Sortclient 2002

As described in detail in Ribeiro et al. (2007 (link)), action potentials (spikes) and local field potentials (LFP) were recorded with multi-electrode arrays placed in the dorsal CA1 region and dentate gyrus of HP, in the barrel field of S1, and in V1. Animals were recorded after a 1-week recovery period following surgery. A 96-channel multineuron acquisition processor (MAP, Plexon Inc, Dallas, TX) was used for digital spike waveform discrimination and storage. Action potentials (spikes) were extracted from the high frequency band data and sorted into units using supervised online spike sorting (SortClient 2002, Plexon Inc.) associated with posterior offline validation (Offline Sorter 2.3, Plexon Inc). LFPs recorded from the same wires were pre-amplified, filtered, and digitized using a Digital Acquisition card (National Instruments, Austin, TX) and a MAP (Plexon Inc). Behaviors were recorded throughout the entire experiment under infrared illumination, by way of two CCD video cameras and a videocassette recorder. Video and neural recordings were synchronized with a millisecond-precision timer (model VTG-55; For-A, Tokyo, Japan). Within each region, the amount of units consisted of 42 HP, 33 S1 and 20 V1 for rat # 1, 59 HP, 23 S1 and 28 V1 for rat # 2, 34 HP, 25 S1 and 23 V1 for rat # 3, 39 HP, 27 S1 and 37 V1 for rat # 4 and 45 HP, 39 S1 and 42 V1 for rat # 5.

A 32-channel multi-neuron acquisition processor (MAP, Plexon Inc., Dallas, TX, USA) was used for spike recording and sorting in a weekly basis, for 30–45 min in rats freely behaving in their cages. Online spike sorting was conducted with the help of the SortClient 2002 software (Plexon Inc., USA). A maximum of 4 neuronal action potentials per channel were sorted online and validated by offline analysis (Offline Sorter 2.8, Plexon Inc., USA) according to some criteria, as previously described [22 (link)]: voltage thresholds, amplitude distributions, signal-to-noise ratio, waveform shapes, and principal component analysis. The temporal variation of the electrophysiological pattern in each group during its time of implant (increase or decrease of neural signal) was evaluated by comparing neural signal collected in first and last week of recording.

A Multineuronal Acquisition Processor (64 channels, Plexon Inc, Dallas, TX) was used to record neuronal spikes, as previously described15 . Briefly, differentiated neural signals were amplified (20000–32,000×) and digitized at 40 kHz. Up to four single neurons per recording channel were sorted online (Sort client 2002, Plexon inc, Dallas, TX).