Motor simulation is disturbed when experiencing pain

Group membership does not modulate goal- versus movement-based imitation

It is often put forward that in-group members are imitated more strongly than out-group members. However, the validity of this claim has been questioned as recent investigations were not able to find differences for the imitation of in- versus out-group members. A central characteristic of these failed replications is their mere focus on movement-based imitation, thereby neglecting to take into consideration the superior goal of the movements. By using a computerised version of the pen-and-cups task, we disentangled movement- from goal-based imitation to shed further light onto the link between group membership and imitation. As previous research demonstrated that out-group members (as compared with in-group members) are represented psychologically distant and as psychological distance shifts the degree to which participants engage in goal- versus movement-based imitation, we predicted that in-group members (as compared with out-group members) shift the degree to which individuals imitate movements versus goals. The results did not confirm our predictions, as group membership does not modulate the degree of movement- versus goal-based imitation. Theoretical implications and the question whether imitative behaviour is socially modulated are discussed.

Empathic pain observation does not influence automatic imitation in an online setting

Previous research has shown that empathic pain observation can lead to motor facilitation in the form of faster reaction times. However, it is unclear whether participants are focusing on the others' pain or simply focusing on their own discomfort/distress (from watching the videos) during the task. This is an important issue as self- vs other-oriented focusing plays a key role in empathic processing. To address this issue, we combined empathic pain observation with the automatic imitation task (AIT). Previous work has shown that AIT effects are smaller after experiencing pain, which has been interpreted as the result of the experience of pain leading to a self-oriented focus. If empathic pain observation similarly leads to a self-oriented focus, then we should expect similar AIT results after pain observation (smaller AIT effects); however, if it instead leads to an other-oriented focus, then we should see the opposite (larger AIT effects). Although we found initial evidence for the latter hypothesis (Experiment 1), subsequent failed replications suggests that we do not have sufficient evidence to claim that pain observation influences automatic imitation one way or the other (Experiment 2 and 3). We discuss some possible reasons for finding null results in these experiments and suggest future avenues of research to better elucidate this topic.

Radiological Changes of Paraspinal Muscles: A Comparative Study of Patients with Isthmic Spondylolisthesis, Patients with Degenerative Lumbar Spondylolisthesis, and Healthy Subjects

Objective

To investigate the differences, correlations, and clinical significance of the paraspinal muscles among patients with isthmic spondylolisthesis (IS), degenerative lumbar spondylolisthesis (DLS), and age-matched healthy subjects.

Methods

This study involved 159 age-matched patients with L4 anterior spondylolisthesis. The patients were divided into the IS group (n = 81) and DLS group (n = 78). Eighty-four age-matched healthy adults were enrolled as the control group. The cross-sectional area (CSA) of paraspinal muscles (multifidus [MF], erector spinae [ES], and psoas [PS]) and the relative CSA of the paraspinal muscles (paraspinal muscle CSA/vertebral CSA) were measured in the IS group, DLS group, and control group. The degree of fat infiltration was simultaneously observed.

Results

There was no significant difference in age or sex among the three groups. The relative CSA of the MF and PS was higher in control group than in IS and DLS groups (p < 0.05). The relative CSA of ES was higher in IS and control groups than in DLS group (p < 0.05). The relative CSA of total paraspinal muscles decreased in the order of control group > IS group > DLS group (p < 0.05). Logistic regression analysis showed that the relative CSA of MF, and the degree of fat infiltration of ES were independent protective factors for IS (odds ratio < 1, p < 0.05). The relative CSA of MF was an independent protective factor for DLS (odds ratio < 1, p < 0.05), whereas BMI and the degree of fat infiltration of MF were independent risk factor for DLS (odds ratio > 1, p < 0.05).

Conclusion

Compared with the control group, patients with IS and DLS showed varying degrees of degeneration, and the degree of degeneration in patients with DLS was more severe at the same age. Lower fat infiltration and higher paraspinal muscle CSA are protective factors for IS and DLS, whereas the higher BMI is risk factor for DLS.

Movement observation activates motor cortex in fibromyalgia patients: a fNIRS study

Scientific evidence points to a shared neural representation between performing and observing an action. The action observation notoriously determines a modulation of the observer’s sensorimotor system, a phenomenon called Motor Resonance (MR). Fibromyalgia (FM) patients suffer from a condition characterized by generalized musculoskeletal pain in which even simple movement can exacerbate their symptoms. Maladaptive functioning of the primary motor cortex is a common finding in patients with chronic pain. Activation of the motor cortex is known to induce an analgesic effect in patients with chronic pain. In this exploratory study, we intend to verify if the mere observation of a movement could elicit activation of the motor cortical areas in patients with FM. Therefore, the purpose of this study was to examine the presence of MR in patients affected by fibromyalgia. We adopted a behavioral paradigm known for detecting the presence of MR and a neurophysiological experiment. Participants watched videos showing gripping movements towards a graspable or an ungraspable object, respectively, and were asked to press a button the instant the agent touched the object (Time-to-contact detection session). In a different experimental session, participants were only requested to observe and pay attention to the videos (Observation-only session). During each experimental session, the participants’ cerebral hemodynamic activity was recorded using the functional Near-Infrared Spectroscopy method. The behavioral task analysis revealed the presence of MR in both FM patients and healthy controls. Moreover, neurophysiological findings suggested that the observation of movement during the Observation-only session provoked activation and modulation of the cortical motor networks of FM patients. These results could represent evidence of the possible beneficial effects of movement observation in restarting motor activation, notoriously reduced, in FM patients.

Group membership does not modulate automatic imitation

Individuals have the automatic tendency to imitate each other. A key prediction of different theories explaining automatic imitation is that individuals imitate in-group members more strongly than out-group members. However, the empirical basis for this prediction is rather inconclusive. Only a few experiments have investigated the influence of group membership using classic automatic imitation paradigms and these experiments led to mixed results. To put the group membership prediction to a critical test, we carried out six high-powered experiments (total N = 1538) in which we assessed imitation with the imitation-inhibition task and manipulated group membership in different ways. Evidence across all experiments indicates that group membership does not modulate automatic imitation. Moreover, we do not find support for the idea that feelings of affiliation or perceived similarity moderate the effect of group membership on automatic imitation. These results have important implications for theories explaining automatic imitation and contribute to the current discussion of whether automatic imitation can be socially modulated.

The Effect of Money Priming on Self-Focus in the Imitation-Inhibition Task

Abstract. The self-sufficiency hypothesis suggests that priming individuals with money makes them focus more strongly on themselves than on others. However, recently, research supporting this claim has been heavily criticized and some attempts to replicate have failed. A reason for the inconsistent findings in the field may lay in the common use of explicit measures, because they tend to rely on one or just a few items and are thus prone to demand effects and low reliability. In the present research, we administered, in two experiments, the imitation-inhibition task – a robust, unobtrusive, and reliable paradigm that is sensitive to self-other focus on a trial-by-trial basis. A pilot study found an increased focus on the self as compared to others when primed with money. Building on this finding, a preregistered high-powered experiment replicated this effect, suggesting that money primes may indeed increase a focus on the self. An additionally carried out meta-analysis indicates that automatic imitation is modulated by self-other focus and that money primes lead to a smaller focus on the self than conventional methods. Overall, the found effects are rather small and several limitations, such as order effects, call for a cautious interpretation of the findings.