Custom-Built Operant Conditioning Setup for Calcium Imaging and Cognitive Testing in Freely Moving Mice

Overview of the setup. A desktop PC powers and controls an Arduino UNO microcontroller which in turn controls the nose poke sensors, food dispenser and audiovisual stimuli of the operant chamber. The Arduino and PC are also connected to the miniscope data acquisition box (DAQ). The DAQ, in turn, controls the USB camera for observation of the animal and the miniscope camera for recording of calcium activity. The USB camera is powered by the PC via a USB cable and the parameters of the recording can be manipulated both through the miniscope software and through other software installed for that purpose (e.g., ManyCam, Visicom Media Inc.).

Operant chamber components. A–C, The base of the operant chamber is composed of the floor and the front wall with two nose poke holes and an opening for the food receptacle (A). The back of this wall holds the electronic components (B) and the pellet dispenser (C). The individual polycarbonate pieces comprising the base of the chamber are shown in (L) and their dimensions are shown in Table 1; M represents a schematic of the electronic circuit controlling the sensors and stimuli of the chamber. D–F, An additional set of removable walls limits the exploration of the mouse and focuses the behavior on the nose poke holes and pellet dispenser (optional). G–I, A removable outer casing completes the box with outer walls and two strips above the box allow for the attachment of a pipette tip box with a commutator and the USB camera (data not shown; J). The pipette box with the commutator is hinged using masking tape. K, The operant chamber in its entirety. Extended Data Figure 2-1 shows the DAQ modification for connecting to the Arduino circuit, and Extended Data Figures 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, 2-8, 2-9, 2-10, 2-11 contain the Arduino code for the Go/No-Go task.

Validation of the operant setup – assessing the effect of adolescent social stress on cognition in adulthood. Adolescent mice were exposed to 4 days of accelerated social defeat stress (AcSD) and separated into resilient and susceptible groups based on a social interaction test (SIT). A, Susceptible mice had interaction ratios (IR) < 1, while resilient mice had IR >/= 1. * significantly different from control, p = 0.01. B, Susceptible mice spent less time in the interaction zone (IZ) of the SIT arena - avoiding an unfamiliar CD-1 mouse - and spent more time in the corner zones of the SIT arena (C) * significantly different from control, p = 0.02. D, The majority (60%) of mice exposed to AcSD in adolescence were resilient. E, One month after AcSD and SIT, in adulthood, mice were first trained and then tested on the Go/No-Go task. F, Schematic representation of the Go/No-Go task. Mice receive rewards by nose-poking on “Go” trials (“hits”) and withholding a nose poke during No-Go trials. Commission errors represent incorrect responses on No-Go trials. Responses before the Go (light) or No-Go (light + tone) cues on any trial are considered “premature” responses and not rewarded. G, The correct response rate represents the proportion of available rewards that were acquired by control and defeated mice across both Go and No-Go trials. H, Defeated mice made more commission errors during No-Go trials. I, There were no differences between control and defeated mice in the number of correct responses on Go trials.