relacs (pronounced "relax!") is a software platform for data acquisition, online analysis, and stimulus generation specifically designed for (but not limited to) electrophysiological recordings.

relacs is free and open software to foster development and exchange of innovative experimental protocols and analysis techniques.

Overview

Closed loop experiments. From Benda et al. 2007.

The main reason for developing relacs was to create a platform for implementing

• Closed-loop experiments.

relacs offers many more features, that sets it apart from other data acquisition software:

• Hardware independence
• Meta-data storage
• Dynamic clamp
• Integration of experiments and model simulations

In addition, relacs provides:

• C++ plugins for powerful flexibility
• Data-analysis library

We are using this program very succesfully in our lab for many years (see list of publications).

Specifications

Open source

relacs is programmed in C++:

• 145 header files
• 155 C++ source code files
• Altogether 121919 lines of code and inline documentation

relacs is published under the GPL. More ...

Sweep-based quasi-continuous acquisition

Stimulation (analog output) and data-recording (analog input) are started simultaneously for each stimulus to ensure best synchronization, but data are recorded all the time and can be viewed continuously.

relacs has been designed initially for up to about 10 input traces. More traces are possible, but might require a different widget for showing the raw voltage traces.

Stimulation via analog output channels

The neuron (or whatever system) can be stimulated via the analog output channels of the data acquisition boards with continuous freely programmable waveforms. Depending on the hardware of your experimental setup this can be, for example, a current injected into the cell, a sound wave, an electric field, ...

Seamless integration of attenuators

For adjusting the amplitude of a stimulus and still make use of the full resolution of the data aquisition board one can use digitally controlled attenuators. This is especially usefull for acoustic stimuli. relacs uses two levels of abstraction to support attenuators. First, the Attenuator device interface provides an unique interface to various attenuator device types. Second, the Attenuate interface translates an intensity variable to the appropriate attenuation level. How the intensity variable is interpreted (e.g. as dB SPL or sound pressure) depends on the implementation of the Attenuate interface as well as on the corresponding calibration program.

Multi-threaded design

The acquisition of the data, filtering and spike detection, data analysis and stimulus generation, and GUI interaction are running in parallel as different threads. This way, relacs makes use of the computing power of multi-processor machines and therefore pushes the applicability of closed-loop algorithms to much larger data volumes, as they are acquired from multi-unit recordings, for example.

News

Version 0.9.6

July, 2009

Introduced DigitalIO device interface and got attenuator back into RELACS

Read all NEWS announcements.