The same dorsal root ganglion neurons innervate uterus and colon in the rat

The purpose of this study was to determine whether primary sensory neurons that innervate the uterus receive convergent input from the colon. To test this, in the rat, cell bodies of colonic and uterine dorsal root ganglia were retrogradely labeled with fluorescent tracer dyes microinjected into the colon/rectum and bilaterally into the uterine horns. Ganglia were harvested, cryoprotected and cut into 20 microm slices to identify positively stained cells for fluorescent microscopy. Up to 5% of neurons were colon-specific or uterus-specific, and 10-15% of labeled ganglion neurons innervate both viscera in the L1, L2, L6 and S1-S3 levels. These results suggest a novel form of visceral sensory integration in the dorsal root ganglion that may underlie comorbidity of many functional pain syndromes.     

Distinct neurophysiological mechanisms mediate mixing costs and switch costs

Using event-related potentials (ERPs), we investigated the neural response associated with preparing to switch from one task to another. We used a cued task-switching paradigm in which the interval between the cue and the imperative stimulus was varied. The difference between response time (RT) to trials on which the task switched and trials on which the task repeated (switch cost) decreased as the interval between cue and target (CTI) was increased, demonstrating that subjects used the CTI to prepare for the forthcoming task. However, the RT on repeated-task trials in blocks during which the task could switch (mixed-task blocks) were never as short as RTs during single-task blocks (mixing cost). This replicates previous research. The ERPs in response to the cue were compared across three conditions: single-task trials, switch trials, and repeat trials. ERP topographic differences were found between single-task trials and mixed-task (switch and repeat) trials at approximately 160 and approximately 310 msec after the cue, indicative of changes in the underlying neural generator configuration as a basis for the mixing cost. In contrast, there were no topographic differences evident between switch and repeat trials during the CTI. Rather, the response of statistically indistinguishable generator configurations was stronger at approximately 310 msec on switch than on repeat trials. By separating differences in ERP topography from differences in response strength, these results suggest that a reappraisal of previous research is appropriate.     

Neonatal and juvenile stress induces changes in adult social behavior without affecting cognitive function

The aim of the present study was to test the hypothesis that exposure to neonatal and/or juvenile stress results in distinct persisting modification of adult male rats' emotional and social competence. Compared to non-stressed control rats, neonatally stressed rats and rats exposed to combined neonatal and juvenile stress, had reduced frequency and duration of social encounters, and lower anxiety levels. Juvenile stress alone, induced more frequent, but shorter social encounters in adulthood. No significant differences in aggressive behavior were found between any of the groups. The findings confirm the existence of developmental time windows during which exposure to unpredictable stress can affect adult emotional and social behavior without affecting cognitive function.     

Testosterone replacement therapy and motor function in men with spinal cord injury: a retrospective analysis

OBJECTIVE: To evaluate motor function in men with spinal cord injury (SCI) given testosterone replacement therapy (TRT). DESIGN: American Spinal Injury Association (ASIA) rehabilitation discharge motor index scores were compared between men with SCI given TRT (testosterone cypionate, 200 mg, monthly; n = 50) and a comparison group (n = 480) in a retrospective study. Covariates included admission motor and FIM scores, level of injury (paraplegia/tetraplegia), days since injury, and age. RESULTS: ASIA discharge motor scores for ASIA impairment scale grades C and D were significantly different (P < 0.05) in men with incomplete SCI given TRT, relative to the comparison group. The covariate-adjusted mean discharge score for the TRT group was higher than for the comparison group. There were no significant differences in discharge FIM scores (P = 0.34) for men with incomplete injuries and no differences in the adjusted discharge ASIA motor scores (P = 0.92) or adjusted discharge FIM scores (P = 0.16) for men with complete injuries. CONCLUSION: The data support a relationship between TRT and strength gains in men with residual motor function after SCI. Prospective studies are necessary to validate these findings.     

An overview of chronic kidney disease management and CAPD in the home

Chronic kidney disease (CKD) is a common, harmful, but treatable long term condition. An overview of CKD is provided in this article. Kidney Research UK, www.kidneyresearchuk.org a national charity dedicated to research, has developed the A Better Life through Education and empowerment (ABLE) programme which seeks to research and raise awareness o the issues among 'at risk' groups as well as among relevant health professionals. Part Two of the renal NSF suggests many actions that can be taken in primary care to prevent CKD. In the event of Established Renal Failure (ERF), there are a number of treatment options available including continuous ambulatory peritoneal dialysis (CAPD), described here. Kidney Research UK's Patient DVD module two (complimentary copy attached to this issue) provides more detail using case studies. The DVD offers practical help, support and guidance on how to overcome some of the challenges.     

Interactions between auditory 'what' and 'where' pathways revealed by enhanced near-threshold discrimination of frequency and position

Partially segregated neuronal pathways ("what" and "where" pathways, respectively) are thought to mediate sound recognition and localization. Less studied are interactions between these pathways. In two experiments, we investigated whether near-threshold pitch discrimination sensitivity (d') is altered by supra-threshold task-irrelevant position differences and likewise whether near-threshold position discrimination sensitivity is altered by supra-threshold task-irrelevant pitch differences. Each experiment followed a 2 x 2 within-subjects design regarding changes/no change in the task-relevant and task-irrelevant stimulus dimensions. In Experiment 1, subjects discriminated between 750 Hz and 752 Hz pure tones, and d' for this near-threshold pitch change significantly increased by a factor of 1.09 when accompanied by a task-irrelevant position change of 65 micros interaural time difference (ITD). No response bias was induced by the task-irrelevant position change. In Experiment 2, subjects discriminated between 385 micros and 431 micros ITDs, and d' for this near-threshold position change significantly increased by a factor of 0.73 when accompanied by task-irrelevant pitch changes (6 Hz). In contrast to Experiment 1, task-irrelevant pitch changes induced a response criterion bias toward responding that the two stimuli differed. The collective results are indicative of facilitative interactions between "what" and "where" pathways. By demonstrating how these pathways may cooperate under impoverished listening conditions, our results bear implications for possible neuro-rehabilitation strategies. We discuss our results in terms of the dual-pathway model of auditory processing.