Tapping Hand Research Articles

Infant attention to rhythmic audiovisual synchrony is modulated by stimulus properties.

Musical interactions are a common and multimodal part of an infant's daily experiences. Infants hear their parents sing while watching their lips move and see their older siblings dance along to music playing over the radio. Here, we explore whether 8- to 12-month-old infants associate musical rhythms they hear with synchronous visual displays by tracking their dynamic visual attention to matched and mismatched displays. Visual attention was measured using eye-tracking while they attended to a screen displaying two videos of a finger tapping at different speeds. These videos were presented side by side while infants listened to an auditory rhythm (high or low pitch) synchronized with one of the two videos. Infants attended more to the low-pitch trials than to the high-pitch trials but did not display a preference for attending to the synchronous hand over the asynchronous hand within trials. Exploratory evidence, however, suggests that tempo, pitch, and rhythmic complexity interactively engage infants' visual attention to a tapping hand, especially when that hand is aligned with the auditory stimulus. For example, when the rhythm was complex and the auditory stimulus was low in pitch, infants attended to the fast hand more when it aligned with the auditory stream than to misaligned trials. These results suggest that the audiovisual integration in rhythmic non-speech contexts is influenced by stimulus properties.

Distortions of visual time induced by motor adaptation.

As perception of time is fundamental for action planning and execution, we investigated how action distorts the perception of visual duration. Participants adapted to tapping in midair for a few seconds, either slowly or quickly, then judged the relative duration of 2 drifting gratings, 1 spatially coincident with the tapped region and the other in the opposite field. Fast tapping decreased apparent duration in the tapping region while slow tapping increased it. The effect was spatially specific in external (not body-centered) coordinates, occurring within a 10° region centered on the tapping hand. Within this space, motor adaptation similarly distorts visual numerosity, suggesting common mechanisms for number and time. However, motor adaptation did not affect the perception of speed, a lower level visual property, suggesting that the interactions were at a high level of processing. These results reinforce studies that suggest that visual time perception is coupled with action and suggest the existence of multiple local visuomotor clocks. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Motion tracking and electromyography-assisted identification of mirror hand contributions to functional near-infrared spectroscopy images acquired during a finger-tapping task performed by children with cerebral palsy.

Recent studies have demonstrated functional near-infrared spectroscopy (fNIRS) to be a viable and sensitive method for imaging sensorimotor cortex activity in children with cerebral palsy (CP). However, during unilateral finger tapping, children with CP often exhibit unintended motions in the nontapping hand, known as mirror motions, which confuse the interpretation of resulting fNIRS images. This work presents a method for separating some of the mirror motion contributions to fNIRS images and demonstrates its application to fNIRS data from four children with CP performing a finger-tapping task with mirror motions. Finger motion and arm muscle activity were measured simultaneously with fNIRS signals using motion tracking and electromyography (EMG), respectively. Subsequently, subject-specific regressors were created from the motion capture or EMG data and independent component analysis was combined with a general linear model to create an fNIRS image representing activation due to the tapping hand and one image representing activation due to the mirror hand. The proposed method can provide information on how mirror motions contribute to fNIRS images, and in some cases, it helps remove mirror motion contamination from the tapping hand activation images.

The Effect of Delayed Visual Feedback on Synchrony Perception in a Tapping Task

Sensory events following a motor action are, within limits, interpreted as a causal consequence of those actions. For example, the clapping of the hands is initiated by the motor system, but subsequently visual, auditory, and tactile information is provided and processed. In the present study we examine the effect of temporal disturbances in this chain of motor-sensory events. Participants are instructed to tap a surface with their finger in synchrony with a chain of 20 sound clicks (ISI 750 ms). We examined the effect of additional visual information on this ‘tap-sound’-synchronization task. During tapping, subjects will see a video of their own tapping hand on a screen in front of them. The video can either be in synchrony with the tap (real-time recording), or can be slightly delayed (∼40–160 ms). In a control condition, no video is provided. We explore whether ‘tap-sound’ synchrony will be shifted as a function of the delayed visual feedback. Results will provide fundamental insights into how the brai...

Intersubject variability of near-infrared spectroscopy signals during sensorimotor cortex activation

We investigate the intersubject signal variability of near-infrared spectroscopy (NIRS), which is commonly used for noninvasive measurement of the product of the optical path length and the concentration change in oxygenated hemoglobin (DeltaC'oxy) and deoxygenated hemoglobin (DeltaC'deoxy) and their sum (DeltaC'total) related to human cortical activation. We do this by measuring sensorimotor cortex activation in 31 healthy adults using 24-measurement-position near-infrared (NIR) topography. A finger-tapping task is used to activate the sensorimotor cortex, and significant changes in the hemisphere contralateral to the tapping hand are assessed as being due to the activation. Of the possible patterns of signal changes, 90% include a positive DeltaC'oxy, 76% included a negative DeltaC'deoxy, and 73% included a positive DeltaC'total. The DeltaC'deoxy and DeltaC'total are less consistent because of a large intersubject variability in DeltaC'deoxy; in some cases there is a positive DeltaC'deoxy. In the cases with no positive DeltaC'oxy in the contralateral hemisphere, there are cases of other possible changes for either or both hemispheres and no cases of no change in any hemoglobin species in either hemisphere. These results suggest that NIR topography is useful for observing brain activity in most cases, although intersubject signal variability still needs to be resolved.

The cerebral oscillatory network associated with auditorily paced finger movements

Motor tasks involve neural activity in a spatially distributed network. It is assumed that coherent activity between these brain structures reflects functional connectivity. The aim of the present study was to investigate brain areas associated with a unimanual auditorily paced finger-tapping task and to characterize their dynamic interplay. We examined cerebromuscular and cerebrocerebral coupling in 10 right-handed subjects using recordings of continuous brain activity with a 122-channel whole-head neuromagnetometer while subjects performed the task with both hands consecutively. Additionally, surface EMG of the first dorsal interosseus was measured. Our data demonstrate that an oscillatory network composed of primary sensorimotor cortex, lateral as well as mesial premotor areas, the posterior parietal cortex and thalamus contralateral, and cerebellum and primary auditory cortex ipsilateral to the tapping hand subserves task execution. Connectivity between these areas and direction of coupling agree well with anatomical findings. During the right-hand condition, additional oscillatory activity in the primary sensorimotor cortex ipsilateral to the tapping hand was evident. This result suggests an asymmetric motor control in right-handers. Cerebrocerebral coupling predominantly occurs at 8–12 Hz. Therefore, our data support the hypothesis that coupling at 8–12 Hz in a cerebello-thalamic-cortical network represents a fundamental characteristic of the motor system and provides evidence for the significance of 8–12 Hz oscillations in a large scale network during the execution of simple motor tasks.

The role of the primary somatosensory cortex in an auditorily paced finger tapping task.

It has been suggested that a simple auditorily paced finger tapping task is associated with three tap-related neuromagnetic sources in the primary sensorimotor cortex contralateral to the tapping hand. Since a first source peaking at approximately 100 ms before tap-onset most likely represents activation of the primary motor cortex (M1) due to the motor command, a second source localized in the primary somatosensory cortex (S1) peaking around tap-onset could be due to kinesthetic feedback of the finger movement. A third source peaking at approximately 100 ms after tap-onset is also localized in the primary somatosensory cortex but inferior to the first S1 source (S1 inferior). The functional meaning of this source is still under debate. On the one hand it has been argued that S1 inferior represents the neuromagnetic correlate of tactile-kinesthetic feedback due to finger-taps and movements. On the other hand the functional meaning of this source could go beyond the sole processing of somatosensory feedback monitoring the temporal distance between tap and pacer (click) to keep the subject in time with the external event. This hypothesis is based on the observation that (1). S1 inferior seems to be coupled equally well to tap and click and (2). that this source might be triggered by the last event (i.e. tap or click). In the present study we re-examined this hypothesis by using a 122-channel whole-head neuromagnetometer. Eight healthy subjects synchronized their right index finger taps to an auditory pacing signal presented with a constant interstimulus interval of 800 ms. To test the hypothesis that the last event triggers S1 inferior we compared neuromagnetic activity following the tap as the first and the last event. In the auditorily paced finger tapping task usually the tap leads over the click (negative asynchrony). Therefore, the tap usually occurs as the first event. Since it has been shown that delivering additional feedback at the time of tap-onset results in a reduced negative asynchrony, in a second run auditory feedback was presented at tap-onset to enhance the number of positive asynchronies (i.e. the tap is the last event). Since no latency differences of S1 inferior associated with positive and negative asynchronies were found, results from the present study do not support the assumption that S1 inferior is triggered by the last event. Moreover, the amplitude of S1 inferior is significantly reduced following positive asynchronies as compared to negative asynchronies. Additionally, tap duration (i.e. the time between tap-onset and tap-offset) is significantly reduced while subjects produce positive asynchronies. Therefore, the amplitude of S1 inferior seems to be modulated by movement kinematics. This observation agrees well with the idea that activation of S1 is solely associated with the processing of somatosensory information. To conclude, our data contradict the hypothesis of an evaluation process localized in the primary somatosensory cortex and substantiate the idea that S1 inferior exclusively represents the processing of somatosensory feedback information.

Rapid Changes of Optical Parameters in the Human Brain During a Tapping Task

Measures of parameters of the migration of near-infrared photons through the head (attenuation, or intensity, and time-of-flight, or delay) have been proposed as a way of assessing noninvasively and in a quasicontinuous fashion changes in the scattering and absorption properties of brain tissue. These, in turn, may reflect functional changes associated with behavioral tasks. To test this hypothesis, we measured changes of photon migration parameters from scalp locations proximal to the motor cortex from four human subjects, tapping at a rate of 0.8 Hz with their left or right hand, or with their left or right foot. Tapping produced both slow effects (requiring several seconds) and fast effects (tracking the tapping frequency). Slow effects were characterized by increase and delay of the light passing through the hemisphere contralateral to the tapping hand. Fast effects consisted of changes in the light delay during hand tapping. Monte Carlo simulations based on layer models of the brain indicated that fast effects are consistent with changes in deep layers of the head (presumably in the cortex), and that slow effects are consistent with either a shift of absorbing material toward deeper layers or a reduction in scattering. These results suggest that optical parameters can monitor rapid changes of brain activity, matching the contralateral organization of the motor cortex.

The effects of two matched memory tasks on concurrent finger tapping

In a dual task experiment, subjects were instructed to perform a single finger tapping task whilst either, concurrently memorizing words appearing randomly on a screen in front of them, or concurrently memorizing the positions of the words. Analysis of percentage change scores revealed a significant tapping hand by task interaction; subjects showed a significantly larger left- than right- hand decrement when the task required memorizing the positions of the words and a non-significantly larger right- than left-hand decrement when the task required memorizing the words. These results suggest that the nature of the task demands determined the pattern of interference observed.

Rate and variability of finger tapping as measures of lateralized concurrent task effects

Using a sample of 48 normal right-handed adults, we assessed the effects of oral reading on concurrent unimanual finger tapping under all combinations of instructional set (speeded vs. consistent tapping), tapping movement (repetitive vs. alternating), task emphasis (reading emphasized vs. tapping emphasized), and tapping hand. Change in tapping rate and variability was measured relative to the corresponding single task control condition. Reading decreased the rate of speeded finger tapping but increased the rate of consistent tapping. In both instances, the right hand was affected more than the left hand. Asymmetries were comparable for repetitive and alternating tapping. When measured in terms of variability, however, effects were largely, symmetric. The findings clarify the conditions under which lateralized concurrent task effects are most likely to occur and show that such effects are not statistical artifacts. It appears that subjects attempt to coordinate the timing of concurrent activities and that speech timing is more strongly linked to right-hand control than to left-hand control in right-handers.

II Sensory Feedback Influences on Keytapping Motor Tasks

Subjects were trained to tap a key continuously at a specific rate, and with a specific amount of pressure (regularity task). Performance of this task was studied under conditions of: (a) decreased auditory feedback (masking noise through earphones), (b) decreased visual feedback (tapping hand screened from view), (c) vibration (vibrators applied to forearm in order to “mask” proprioceptive feedback), (d) digital block of tapping finger, and (e) combination of all four conditions. Significant changes in rate and intensity of tapping resulted under conditions of decreased auditory feedback, vibration, and the combined condition. In the second part of the study, the effects of different delayed sensory events on keytapping were examined. The five conditions of delayed sensory feedback were: (a) delayed auditory feedback, (b) delayed visual feedback, (c) delayed tactile feedback, (d) the first three delayed sensory events presented simultaneously, and (e) condition (d) repeated with digital block of the tapping finger. The conditions of delayed sensory feedback did not markedly alter performance of the regularity task. The same conditions of delayed sensory feedback did, however, produce highly significant changes in the performance of a more complex pattern task. All of these delay conditions produced parallel changes in the pattern task, namely increased intensity and decreased rate of tapping. The fact that the pattern task is more disturbed by delayed sensory feedback than the regularity task suggests that temporal complexity of the task is one determinant of the degree to which it will be disturbed by a delay in sensory feedback.