Multidimensional recording (MDR) and data sharing: an ecological open research and educational platform for neuroscience

Abstract

Primate neurophysiology has revealed various neural mechanisms at the single-cell level and population level. However, because recording techniques have not been updated for several decades, the types of experimental design that can be applied in the emerging field of social neuroscience are limited, in particular those involving interactions within a realistic social environment. To address these limitations and allow more freedom in experimental design to understand dynamic adaptive neural functions, multidimensional recording (MDR) was developed. MDR obtains behavioral, neural, eye position, and other biological data simultaneously by using integrated multiple recording systems. MDR gives a wide degree of freedom in experimental design because the level of behavioral restraint is adjustable depending on the experimental requirements while still maintaining the signal quality. The biggest advantage of MDR is that it can provide a stable neural signal at higher temporal resolution at the network level from multiple subjects for months, which no other method can provide. Conventional event-related analysis of MDR data shows results consistent with previous findings, whereas new methods of analysis can reveal network mechanisms that could not have been investigated previously. MDR data are now shared in the public server Neurotycho.org. These recording and sharing methods support an ecological system that is open to everyone and will be a valuable and powerful research/educational platform for understanding the dynamic mechanisms of neural networks.

Figure 1. ECoG array, implantation and cortical coverage.

a) Sixty-four channel ECoG array with connectors and the reference and ground electrodes. b) Schematic figure showing how and where the ECoG array, reference electrode, ground electrode, and connectors were implanted c) Schematic view showing how the 128-channel ECoG electrode can cover the entire lateral cortical surface.

Figure 2. Experimental environment and eye tracking system.

a) Sketch of the recording environment of MDR while the monkeys performed a social food-grab task. The monkeys wore an elastic motion capture suit tailored for each monkey. The monkeys sit on a primate chair with the lower body including the legs covered and restrained by a box and a collar fixed to a pole attached to the chair. Two monkeys were placed around a table. Reflective markers for motion capture were attached at the joints of both arms (shoulder, elbow and wrist) and the head. One monkey (left) whose ECoG activity was recorded wore a head-free eye-tracking system. Motion capture and video cameras were hung from the ceiling. b) Illustration of the head-free eye-tracking system. The eye-tracking system comprises two parts: a fixture part and an optical part. The fixture part was made of dental acrylic that fit the monkey's facial surface. The optical part had an infrared (IR) LED, dichroic mirror, eye-track camera, and view camera. The fixture part is tailored for each monkey and is attached to the optical part by screws.

Figure 3. Simultaneously recorded motion capture data, eye tracking data and neural data for 10 sec.

a) Three dimensional trajectories (X, Y and Z position indicated by red, green and blue lines respectively) of motion markers attached at Monkey A's right wrist, head, Monkey B's right wrist and Experimenter's right wrist. b) X (red) and Y (green) positions of eye tracking data of Monkey A's right eye. c) Normalized (z-score) power of neural data at 70 Hz recorded from 128 channel ECoG array.

Figure 4. Neurotycho and open research platform.

The combination of MDR and Neurotycho.org will provide an open platform for research and education in neuroscience. The interaction between the users and us will improve the quality of the service.