Research Report Therapeutic effects of a restraint procedure on posttraumatic place learning in fimbria-fornix transected rats Hana Malá, María Rodríguez Castro, Julia Knippel, Peter Jes Køhler, Pia Lassen, Jesper Mogensen ⁎ The Unit for Cognitive Neuroscience, Department of Psychology, University of Copenhagen, Oester Farimagsgade 5A, building 10, DK-1353 Copenhagen K, Denmark ARTICLE INFO ABSTRACT Article history: Accepted 4 April 2008 Available online 16 April 2008 Restraint procedures have been shown to influence the neural processes in the brain (dendritic changes or changes in the expression of neurotrophines, etc.) as well as to alter the behavioural performance. While many report deleterious effects of this procedure in normal animals, there are also indications of positive effects in the context of brain injury. In order to address the issue from the perspective of functional posttraumatic recovery, we studied 6 experimental groups of rats—3 groups undergoing a fimbria-fornix transection, and 3 groups remaining neurally intact. Within the lesioned and intact groups, respectively, one group of animals was subjected to an 8-day long restraint procedure (2 h daily) that ended immediately prior to the infliction of trauma; another group was subjected to the same procedure starting immediately after the infliction of trauma; and one group was not subjected to the restraint procedure at all. After a brief period of postoperative pause, the animals were tested on their acquisition of an 8-arm radial maze based place learning task and the effects of the restraint procedure on the task acquisition were evaluated. The results show that within the neurally intact groups, the administration of this procedure had no effect at all. However, the lesioned groups that were subjected to the restraint procedure showed significantly improved acquisition of the studied task compared to the lesioned animals that did not undergo the restraint procedure. The improved task performance suggests a therapeutic effect of this manipulation on the functional recovery after a mechanical trauma. © 2008 Elsevier B.V. All rights reserved. Keywords: Restraint procedure Brain injury Recovery Rat Hippocampus Therapy 1. Introduction Every type of injury to the brain initiates a multitude of neural processes that are likely to influence the posttraumatic plastic reorganization of the brain—and thereby potentially the out- come of subsequent rehabilitation training. Posttraumatic functional outcome can be influenced by, for instance, the immediate pretraumatic and/or posttraumatic activity within endocrine (Grasso et al., 2004; Stein, 2005), neurotransmitter (Barbay et al., 2006; M'Harzi et al., 1988) and neurotrophic (Radecki et al., 2005) systems—all of which may respond to various types of intense activity and/or experience (e.g. Harvey et al., 2006; Murakami et al., 2005; Shansky et al., 2006; Vaynman et al., 2004). This study utilized the restraint procedure as experimental paradigm. During such a procedure the animal is placed in a wire mesh restrainer, plastic tube or box that effectively restrains its mobility. The level of immobilization varies from a complete BRAIN RESEARCH 1217 (2008) 221 – 231 ⁎ Corresponding author. Fax: +45 35324802. E-mail address: jesper.mogensen@psy.ku.dk (J. Mogensen). 0006-8993/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.brainres.2008.04.005 available at www.sciencedirect.com www.elsevier.com/locate/brainres