README for rat behavioral data (last updated on April 24, 2020) The accompanying file `rat_behavior.csv` contains all behavioral data from the rat auditory task, first presented in Akrami et al. 2018 [1]. The data set contains behavior for 19 rats across a combined 2540006 trials. Data from rats trained on "delay" intervals of longer than 8 seconds are omitted, as this is an area of continuing research. Relevant portions from the Methods section of the paper ("Rat subjects" and "Rat behavior") are reproduced below: "A total of 33 male Long–Evans rats (Rattus norvegicus) between the ages of 6 and 24 months were used for this study. Of these, 25 rats were used for behavioural assessments ... Animal use procedures were approved by the Princeton University Institutional Animal Care and Use Committee and carried out in accordance with National Institutes of Health standards." "We developed a computerized protocol to train rats, in high-throughput facilities, to perform an auditory delayed comparison task, adapted from a tactile version. All training takes place in three-port operant conditioning chambers, in which ports are arranged side-by-side along one wall, with two speakers placed above the left and right nose ports. Figure 1a shows the task structure. A visible light-emitting diode in the centre port signals the availability of each trial. Rat subjects initiate a trial by inserting their nose into the centre port, which causes the centre light to turn off. Rats must keep their nose in the centre port (fixation period), until an auditory ‘go’ cue (a 6-kHz pure tone for 200 ms) signals the end of fixation. Only after the ‘go’ cue can subjects withdraw and orient to one of the side ports in order to receive a reward of water. During the fixation period two auditory stimuli, s_a and s_b, separated by a variable delay, are played for 400 ms, with short delay periods of 250 ms inserted before s_a and after sb. The stimuli consist of broadband noise (2,000–20,000 Hz), generated as a series of sound pressure level (SPL) values sampled from a zero-mean normal distribution. The overall mean intensity of sounds varies from 60–92 dB. Rats should judge which out of the two stimuli, s_a and s_b, had the greater SPL standard deviation. If s_a > s_b, the correct action is to poke the nose into the right-hand nose port in order to collect the reward, and if s_a < s_b, rats should orient to the left-hand nose port. Trial durations are independently varied on a trial-by-trial basis, by varying the delay interval between the two stimuli, which can be as short as 2 s or as long as 12 s. Rats progressed through a series of shaping stages before the final version of the delayed comparison task, in which they learned to: associate light in the centre poke with the availability of trials; associate special sounds from the side pokes with reward; maintain their nose in the centre poke until they hear an auditory ‘go’ signal; and compare the two s_a and s_b stimuli. Although a substantial amount of data has been collected on all delay intervals from 2 to 12 s, in this manuscript we focus on delay durations of 2, 4 and 6 s, as most of the rats were consistently trained on these values. Training began when rats were two months old, and typically required three to four months for rats to display stable performance on the complete version of the task." Data description, by column: 1) subject_id: The name of the rat (19 total subjects) 2) session: The session number, where 1 is the first session of training 3) trial: The trial number within a session, where 1 is the first trial 4) s_a: The loudness of stimulus A (pink noise) in decibels (dB) (NaN during training_stage 1) 5) s_b: The loudness of stimulus B (pink noise) in decibels (dB) (NaN during training_stage 1) 6) choice: The choice made by the rat, where Left=0 and Right=1 (and Mistrial=NaN) 7) correct_side: The correct side, where Left=0 and Right=1 8) hit: If the rat made the correct choice, where Incorrect=0 and Correct=1 (and Mistrial=NaN) 9) delay: The duration of the delay between the end of Tone A and the start of Tone B, in seconds. See the example trial timeline below for more information. 10) training_stage: Index indicating the stage of training (1-4, see below) Timeline of an example trial during the final stage (4) of training: 1) A light in the center port indicates that a new trial can be initiated, at which point the rat can nose-poke in the center port 2) After the start of the nose-poke, there is a 0.25 sec delay before the start of Tone A 3) Tone A plays for 0.4 sec 4) There is a variable delay (recorded in the "delay" column in the CSV file) 5) Tone B plays for 0.4 sec 6) After the end of Tone B, there is a 0.25 sec delay before the Go cue is played 7) A Go cue plays for 0.2 sec The rat is free to withdraw from the center port and make a choice at the start of the Go cue. The total duration of the center nose-poke on each trial is thus 0.25 + 0.4 + "delay" + 0.4 + 0.25, or 1.3 + "delay" seconds. Any break of center nose-poke during this time (steps 2-6) results in a Mistrial. During training_stage 1 (ShapingStage), there is no tone played. training_stage descriptions: 1) ShapingStage: chasing lights, no tones, building center nose-poke, s_a and s_b are NaN 2) ImmediateReward: s_a and s_b are played, and independent of the animals's choice reward is delivered according to the rule (s_a > s_b -> Right, s_b > s_a -> Left), and animal can immediately collect the reward from the other side, after a wrong choice. 3) DelayedReward: the standard task, except the wrong side will still deliver a reward after a 1-5 sec delay 4) NoReward: the standard task Notes: - Two types of trials were omitted from the dataset due to anomalies: (1) 14 trials were omitted for having anomalous stimulus values, and (2) 26 trials were omitted for having inconsistent correct_side values. These omissions are reflected in the data set as gaps in the "trial" count. - There are 256691 trials that are Mistrials, where both "choice" and "hit" are NaN. These are trials where the rat did not complete the trial for various reasons (e.g. it broke center fixation early). Also, at some point after session 100 (differs for each rat), mistrials are no longer included in the data. - For some rats, there are a few sessions late in training where training_stage reverts back to 1. This is for rats that suddenly started to do poorly and had their training reverted back to initial shaping stages, temporarily. [1] Akrami, A., Kopec, C.D., Diamond, M.E. and Brody, C.D., 2018. Posterior parietal cortex represents sensory history and mediates its effects on behaviour. Nature, 554(7692), pp.368-372.