The existing mazes are mainly used to study the learning and memory of animals. However, there is still a lack of corresponding maze and method in the aspect of the observation and test of aquatic animal robots. For this purpose, the authors have developed a three-dimensional water maze combined with bilayer multi-channel which equips with stratified lines and tick marks. This device is a rectangular structure composed of one square bottom and four rectangular side walls, and the channels of every side wall are composed of one upper channel and two lower channels. The center of the upper channels is in the vertical center line of every side wall, and the two uper channels of adjacent side walls are at 90° degrees with each other, and the two lower channels of adjacent side walls are at 45° degrees with each other. There are stratified lines and tick marks on the side wall to test the spatial location and movement trajectories of aquatic animals. The carp robot was put into the water maze for the underwater experimental detection. The success rates of left and right steering at 135, 90 and 45 degrees as well as forward motion of the carp robots (n = 10) were over 60%. This study showed that the device could be used to observe and test the motion of the carp robot.
In order to solve the problems that the injury, hemorrhage, infection and edema of the brain tissue caused by brain electrodes implantation for aquatic animal robots, a light stimulation device and an optical control experiment method for carp robots are proposed in this paper. According to the shape of the carp skull, the device is a structure of Chinese character " 王” cut by a printed circuit board which can provide three groups of A, B and C bridge platforms for the light stimulation source. The two ends of a bridge in every group are welded with a jumper board, and the light emitting diodes (LED) are inserted into the jumper boards as the light stimulation source, and all negative poles of the jumper boards are connected to the console by the wire. A LED light can be replaced by another LED light according to the need of the wavelength of the LED light, and various combinations of the light stimulation modes can be also selected. This device was mounted on the carp robot’s head, the carp robot was placed in a water maze, and the optical control experiment method was observed to control the forward movement and steering movement of the carp robots (n = 10) under the dark light condition. The results showed that the success rates of the three groups of red light control experiments were 53%–87%, and the success rates of the three groups of blue light control experiments were 50%–80%. This study shows that the apparatus and the method are feasible.
To solve the problem of precise positioning of carp brain tissue coordinates, it is proposed in this paper for a method for transforming the coordinates of magnetic resonance imaging of carp brain tissue into the coordinates of electrode implantation using a brain stereotaxic apparatus. In this study, the 3.0T magnetic resonance imaging instrument was used to scan the carp brain. We independently established the three-dimensional positioning coordinate system of the brain, the three-dimensional coordinate assistance system of skull surface and the three-dimensional coordinate assistance system in brain tissue. After two coordinate transformations, the magnetic resonance image coordinates of the brain electrodes implantation sites were converted into the three-dimensional stereotactic coordinate system to guide the electrodes implantation. The experimental groups were divided into two groups, A and B. Group A was the group of magnetic resonance imaging apparatus combining with the brain stereotaxic apparatus, and group B was the group of brain atlas combining with the brain stereotaxic apparatus. Each group had 20 tails of carps (n = 20). This two methods were used to implant the electrodes into the cerebellar motor area. The underwater experiments of the carp robots were carried out to test the two methods. The results showed that the accuracy of the implanted electrodes were 90% in group A and 60% in group B. The success rate of group A was significantly higher than that of group B (P < 0.05). Therefore, the new method in this paper can accurately determine the coordinates of carp brain tissue.