02091nas a2200253   4500008004100000022001400041245004000055210003800095260001200133300001400145490000800159520142300167653002101590653002101611653002501632653001701657653001101674653001601685100002301701700002301724700002101747700002101768856004801789       2006                        eng d  a0014-481900aDiurnal H-reflex variation in mice.0 aDiurnal Hreflex variation in mice  c01/2006  a517–5280 v1683 aMice exhibit diurnal variation in complex motor behaviors, but little is known about diurnal variation in simple spinally mediated functions. This study describes diurnal variation in the H-reflex (HR), a wholly spinal and largely monosynaptic reflex. Six mice were implanted with tibial nerve cuff electrodes and electrodes in the soleus and gastrocnemius muscles, for recording of ongoing and nerve-evoked electromyographic activity (EMG). Stimulation and recording were under computer control 24 h/day. During a 10-day recording period, HR amplitude varied throughout the day, usually being larger in the dark than in the light. This diurnal HR variation could not be attributed solely to differences in the net ongoing level of descending and segmental excitation to the spinal cord or stimulus intensity. HRs were larger in the dark than in the light even after restricting the evoked responses to subsets of trials having similar ongoing EMG and M-responses. The diurnal variation in the HR was out of phase with that reported previously for rats, but was in phase with that observed in monkeys. These data, supported by those in other species, suggest that the supraspinal control of the excitability of the HR pathway varies throughout the day in a species-specific pattern. This variation should be taken into account in experimental and clinical studies of spinal reflexes recorded at different times of day.10acircadian rhythm10aElectromyography10aimplanted electrodes10aMonosynaptic10aReflex10aSpinal Cord1 aCarp, Jonathan, S.1 aTennissen, Ann, M.1 aChen, Xiang Yang1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/1615178102315nas a2200241   4500008004100000022001400041245006000055210005800115260001200173300001400185490000800199520163200207653002101839653002501860653001701885653001601902100002301918700002301941700002101964700001901985700002102004856004802025       2005                        eng d  a0165-027000aLong-term spinal reflex studies in awake behaving mice.0 aLongterm spinal reflex studies in awake behaving mice  c12/2005  a134–1430 v1493 aThe increasing availability of genetic variants of mice has facilitated studies of the roles of specific molecules in specific behaviors. The contributions of such studies could be strengthened and extended by correlation with detailed information on the patterns of motor commands throughout the course of specific behaviors in freely moving animals. Previously reported methodologies for long-term recording of electromyographic activity (EMG) in mice using implanted electrodes were designed for intermittent, but not continuous operation. This report describes the fabrication, implantation, and utilization of fine wire electrodes for continuous long-term recordings of spontaneous and nerve-evoked EMG in mice. Six mice were implanted with a tibial nerve cuff electrode and EMG electrodes in soleus and gastrocnemius muscles. Wires exited through a skin button and traveled through an armored cable to an electrical commutator. In mice implanted for 59-144 days, ongoing EMG was monitored continuously (i.e., 24 h/day, 7 days/week) by computer for 18-92 days (total intermittent recording for 25-130 days). When the ongoing EMG criteria were met, the computer applied the nerve stimulus, recorded the evoked EMG response, and determined the size of the M-response (MR) and the H-reflex (HR). It continually adjusted stimulation intensity to maintain a stable MR size. Stable recordings of ongoing EMG, MR, and HR were obtained typically 3 weeks after implantation. This study demonstrates the feasibility of long-term continuous EMG recordings in mice for addressing a variety of neurophysiological and behavioral issues.10aElectromyography10aimplanted electrodes10aMonosynaptic10aSpinal Cord1 aCarp, Jonathan, S.1 aTennissen, Ann, M.1 aChen, Xiang Yang1 aSchalk, Gerwin1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/1602684801678nas a2200277   4500008004100000022001400041245009700055210006900152260001200221300001000233490000800243520088300251653002201134653002101156653001301177653002501190653001601215653001501231653001801246653000801264100002301272700002101295700001501316700002101331856004801352       2001                        eng d  a0304-394000aEffects of chronic nerve cuff and intramuscular electrodes on rat triceps surae motor units.0 aEffects of chronic nerve cuff and intramuscular electrodes on ra  c10/2001  a1–40 v3123 aIn order to assess the long-term effects of implanted electrodes on motor unit properties, we studied triceps surae (TS) motor units in rats implanted for 3-10 months with a tibial nerve cuff electrode for H-reflex elicitation and intramuscular electrodes for recording TS electromyographic activity. Motor units with sag from implanted rats displayed greater tetanic force than those from unimplanted rats. Motor units without sag had shorter twitch contraction times. This disrupted the relationship between sag and contraction time that was always present in unimplanted rats. These differences were consistent with a small degree of muscle denervation and subsequent reinnervation. Further analyses ascribed this effect to the nerve cuff rather than to the intramuscular electrodes. Comparable changes in motor unit properties may occur in humans with implanted nerve cuffs.10achronic recording10acontraction time10aH-Reflex10aimplanted electrodes10amotor units10anerve cuff10areinnervation10asag1 aCarp, Jonathan, S.1 aChen, Xiang Yang1 aSheikh, H.1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/11578831