Journal of Neuroscience Methods 92 (1999) 169 – 177 A combined electrophysiological and video data acquisition system using a single computer Patrick D. Martin, Hisao Nishijo, Taketoshi Ono * Department of Physiology, Faculty of Medicine, Toyama Medical and Pharmaceutical Uniersity, Sugitani 2630, Toyama 930 -01, Japan Received 16 February 1999; received in revised form 8 July 1999; accepted 18 July 1999 Abstract Numerous experimental paradigms in behavioral electrophysiology and neuroethology require simultaneous recording of neural signals and behavior. A computer fitted with an analog to digital converter and a frame grabber was configured to perform both tasks. The analog to digital converter collected electrophysiological data while the frame grabber recorded video images. Since spike and image information were present in one computer, arbitrary combinations of electrophysiological and behavioral parameters could be used as the basis of an operant conditioning paradigm. The system was used to record subicular cell firing in rats performing a place search task. The computer monitored the output of the analog to digital converter for supra-threshold events. When one was detected, a block of samples (pre- and post-trigger) was stored in memory. The same computer also scanned every video frame to find the rat, and recorded a image of its behavior. The location of the rat was then quickly calculated. If it satisfied the task conditions, a brain reward pathway (medial forebrain bundle) was stimulated. The recording of neural and image data was monitored in real-time by writing spike waveforms and location data directly to video card RAM. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Angular velocity; Body curvature; Head direction; Location; Medial forebrain bundle; Rotation; Running speed; Subiculum; Tetrode www.elsevier.com/locate/jneumeth 1. Introduction Numerous problems in behavioral electrophysiology and neuroethology require simultaneous recording of electrophysiological and behavioral information. Sys- tems have been described which can merge electrophys- iological and video data (Fenton and Muller, 1996; Rasnow et al., 1997). However, either because the merger occurs off-line, or else the video data remains in analogue form, the image information can not be em- ployed in an operant conditioning task. We describe a system in which both neural spiking and behavioral images are collected in real time by a single computer. Using a standard personal computer equipped with commercially-available data acquisition hardware it was possible to monitor up to 16 channels of spike data (each sampled at 50 kHz) while digitizing successive video images at 30 Hz. The data acquisition cards employed the Peripheral Component Interface (PCI) in ‘bus master’ mode. In this mode data is transferred directly into memory without the intervention of the computer’s central pro- cessor. Therefore, all of the processing power is avail- able to extract spikes from the analogue data, locate the animal in the image data, and service any desired behavioral paradigm. Moreover, because all electro- physiological and behavioral data is present in one machine, any arbitrary coincidence of neuronal spikes and animal activity can be used as the variables in an operant conditioning task. Rats were implanted with extracellular single neuron recording ‘tetrodes’ (Recce and O’Keefe, 1989) in subiculum (Sharp and Green, 1994). A monopolar stimulating electrode was placed in the medial forebrain bundle (MFB) at the level of the lateral hypothalamus (Fukuda et al., 1992). The rats were run on a modified version of the random reward place search task (Kobayashi et al., 1997), designed to insure the rat traversed the environment continuously and at random. * Corresponding author. Tel.: +81-764-342281 Ext. 2325; fax: +81-764-345013. E-mail address: onotake@ms.toyama-mpu.ac.jp (T. Ono) 0165-0270/99/$ - see front matter © 1999 Elsevier Science B.V. All rights reserved. PII:S0165-0270(99)00110-7