The current study focused solely on the modulation of phase in a single trial at a single electrode, but an analysis of both spikes and phase across multiple brain regions may shed light on the neural communication PF-02341066 chemical structure involved in these computations. We tested six patients (two males and four females with average age 38.6 ± 14.0 years), who had been surgically implanted with depth electrodes as part of treatment for medically refractory epilepsy. Each one provided informed consent to participate in the study, which was approved by the Medical Institutional Review Board at the University

of California, Los Angeles. The subjects performed the task well, having an average of 87.9 ± 20.1 incorrect answers for each set of ten puzzles (80 correct answers). Given the need for the subject to guess the location of the matching cards at the beginning of each puzzle, this baseline level of incorrect answers is expected. The electrode locations were chosen based exclusively on clinical criteria for the purpose of identifying Selleck IOX1 the seizure focus. Typically, the targeted regions included structures in both the temporal lobe (amygdala, hippocampus, entorhinal cortex, parahippocampal gyrus, and superior

temporal gyrus) and the frontal lobe (orbitofrontal cortex, anterior cingulate gyrus, middle cingulate, and supplementary motor area). Each patient underwent whole brain magnetic resonance imaging (MRI) before being bilaterally implanted with 8–12 depth electrodes.

After implantation, each patient received a computed tomography scan, which was coregistered to the MRI to verify the placement of the electrodes. The data were initially recorded at 30 kHz using a 128-channel Neuroport system (Blackrock Microsystems) and were down-sampled to 2 kHz using the MATLAB “resample” function. In total, we analyzed data from 472 microwires from 59 depth electrodes (Table 1). The depth electrodes had eight 1.5 mm wide platinum contacts along the length and eight 40 μm platinum-iridium microwires protruding from the tip. These microwires were used to record extracellular LFP activity. A ninth microwire of lower impedance was available as a reference for the recordings. One of these low-impedance references was used for each group of 32 microwires (four brain regions). 4-Aminobutyrate aminotransferase It would have been desirable to use the low-impedance microwire from each depth electrode as a local reference; however, this was not possible due to technical limitations at the time. Because of this, the LFP data were converted to a bipolar montage offline (using software) to ensure that all neural responses were local to the microwire region. The microwires on each depth electrode were not evenly spaced throughout the tissue, so all 28 bipolar combinations were used for each group of eight microwires. This brings the total data set to (59 depth electrodes) × (28 bipolar combinations) = 1,652 electrode measurements.