Carl-Johan Olsson

Motor Representations and Practice Affect Brain Systems Underlying Imagery: An fMRI Study of Internal Imagery in Novices and Active High Jumpers

This study used functional magnetic resonance imaging (fMRI) to investigate differences in brain activity between one group of active high jumpers and one group of high jumping novices (controls) when performing motor imagery of a high jump. It was also investigated how internal imagery training affects neural activity. The results showed that active high jumpers primarily activated motor areas, e.g. pre-motor cortex and cerebellum. Novices activated visual areas, e.g. superior occipital cortex. Imagery training resulted in a reduction of activity in parietal cortex. These results indicate that in order to use an internal perspective during motor imagery of a complex skill, one must have well established motor representations of the skill which then translates into a motor/internal pattern of brain activity. If not, an external perspective will be used and the corresponding brain activation will be a visual/external pattern. Moreover, the findings imply that imagery training reduces the activity in parietal cortex suggesting that imagery is performed more automatic and results in a more efficient motor representation more easily accessed during motor performance.

Motor imagery : if you can't do it, you won't think it

Since long, motor imagery has been recognized as a method for studying motor representations. In the last few years, important advances regarding the use of motor imagery have been made. In particular, issues concerning the functional equivalence between imagery and action have been addressed, and how equivalence affects the use of imagery to study motor representations. In this paper, we review recent findings in order to highlight the current state of knowledge about motor imagery and its relation to motor action. Three topics are discussed: (i) the imagery perspective, (ii) task complexity, and (iii) the importance of physical experience. It is shown how theses factors are closely related and how previous studies may have underestimated to what extent these factors affect the interpretation of results. Practical implications for imagery interventions are considered. It is concluded that if you cannot perform an action physically, you cannot imagine it in a way that is necessary for a high degree of functional equivalence.

Altered neural correlates of affective processing after internet-delivered cognitive behavior therapy for social anxiety disorder

Randomized controlled trials have yielded promising results for internet-delivered cognitive behavior therapy (iCBT) for patients with social anxiety disorder (SAD). The present study investigated anxiety-related neural changes after iCBT for SAD. The amygdala is a critical hub in the neural fear network, receptive to change using emotion regulation strategies and a putative target for iCBT. Twenty-two subjects were included in pre- and post-treatment functional magnetic resonance imaging at 3T assessing neural changes during an affective face processing task. Treatment outcome was assessed using social anxiety self-reports and the Clinical Global Impression-Improvement (CGI-I) scale. ICBT yielded better outcome than ABM (66% vs. 25% CGI-I responders). A significant differential activation of the left amygdala was found with relatively decreased reactivity after iCBT. Changes in the amygdala were related to a behavioral measure of social anxiety. Functional connectivity analysis in the iCBT group showed that the amygdala attenuation was associated with increased activity in the medial orbitofrontal cortex and decreased activity in the right ventrolateral and dorsolateral (dlPFC) cortices. Treatment-induced neural changes with iCBT were consistent with previously reported studies on regular CBT and emotion regulation in general.

Internal imagery training in active high jumpers

The main purpose of this study was to examine whether the use of internal imagery would affect high jumping performance for active high jumping athletes. Over a period of six weeks, a group of active high jumpers were trained with an internal imagery program for a total of 72 minutes. This group was compared to a control group consisting of active high jumpers that only maintained their regular work-outs during the same time period. Four variables were measured; jumping height, number of failed attempts, take-off angle, and bar clearance. There was a significant improvement on bar clearance for the group that trained imagery (p < 0.05) but not for the control group. No other differences were found. The results suggest that internal imagery training may be used to improve a component of a complex motor skill. Possible explanations and future recommendations are discussed.

Learning by Doing and Learning by Thinking: An fMRI Study of Combining Motor and Mental Training

The current study investigated behavioral and neural effects of motor, mental, and combined motor and mental training on a finger tapping task. The motor or mental training groups trained on a finger-sequence for a total of 72 min over 6 weeks. The motor and mental training group received 72 min motor training and in addition 72 min mental training. Results showed that all groups increased their tapping performance significantly on the trained sequence. After training functional magnetic resonance imaging (fMRI) data was collected and indicated training specific increases in ventral pre-motor cortex following motor training, and in fusiform gyrus following mental training. Combined motor and mental training activated both the motor and the visual regions. In addition, motor and mental training showed a significant increase in tapping performance on an untrained sequence (transfer). fMRI scanning indicated that the transfer effect involved the cerebellum. Conclusions were that combined motor and mental training recruited both motor and visual systems, and that combined motor and mental training improves motor flexibility via connections from both motor and cognitive systems to the cerebellum.

Dynamic switching between semantic and episodic memory systems

It has been suggested that episodic and semantic long-term memory systems interact during retrieval. Here we examined the flexibility of memory retrieval in an associative task taxing memories of different strength, assumed to differentially engage episodic and semantic memory. Healthy volunteers were pre-trained on a set of 36 face-name pairs over a 6-week period. Another set of 36 items was shown only once during the same time period. About 3 months after the training period all items were presented in a randomly intermixed order in an event-related fMRI study of face-name memory. Once presented items differentially activated anterior cingulate cortex and a right prefrontal region that previously have been associated with episodic retrieval mode. High-familiar items were associated with stronger activation of posterior cortices and a left frontal region. These findings fit a model of memory retrieval by which early processes determine, on a trial-by-trial basis, if the task can be solved by the default semantic system. If not, there is a dynamic shift to cognitive control processes that guide retrieval from episodic memory.

Complex motor representations may not be preserved after complete spinal cord injury.

When using motor imagery to improve rehabilitation after spinal cord injury it is assumed that the motor representations are preserved and that task specific physical training is not necessary. Here I tested this hypothesis by examining P.W. who has a complete spinal cord injury due to an accident. However, P.W. was an elite wheelchair athlete, hence, has experienced a high load of physical training in general. During functional magnetic resonance imaging (fMRI), P.W. imagined wheelchair slalom (a complex motor task P.W. can perform) and stair walking (a complex motor task P.W. no longer can perform). A control group of neurologically intact participants were also included. The results showed that only for the task (wheelchair slalom) P.W. currently could physically perform was the pre-motor cortex recruited. For stair walking P.W. recruited inferior frontal cortex and parietal cortex. The results were confirmed with the control group showing similar pattern but for the opposite tasks. The conclusions from this study are that complex motor representations may not be preserved after a complete spinal cord injury and motor imagery is dependent on the current ability to perform the task physically.

Brain simulation of action may be grounded in physical experience.

An intriguing quality of our brain is that when actions are imagined, corresponding brain regions are recruited as when the actions are actually performed. It has been hypothesized that the similarity between real and simulated actions depends on the nature of motor representations. Here we tested this hypothesis by examining S.D., who never used her legs but is an elite wheel chair athlete. Controls recruited motor brain regions during imagery of stair walking and frontal regions during imagery of wheel chair slalom. S.D. showed the opposite pattern. Thus, brain simulation of actions may be grounded in specific physical experiences.

Increased prefrontal activity and reduced motor cortex activity during imagined eccentric compared to concentric muscle actions.

In this study we used functional magnetic resonance imaging (fMRI) to examine differences in recruited brain regions during the concentric and the eccentric phase of an imagined maximum resistance training task of the elbow flexors in healthy young subjects. The results showed that during the eccentric phase, pre-frontal cortex (BA44) bilaterally was recruited when contrasted to the concentric phase. During the concentric phase, however, the motor and pre-motor cortex (BA 4/6) was recruited when contrasted to the eccentric phase. Interestingly, the brain activity of this region was reduced, when compared to the mean activity of the session, during the eccentric phase. Thus, the neural mechanisms governing imagined concentric and eccentric contractions appear to differ. We propose that the recruitment of the pre-frontal cortex is due to an increased demand of regulating force during the eccentric phase. Moreover, it is possible that the inability to fully activate a muscle during eccentric contractions may partly be explained by a reduction of activity in the motor and pre-motor cortex.

Neural Correlates of Time Perspective

The primary aim of this chapter is to summarize our present knowledge about the neural correlates of time perspective and related constructs. We first briefly introduce functional magnetic resonance functional magnetic resonance imaging as a suitable technique to understand the underlying neural mechanisms when studying various constructs of time. Then, we discuss how the use of brain imaging techniques has improved our knowledge regarding concepts of time perspective. In this section it becomes evident that most studies have focused on mental time traveling. Finally we introduce a novel line of research in which we try to study neural correlates of time within the context of the Zimbardo framework. By such approach we are able to include the personality-like construct from the ZTPI to further understand the neural correlates of temporal processing.