Our previous studies (Inui et al. in J Physiol 589:5775-5784, 2011, Exp Brain Res 218:487-494, 2012) showed that a fully flexed or extended finger, wrist, and elbow became perceived as an extended or flexed 'phantom' hand and arm as ischemic anesthesia progressed. Here, we examined what happened if the wrist was fixed in full extension while the elbow was in full flexion before and during the anesthesia, and vice versa. Ten healthy participants demonstrated the perceived postures of their right wrist and elbow during an ischemic block of the right upper arm with the left hand and arm. If the actual wrist was fully extended while the actual elbow was fully flexed, then the perceived position of the wrist moved toward flexion and that of the elbow moved toward extension. Conversely, if the actual wrist was fully flexed while the actual elbow was fully extended, then the wrist was perceived to extend and the elbow was perceived to flex. Following the loss of the afferent signal coming from the main muscles acting at the two joints, the two perceived postures moved toward the opposite direction independently. The changes in the perceived postures are a shift in the body schema depending on the balance of the proprioceptive inputs that determine limb posture.

Abstract:Currently little is known about how the color of non-edible items such as tableware affect people's perception of food, emotional responses and mood in dining activities. The emotional responses and mood during dining activities are considered more easily affected by colors. In this study, we conducted an experiment to understand Japanese female participants' preference and association about 8 different colors. We also designed 6 different illustration indicating typical dining situations to evaluate the perception of dining activities and color preference in each dining situations. Analysis of variance and correlation analysis were carried out to detect the significant differences between preference of colors and the relationship between color selection and adjective words. The results showed the tendency of light color being preferred to dark color, and explained that different dining situations evoked different mood and interpretation, which might lead to different choice of colors for tableware.

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Reinforcement learning is a useful tool for complex control problems that cannot be modeled mathematically nor solved theoretically. However, a traditional value function approach such as Q-learning includes the difficulty of combinatorial explosion. Direct policy search, (DPS) is an alternative approach that represents a policy using some model and searches a parameter space directly for an optimum by optimization techniques such as genetic algorithms (GA). Instance-based policy (IBP) is a policy representation model of DPS. IBP represents a policy using a set of instances that are pairs of state and action. This paper presents a hybrid GA to optimize efficiently a set of instances with continuous state and continuous action, given an episodic task. The hybrid GA is composed of a combinatorial GA with BDX (Binomial Distribution Crossover) and a real-coded GA with INDX (Instance-wise Normal Distribution Crossover). The proposed method named SLIP (Sophisticated Learner for Instance-based Policy) was applied to a cat twist problem and a parallel-type double inverted pendulum problem. The results of experiments show the effectiveness and usefulness of SLIP.