Bladder and bowel responses to lumbosacral epidural stimulation in uninjured and transected anesthetized rats

Spinal cord epidural stimulation (scES) mapping at L5-S1 was performed to identify parameters for bladder and bowel inhibition and/or contraction. Using spinally intact and chronic transected rats of both sexes in acute urethane-anesthetized terminal preparations, scES was systematically applied using a modified Specify 5–6–5 (Medtronic) electrode during bladder filling/emptying cycles while recording bladder and colorectal pressures and external urethral and anal sphincter electromyography activity. The results indicate frequency-dependent effects on void volume, micturition, bowel peristalsis, and sphincter activity just above visualized movement threshold intensities that differed depending upon neurological intactness, with some sex-dependent differences. Thereafter, a custom-designed miniature 15-electrode array designed for greater selectivity was tested and exhibited the same frequency-dependent urinary effects over a much smaller surface area without any concurrent movements. Thus, select activation of autonomic nervous system circuitries with scES is a promising neuromodulation approach for expedient translation to individuals with SCI and potentially other neurologic disorders.

Low Frequency Extension Filter and ActiGraph-Calculated Sleep Intervals in Older Adults

Actigraphy has become a popular, non-invasive means of continuously monitoring physical activity and sleep. One optional setting, the low frequency extension (LFE) filter, reduces the movement threshold to capture low acceleration activity that is common in older adults. This filter significantly alters physical activity outcomes (e.g., step counts), but it is unclear if this has implications for sleep interval calculations that rely upon accurate differentiation between physical activity and sleep. We investigated the effects of the LFE filter on wrist-worn sleep estimates in older adults. Participants were 9 older adults who wore the ActiGraph GT9X on their non-dominant wrist for 7 days in a free-living environment. Raw data was processed with and without the LFE filter enabled, and sleep intervals were calculated by a proprietary ActiGraph algorithm. Paired samples t-tests demonstrated that the LFE filter generated significantly later bedtimes, fewer minutes spent in bed, shorter sleep duration, and fewer awakenings during the night compared to when the filter was disabled (all p < .043). Use of the LFE filter did not lead to differences in arise time, sleep latency, efficiency, or wake after sleep onset (all p > .052). While the LFE filter was designed to improve accuracy of physical activity estimates in more sedentary populations, these findings suggest that the LFE filter also has the potential to impact sleep estimates of older adults. Researchers using ActiGraph-calculated sleep would benefit from careful consideration of this software-dependent impact.

Absence of an Analgesic Effect of Qigong "External Qi" in Rats

The analgesic effect of "external Qi" emitted from the Qigong practitioner was investigated in rats. In behavioral experiments, the rat's tail-flick and head-movement threshold measurements were used to determine if the "external Qi" had analgesic effect. The Results were negative. In electro-physiological study, the "external Qi" shows no significant changes in the pain-related evoked cortical potentials to tooth-pulp stimulation. Thus the results of this study are different from those reported by other investigators. It is proposed that this research be repeated and extended.

Topographical distribution and functional properties of cortically induced rhythmical jaw movements in the monkey (Macaca fascicularis)

1. The lateral part of the pericentral cortex of both hemispheres in three awake monkeys was explored with intracortical microstimulation (ICMS) using short trains (T/S; 200-microseconds pulses at 333 Hz for 35 ms, less than or equal to microA) and long trains (C/S; 200-microseconds pulses at 50 Hz for 3 s, less than or equal to 60 microA). In both hemispheres of one of these monkeys, the responsiveness of single cortical neurons to stimulation of the orofacial region was tested at the same intracortical sites where ICMS was applied. 2. Movements were evoked from four physiologically defined cortical regions: the primary face motor cortex (MI), the primary face somatosensory cortex (SI), the principal part of the cortical masticatory area (CMAp) which was located in the precentral gyrus lateral to MI, and a deep part of the cortical masticatory area (CMAd) which was located in the inferior face of the frontal operculum. 3. Two types of cortically induced movements were observed: a single twitch movement and EMG activity of the orofacial muscles that was evoked by T/S at a short latency (10–45 ms) and rhythmical jaw movements (RJMs) which were only evoked by C/S. 4. RJMs were evoked at C/S frequencies ranging from 20 to 300 Hz. At movement threshold, the frequency of the cortically induced RJMs varied from 0.7 to 1.5 Hz and usually increased with the increase of C/S intensity up to 2 times movement threshold. The vertical amplitude of RJMs was also stimulus dependent, and at movement threshold it ranged from 3 to 9 mm. 5. The movement patterns of the cortically induced RJMs remained constant during the course of C/S but could be differentiated in the frontal plane into ipsilateral- (RJMi), vertical-(RJMv), and contralateral- (RJMc) directed movements. These three different patterns of RJMs were associated with different patterns of masticatory muscle activity. 6. Each cortical region contained many sites from which RJMs could be induced (so-called RJM sites). The RJMi sites were more numerous than RJMc sites in all regions except SI and were located anterolateral or lateral to the RJMc sites in each region; the RJMv sites were scattered throughout each cortical region. 7. In MI, C/S elicited RJMs from 94 intracortical sites from which short-latency twitch movements could also be evoked by T/S.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of Information Content and Size upon the Absolute Threshold for Movement

From the finding that the absolute threshold for rotational movement was significantly lower for a field of randomly, as opposed to regularly, distributed black and white squares it was hypothesized that only in the case of high selective information-content fields would there be an inverse relationship between size of elements and the movement threshold. Movement thresholds, obtained for random and regular displays containing different sizes of internal element, confirmed the crucial role of selective information in determining the movement threshold but did not support the predicted size effect. This apparent paradox may be explained by the reduced confidence which Ss experience when judging the movement of random displays.