Figure 2.

The animal exposure chamber inside the hyperbaric chamber. The main hyperbaric chamber houses the animal exposure chamber, which contains the animal cage (c1) and wire cage lid (c2). The main chamber is compressed using air only while the animal exposure chamber is ventilated with either air at 1 ATA (control) or 100% O₂ at 1 or 5 ATA (hyperoxia). In this experiment, the front edge of the lid to the animal exposure chamber is demarcated by the horizontal white dashed line; one of six buckles used to seal the cover of the animal exposure chamber is seen here. A preset pressure relief valve (5) prevents over-pressurization of the animal exposure chamber during the experiment. Other important items seen here include the animal’s jacket and tether (1) that passes up through an opening in the wire cage lid (c2) and connects to the moveable tether assembly (2) mounted on the cage lid (c2). The two, needle electrode leads pass upwards through the tether cable to the tether assembly (2), exit through the roof the animal exposure chamber (3), and plug into the internal electrical connector panel behind the animal exposure chamber (4). The welded window port (6) is barely visible in this image through which the animal’s behavior is monitored continuously using a video camera. This animal was not implanted with a radio telemetry module; however, if it was the receiver would have been stood on its side and resting against the exterior of the animal exposure chamber. Cabling for the telemetry receiver then plugs into the internal electrical connector panel (4).