title: Versatile 3D-printed headstage implant for group housing of rodents.
abstract: BACKGROUND
  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.
  
  
  RESULTS
  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. Comparison with existing method(s). 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Medical Centre - University of Freiburg, Department of Neurosurgery, Section for Neuroelectronic Systems, Freiburg, Germany. Electronic address: rpinne@gmail.com.
authors.forename: R C
authors.initials: RC
authors.lastname: Pinnell
authors.affiliation: Medical Centre - University of Freiburg, Department of Neurosurgery, Section for Neuroelectronic Systems, Freiburg, Germany; Institute for Signal Processing, University of Lubeck, Lubeck, Germany; College of Medicine, University of Diyala, Baqubah, Diyala, Iraq.
authors.forename: R K
authors.initials: RK
authors.lastname: Almajidy
authors.affiliation: Medical Centre - University of Freiburg, Department of Neurosurgery, Section for Neuroelectronic Systems, Freiburg, Germany.
authors.forename: U G
authors.initials: UG
authors.lastname: Hofmann
mesh_terms: D000827:Animal Welfare / Q000191:economics; D000818:Animals; D001522:Behavior, Animal; D046690:Deep Brain Stimulation / Q000295:instrumentation; D000069280:Electrocorticography / Q000295:instrumentation; D005260:Female; D006257:Head / Q000601:surgery; D006799:Housing, Animal / Q000191:economics; D020007:Implants, Experimental; D018782:Maze Learning; D066330:Printing, Three-Dimensional; D011474:Prosthesis Design; D017207:Rats, Sprague-Dawley; D012886:Skull / Q000601:surgery; D012934:Social Isolation; D015430:Weight Gain
keywords: Isolation; Pair housing; Rodents; Skull implant; Social environment; Well-being