The precise mechanisms of pain perception and transmission in the central nervous system have not been fully elucidated. However, extensive data support a role for the monoamine neurotransmitters, serotonin and norepinephrine, in the modulation of pain. Experiments with animal models of pain indicate that noradrenergic interventions, and to a lesser extent serotonergic interventions, reduce pain-related behavior. This is supported by data from clinical trials in humans in which antidepressants have been shown to reduce pain and functional impairment in central and neuropathic pain conditions. These effects are particularly well-studied in trials with serotonin-norepinephrine reuptake inhibitors (SNRIs), which have provided a useful tool in the clinician’s arsenal, particularly considering the limitations of other classes of pain medications such as opioids, anti-inflammatories, and anticonvulsants (i.e., limited efficacy, safety and tolerability issues). Moreover, painful physical symptoms are frequently comorbid with major psychiatric disorders such as major depressive disorder and anxiety disorders. This paper reviewed and summarized the rationale and potential role of SNRIs for the control of pain including clinical and preclinical background. Currently evidence does not definitely support a role of the SNRIs, while limited data propose a putative promise of SNRIs in the treatment of pain related disorders including fibromyalgia and depressed patients with multiple somatic complaints. More researches are warranted to generalize currently available preliminary evidences.

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The cerebellum communicates with the cerebral cortex through the cortico‐ponto‐cerebellar tract (CPCT, cerebellar afferent) and the dentato‐rubro‐thalamo‐cortical tract (DRTCT, cerebellar efferent). This study explored the laterality of CPCT and DRTCT in a right‐handed population. Forty healthy right‐handed subjects (18 males and 22 females with age range of 26–79 years old) who underwent diffusion tensor imaging (DTI) were retrospectively enrolled. Bilateral CPCT, DRTCT, and the corticospinal tract (CST) were reconstructed using probabilistic diffusion tensor tractography (DTT). Tract volume (TV) and fractional anisotropy (FA) were compared between dominant and non‐dominant tracts. Subjects were divided into age groups (20–40, 41–60, and 61–80 years), and the DTI‐derived parameters of the groups were compared to determine age‐related differences. TV and FA of non‐dominant CPCT were higher than those of dominant CPCT, and the dominant CST was higher than the non‐dominant CST. The TV and FA of DRTCT showed no side‐to‐side difference. The 61–80 years age group had the highest TV of the dominant and non‐dominant DRTCT among the three groups and the highest FA of the non‐dominant CPCT and DRTCT. The results revealed the structural characteristics of CPCT and DRTCT using probabilistic DTT. Normal asymmetric patterns and age‐related changes in cerebellar white matter tracts may be important to researchers investigating cerebro‐cerebellar structural connectivity.

Botulinum toxin A injection was associated with a significant improvement from baseline to week 8 in both treatment groups, however, no significant difference between the 2 groups was observed, based on the electrophysiological and clinical parameters employed in this study.