Published at 25-February-2012.
The underlying idea governing neural control of behavior is the three-step structure of nervous systems that have evolved over billions of years, which can be stated in its simplest form as follows:
a) specialized neurons transform environmental stimuli into a neural code;
b) this encoded information travels along specific pathways to the brain or central nervous system composed of billions of nerve cells, where it is combined with other information;
c) a decision to act on the incoming information then requires the generation of a different motor instruction set to produce the properly timed muscle activity we recognize as behavior.
Neurons receive patterned synaptic input and compute and communicate by transforming these synaptic input patterns into an output sequence of spikes. As spike waveforms emitting by each particular neuron are similar, information encoded in spike trains mainly relies on the interspike intervals.
From one side, relying on timing rather than on the details of action-potential waveforms increases the reliability and reproducibility in interneural communication. On the other part, the intrinsic membrane conductances can enable neurons to generate different spike patterns, including high-frequency bursts of different durations which are commonly observed in a variety of motor neural circuits and brain regions. The biophysical mechanisms of spike generation enable individual neurons to encode different stimulus features into distinct spike patterns. Spikes, and bursts of spikes of different durations, code for different stimulus features, which can be quantified without a priori assumptions about those features.
Simultaneous recording of activity from many neurons can greatly expand our understanding of how information is coded in neural systems. Multiple electrodes or multi-site electrophysiological recordings have become a standard tool for exploring complex brain functions and behaviour. However, these techniques point out the necessity of fast and reliable unsupervised spike sorting.
Our FSPS™ software and algorithms performs highly accurate online spike sorting for any type of the continuous data stream. Besides, it is completely automatic in determining the number of firing cells and their classification thus could be successfully applied for multi-electrodes. Indeed, since the version 2.1 FSPS™ supports multi-sites acquisition and analysis. Most intriguing things (what we're working on now) is the processing of spike occurrences and latencies that could allows FSPS™ application to study of neuronal activity patterns and their dynamical changes under various experimental tasks or clinically recorded data. Since the graphical user interface was built on LabVIEW™ (National Instrument, USA) the FSPS™ spike sorting software has become multi-platform compatible and can be easily adapted for any experimental design.