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Regarding the stage of arousal level required for working memory to function properly, limited studies have been conducted on changes in working memory performance when the arousal level of consciousness decreases. This study aimed to experimentally clarify the stages of consciousness necessary for optimal working memory function. In this experiment, the sedation levels were changed step‐by‐step using anaesthesia, and the performance accuracy during the execution of working memory was assessed using a dual‐task paradigm. Participants were required to categorize and remember words in a specific target category. Categorization performance was measured across four different sedative phases: before anaesthesia (baseline), and deep, moderate and light stages of sedation. Short‐delay recognition tasks were performed under these four sedative stages, followed by long‐delay recognition tasks after participants recovered from sedation. The results of the short‐delay recognition task showed that the performance was lowest at the deep stage. The performance of the moderate stage was lower than the baseline. In the long‐delay recognition task, the performance under moderate sedation was lower than that under baseline and light sedation. In addition, the performance under light sedation was lower than that under baseline. These results suggest that task performance becomes difficult under half sedation and that transferring information to long‐term memory is difficult even under one‐quarter sedation. [ABSTRACT FROM AUTHOR]

Muscle paralysis after spinal cord injury is partly caused by a loss of brainstem-derived serotonin (5-HT), which normally maintains motoneuron excitability by regulating crucial persistent calcium currents. Here we examine how over time motoneurons compensate for lost 5-HT to regain excitability. We find that, months after a spinal transection in rats, changes in posttranscriptional editing of [5-HT.sub.2C] receptor mRNA lead to increased expression of [5- HT.sub.2C] receptor isoforms that are spontaneously active (constitutively active) without 5-HT. Such constitutive receptor activity restores large persistent calcium currents in motoneurons in the absence of 5-HT. We show that this helps motoneurons recover their ability to produce sustained muscle contractions and ultimately enables recovery of motor functions such as locomotion. However, without regulation from the brain, these sustained contractions can also cause debilitating muscle spasms. Accordingly, blocking constitutively active [5-HT.sub.2C] receptors with SB206553 or cyproheptadine, in both rats and humans, largely eliminates these calcium currents and muscle spasms, providing a new rationale for antispastic drug therapy., Severe spinal cord injury (SCI) causes an immediate paralysis of muscles innervated by motoneurons directly caudal to the injury site. This results not only from a loss of supraspinal tracts [...]

1. Introduction Spinal cord injury (SCI) often results in severe motor dysfunction, such as complete paralysis. These patients typically cannot only walk, but also lose bowel, bladder, and sexual functions. [...], Pain, which remains largely unsolved, is one of the most crucial problems for spinal cord injury patients. Due to sensory problems, as well as motor dysfunctions, spinal cord injury research has proven to be complex and difficult. Furthermore, many types of pain are associated with spinal cord injury, such as neuropathic, visceral, and musculoskeletal pain. Many animal models of spinal cord injury exist to emulate clinical situations, which could help to determine common mechanisms of pathology. However, results can be easily misunderstood and falsely interpreted. Therefore, it is important to fully understand the symptoms of human spinal cord injury, as well as the various spinal cord injury models and the possible pathologies. The present paper summarizes results from animal models of spinal cord injury, as well as the most effective use of these models.

Objectives: The present study sought to examine associations between the pain‐catastrophizing subcomponents and multiple pain‐related outcomes in Japanese individuals with chronic pain. Methods: A cross‐sectional study design was employed with 213 chronic pain outpatients. The participants were recruited from 3 units at a university hospital and from a pain clinic at a municipal hospital. Study measures were used to assess pain catastrophizing, anxiety, depression, pain interference, and pain severity. Results: Path analysis with multiple pain‐related outcomes while controlling for age and gender revealed that the Helplessness subcomponent was associated with anxiety, depression, pain interference, and pain severity. The Magnification subcomponent was related to anxiety and depression, and the Rumination subcomponent accounted for the variance of pain interference. Discussion: The present results suggested the important role of helplessness across cultural backgrounds. It also provides guidance on the application of cognitive behavioral techniques for chronic pain management in Japan. [ABSTRACT FROM AUTHOR]