Britta Lorey

Cognitive motor processes. The role of motor imagery in the study of motor representations

Motor imagery is viewed as a window to cognitive motor processes and particularly to motor control. Mental simulation theory [Jeannerod, M., 2001. Neural simulation of action: a unifying mechanism for motor cognition. NeuroImage 14, 103-109] stresses that cognitive motor processes such as motor imagery and action observation share the same representations as motor execution. This article presents an overview of motor imagery studies in cognitive psychology and neuroscience that support and extend predictions from mental simulation theory. In general, behavioral data as well as fMRI and TMS data demonstrate that motor areas in the brain play an important role in motor imagery. After discussing results on a close overlap between mental and actual performance durations, the review focuses specifically on studies reporting an activation of primary motor cortex during motor imagery. This focus is extended to studies on motor imagery in patients. Motor imagery is also analyzed in more applied fields such as mental training procedures in patients and athletes. These findings support the notion that mental training procedures can be applied as a therapeutic tool in rehabilitation and in applications for power training.

The embodied nature of motor imagery: the influence of posture and perspective

It is assumed that imagining oneself from a first-person perspective (1PP) is more embodied than a third-person perspective (3PP). Therefore, 1PP imagery should lead to more activity in motor and motor-related structures, and the postural configuration of one’s own body should be particularly relevant in 1PP simulation. The present study investigated whether proprioceptive information on hand position is integrated similarly in 1PP and 3PP imagery of hand movements. During functional magnetic resonance imaging (fMRI) scanning, 20 right-handed female college students watched video sequences of different hand movements with their right hand in a compatible versus incompatible posture and subsequently performed 1PP or 3PP imagery of the movement. Results showed stronger activation in left hemisphere motor and motor-related structures, especially the inferior parietal lobe, on 1PP compared with 3PP trials. Activation in the left inferior parietal lobe (parietal operculum, SII) and the insula was stronger in 1PP trials with compatible compared with incompatible posture. Thus, proprioceptive information on actual body posture is more relevant for 1PP imagery processes. Results support the embodied nature of 1PP imagery and indicate possible applications in athletic training or rehabilitation.

Activation of the parieto-premotor network is associated with vivid motor imagery - a parametric FMRI study

The present study examined the neural basis of vivid motor imagery with parametrical functional magnetic resonance imaging. 22 participants performed motor imagery (MI) of six different right-hand movements that differed in terms of pointing accuracy needs and object involvement, i.e., either none, two big or two small squares had to be pointed at in alternation either with or without an object grasped with the fingers. After each imagery trial, they rated the perceived vividness of motor imagery on a 7-point scale. Results showed that increased perceived imagery vividness was parametrically associated with increasing neural activation within the left putamen, the left premotor cortex (PMC), the posterior parietal cortex of the left hemisphere, the left primary motor cortex, the left somatosensory cortex, and the left cerebellum. Within the right hemisphere, activation was found within the right cerebellum, the right putamen, and the right PMC. It is concluded that the perceived vividness of MI is parametrically associated with neural activity within sensorimotor areas. The results corroborate the hypothesis that MI is an outcome of neural computations based on movement representations located within motor areas.

Your mind's hand: Motor imagery of pointing movements with different accuracy

Jeannerod (2001) postulated that motor control and motor simulation states are functionally equivalent. If this is the case, the specifically relevant task parameters in online motor control should also be represented in motor imagery. We tested whether the different spatial accuracy demands of manual pointing movements are reflected on a neural level in motor imagery. During functional magnetic resonance imaging (fMRI) scanning, 23 participants imagined hand movements that differed systematically in terms of pointing accuracy needs (i.e., none, low, high). In a low-accuracy condition, two big squares were presented visually prior to the imagery phase. These squares had to be pointed at alternately on a mental level. In the high-accuracy condition, two little squares had to be hit. As expected on the basis of speed-accuracy trade-off principles, results showed that participants required more time when accuracy of the imagined movements increased. The fMRI results showed a stepwise increase in activation in the anterior cerebellum and the anterior part of the superior parietal lobe (SPL) with rising accuracy needs. Moreover, we found increased activation of the anterior part of the SPL and of the dorsal premotor cortex (dPMC) when imagery included a square (i.e., in the low- and high-accuracy conditions) compared to the no-square condition. These areas have also been discussed in relation to online motor control, suggesting that specific task parameters relevant in the domain of motor control are also coded in motor imagery. We suggest that the functional equivalence of action states is due mostly to internal estimations of the expected sensory feedback in both motor control and motor imagery.

Differential activation of the lateral premotor cortex during action observation

BackgroundAction observation leads to neural activation of the human premotor cortex. This study examined how the level of motor expertise (expert vs. novice) in ballroom dancing and the visual viewpoint (internal vs. external viewpoint) influence this activation within different parts of this area of the brain.ResultsSixteen dance experts and 16 novices observed ballroom dance videos from internal or external viewpoints while lying in a functional magnetic resonance imaging scanner. A conjunction analysis of all observation conditions showed that action observation activated distinct networks of premotor, parietal, and cerebellar structures. Experts revealed increased activation in the ventral premotor cortex compared to novices. An internal viewpoint led to higher activation of the dorsal premotor cortex.ConclusionsThe present results suggest that the ventral and dorsal premotor cortex adopt differential roles during action observation depending on the level of motor expertise and the viewpoint.

Neural Correlates of Attentional Focusing during Finger Movements: A fMRI Study

ABSTRACT One finding in recent motor control and learning research is that an external focus (i.e., attending to environmental aspects) improves performance, whereas an internal focus (i.e., controlling bodily movements) impedes it. Despite being replicated in behavioral studies, the neurophysiological basis of this phenomenon remains largely unknown. The present authors separate global attention to actions into an external and an internal focus. Using a between-participants design, participants were either trained to attend to moving their fingers (internal focus) or to the keys to be hit (external focus) during learning a finger sequence. Subsequently, they applied functional magnetic resonance imaging under focus (internal/external), dual task, and move-only conditions. Results revealed higher activation in primary somatosensory and motor cortex for an external compared to an internal focus. The authors conclude that external participants focused on the task-related environment (i.e., the keys) to enhance tactile input to somatosensory areas that closely connect to motor areas.

How equivalent are the action execution, imagery, and observation of intransitive movements? Revisiting the concept of somatotopy during action simulation

Jeannerod (2001) hypothesized that action execution, imagery, and observation are functionally equivalent. This led to the major prediction that these motor states are based on the same action-specific and even effector-specific motor representations. The present study examined whether hand and foot movements are represented in a somatotopic manner during action execution, imagery, and action observation. The experiment contained ten conditions: three execution conditions, three imagery conditions, three observation conditions, and one baseline condition. In the nine experimental conditions, participants had to execute, observe, or imagine right-hand extension/flexion movements or right-foot extension/flexion movements. The fMRI results showed a somatotopic organization within the contralateral premotor and primary motor cortex during motor imagery and motor execution. However, there was no clear somatotopic organization of action observation in the given regions of interest within the contralateral hemisphere, although observation of these movements activated these areas significantly.

Confidence in emotion perception in point-light displays varies with the ability to perceive own emotions.

One central issue in social cognitive neuroscience is that perceiving emotions in others relates to activating the same emotion in oneself. In this study we sought to examine how the ability to perceive own emotions assessed with the Toronto Alexithymia Scale related to both the ability to perceive emotions depicted in point-light displays and the confidence in these perceptions. Participants observed video scenes of human interactions, rated the depicted valence, and judged their confidence in this rating. Results showed that people with higher alexithymia scores were significantly less confident about their decisions, but did not differ from people with lower alexithymia scores in the valence of their ratings. Furthermore, no modulating effect of social context on the effect of higher alexithymia scores was found. It is concluded that the used stimuli are fit to investigate the kinematic aspect of emotion perception and possibly separate people with high and low alexithymia scores via confidence differences. However, a general difference in emotion perception was not detected in the present setting.

Major depressive disorder alters perception of emotional body movements

Much recent research has shown an association between mood disorders and an altered emotion perception. However, these studies were conducted mainly with stimuli such as faces. This is the first study to examine possible differences in how people with major depressive disorder (MDD) and healthy controls perceive emotions expressed via body movements. Thirty patients with MDD and thirty healthy controls observed the video scenes of human interactions conveyed by point-light displays (PLDs). They rated the depicted emotions and judged their confidence in their rating. Results showed that patients with MDD rated the depicted interactions more negatively than healthy controls. They also rated interactions with negative emotionality as being more intense and were more confident in their ratings. It is concluded that patients with MDD exhibit an altered emotion perception compared to healthy controls when rating emotions expressed via body movements depicted in PLDs.

Neural simulation of actions: Effector- versus action-specific motor maps within the human premotor and posterior parietal area?

This study addresses the controversy over how motor maps are organized during action simulation by examining whether action simulation states, that is, motor imagery and action observation, run on either effector‐specific and/or action‐specific motor maps. Subjects had to observe or imagine three types of movements effected by the right hand or the right foot with different action goals. The functional magnetic resonance imaging results showed an action‐specific organization within premotor and posterior parietal areas of both hemispheres during action simulation, especially during action observation. There were also less pronounced effector‐specific activation sites during both simulation processes. It is concluded that the premotor and parietal areas contain multiple motor maps rather than a single, continuous map of the body. The forms of simulation (observation, imagery), the task contexts (movements related to an object, with usual/unusual effector), and the underlying reason for performing the simulation (rate your subjective success afterwards) lead to the specific use of different representational motor maps within both regions. In our experimental setting, action‐specific maps are dominant especially, during action observation, whereas effector‐specific maps are recruited to only a lesser degree. Hum Brain Mapp 35:1212–1225, 2014.