Intrasensory Attention: Kinaesthetic versus Cutaneous Inputs

The Effect of Different Attentional Focus Instructions during Finger Movement Tasks in Healthy Subjects: An Exploratory Study

External focus of attention (EFA) and internal focus of attention (IFA) represent commonly used strategies to instruct subjects during exercise. Several studies showed EFA to be more effective than IFA to improve motor performance and learning. To date the role of these strategies on motor performance during finger movement was less studied. The objective of the study was to investigate motor performance, patient's preference induced by IFA and EFA, and the focus during control condition. Ten healthy right-handed participants performed a finger movement task in control, EFA, and IFA conditions (counterbalanced). Errors, patient's preference, and type of attentional focus spontaneously adopted during the control condition were recorded. EFA determined less error (p < 0.01) compared to control and IFA. Participants preferred EFA against IFA and control condition. In the control group 10% of subjects adopted a purely EFA, 70% of subjects adopted a purely IFA, and 20% of subjects adopted a mixture of the two foci. Our results confirm that EFA is more effective than IFA and control in finger movement task. Due its clinical relevance, the interaction between attention and finger movement should be further investigated.

Touch can be as accurate as passively-guided kinaesthesis in length perception

Two experiments were designed to investigate the contribution of touch and kinaesthesis to haptic perception of the length of raised lines. Experiment 1 showed that judgements based on kinaesthetic information were not more accurate than those based on cutaneous information. Instead, kinaesthetic and cutaneous inputs appear to be weighted almost equally in the haptic percept, with haptic performance more closely approximated by cutaneous performance than by kinaesthetic. In Experiment 2 it was shown that effects attributed to condition (modality) were not due to the speed with which the stimulus or exploring finger moved. Our results challenge the view that kinaesthesis is more important than touch for identification of raised line drawings.

Neural Correlates of Switching Attentional Focus during Finger Movements: An fMRI Study

Research on motor-related attentional foci suggests that switching from an internal to an external focus of attention has advantageous effects on motor performance whereas switching from an external to an internal focus has disadvantageous effects. We used functional magnetic resonance imaging to investigate the neural correlates of switching the focus of attention. Two experimental groups were trained to apply one focus direction – internal or external – on a previously learned finger tapping sequence. Participants with an internal focus training were instructed to attend to their moving fingers; those with an external focus training were instructed to attend to the response buttons. In the first half of the experiment, participants performed with their trained focus, in the second half, they were unexpectedly asked to switch to the untrained attentional focus. Our data showed that the switch from a trained internal to an unfamiliar external focus of attention elicited increased activation of the left lateral premotor cortex (PMC). We propose that this activation can be linked to the role of the PMC in action planning – probably indicating a facilitation effect on selectional motor processes. Switching from a trained external to an unfamiliar internal focus of attention revealed enhanced activation of the left primary somatosensory cortex and intraparietal lobule. We interpret these modulations as a result of the amplifying influence of afferent information on motor processing when asked to attend internally in a motor task after being trained with an external focus.

Design of Dynamic Vibrotactile Textures

This paper describes a method for creating virtual textures without force feedback by using a simple motion sensor and a single vibrotactile actuator. It is based on wavetable synthesis driven by the user's hand movements. The output of the synthesis is rendered with the tactile actuator attached in a hand-held box together with the motion sensor. The method provides a solution for creating tangible properties for virtual objects which can be explored by pointing at them with the sensor-actuator device. The study introduces 12 virtual textures which were based on three different envelope ridge lengths, two spatial densities, and were either regularly or irregularly organized. To evaluate the role of each design parameter in the perception of the texture, a series of experiments was conducted. The perceived similarity was assessed in a pairwise comparison test and the outcome was analyzed by using multidimensional scaling. The analysis revealed that envelope ridge length and spatial density were distinguishable design parameters while regularity was not. The textures were also rated according to five attribute scales previously determined in the pilot experiment. The results show that ridge length and spatial density influence perceived roughness and flatness similarly as with real textures.