3-back scores of participants before, during and after tDCS stimulation to their left dorsolateral prefronatal cortex
Datasets usually provide raw data for analysis. This raw data often comes in spreadsheet form, but can be any collection of data, on which analysis can be performed.
Files are named by date, subject code, day and task condition. There are four different conditions: Exposure, Baseline, DCS and Test. Exposure was a brief training on the n-back task. Baseline was a 5 minute period of the 3-back. Exposure and Baseline occurred only on day 1. DCS stands for direct current stimulation and indicates performance of the 3-back (10 minutes) that occurred while participants were stimulated. The test condition (10 minutes of 3-back) occurred post-stimulation. Both DCS and the Test conditions occurred on days 1 and 2.
For example: 01-Jan-2012_AA01_1_DCS - indicates the performance during stimulation on day 1 01-Jan-2012_AA01_2_Test - indicates the performance during post-stimulation test phase on day 2
Variables in the files are presented in the following order:
shudaprsd = indicates instances where the letter on screen was the same as the letter 3-back (1) or not (0) key_press = the key pressed (6 = F, letter on screen is not the same as 3-back; 8 = h, letter on screen is the same as letter 3-back) instructions = time relative to the start of the file when the instructions appeared on screen fixation = time relative to the start of the file when the first fixation cross appeared on screen letter_onscreen = time relative to the start of the file when the letter appeared on screen stimulus_interval = time relative to the start of the file when the fixation cross disappeared off screen RT = reaction time in seconds from the time stimulus onset to the button press Hits = the amount of correct hits (3-back) CRs = the number of correct rejections FAs = false alarms, pressing the hit button at the wrong occasion Misses = incorrect rejection of hit trial (opposite to false alarm) or = omitted rejection response oh = omitted hit response HR = hit rate calculated as the number of hits per chances FAR = false alarm rate calculated as the number of false alarms per opportunity Z_HR = Z normalised hit rate, where Z is the inverse of the cumulative Gaussian distribution Z_FAR = Z normalised false alarm rate, where Z is the inverse of the cumulative Gaussian distribution d = d prime calculated as Z_HR - Z_FAR