The Impact of Flow in an EEG-based Brain Computer Interface

Major issues in Brain Computer Interfaces (BCIs) include low usability and poor user performance. This paper tackles them by ensuring the users to be in a state of immersion, control and motivation, called state of flow. Indeed, in various disciplines, being in the state of flow was shown to improve performances and learning. Hence, we intended to draw BCI users in a flow state to improve both their subjective experience and their performances. In a Motor Imagery BCI game, we manipulated flow in two ways: 1) by adapting the task difficulty and 2) by using background music. Results showed that the difficulty adaptation induced a higher flow state, however music had no effect. There was a positive correlation between subjective flow scores and offline performance, although the flow factors had no effect (adaptation) or negative effect (music) on online performance. Overall, favouring the flow state seems a promising approach for enhancing users' satisfaction, although its complexity requires more thorough investigations

Evaluation of Switch and Continuous Navigation Paradigms to Command a Brain-Controlled Wheelchair

A brain-computer interface (BCI) is a technology allowing patients with severe motor dysfunctions to use their electroencephalographic signals to create a communication channel to control devices. The objective of this paper is to study the feasibility of continuous and switch control modes for a brain-controlled wheelchair (BCW) using sensorimotor rhythms (SMR) modulated through a right-hand motor imagery task. Previous studies, which used a continuous navigation control with SMR, have reported the difficulty of maintaining the motor imagery task for a long time, especially for the forward command. The switch control has been presented as a proposal that may help to solve this issue since this task is only used temporary for either disabling or enabling the movement. Regarding the methodology, 10 of 15 able-bodied users, who had overcome the criterion of 30% error rate in the calibration phase, controlled the BCW using both paradigms. The navigation tasks consisted of a straight path divided in five sections: in three of them the users had to move forward, and in the other two the users had to maintain their position. To assess user performance in the device management, a usability approach was adopted, measuring the factors of effectiveness, efficiency, and satisfaction. Then, variables related to the time employed and commands selected by the user or parameters related to the confusion matrix were applied. In addition, the scores in NASA-TLX and two ad hoc questionnaires were considered to discuss the user experience controlling the wheelchair. Despite the results showed that the best system for a specific user relies on his/her abilities and preferences, the switch control mode obtained better accuracy (0.59 ± 0.17 for continuous and 0.72 ± 0.05 for switch). Furthermore, the switch paradigm can be recommended for the advance sections as with it users could complete the advance sections in less time (42.2 ± 28.7 s for continuous and 15.47 ± 3.43 s for switch), while the continuous mode seems to be better at keeping the wheelchair stopped (42.45 ± 16.01 s for continuous and 24.35 ± 10.94 s for switch)

Setting A Behavioral Task For Assessing Decision Making In Urodele Amphibian

International audienceDecision making takes a crucial role in daily life and can be seriously impaired in neurodegenerative diseases. It implies cortical-basal ganglia loops, but the respective roles of each structure are still debated. Urodeles offer a remarkable opportunity to address this question.First, whereas the organization of the basal ganglia in these animals is similar to the one of mammals, it has orders of magnitudes fewer neurons1 and is therefore at a level of complexity that is more tractable in terms of comprehension and modelling. Second, the extensive regenerative capacities of their midbrain networks allow the use of local lesions to investigate their connectivity and functionality. This also makes the urodele a unique experimental model for investigating the mechanisms of decision-making network plasticity after a midbrain injury.Therefore, we decided to set up a behavioral test of decision making in this animal model. Our task was based on the ability of urodele to discriminate polarized light. The animals were trained2,3 to associate the location of a shade shelter (urodeles do not like exposure to direct light) with a specific orientation of the polarization axis. We then performed a test to assess if the animals learned this association. This paradigm gave us access to a motor decision making mode. In a second step, we will perform selective lesions of the pallium (i.e. the cortex in lower vertebrates), the thalamus and the basal ganglia to determine the respective role of each structure. We will then study implication of dopamine4 in this behavioral task. To our knowledge, urodele is the earliest group of limbed vertebrates in which decision-making process has been successfully addressed yet