Oxycodone lengthens reproductions of suprasecond time intervals in human research volunteers

Variability in interval production is due to timing-dependent deficits in Huntington's disease

In Huntington's disease (HD), increased variability is seen in performance of motor tasks that require implicit control of timing. We examined whether timing variability was also evident in an explicit interval-timing task. Sixty subjects (21 controls, 19 manifest HD, and 20 pre-manifest HD) performed a single-interval production task with three target intervals (1.1 s, 2.2 s, 3.3 s). We analyzed accuracy (proportional error) and precision (standard deviation) across groups and intervals. No differences were seen in accuracy across groups or intervals. Precision was significantly lower in manifest (P = 0.0001) and pre-manifest HD (P = 0.04) compared with controls. This was particularly true for pre-manifest subjects close to diagnosis (based on probability of diagnosis in 5 years). Precision was correlated with proximity to diagnosis (r2  = 0.3, P < 0.01). To examine the source of reduced precision, we conducted linear regression of standard deviation with interval duration. Slope of the regression was significantly higher in manifest HD (P = 0.02) and in pre-manifest HD close to diagnosis (P = 0.04) compared with controls and pre-manifest participants far from diagnosis. Timing precision is impaired before clinical diagnosis in Huntington's disease. Slope analysis suggests that timing variability (decreased precision) was attributable to deficits in timing-dependent processes. Our results provide additional support for the proposal that the basal ganglia are implicated in central timekeeping functions. Because the single interval production task was sensitive to deficits in pre-manifest HD, temporal precision may be a useful outcome measure in future clinical trials.

Endogenous opiates and behavior: 2011

This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).

The study of time perception in migraineurs

OBJECTIVE

The study aimed to explore the impairment of time perception in migraineurs.

BACKGROUND

Headache is the most common pain syndrome in middle-aged adults, and migraine is highly prevalent and severely disabling. Although the mechanisms of and the therapies for migraines have long been explored, less is known about the functional impairments associated with them, especially the impairment in time perception, that is, the ability to estimate the passage of time.

METHODS

In this study, we used a temporal reproduction task to assess the estimation of the duration of visual stimulus in 27 migraine patients. The stimulus was delivered at different intervals over the milliseconds and seconds range.

RESULTS

In the setting of an interstimulus interval for 1 second and an interstimulus interval for 5 seconds in the 600-millisecond-duration reproduction task, the migraineurs showed impairment in time perception, and in that they significantly overestimated the duration, as compared with the healthy subjects. When compared with the healthy controls for the 3-second and 5-second duration reproduction task, migraineurs in the setting of an interstimulus interval for 1 second and an interstimulus interval for 5 seconds did not show impairment in time perception.

CONCLUSIONS

This study indicates that not only is time perception impaired in migraineurs, but that this impairment is exhibited for durations in the milliseconds range, and not the seconds range.

Use of oxycodone in pain management

Oxycodone is widely used to alleviate moderate-to severe acute pain, It is an effective analgesic for many types of pain, and is especially useful for paroxysmal spontaneous pain, steady pain, allodynia associated with postherpetic neuralgia, and it is also increasingly used in the management of cancer-related and chronic pain, oxycodone has been found to improve the quality of life of patients with many types of pain.

In 2011, following chemical and physical manipulation, an extended-release form of oxycodone was developed in order to maintain its rate-controlling mechanism. This new formulation significantly improved analgesia among patients with moderate-to-severe chronic osteoarthritis pain with an adverse event profile similar to that of other opioids. The long-term safety and efficacy of extended-release form of oxycodone in relieving moderate-to-severe chronic pain has been demonstrated. In this study we discussed about different aspects of this drug in managing of various types of pain.