A video based feedback system for control of an active commutator during behavioral physiology.

Mootaek Roh,Kyungmin Lee,Thomas J Mchugh

doi:10.1186/s13041-015-0152-8

Mootaek Roh, Kyungmin Lee + Show 1 more

Open Access

https://doi.org/10.1186/s13041-015-0152-8

Copy DOI

Abstract

BackgroundTo investigate the relationship between neural function and behavior it is necessary to record neuronal activity in the brains of freely behaving animals, a technique that typically involves tethering to a data acquisition system. Optimally this approach allows animals to behave without any interference of movement or task performance. Currently many laboratories in the cognitive and behavioral neuroscience fields employ commercial motorized commutator systems using torque sensors to detect tether movement induced by the trajectory behaviors of animals.ResultsIn this study we describe a novel motorized commutator system which is automatically controlled by video tracking. To obtain accurate head direction data two light emitting diodes were used and video image noise was minimized by physical light source manipulation. The system calculates the rotation of the animal across a single trial by processing head direction data and the software, which calibrates the motor rotation angle, subsequently generates voltage pulses to actively untwist the tether. This system successfully provides a tether twist-free environment for animals performing behavioral tasks and simultaneous neural activity recording.ConclusionsTo the best of our knowledge, it is the first to utilize video tracking generated head direction to detect tether twisting and compensate with a motorized commutator system. Our automatic commutator control system promises an affordable and accessible method to improve behavioral neurophysiology experiments, particularly in mice.Electronic supplementary materialThe online version of this article (doi:10.1186/s13041-015-0152-8) contains supplementary material, which is available to authorized users.

Highlights

To investigate the relationship between neural function and behavior it is necessary to record neuronal activity in the brains of freely behaving animals, a technique that typically involves tethering to a data acquisition system
We describe a novel and simpler approach to automatically motorize a commutator control system using video tracking information in lieu of a torque sensor
We will describe below the four major components of the implementation of this approach: 1) the refinement of the video tracking to improve the accuracy of the acquired data, 2) the mechanical assembly of the commutator system, 3) the development of the algorithm to link the tracking data to the motion of the motor and 4) the calibration of the commutator with open loop tracking

Summary

Introduction

To investigate the relationship between neural function and behavior it is necessary to record neuronal activity in the brains of freely behaving animals, a technique that typically involves tethering to a data acquisition system. This approach allows animals to behave without any interference of movement or task performance. The trace of head direction is sampled during a single trial of behavioral task and subsequently analyzed by a custom algorithm which triggers a calibrated DC motor to correct any twist in the tether This technique was applied to mice performing a behavioral task and allowed successful performance without tether interference

Methods

Results

Discussion

Conclusion