The readouts of the living neural system are the neural action potentials and LFPs recorded by extracellular microelectrode arrays (Figure 1). The recording components include a headstage/preamp for amplifying the microvolt-level electrode signals and isolating stimuli, interface circuitry for analog filtering, an analog-to-digital converter (ADC), and software for real-time signal processing and recording (Rolston et al., 2009c). The system is modular, recording from 8 to 64 channels simultaneously at up to 30 kHz per channel. Three technological advances helped make this system less expensive than commercial counterparts. First, high-gain headstages/preamps (100–1000×) reduce the need for second stage amplifiers (sometimes also called “preamps”). Second, modern multifunction ADC cards have high precision (for example, the PCI-6259 we use from National Instruments is 16-bit with a full-scale range as sensitive as 200 mV). This high precision and sensitivity relaxes preamp and second stage amplification requirements. Third, computers are now powerful enough to do most filtering, spike detection, etc. in real-time. The advantage of implementing these features in software, rather than hardware, is the ease at which they can be improved or rapidly reconfigured for different applications. For example, when we devised a new method of digital referencing for multi-electrode recordings based on subtracting the common median, we added this feature and used it immediately (Rolston et al., 2009b). Since these advances lead to fewer components, the cost for a 64-channel system was less than US$10,000, compared to US$40,000–100,000 for comparable but more highly polished commercial systems (Rolston et al., 2009c).