title: Of mice and marbles: Novel perspectives on burying behavior as a screening test for psychiatric illness.
abstract: Burying forms part of the normal behavioral routine of rodents, although its expression is species-specific. However, it has been suggested that aberrant burying behavior, of which marble-burying (MB) is an example, may represent neophobic and/or compulsive-like behavior. In the present investigation, we assessed MB in an established animal model of obsessive-compulsive disorder (OCD)-namely, spontaneous stereotypy in the deer mouse-to establish whether high (H) stereotypy is associated with neophobia and/or another compulsive endophenotype, i.e. MB, as compared to nonstereotypical (N) controls. A three-trial, one-zone MB test was performed over three consecutive evenings both before and after chronic treatment with high-dose (50 mg/kg/day) oral escitalopram. Neophobia was measured via the number of marbles buried during the first pre- and posttreatment MB trials, and compulsive-like behavior via the number of marbles buried over all pre- and posttreatment MB trials. The data from the present study support earlier findings that burying is a normal behavioral routine (inherent burying behavior, IBB) that is expressed by all deer mice, irrespective of stereotypical cohort, and is not associated with either neophobia or compulsiveness. Indeed, chronic escitalopram treatment, which is similarly effective in treating clinical anxiety and OCD, as well as in attenuating H behavior, failed to influence IBB. Although 11 % of the animals presented with a unique burying endophenotype (high burying behavior), escitalopram also failed to attenuate said behavior, necessitating further investigation as to its relevance. In conclusion, MB cannot be regarded as a measure of anxiety-like or compulsive behavior in the deer mouse model of OCD.
authors.affiliation: Division of Pharmacology, North-West University, Potchefstroom, South Africa.
authors.forename: De Wet
authors.initials: de W
authors.lastname: Wolmarans
authors.affiliation: Department of Psychiatry and Mental Health, MRC Unit on Anxiety & Stress Disorders, University of Cape Town, Cape Town, South Africa.
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Stein
authors.affiliation: Center of Excellence for Pharmaceutical Sciences, MRC Unit on Stress and Anxiety Disorders, North-West University (Potchefstroom Campus), Hoffman Street, Potchefstroom, 2520, South Africa. brian.harvey@nwu.ac.za.
authors.forename: Brian H
authors.initials: BH
authors.lastname: Harvey
mesh_terms: D000818:Animals; D001007:Anxiety / Q000523:psychology*; D001008:Anxiety Disorders / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects*; D002119:Calcium Carbonate / Q000494:pharmacology*; D004195:Disease Models, Animal; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009771:Obsessive-Compulsive Disorder / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D002119:Calcium Carbonate
keywords: Animal model; Deer mouse; Escitalopram; Marble-burying; Neophobia; Obsessive–compulsive disorder