Available online at www.sciencedirect.com
Behavioural Brain Research 188 (2008) 281–290
Research report
“Learned baduse” limits recovery of skilled reaching for food
after forelimb motor cortex stroke in rats: A new analysis
of the effect of gestures on success
Mariam Alaverdashvili
∗
, Afra Foroud, Diana H. Lim, Ian Q. Whishaw
Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge,
4401 University Drive, Lethbridge, Alberta, Canada T1K 3M4
Received 16 August 2007; received in revised form 31 October 2007; accepted 11 November 2007
Available online 19 November 2007
Abstract
Trauma or stroke to motor cortex (MtCx) results in motor impairments that include movements of the contralateral forelimb in reaching for
food that is to be placed in the mouth for eating (skilled reaching). In the rat, post-lesion recovery of success is incomplete and achieved using
compensatory movements. A striking and puzzling feature of post-lesion performance is an increase in the numbers of reaching attempts. Whereas
successful movements, whether normal or compensatory, have been extensively described, there has been no previous analysis of the movements
comprising reach attempts, especially those that are unsuccessful. Here, rats pretrained in a single pellet reaching task received MtCx stroke via
pial removal contralateral to the preferred-for-reaching forelimb. They then received daily physical rehabilitation and assessment in reaching. In
addition to conventional end-point measures of performance, reaching behavior was evaluated by a new measure, gestures, derived from Laban
Movement Analysis. Gestural analysis describes all non-weight bearing limb movements and so can document movements not explicitly directed to,
or successful in, grasping food. In the acute post-stroke period, MtCx rats made few gestures, but thereafter gesture number escalated with recovery
time, and eventually exceeded preoperative levels. Gestures were frequently repetitive and included combinations not used prior to stroke. The
escalation in gestures number with recovery training suggests that excessive and inappropriate gestures may represent motor habits that substitute
for, and compete with, successful movements. This description of “learned baduse” furthers the understanding of MtCx contributions to skilled
movements and could potentially contribute to the modification of rehabilitative strategies for the treatment of stroke.
© 2007 Elsevier B.V. All rights reserved.
Keywords: Forelimb motor cortex stroke; Gestural analyses; Learned baduse; Skilled reaching; Recovery of function; Rehabilitation after stroke
1. Introduction
Skilled reaching (reaching for food to eat) is a natu-
ral behavior for many animal species [27,49]. Accordingly,
it is useful for assessing injury to the motor system after
stroke, traumatic brain injury, and other neurological disorders
[5,9,11,14,17,44,53]. It is also useful for assessing the efficacy
of rehabilitation strategies, such as pharmacological interven-
tions and physical rehabilitation [1,2,5]. For example, a number
of studies have demonstrated the benefit of purposeful prac-
tice for deficit reduction in skilled reaching movements after
motor cortex (MtCx) stroke [3,4,18,23,25,28,33,39,42,51,55]
∗
Corresponding author. Tel.: +1 403 394 3998; fax: +1 403 329 2775.
E-mail address: mariam.alaverdashvil@uleth.ca (M. Alaverdashvili).
and other studies have shown that recovery is invariably incom-
plete [10,28,33,36,37,48]. The utility of the behavior is that it
can be evaluated by a number of objective measures, including
end-point measures of success, kinematics, and movement ele-
ment evaluation [6,8,21,34,52]. Nevertheless, despite extensive
study, knowledge of the effects of nervous system injury and
understanding the obstacles to obtaining recovery are incom-
plete.
A puzzling feature of the incomplete recovery after MtCx
stroke is that although success approaches prestroke levels, the
number of reaching attempts escalates with recovery time and
comes to exceed control levels. Possible explanations for this
increase in reach attempts is that injury: (1) precludes the dis-
play of motor behavior compatible with success [8], (2) hinders
motor feedback required to monitor and improve performance
[10,12,41], (3) contributes to habits that hinder further improve-
0166-4328/$ – see front matter © 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.bbr.2007.11.007