**Brain Activity and Movement Cognition – Vibratory Stimulation-Induced Illusions of Movements**

Shu Morioka *Kio University Japan* 

#### **1. Introduction**

102 Infrared Spectroscopy – Life and Biomedical Sciences

addition, infrared spectroscopy can also detect very small concentrations and small quantities such as invisible. So, you will be able to be developed a better measurement

Challenges of Infrared Spectroscopy, is miniaturization or lighter or less expensive. In the now, these challenges are resolved in the near infrared wavelength range. However, in the mid-infrared wavelength range has not yet been resolved. This is a challenge must be overcome if you want to commercialization. However, if you will be successfully to size down, would be used as more advanced sensors. By using infrared spectroscopy, it will be developed a sensor that can measure accurately than current sensors. We want to propose, the Infrared spectroscopy is not just equipment but can be applied to a variety of measurements. We are wishing, in the future, infrared spectroscopy research will be expanded, and, FT-IR become more familiar measuring device. If that era will be arrival, the

Dozono, T. et al. (2011). Identification and Quantitative Analysis of Fiber Mixtures by

Koyama, S. et al. (2011). SICE Annual Conference 2011, *Proceedings of SICE Annual Conference 2011*, pp. 82-86, ISBN 978-4-907764-38-8, Tokyo, Japan, Sep 13-18, 2011 Koyama, S.; Miyauchi,. Y. & Ishizawa, H. (2010). Clinical Application of Non-invasive Blood

Koyama, S.; Miyauchi,. Y. & Ishizawa, H. (2010). SICE Annual Conference 2010, *Proceedings* 

Infrared Spectroscopy, *Journal of the Illuminating Engineering Institute of Japan,* 

Glucose Monitoring System by Infrared Spectroscopy, *Journal of the Illuminating Engineering Institute of Japan,* Vol.95, No.5, (May 2011), pp. 251-254, ISSN 0019-2341

*of SICE Annual Conference 2010*, pp. 3425-3426, ISBN 978-4-907764-35-7, Taipei,

people would be receiving significant benefits from the infrared spectroscopy.

Aishima, T. (1992). *Chemometrics*, Maruzen, ISBN 4-621-03721-8, Tokyo, Japan

Vol.95, No.8A, (Aug 2011), pp. 450-453, ISSN 0019-2341

Taiwan, Aug 18-21, 2010

systems and sensors that measure did not previously exist.

**8. References** 

Feedback information on movement from the musculoskeletal system plays an important role in appropriate control of movement as well as acquisition of new movements. Especially, information on limb movement and location of the movement conveyed from the musculoskeletal system to the brain is assumed to play an essential role in the creation of a body image in the brain. When human limbs actually move, multiple pieces of sensory information are input into the brain by the skin, muscles, joints, etc. Information from muscle spindles has been demonstrated to be most important for cognition of limb movement.1,2)

A sense of movement can be intentionally aroused by imposing vibratory stimulus to the tendon, regardless of whether actual movement takes place. Such stimulation makes muscle spindles discharge signals as afferent impulses toward the brain. A human recipient of these impulses feels movement of the body in an illusion through perception of muscle extension. (Fig. 1)1) This illusion is elicited mainly by activation of Ia fibers from the muscle spindle. In usual movements, muscle spindles are activated as the muscle is extended. Therefore, if vibratory stimulus activates muscle spindles, information on movement is conveyed to the brain as if the muscle were extended. Hence, a subject can experience limb movement during vibratory stimulation of the tendon despite the absence of actual limb movement. Specifically, tendon stimulation by vibration can induce a sense of movement in the absence of real movement. If brain activity at that moment can be detected, it is possible to study brain activity at the time movement is perceived.

In fact, it was demonstrated that the motor area contralateral to the stimulated limb was activated when illusory hand joint extension was produced by vibratory stimulation of the hand extensor tendon.3) It was, however, reported that the brain was predominantly active in the right hemisphere irrespective of which hand was stimulated as far as premotor and parietal areas were concerned.4) Such vibratory stimulation-based illusory movementinduced activity of the brain is nearly identical to that occurring during real movement; this is especially true of premotor and supplementary motor areas, the cerebellum, and the parietal lobe.5) On the other hand, when the hand extensor tendon is stimulated with vibration while an object is being held by the hand, an illusory sense of both hand flexion

Brain Activity and Movement Cognition:

(Situation 1)

could be calculated.

**2.3 Protocol of tasks** 

b) Illustration of illusory movement.

Fig. 2. Application of vibratory stimulus

Vibratory Stimulation-Induced Illusions of Movements 105

a) b)

a) Apparatus is in contact with the hand extensor tendon to elicit an illusion of hand joint flexion.

Fig. 3. An object (umbrella) is placed within range of illusory movement. Situa (tion 2)

A task to create an illusion for a period of more than 20 seconds was imposed between two 10-second resting times. This session was uninterruptedly repeated under each situation. The illusory flexion angle was estimated as follows. After accomplishment of a task, a

efficiently excite illusions by an earlier study.4) There were two experimental situations. In situation 1, vibratory stimulation was imposed to the hand extensor tendon without placing an object near the subject; In situation 2, stimulation was similarly imposed with an object (umbrella) standing upright within range of illusory flexion. (Fig. 3) In either situation, the skin near the tendon was stimulated, which served as a control. The purpose of this stimulation was to acquire data on brain activity that was elicited when skin irritation receptors (Meissner corpuscles, Pacinian corpuscles, etc.) were excited that could be subtracted from data acquired by tendon stimulation so that pure illusory brain activity

Fig. 1. Schema of tendon stimulation-induced illusory movement

and of the object moving in the same direction is felt. When an object is felt to move in an illusion, the left hemisphere is predominantly activated and regions of interest are the lobule of the inferior parietal lobe and Brodmann's area 44/45.6-8)

However, when an object is placed within the angle of a self-experienced illusion without the object being grasped, it remains to be clarified how much such visual information influences the degree of illusory movement and how the brain is activated. This chapter reports such influences as well as brain activity **as** explored by functional near-infrared spectroscopy (fNIRS).
