necessary for motor performance in both groups.

Adult↗
PubMed2004

Bimanual versus unimanual coordination: what makes the difference?

Using fMRI, we investigated the neuronal structures controlling bimanual coordination applying a visuomotor coordination task. Recent studies suggest the existence of a widespread network for the neuronal control of bimanual coordination including primary sensorimotor cortices (M1/S1), lateral and medial premotor cortices (PMC, SMA), cingulate motor area (CMA), and cerebellum (CB). In the present study, subjects performed bimanual and unimanual tasks requiring the coordination of two fingers at a time to navigate a cursor on a computer screen. Thus, in contrast to previous studies, we are using appropriate unimanual control (UNI) tasks. By using this new motor task, we identified a similar activation network for uni- and bimanual movements. Subjects exhibited bilateral activations in PMC, SMA, posterior-parietal cortex (PPC), occipital, and inferiotemporal cortex, as well as in the contralateral M1/S1 and ipsilateral CB. We did not find any additional activation when comparing bimanual with unimanual conditions. The lack of significant activation in the comparison "bimanual > unimanual" gives reason to suggest that this network is not limited to the control of bimanual motor actions, but responsible for unimanually coordinated movements as well. Interestingly, we found stronger activations for unimanual as compared to bimanual coordination. We hypothesize that task difficulty (degrees of freedom to control, e.g., number of limbs) is more important in determining which network components are activated and to what extent, compared to the factor of bimanuality. It even seemed to be less demanding for the motor system to control the cursor bimanually compared to the unimanual performance with two adjacent fingers.

Adult↗