Friday, July 25, 2014

MScan 2.1. New feature: behavioral camera

Concurrent video streaming.

Cutting-edge multiphoton experiments now deal with imaging neurons in awake animals performing a behavioral task. Observing animal actions and timing them accurately with respect to functional imaging is of paramount importance to correlate behavior with neural activity. MCS is well-suited for these kinds of experiments. Information from sensors for touch or licking behavior can be displayed and recorded using the eight analog channels available on the analog input board, a National Instruments PCIe-6321 board which is capable of sampling data at up to 250 kHz.

In addition, MScan 2.1 now supports a second, optional video camera dedicated to filming behavior during scanning. The first camera, also optional, is used for focusing the microscope. The cameras, which are identical, are designated as CSFV90BC3-B from their manufacturer, Toshiba-Teli. They output VGA-style black and white frames with 256 levels of gray (i.e., 640 x 480 pixels with an 8-bit resolution).

MScan 2.1 takes advantage of the fact that Toshiba-Teli FireDragon cameras can be triggered externally, a feature that is seldom found on cameras in that price range. This capability allows accurate hardware synchronization of frames from the camera with those taken by the MOM. Because CSFV90BC3-B  cameras can acquire frames at a rate of up to 90 fps, video streaming can be performed simultaneously even with resonant scanning. Internal frame buffering inside the camer and computer interfacing through IEEE 1394B (i.e., FireWireB), which guarantees data transfer at up to 800 Mbit/s ensure loss-free streaming. In MScan, the video stream is displayed live during two-photon imaging and is stored in parallel with the two-photon imaging frames in the same data file to facilitate analysis with MView. A custom cable is used to convey the Frame Sync signal from the computer to the camera. Initial testing shows concurrent video and two-photon display and streaming with two imaging channels at close to 90 fps.

MView 2.1 has been enhanced to open and display the video stream stored in data files synchronously with the two-photon images. Multiple video stream windows can be opened simultaneously to ease frame-to-frame comparisons. The video stream can be converted into an AVI movie or individual frames can be saved as bitmap files.

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