scholarly journals Visual acuity performance level is independent of locomotion

2019 ◽  
Alex D. Swain ◽  
Eunsol Park ◽  
Zhang Yu Cheng ◽  
Nina Kowalewski ◽  
Angela Sun ◽  

ABSTRACTLocomotion has a global impact on circuit function throughout the cortex, including regulation of spatiotemporal dynamics in primary visual cortex (V1). The mechanisms driving state-changes in V1 result in a 2-3 fold gain of responsiveness to visual stimuli. To determine whether locomotion-mediated increases in response gain improve the perception of spatial acuity we developed a head-fixed task in which mice were free to run or sit still during acuity testing. Spatial acuity, ranging from 0.1 to 0.7 cycles/°, was assessed before and after 3-4 weeks of reward-based training in adult mice. Training on vertical orientations once a day improved the average performance across mice by 22.5 ± 0.05%. Improvement transferred to non-trained orientations presented at 45°, indicating that the improvement in acuity generalized. Furthermore we designed a second closed-loop task in which acuity threshold could be directly assessed in a single session. Using this design, we established that acuity threshold matched the upper limit of the trained spatial frequency; in two mice spatial acuity threshold reached as high as 1.5 cycles/°. During the 3-4 weeks of training we collected a sufficient number of stimulus trials in which mice performed above chance but below 100% accuracy. Using this subset of stimulus trials, we found that perceptual acuity was not enhanced on trials in which mice were running compared to trials in which mice were still. Our results demonstrate that perception of spatial acuity is not improved by locomotion.

1973 ◽  
Vol 40 (3) ◽  
pp. 383-392 ◽  
H. S. Juffs

SummaryA study is reported of the effect of preincubation of raw and laboratory pasteurized bulk milk samples on the tyrosine value (TV) of milk and its relationship with bacterial populations. For raw samples, mean TVs before and after preincubation for 20±2 h at both 25 and 30 °C differed (P < 0·001). After preincubation at 30 °C, the TV of 47 % of raw samples exceeded that considered to represent the upper limit of variation in the TV of a normal bulk milk supply. At this temperature, however, there was no indication that proteolytic psychrotrophs were a major contributor to increased TV. With preincubation of raw samples at 25 °C, an increase to above the upper limit of variation occurred in only 20 % of samples; however, proteolytic psychrotrophs appeared more active at this temperature. In similar samples preincubated after laboratory pasteurization, large increases occurred in TV after 20 ±2 h at 30 °C, while at 25 °C the increases were much smaller and of the order found for preincubated raw samples. The results showed, however, that nonpsychrotrophic bacteria were also the principal source of proteinase giving rise to increased TVs in laboratory pasteurized samples.

Arundhati Goley ◽  
A. Mooventhan ◽  
NK. Manjunath

Abstract Background Hydrotherapeutic applications to the head and spine have shown to improve cardiovascular and autonomic functions. There is lack of study reporting the effect of either neutral spinal bath (NSB) or neutral spinal spray (NSS). Hence, the present study was conducted to evaluate and compare the effects of both NSB and NSS in healthy volunteers. Methods Thirty healthy subjects were recruited and randomized into either neutral spinal bath group (NSBG) or neutral spinal spray group (NSSG). A single session of NSB, NSS was given for 15 min to the NSBG and NSSG, respectively. Assessments were taken before and after the interventions. Results Results of this study showed a significant reduction in low-frequency (LF) to high-frequency (HF) (LF/HF) ratio of heart rate variability (HRV) spectrum in NSBG compared with NSSG (p=0.026). Within-group analysis of both NSBG and NSSG showed a significant increase in the mean of the intervals between adjacent QRS complexes or the instantaneous heart rate (HR) (RRI) (p=0.002; p=0.009, respectively), along with a significant reduction in HR (p=0.002; p=0.004, respectively). But, a significant reduction in systolic blood pressure (SBP) (p=0.037) and pulse pressure (PP) (p=0.017) was observed in NSSG, while a significant reduction in diastolic blood pressure (DBP) (p=0.008), mean arterial blood pressure (MAP) (p=0.008) and LF/HF ratio (p=0.041) was observed in NSBG. Conclusion Results of the study suggest that 15 min of both NSB and NSS might be effective in reducing HR and improving HRV. However, NSS is particularly effective in reducing SBP and PP, while NSB is particularly effective in reducing DBP and MAP along with improving sympathovagal balance in healthy volunteers.

2021 ◽  
Vol 65 ◽  
pp. 162-166
B. N. Keerthy ◽  
Sai Sreevalli Sarma Sreepada ◽  
Shalini S. Naik ◽  
Anushree Bose ◽  
Raju Hanumegowda ◽  

Objectives: Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) have been used as neuromodulators in neuropsychiatric conditions. This study is aimed to find the effects of a single session of priming cathodal tDCS with intermittent theta-burst stimulation (iTBS) over left dorsolateral prefrontal cortex on heart rate variability (HRV) and cortical excitability parameters before and after perturbation. Materials and Methods: The neuromodulatory techniques used in the study were Cathodal tDCS for 20 min followed by iTBS for 3 min on the left dorsolateral prefrontal cortex (DLPFC). HRV variables and TMS parameters were recorded before and after this intervention of combined neuromodulation in 31 healthy volunteers (20 males and 11 females; age range of 19–35 years with Mean ± SD = 24.2 ± 4.7 years). Results: The results showed an overall increase in cortical excitability and parasympathetic dominance in healthy volunteers. Other measures of cortical excitability and HRV did not change significantly following single session of combined neuromodulation. Conclusion: This study showed that there is an overall increase in cortical excitability and parasympathetic dominance in the cohort of healthy volunteers following a combination of neuromodulation involving cathodal tDCS followed by iTBS over left DLPFC. Future studies exploring the effects of other possible combinations with sham stimulation could be carried out to explore the utility of dual stimulation as add-on therapy in disorders.

2020 ◽  
Vol 11 (02) ◽  
pp. 250-255
Vasantmeghna S. Murthy ◽  
Vedant S. Shukla

Abstract Background Executive functions (EFs) are critical to daily life and sensitive to our physiological functioning and emotional states. The number of people living with chronic kidney disease (CKD) on hemodialysis (HD) globally is increasing steadily. We aimed to determine the impact of a single session of HD on EFs in patients with CKD receiving maintenance HD (MHD). Methods This was a quasi-experimental study conducted at the department of psychiatry and dialysis unit of a tertiary hospital. Patients undergoing MHD underwent screening to rule out delirium, using the Confusion Assessment Method prior to EF testing. The tests of EF used were the Trail-Making Test—Part B (TMT-B) and Frontal Assessment Battery (FAB), both of which were administered before and after a session of HD. Statistical tests used were Wilcoxon matched pairs signed ranks test, paired t-test, single sample t-test, and correlation analyses. Results The mean time taken on TMT-B before HD was 195.36 seconds and after HD, 171.1 seconds; difference is significant (p = 0.0001). The mean FAB score was 13.19 before HD and 14.83 after HD; the difference is significant (p < 0.0001). Significant differences were observed on similarities (p = 0.003), lexical fluency (p = 0.02), and go–no go (p = 0.003) subtests of FAB. Mean TMT-B scores before and after HD differed significantly from that of a reference study (reference TMT-B 150.69 seconds), p = 0.0002 and 0.04, respectively. Conclusion We conclude that patients with CKD on MHD, in general, have worse executive cognitive functioning compared with healthy populations. A session of HD results in significant improvement in these functions.

Pain Medicine ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. e172-e181 ◽  
María Benito-de-Pedro ◽  
Ricardo Becerro-de-Bengoa-Vallejo ◽  
Marta Elena Losa-Iglesias ◽  
David Rodríguez-Sanz ◽  
Daniel López-López ◽  

Abstract Objective To determine the immediate efficacy of a single session of deep dry needling (DDN) vs ischemic compression (ICT) in a latent myofascial trigger point (MTrP) of the shortened triceps surae from triathletes for ankle dorsiflexion and redistribution of plantar pressures and stability. Design A randomized simple blind clinical trial (NCT03273985). Setting An outpatient clinic. Subjects Thirty-four triathletes with a latent MTrP in the shortened gastrocnemius. Methods Triathletes were randomized to receive a single session of DDN (N = 17) or ICT (N = 17) in a latent MTrP of the shortened triceps surae. The primary outcome was ankle dorsiflexion range of motion (ROM) by a universal goniometer. Secondary objectives were distribution of dynamic and static plantar pressures by T-Plate platform pressure, with measurements both before and after five, 10, 15, 20, and 25 minutes of treatment. Results There were no statistically significant differences (P &gt; 0.05) for ankle dorsiflexion ROM or dynamic and static plantar pressures between the experimental group treated with DDN and the control group treated with ICT before and after treatment. Conclusions DDN vs ICT carried out in latent MTrPs of the shortened gastrocnemius of triathletes did not present differences in terms of dorsiflexion ROM of the tibiofibular-talar joint or in static and dynamic plantar pressure changes before and immediately after treatment.

2020 ◽  
Vol 222 (10) ◽  
pp. 1731-1739 ◽  
Eleanor Burnett ◽  
Umesh D Parashar ◽  
Jacqueline E Tate

Abstract Background Since 2006, more than 100 countries have introduced rotavirus vaccine into their immunization programs. We reviewed published data on relative reductions of rotavirus hospitalizations, acute gastroenteritis (AGE) hospitalizations, and AGE deaths among children &lt;5 years old. Methods Articles published from January 1, 2006 to December 31, 2019 with at least 12 months of data before and after rotavirus vaccine introduction were included. Relative reductions were abstracted into a standardized form. Descriptive statistics are presented as medians and interquartile ranges (IQRs). Results We reviewed 1827 total records and included 105 articles from 49 countries. Among children &lt;5 years old, there was a median reduction of 59% (IQR, 46–74) in rotavirus hospitalizations, 36% (IQR, 23–47) in AGE hospitalizations, and 36% (IQR, 28–46) AGE mortality. Reductions were larger in countries with low child mortality, among younger age groups, and in countries with higher coverage. The median percentage of specimens that tested positive for rotavirus among children &lt;5 years old hospitalized for diarrhea was 40% (IQR, 28–45) before rotavirus vaccine introduction and 20% (IQR, 20–20) 4 years after introduction. Conclusions Overall, we found sustained impact on rotavirus and AGE hospitalizations and deaths. These results should encourage countries still considering rotavirus vaccine implementation.

1994 ◽  
Vol 77 (4) ◽  
pp. 1644-1652 ◽  
M. Bonora ◽  
M. Boule

The influence of steady-state changes in chemical stimuli on ventilation and electromyographic activity of the diaphragm during both inspiration (total DI) and expiration (total DE) was studied in unanesthetized intact adult cats before and after carotid denervation. In intact animals, during hypercapnia (2 4, and 6% CO2), tidal volume (VT) and total DI increase, whereas total DE did not consistently change. During ambient hypocapnic hypoxia (14, 12, and 10% O2), VT increased only at 10% O2, whereas total DI increased at all levels studied. Total DE increased substantially at 14% O2, persisting up to the end of expiration with 12 and 10% O2. This effect was markedly attenuated during normocapnic hypoxia. During CO hypoxemia (1,700 ppm in air), VT as well as total DI and total DE decreased because of a large reduction in inspiratory and expiratory time elicited by tachypneic breathing. The effects of hypercapnia and hypoxia persisted after carotid denervation. Therefore, 1) in contrast to hypercapnia, hypoxia markedly enhances the expiratory diaphragmatic activity, 1) this expiratory braking mechanism depends on the severity of hypoxia and is partly due to hypocapnia secondary to hypoxia; and 3) because this effect was observed after carotid denervation and during CO hypoxemia, it may arise in the central nervous system, possibly in bulbopontine structures.

2016 ◽  
Vol 29 (06) ◽  
pp. 499-506
James Roush ◽  
David Biller ◽  
Julie Gervais

SummaryObjectives: To assess the potential of a new single-session surgical procedure, the overlapping pubic and ischiatic osteotomy (OPIO) for modification of bilateral hip conformation. We hypothesized that OPIO would be simple to perform with currently available surgical equipment, through a single surgical approach, with minimal potential morbidity, and that it would allow adequate simultaneous bilateral improvement of coxofemoral joint conformation in patients at risk of canine hip dysplasia.Methods: The OPIO procedure was performed in the pelves of five large breed canine cadavers. Computed tomography images of each cadaver were compared by measurement of the dorsal acetabular rim angle (DARA), acetabular angle (AA), dorso-ventral sacroiliac ratio (SR), and pubic inlet area before and after OPIO.Results: Coxofemoral joint conformation was improved after OPIO. Postoperative DARA was significantly decreased (mean: –5.09°) and AA was significantly increased (mean: 3.54°) after OPIO. The SR was not significantly different after OPIO, indicating minimal impact on the sacro-illiac joints by the procedure. Pubic inlet dimensions and area were significantly decreased after OPIO, but the overall effect on pelvic inlet area was clinically insignificant.Clinical significance: An OPIO allows some improvement of coxofemoral joint conformation in canine cadavers.

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