scholarly journals Modeling Post-Scratching Locomotion with Two Rhythm Generators and a Shared Pattern Formation

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 663
Author(s):  
Jesus A. Tapia ◽  
Argelia Reid ◽  
John Reid ◽  
Saul M. Dominguez-Nicolas ◽  
Elias Manjarrez
Keyword(s):  
Spinal Cord ◽  
Pattern Formation ◽  
Effective Connectivity ◽  
Pattern Generator ◽  
Rhythmic Movements ◽  
Common Pattern ◽  
The Mean ◽  
Motor Outputs ◽  
Mean Cycle ◽  
Previous Experimental Study

This study aimed to present a model of post-scratching locomotion with two intermixed central pattern generator (CPG) networks, one for scratching and another for locomotion. We hypothesized that the rhythm generator layers for each CPG are different, with the condition that both CPGs share their supraspinal circuits and their motor outputs at the level of their pattern formation networks. We show that the model reproduces the post-scratching locomotion latency of 6.2 ± 3.5 s, and the mean cycle durations for scratching and post-scratching locomotion of 0.3 ± 0.09 s and 1.7 ± 0.6 s, respectively, which were observed in a previous experimental study. Our findings show how the transition of two rhythmic movements could be mediated by information exchanged between their CPG circuits through routes converging in a common pattern formation layer. This integrated organization may provide flexible and effective connectivity despite the rigidity of the anatomical connections in the spinal cord circuitry.

scholarly journals The BCM rule allows a spinal cord model to learn rhythmic movements

2021 ◽  
Author(s):  
Matthias Kohler ◽  
Philipp Stratmann ◽  
Florian Roehrbein ◽  
Alois Knoll ◽  
Alin Albu-Schaeffer ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Visual Cortex ◽  
Learning Rule ◽  
Biomechanical Properties ◽  
Pattern Generator ◽  
Alternative Theory ◽  
Rhythmic Movements ◽  
Animal Locomotion ◽  
Network Properties ◽  
Genetically Determined

Animal locomotion is hypothesized to be controlled by a central pattern generator in the spinal cord. Experiments and models show that rhythm generating neurons and genetically determined network properties could sustain oscillatory output activity suitable for locomotion. However, current CPG models do not explain how a spinal cord circuitry, which has the same basic genetic plan across species, can adapt to control the different biomechanical properties and locomotion patterns existing in these species. Here we demonstrate that rhythmic and alternating movements in pendulum models can be learned by a monolayer spinal cord circuitry model using the BCM learning rule, which has been previously proposed to explain learning in the visual cortex. These results provide an alternative theory to CPG models, because rhythm generating neurons and genetically defined connectivity are not required in our model.

scholarly journals Developmental stochasticity and variation in floral phyllotaxis

2021 ◽  
Author(s):  
Miho Stephanie Kitazawa
Keyword(s):  
Pattern Formation ◽  
Gene Networks ◽  
Recent Progress ◽  
Phyllotactic Pattern ◽  
Floral Diversity ◽  
Core Eudicots ◽  
Common Process ◽  
The Mean ◽  
Floral Phyllotaxis ◽  
Regular Patterns

AbstractFloral phyllotaxis is a relatively robust phenotype; trimerous and pentamerous arrangements are widely observed in monocots and core eudicots. Conversely, it also shows variability in some angiosperm clades such as ‘ANA’ grade (Amborellales, Nymphaeales, and Austrobaileyales), magnoliids, and Ranunculales. Regardless of the phylogenetic relationship, however, phyllotactic pattern formation appears to be a common process. What are the causes of the variability in floral phyllotaxis and how has the variation of floral phyllotaxis contributed to floral diversity? In this review, I summarize recent progress in studies on two related fields to develop answers to these questions. First, it is known that molecular and cellular stochasticity are inevitably found in biological systems, including plant development. Organisms deal with molecular stochasticity in several ways, such as dampening noise through gene networks or maintaining function through cellular redundancy. Recent studies on molecular and cellular stochasticity suggest that stochasticity is not always detrimental to plants and that it is also essential in development. Second, studies on vegetative and inflorescence phyllotaxis have shown that plants often exhibit variability and flexibility in phenotypes. Three types of phyllotaxis variations are observed, namely, fluctuation around the mean, transition between regular patterns, and a transient irregular organ arrangement called permutation. Computer models have demonstrated that stochasticity in the phyllotactic pattern formation plays a role in pattern transitions and irregularities. Variations are also found in the number and positioning of floral organs, although it is not known whether such variations provide any functional advantages. Two ways of diversification may be involved in angiosperm floral evolution: precise regulation of organ position and identity that leads to further specialization of organs and organ redundancy that leads to flexibility in floral phyllotaxis.

scholarly journals Utilization of laser interstitial thermotherapy guided by real-time thermal MRI as an alternative to separation surgery in the management of spinal metastasis

2015 ◽  
Vol 23 (4) ◽  
pp. 400-411 ◽  
Author(s):  
Claudio E. Tatsui ◽  
R. Jason Stafford ◽  
Jing Li ◽  
Jonathan N. Sellin ◽  
Behrang Amini ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Spinal Cord ◽  
Real Time ◽  
Spinal Cord Compression ◽  
Spinal Metastasis ◽  
Cord Compression ◽  
The Mean ◽  
Interstitial Thermotherapy

OBJECT High-grade malignant spinal cord compression is commonly managed with a combination of surgery aimed at removing the epidural tumor, followed by spinal stereotactic radiosurgery (SSRS) aimed at local tumor control. The authors here introduce the use of spinal laser interstitial thermotherapy (SLITT) as an alternative to surgery prior to SSRS. METHODS Patients with a high degree of epidural malignant compression due to radioresistant tumors were selected for study. Visual analog scale (VAS) scores for pain and quality of life were obtained before and within 30 and 60 days after treatment. A laser probe was percutaneously placed in the epidural space. Real-time thermal MRI was used to monitor tissue damage in the region of interest. All patients received postoperative SSRS. The maximum thickness of the epidural tumor was measured, and the degree of epidural spinal cord compression (ESCC) was scored in pre- and postprocedure MRI. RESULTS In the 11 patients eligible for study, the mean VAS score for pain decreased from 6.18 in the preoperative period to 4.27 within 30 days and 2.8 within 60 days after the procedure. A similar VAS interrogating the percentage of quality of life demonstrated improvement from 60% preoperatively to 70% within both 30 and 60 days after treatment. Imaging follow-up 2 months after the procedure demonstrated a significant reduction in the mean thickness of the epidural tumor from 8.82 mm (95% CI 7.38–10.25) before treatment to 6.36 mm (95% CI 4.65–8.07) after SLITT and SSRS (p = 0.0001). The median preoperative ESCC Grade 2 was scored as 4, which was significantly higher than the score of 2 for Grade 1b (p = 0.04) on imaging follow-up 2 months after the procedure. CONCLUTIONS The authors present the first report on an innovative minimally invasive alternative to surgery in the management of spinal metastasis. In their early experience, SLITT has provided local control with low morbidity and improvement in both pain and the quality of life of patients.

Split spinal cord malformations in children

1998 ◽  
Vol 88 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Yusuf Ersşahin ◽  
Saffet Mutluer ◽  
Sevgül Kocaman ◽  
Eren Demirtasş
Keyword(s):  
Spinal Cord ◽  
Neurological Deficits ◽  
Single Type ◽  
Type I ◽  
Type Ii ◽  
Content Type ◽  
Spinal Lesion ◽  
The Mean ◽  
Fine Print

Object. The authors reviewed and analyzed information on 74 patients with split spinal cord malformations (SSCMs) treated between January 1, 1980 and December 31, 1996 at their institution with the aim of defining and classifying the malformations according to the method of Pang, et al. Methods. Computerized tomography myelography was superior to other radiological tools in defining the type of SSCM. There were 46 girls (62%) and 28 boys (38%) ranging in age from less than 1 day to 12 years (mean 33.08 months). The mean age (43.2 months) of the patients who exhibited neurological deficits and orthopedic deformities was significantly older than those (8.2 months) without deficits (p = 0.003). Fifty-two patients had a single Type I and 18 patients a single Type II SSCM; four patients had composite SSCMs. Sixty-two patients had at least one associated spinal lesion that could lead to spinal cord tethering. After surgery, the majority of the patients remained stable and clinical improvement was observed in 18 patients. Conclusions. The classification of SSCMs proposed by Pang, et al., will eliminate the current chaos in terminology. In all SSCMs, either a rigid or a fibrous septum was found to transfix the spinal cord. There was at least one unrelated lesion that caused tethering of the spinal cord in 85% of the patients. The risk of neurological deficits resulting from SSCMs increases with the age of the patient; therefore, all patients should be surgically treated when diagnosed, especially before the development of orthopedic and neurological manifestations.

Interspecific differences in the distribution of adult and juvenile ponyfish (Leiognathidae) in the Gulf of Carpentaria, Australia

1999 ◽  
Vol 50 (7) ◽  
pp. 643 ◽  
Author(s):  
J. Staunton-Smith ◽  
S. J. M. Blaber ◽  
J. G. Greenwood
Keyword(s):  
Linear Increase ◽  
Small Fish ◽  
Common Pattern ◽  
Widespread Species ◽  
Nursery Areas ◽  
Interspecific Differences ◽  
Coastal Species ◽  
The Common ◽  
The Mean ◽  
Coexisting Species

The distribution of leiognathids was investigated at 261 sites spread throughout the Gulf of Carpentaria. Eight species, Gazza minuta, Leiognathus decorus, L. equulus, L. fasciatus, L. leuciscus, L. smithursti, L. splendens and Secutor ruconius, were usually restricted to coastal areas, whereas four species, L. bindus, L. moretoniensis, Leiognathus sp. and S. insidiator, were not. Two other species, L. aureus and L. elongatus, were caught at only one site each. The relationships between size of fish and depth in Albatross Bay were investigated by examining the mean weight and minimum and maximum lengths of different species in 356 trawls. Six of the coastal species showed the common pattern of linear increase in size with depth. This pattern is consistent with the existence of estuarine and/or inshore nursery areas, and supports previous observations of these species. In contrast, three of the widespread species exhibited approximately quadratic relationships between size and depth. This unusual pattern resulted from small fish living in both the shallow inshore areas and deeper offshore areas, and it may reduce competition among the juveniles of the large number of very abundant, coexisting species of leiognathid.

Evaluation of the daily cycle in the simulation of the ClimEx large-ensemble

2021 ◽  
Author(s):  
Anne-Marie Begin
Keyword(s):  
Climate Change ◽  
Estimation Error ◽  
Natural Variability ◽  
Extreme Weather Events ◽  
Large Ensemble ◽  
Daily Cycle ◽  
Minimum Number ◽  
The Mean ◽  
Mean Cycle ◽  
The Impact

<p>To estimate the impact of climate change on our society we need to use climate projections based on numerical models. These models make it possible to assess the effects on climate of the increase in greenhouse gases (GHG) as well as natural variability. We know that the global average temperature will increase and that the occurrence, intensity and spatio-temporal distribution of extreme precipitations will change. These extreme weather events cause droughts, floods and other natural disasters that have significant consequences on our life and environment. Precipitation is a key variable in adapting to climate change.</p><p> </p><p>This study focuses on the ClimEx large ensemble, a set of 50 independent simulations created to study the effect of climate change and natural variability on the water network in Quebec. This dataset consists of simulations produced using the Canadian Regional Climate Model version 5 (CRCM5) at 12 km of resolution driven by simulations from the second generation Canadian Earth System Model (CanESM2) global model at 310 km of resolution.</p><p> </p><p>The aim of the project is to evaluate the performance of the ClimEx ensemble in simulating the daily cycle and representing extreme values.  To get there, 30 years of hourly time series for precipitation and 3 hourly for temperature are analyzed. The simulations are compared with the values from the simulation of CRCM5 driven by ERA-Interim reanalysis, the ERA5 reanalysis and Environment and Climate Change Canada (ECCC) stations. An evaluation of the sensitivity of different statistics to the number of members is also performed.</p><p> </p><p>The daily cycle of precipitation from ClimEx shows mainly non-significant correlations with the other datasets and its amplitude is less than the observation datas from ECCC stations. For temperature, the correlation is strong and the amplitude of the cycle is similar to observations. ClimEx provides a fairly good representation of the 95, 97, 99<sup>th</sup> quantiles for precipitation. For temperature it represents a good distribution of quantiles but with a warm bias in southern Quebec. For precipitation hourly maximum, ClimEx shows values 10 times higher than ERA5.  For temperature, minimum and maximum values may exceed the ERA5 limit by up to 20°C. For precipitation, the minimum number of members for the estimation of the 95 and 99<sup>th</sup><sup></sup>quantiles and the mean cycle is between 15 and 50 for an estimation error of less than 5%. For the 95, 99<sup>th</sup> quantiles of temperature, the minimum number of members is between 1 and 17 and for the mean cycle 1 to 2 members are necessary to obtain an estimation error of less than 0.5°C.</p>

Physiology and Morphology of Shared and Specialized Spinal Interneurons for Locomotion and Scratching

2008 ◽  
Vol 99 (6) ◽  
pp. 2887-2901 ◽  
Author(s):  
Ari Berkowitz
Keyword(s):  
Direct Evidence ◽  
Ventral Horn ◽  
Morphological Properties ◽  
Rhythmic Movements ◽  
Potential Oscillations ◽  
Spinal Interneurons ◽  
Firing Rates ◽  
Motor Outputs ◽  
Membrane Potential Oscillations

Distinct types of rhythmic movements that use the same muscles are typically generated largely by shared multifunctional neurons in invertebrates, but less is known for vertebrates. Evidence suggests that locomotion and scratching are produced partly by shared spinal cord interneuronal circuity, although direct evidence with intracellular recording has been lacking. Here, spinal interneurons were recorded intracellularly during fictive swimming and fictive scratching in vivo and filled with Neurobiotin. Some interneurons that were rhythmically activated during both swimming and scratching had axon terminal arborizations in the ventral horn of the hindlimb enlargement, indicating their likely contribution to hindlimb motor outputs during both behaviors. We previously described a morphological group of spinal interneurons (“transverse interneurons” or T neurons) that were rhythmically activated during all forms of fictive scratching at higher peak firing rates and with larger membrane potential oscillations than scratch-activated spinal interneurons with different dendritic orientations. The current study demonstrates that T neurons are activated during both swimming and scratching and thus are components of the shared circuitry. Many spinal interneurons activated during fictive scratching are also activated during fictive swimming (scratch/swim neurons), but others are suppressed during swimming (scratch-specialized neurons). The current study demonstrates that some scratch-specialized neurons receive strong and long-lasting hyperpolarizing inhibition during fictive swimming and are also morphologically distinct from T neurons. Thus this study indicates that locomotion and scratching are produced by a combination of shared and dedicated interneurons whose physiological and morphological properties are beginning to be revealed.

scholarly journals Subcutaneous granulocyte colony-stimulating factor administration for subacute traumatic spinal cord injuries, report of neurological and functional outcomes: a double-blind randomized controlled clinical trial

2019 ◽  
Vol 30 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Nazi Derakhshanrad ◽  
Hooshang Saberi ◽  
Mir Saeed Yekaninejad ◽  
Mohammad Taghi Joghataei
Keyword(s):  
Clinical Trial ◽  
Spinal Cord ◽  
Placebo Group ◽  
Spinal Cord Injuries ◽  
Functional Improvement ◽  
Granulocyte Colony Stimulating Factor ◽  
Double Blind ◽  
Cord Injury ◽  
The Mean ◽  
Stimulating Factor

OBJECTIVEGranulocyte-colony stimulating factor (G-CSF) is a major cytokine that has already been clinically verified for chronic traumatic spinal cord injuries (TSCIs). In this study, the authors set out to determine the safety and efficacy of G-CSF administration for neurological and functional improvement in subacute, incomplete TSCI.METHODSThis phase II/III, prospective, double-blind, placebo-controlled, parallel randomized clinical trial was performed in 60 eligible patients (30 treatment, 30 placebo). Patients with incomplete subacute TSCIs with American Spinal Injury Association Impairment Scale (AIS) grades B, C, and D were enrolled. Patients were assessed using the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) scale, Spinal Cord Independence Measure (SCIM-III) and International Association of Neurorestoratology Spinal Cord Injury Functional Rating Scale (IANR-SCIFRS), just before intervention and at 1, 3, and 6 months, after 7 daily subcutaneous administrations of 300 μg/day of G-CSF in the treatment group and placebo in the control group.RESULTSAmong 60 participants, 28 patients (93.3%) in the G-CSF group and 26 patients (86.6%) in the placebo group completed the study protocol. After 6 months of follow-up, the AIS grade remained unchanged in the placebo group, while in the G-CSF group 5 patients (45.5%) improved from AIS grade B to C, 5 (45.5%) improved from AIS grade C to grade D, and 1 patient (16.7%) improved from AIS grade D to E. The mean ± SEM change in ISNCSCI motor score in the G-CSF group was 14.9 ± 2.6 points, which was significantly greater than in the placebo group (1.4 ± 0.34 points, p < 0.001). The mean ± SEM light-touch and pinprick sensory scores improved by 8.8 ± 1.9 and 10.7 ± 2.6 points in the G-CSF group, while those in the placebo group improved by 2.5 ± 0.60 and 1.2 ± 0.40 points, (p = 0.005 and 0.002, respectively). Evaluation of functional improvement according to the IANR-SCIFRS instrument revealed significantly more functional improvement in the G-CSF group (10.3 ± 1.3 points than in the placebo group (3.0 ± 0.81 points; p < 0.001). A significant difference was also observed between the 2 groups as measured by the SCIM-III instrument (29.6 ± 4.1 vs 10.3 ± 2.2, p < 0.001).CONCLUSIONSIncomplete subacute TSCI is associated with significant motor, sensory, and functional improvement after administration of G-CSF.Clinical trial registration no.: IRCT201407177441N3 (www.irct.ir)

scholarly journals Analysis of Default Mode Network in Social Anxiety Disorder: EEG Resting-State Effective Connectivity Study

2021 ◽  
Author(s):  
Abdulhakim Al-Ezzi ◽  
Nidal Kamel ◽  
Ibrahima Faye ◽  
Esther Gunaseli
Keyword(s):  
Anxiety Disorder ◽  
Social Anxiety ◽  
Social Anxiety Disorder ◽  
Default Mode Network ◽  
Resting State ◽  
Effective Connectivity ◽  
Mean Values ◽  
Default Mode ◽  
Severe Group ◽  
The Mean

Several neuroimaging findings by using different modalities (e.g., fMRI and PET) have suggested that social anxiety disorder (SAD) is correlated with alterations in regional or network-level brain function. However, these modalities do not quantify the fast dynamic connectivity of causal information networks due to their poor temporal resolution. In this study, SAD-related changes in brain connections within the default mode network (DMN) was investigated using Electroencephalogram (EEG). Partial directed coherence (PDC) was used to assess the causal influences of DMN regions on each other and indicate the changes in the DMN effective network related to SAD severity. The EEG data were collected from 88 subjects (control, mild, moderate, severe) and used to estimate the effective connectivity between DMN regions at different frequency bands. Among the healthy control (HC) and the three considered levels of severity of SAD, the results indicated a higher level of causal interactions for the mild and moderate SAD groups than for the severe and HC groups. Between the control and the severe SAD groups, the results indicated a higher level of causal connections for the control throughout all the DMN regions. We found significant increases in the mean PDC in the delta and alpha bands between the SAD groups. Among the DMN regions, the precuneus exhibited a higher level of causal influence than other regions. Therefore, it was suggested to be a major source hub that contributes to the mental exploration and emotional content of SAD. In contrast to the severe group, the HC exhibited higher resting-state connectivity at the mesial prefrontal cortex (mPFC), providing evidence for mPFC dysfunction in the severe SAD group. Furthermore, the total Social Interaction Anxiety Scale (SIAS) was positively correlated with the mean values of the PDC of the severe SAD group and negatively correlated with those of the HC group. The reported results may facilitate greater comprehension of the underlying potential SAD neural biomarkers and can be used to characterize possible targets for further medication.

Sign in / Sign up

Export Citation Format

Share Document