Volition and Imagery in Neurorehabilitation

Abstract

New interventional approaches have been proposed in the last few years to treat the motor deficits resulting from brain lesions. Training protocols represent the gold-standard of these approaches. However, the degree of motor recovery experienced by most patients remains incomplete. It would be important to improve our understanding of the mechanisms underlying functional recovery. This chapter examines the role of two possible mechanisms that could operate to improve motor function in this setting: volition and motor imagery. It is argued that both represent possible strategies to enhance training effects.Key Words: motivation, attention, motor imagery, hemiparesis, rehabilitation, forced use, volition, stroke, motor system, motor cortex (Cog Behav Neurol 2006;19:135-140) M otor training protocols represent one of the fundamental bases of rehabilitative treatments after brain damage. Different strategies have been proposed to enhance training effects, including enhanced motivation, focused attention, motor imagery, progressive transfer of tasks towards the paretic limb, forced use, and integration of multimodal and emotional settings. The neural mechanisms underlying these strategies are poorly understood. In this review, we describe studies performed to better understand the influence of some of these factors on performance improvements and changes in intracortical excitatory and inhibitory mechanisms in humans undergoing training protocols. Focus is on the role of (a) volition in motor learning, (b) imagery in neurorehabilitation and motor control, and (c) neural substrates underlying performance of simple and complex movements after stroke. ROLE OF VOLITION IN MOTOR LEARNINGMotor training protocols in patients with brain lesions elicit well-described changes in brain organization and performance improvements. [1][2][3][4][5][6] One limitation of training protocols is that patients with more profound weakness are unable to carry out the motor routines required. The finding that passively elicited motions lead to activation and cortical reorganization in brain regions common to those activated with performance of voluntary movements suggested that it could also elicit improvements in motor function. 7,8 This proposal has important implications for the design of neurorehabilitative treatments after stroke, particularly in patients who are too weak to perform effective voluntary motor training.One recent study compared behavioral gains after short-term motor learning, changes in functional magnetic resonance imaging (fMRI) activation in the contralateral primary motor cortex (cM1) and in motor cortex excitability measured with transcranial magnetic stimulation (TMS) after a 30 minute training period consisting of either voluntarily or passively induced wrist movements in 2 different sessions in healthy volunteers. 9 During active training, subjects were instructed to perform voluntary wrist flexion-extension movements of a specified duration in an articulated splint. Therefore, voluntary movements f...

Impaired ability to imagine future pleasant events is associated with apathy in schizophrenia

“…More specifically, difficulties imagining future pleasant events, and particularly poor selfreferential information for future pleasant events (i.e., the feelings of pre-experiencing positive events, the feeling of an emotion when imagining a pleasant event and the representation of one's own behavior), were associated with motivation deficits in pursuing personal goals in schizophrenia patients. The relationships between poor representation of one's own behavior in the future and apathy can be interpreted according to a well-known cognitive theory of motor cognition that suggests that cognition is embodied in action and that the ability to vividly simulate acting in the future could actually lead to increased action (Lotze and Cohen, 2006). In other words, the ability to imagine oneself performing (i.e., pre-experiencing) a possible future action could facilitate the later reproduction of this action, by increasing one's motivation and effort to attain imagined future goals and by prompting the effective motor sequences/behaviors needed to achieve these goals (D'Argembeau and Van der Linden, 2012).…”

Motor Imagery and Stroke Neurorehabilitation: An Overview of Basic Concepts and Therapeutic Effects

“…The motor images require conscious activation of brain regions that are also involved in the preparation and performance of the movement, accompanied by a voluntary inhibition of the real movement (Lotze and Cohen 2006). Studies have shown that there is similarity in the physiological and psychophysical functions between executed and imagined movements, suggesting that they are based on the same process.…”

“…Motor Imagery (MI) corresponds to an active process during which the representation of a specific action is internally reproduced into working memory without any motor output (Deepa et al, 2011;Lotze and Cohen, 2006;Dietrich, 2008). It represents the result of conscious access to the content of a movement intention, which is usually performed unconsciously during movement preparation (Gentili et al, 2006;Jackson et al, 2001;Dietrich, 2008).…”

Perceptual decisions regarding object manipulation are selectively impaired in apraxia or when tDCS is applied over the left IPL

“…Predominantly left lateralised, the ventro-dorsal stream extends from occipital cortex to the left IPL, to the ventral premotor cortex and frontal eye fields (Frey 2007;Rizzolatti, Fogassi, & Luppino, 2011). The ventro-dorsal stream is purportedly critical in skilled action execution, movement perception, and mental representations of movement (or motor imagery) that may be necessary when retrieving postural requirements related to skilled object-use and object manipulation (Jeannerod, 1994;Buccino et al, 2001;Kosslyn, Ganis, & Thompson, 2001;Solodkin, Hlustik, Chen, & Small, 2004;Johnson-Frey, Newman-Norland, & Grafton, 2005;Buxbaum, Kyle, Tang, & Detre, 2006;Lotze & Cohen, 2006;Creem-Regehr, 2009;Rizzolatti & Craighero, 2004;Buxbaum & Kalénine, 2010;Gao, Duan, & Chen, 2011). It is therefore possible that skilled action execution, motor imagery and movement perception may involve a common process that critically relies on the ventrodorsal stream.…”