V. Special Considerations
A. Protocol-Restricted Activities
All NHPs at the institution are included in this plan unless excluded for cause by the IACUC or for health or well-being reasons by the attending veterinarian. Some research at USE requires such exclusions, including sleep and vision research in which animals are restrained in chairs for up to 4 hours a day 3 days a week when the electrical activity of the brain is monitored. The procedures for placement of electrodes are detailed in each investigator's protocol and outlined in the electrophysiology SOP. Chair restraint is discussed in the restraint SOP. When the protocol permits, these animals are pair-housed. Such animals are reintroduced to their cagemates after each period of restraint. Replacement of chair restraint with tethering is encouraged by USE and practiced by some investigators. This permits the animal to remain in its home cage but generally does not permit pair housing.
B. Exemptions from Social Housing
All animals housed in nonsocial situations require an exemption from this plan. The social housing exemptions SOP discusses each exemption.
Animals undergoing clinical treatment may be temporarily exempted from social housing at the discretion of the attending veterinarian. Such exemptions will be reviewed every 30 days, and an exemption will terminate when the animal finishes treatment. Long-term exemption from social hous-