The Neural Correlates of Shoulder Apprehension: A Functional MRI Study

<div><p>Although shoulder apprehension is an established clinical finding and is important for the prevention of shoulder dislocation, how this subjective perception is evoked remains unclear. We elucidated the functional neuroplasticity associated with apprehension in patients with recurrent anterior shoulder instability (RSI) using functional magnetic resonance imaging (fMRI). Twelve healthy volunteers and 14 patients with right-sided RSI performed a motor imagery task and a passive shoulder motion task. Brain activity was compared between healthy participants and those with RSI and was correlated with the apprehension intensity reported by participants after each task. Compared to healthy volunteers, participants with RSI exhibited decreased brain activity in the motor network, but increased activity in the hippocampus and amygdala. During the passive motion task, participants with RSI exhibited decreased activity in the left premotor and primary motor/somatosensory areas. Furthermore, brain activity was correlated with apprehension intensity in the left amygdala and left thalamus during the motor imagery task (memory-induced), while a correlation between apprehension intensity and brain activity was found in the left prefrontal cortex during the passive motion task (instability-induced). Our findings provide insight into the pathophysiology of RSI by identifying its associated neural alterations. We elucidated that shoulder apprehension was induced by two different factors, namely instability and memory.</p></div

Group-level statistical parametric map showing the categorical comparison of hemodynamic changes in the comparison of controls > patients with RSI in the passive shoulder motion task (whole-brain uncorrected <i>P</i> < 0.001).

<p>z (mm): z-coordinate in Montreal Neurological Institute (MNI) space, which is the basic brain template from the MNI. Plus and minus values indicate the dorsal and ventral directions, respectively. Red bar indicates T value. M1: primary motor cortex, S1: primary somatosensory cortex.</p

Group-level statistical parametric map showing the categorical comparison of hemodynamic changes in the motor imagery task (whole-brain uncorrected <i>P</i> < 0.001).

<p><b>Upper left</b>: Comparison of patients with RSI > controls in the kettle condition relative to the control condition. <b>Upper right</b>: Comparison of controls > patients with RSI in the kettle condition relative to the control condition. <b>Lower left</b>: Comparison of patients with RSI > controls in the ABER condition relative to the control condition. <b>Lower right</b>: Comparison of controls > patients with RSI in the ABER condition relative to the control condition. z (mm): z-coordinate in Montreal Neurological Institute (MNI) space, which is the basic brain template from the MNI. Plus and minus values indicate the dorsal and ventral directions, respectively. Red bar indicates a T value. M1: primary motor cortex, S1: primary somatosensory cortex, SPL: superior parietal lobule.</p

Correlation analyses between shoulder apprehension intensity and brain activity using tasks and motion as covariates.

<p><b>A</b>: Correlation analysis between apprehension intensity and brain activity using covariates showing the categorical comparison of hemodynamic changes between the kettle and control conditions (uncorrected <i>P</i> < 0.005 for display purposes). <b>B</b>: Correlation analysis between apprehension intensity and brain activity using covariates showing the categorical comparison of hemodynamic changes between the ABER and control conditions (uncorrected <i>P</i> < 0.005 for display purposes). <b>C</b>: Correlation analysis between apprehension intensity and brain activity using covariates showing the categorical comparison of hemodynamic changes between passive shoulder motion and baseline (uncorrected <i>P</i> < 0.005 for display purposes). z (mm): z-coordinate in Montreal Neurological Institute (MNI) space, which is the basic brain template from the MNI. Plus and minus values indicate the dorsal and ventral directions, respectively. Red bar indicates T value. ACC: Anterior cingulate cortex, IPC: Inferior parietal cortex.</p