Design and Use of an Apparatus for Presenting Graspable Objects in 3D Workspace

Summary

Presented here is a protocol to build an automatic apparatus that guides a monkey to perform the flexible reach-to-grasp task. The apparatus combines a 3D translational device and turning table to present multiple objects in an arbitrary position in 3D space.

Abstract

Reaching and grasping are highly-coupled movements, and their underlying neural dynamics have been widely studied in the last decade. To distinguish reaching and grasping encodings, it is essential to present different object identities independent of their positions. Presented here is the design of an automatic apparatus that is assembled with a turning table and three-dimensional (3D) translational device to achieve this goal. The turning table switches different objects corresponding to different grip types while the 3D translational device transports the turning table in 3D space. Both are driven independently by motors so that the target position and object are combined arbitrarily. Meanwhile, wrist trajectory and grip types are recorded via the motion capture system and touch sensors, respectively. Furthermore, representative results that demonstrate successfully trained monkey using this system are described. It is expected that this apparatus will facilitate researchers to study kinematics, neural principles, and brain-machine interfaces related to upper limb function.

Introduction

Various apparatuses have been developed to study the neural principles underlying reaching and grasping movement in non-human primate. In reaching tasks, touch screen^1,2, screen cursor controlled by a joystick^3,4,5,6,7, and virtual reality technology^8,9,10 have all been employed to present 2D and 3D targets, respectively. To introduce different grip types, ....

Protocol

All behavioral and surgical procedures conformed to the Guide for the Care and Use of Laboratory Animals (China Ministry of Health) and were approved by the Animal Care Committee at Zhejiang University, China.

1.Assembling the 3D translational device

1. Build a frame of size 920 mm x 690 mm x 530 mm with aluminum construction rails (cross section: 40 mm x 40 mm).
2. Secure four pedestals to the two ends of the Y-rails with screws (M4) (Figure 1B).
3. Fix two Y-rails onto the top surface of the frame in parallel by securing the four pedestals to the four corners of the top surface with scr....

Results

The size of complete workspace of the apparatus is 600 mm, 300 mm, and 500 mm in x-, y-, and z-axes, respectively. The maximum load of the 3D translational device is 25 kg, while the turning table (including the stepping motor) is weighted 15 kg and can be transported at a speed of up to 500 mm/s. The kinematic precision of the 3D translational device is less than 0.1 mm and the noise of the apparatus is less than 60 dB.

To demonstrate the utility of the system, the monkey is trained (previous.......

Discussion

The behavioral apparatus is described here enables a trial-wise combination of different reaching and grasping movements (i.e., the monkey can grasp differently shaped objects in any arbitrary 3D locations in each trial). This is accomplished through the combination of a custom turning table that switches different objects and a linear translational device that transports the turning table to multiple positions in 3D space. In addition, the neural signals from the monkey, trajectory of wrist, and hand shapes were able to.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Active X-rail	CCM Automation technology Inc., China	W50-25	Effective travel, 600 mm; Load, 25 kg
Active Y-rail	CCM Automation technology Inc., China	W60-35	Effective travel, 300 mm, Load 35 kg
Active Z-rail	CCM Automation technology Inc., China	W50-25	Effective travel, 500 mm; Load 25 kg
Bearing	Taobao.com	6004-2RSH	Acrylic
Case	Custom mechanical processing	TT-C	Acrylic
Connecting ring	CCM Automation technology Inc., China	57/60-W50
Connecting shaft	CCM Automation technology Inc., China	D12-700	Diam., 12 mm;Length, 700 mm
Diaphragm coupling	CCM Automation technology Inc., China	CCM 12-12	Inner diam., 12-12mm
Diaphragm coupling	CCM Automation technology Inc., China	CCM 12-14	Inner diam., 14-12mm
Electric slip ring	Semring Inc., China	SNH020a-12	Acrylic
Locating bar	Custom mechanical processing	TT-L	Acrylic
Motion capture system	Motion Analysis Corp. US	Eagle-2.36
Neural signal acquisition system	Blackrock Microsystems Corp. US	Cerebus
NI DAQ device	National Instruments, US	USB-6341
Object	Custom mechanical processing	TT-O	Acrylic
Passive Y-rail	CCM Automation technology Inc., China	W60-35	Effective travel, 300 mm; Load 35 kg
Passive Z-rail	CCM Automation technology Inc., China	W50-25	Effective travel, 500 mm; Load 25 kg
Pedestal	CCM Automation technology Inc., China	80-W60
Peristaltic pump	Longer Inc., China	BT100-1L
Planetary gearhead	CCM Automation technology Inc., China	PLF60-5	Flange, 60×60 mm; Reduction ratio, 1:5
Right triangle frame	CCM Automation technology Inc., China	290-300
Rotator	Custom mechanical processing	TT-R	Acrylic
Servo motor	Yifeng Inc., China	60ST-M01930	Flange, 60×60 mm; Torque, 1.91 N·m; for Y- and Z-rail
Servo motor	Yifeng Inc., China	60ST-M01330	Flange, 60×60 mm; Torque, 1.27 N·m; for X-rail
Shaft	Custom mechanical processing	TT-S	Acrylic
Stepping motor	Taobao.com	86HBS120	Flange, 86×86 mm; Torque, 1.27 N·m; Driving turning table
Touch sensor	Taobao.com	CM-12X-5V
Tricolor LED	Taobao.com	CK017, RGB
T-shaped connecting board	CCM Automation technology Inc., China	110-120