Pinnell, R. C., Almajidy, R. K., Hofmann, U. G. 2016. Versatile 3-D printed headstage implant for group housing of rodents. Journal of Neuroscience Methods 257, 134-138.

An unfavourable yet necessary side-effect of stereotaxic surgery involves the social isolation of post-surgery rats, in order to protect their wound site or skull-mounted implant from damage. Social isolation can cause a myriad of behavioural and physiological changes that are detrimental to the well-being of rats, with potential negative implications for a range of experimental paradigms. New method. Female Sprague Dawley rats (n = 40) were implanted onto the skull with a novel 3D-printed headstage socket that surrounded an electrode connector. The socket accommodated a removable stainless-steel headcap for the purposes of protecting the implant. Rats were pair-housed following surgery, and their behaviour was monitored for up to several weeks under two experimental conditions that involved EEG recording and deep-brain stimulation, as well as behavioural test sessions inside an open-field maze. Rat weights were compared between individually- and pair-housed rats at up to 3 weeks post-surgery. These experiments were successfully carried out using pair-housed rats, with no damage or complications observed regarding the implant and its headcap. Rats were able to carry out a range of normal behaviours including running, grooming, foraging and sleeping. Compared to individually-housed rats, pair-housed rats gained less weight over the 3 weeks post-implantation period. This method offers additional protection compared to group-housed post-surgical rats that lack the protective headcap. It is also potentially more practical and versatile than a fully-implantable device for the safe post-surgery group housing of rodents. This implant design can reduce the cost of rodent upkeep, whilst potentially avoiding a myriad of behavioural and physiological changes that are known to result from social isolation.