Neurons in the Pontomedullary Reticular Formation Signal Posture and Movement Both as an Integrated Behavior and Independently

2008 ◽  
Vol 100 (4) ◽  
pp. 2235-2253 ◽  
Author(s):  
Bénédicte Schepens ◽  
Paul Stapley ◽  
Trevor Drew
Keyword(s):  
Reticular Formation ◽  
Similar Pattern ◽  
Lever Press ◽  
The Other ◽  
Muscle Tonus ◽  
Contralateral Limb ◽  
Discharge Characteristics ◽  
Flexor Muscles ◽  
Postural Support ◽  
The Right

We have previously suggested that the discharge characteristics of some neurons in the pontomedullary reticular formation (PMRF) are contingent on the simultaneous requirement for activity in both ipsilateral flexor muscles and contralateral extensors. To test this hypothesis we trained cats to stand on four force platforms and to perform a task in which they were required to reach forward with one forelimb or the other and depress a lever. As such the task required the cat to make a flexion movement followed by an extension in the reaching limb while maintaining postural support by increasing extensor muscle tonus in the supporting limbs. We recorded the activity of 131 neurons from the PMRF of three cats during left, ipsilateral reach. Of these, 86/131 (66%) showed a change in discharge frequency prior to the onset of activity in one of the prime flexor muscles and 43/86 (50%) showed a bimodal pattern of discharge in which activity decreased during the lever press. Among the remaining cells, 28/86 (33%) showed maintained activity throughout the reach and the lever press. Most cells showed a broadly similar pattern of discharge during reaches with the right, contralateral limb. We suggest these results support the view that a population of neurons within the PMRF contributes to the control of movement in one forelimb and the control of posture in the other forelimb as a coordinated unit. Another population of neurons contributes to the control of postural support independently of the nature of the activity in the reaching limb.

Descending Signals From the Pontomedullary Reticular Formation Are Bilateral, Asymmetric, and Gated During Reaching Movements in the Cat

2006 ◽  
Vol 96 (5) ◽  
pp. 2229-2252 ◽  
Author(s):  
Bénédicte Schepens ◽  
Trevor Drew
Keyword(s):  
Reticular Formation ◽  
Early Discharge ◽  
Reaching Movements ◽  
Contralateral Limb ◽  
Discharge Activity ◽  
Spike Triggered Averaging ◽  
Extensor Muscles ◽  
Flexor Muscles ◽  
Reticular Neurons ◽  
Initial Change

We examined the contribution of neurons within the pontomedullary reticular formation (PMRF) to the control of reaching movements in the cat. We recorded the activity of 127 reticular neurons, including 56 reticulospinal neurons, during movements of each forelimb; 67/127 of these neurons discharged prior to the onset of activity in the prime flexor muscles during the reach of the ipsilateral limb and form the focus of this report. Most neurons (63/67) showed similar patterns and levels of discharge activity during reaches of either limb, although activity was slightly greater during reach of the ipsilateral limb. In 26/67 cells, the initial change in discharge activity was time-locked to the go signal during reaches of either limb; we have argued that this early discharge contributes to the anticipatory postural adjustments that precede movement. In 11/26 cells, the initial change in activity was reciprocal for reaches with the left and right limbs, although activity during the movement was nonreciprocal. Spike-triggered averaging produced postspike facilitation or depression (PSD) in 12/50 cells during reaches of the limb ipsilateral to the recording site and in 17/49 cells during reach of the contralateral limb. Some cells produced PSD in ipsilateral extensor muscles before the start of the reach and during reaches made with the contralateral, but not the ipsilateral limb; this suggests the signal must be differentially gated. Overall, the results suggest a strong bilateral, albeit asymmetric, contribution from the PMRF to the control of posture and movement during voluntary movement.

Differential modulation of descending signals from the reticulospinal system during reaching and locomotion

2014 ◽  
Vol 112 (10) ◽  
pp. 2505-2528 ◽  
Author(s):  
Kenneth S. Dyson ◽  
Jean-Philippe Miron ◽  
Trevor Drew
Keyword(s):  
Central Pattern Generator ◽  
Reticular Formation ◽  
Muscle Activity ◽  
Pattern Generator ◽  
Swing Phase ◽  
The Other ◽  
Voluntary Movements ◽  
Evoked Responses ◽  
Differential Modulation ◽  
Flexor Muscles

We tested the hypothesis that the same spinal interneuronal pathways are activated by the reticulospinal system during locomotion and reaching. If such were the case, we expected that microstimulation within the pontomedullary reticular formation (PMRF) would evoke qualitatively similar responses in muscles active during both behaviors. To test this, we stimulated in 47 sites within the PMRF during both tasks. Stimulation during locomotion always produced a strongly phase-dependent, bilateral pattern of activity in which activity in muscles was generally facilitated or suppressed during one phase of activity (swing or stance) and was unaffected in the other. During reaching, stimulation generally activated the same muscles as during locomotion, although the modulation of the magnitude of the evoked responses was less limb dependent than during locomotion. An exception was found for some forelimb flexor muscles that were strongly facilitated by stimulation during the swing phase of locomotion but were not influenced by stimulation during the transport phase of the reach. We suggest that during locomotion the activity in interneuronal pathways mediating signals from the reticulospinal system is subject to strong modulation by the central pattern generator for locomotion. During reach, we suggest that, for most muscles, the same spinal interneuronal pathways are used to modify muscle activity but are not as strongly gated according to limb use as during locomotion. Finally, we propose that the command for movement during discrete voluntary movements suppresses the influence of the reticulospinal system on selected forelimb flexor muscles, possibly to enhance fractionated control of movement.

Phase-dependent responses evoked in limb muscles by stimulation of medullary reticular formation during locomotion in thalamic cats

1984 ◽  
Vol 52 (4) ◽  
pp. 653-675 ◽  
Author(s):  
T. Drew ◽  
S. Rossignol
Keyword(s):  
Reticular Formation ◽  
The Body ◽  
The Other ◽  
Step Cycle ◽  
Medullary Reticular Formation ◽  
Locomotor Rhythm ◽  
Extensor Muscles ◽  
Short Period ◽  
Flexor Muscles ◽  
Excitatory Responses

Electromyographic and kinematic responses of all four limbs were studied when loci within the medullary reticular formation (MRF) were stimulated (30-ms train of 0.2-ms pulses at 300 Hz, strength 35 microA) during treadmill locomotion in spontaneously walking thalamic cats. Responses could be evoked in flexor or extensor muscles of any given limb by such stimulation, depending on the time during the step cycle at which the stimulus was delivered. Stimulation normally excited flexor muscles but could either excite or inhibit extensor muscles depending on the exact position of the electrode. Excitatory responses in extensor muscles were often followed by a short period of inhibition of activity. The responses in muscles of the opposing limbs of the same girdle were, in general, reciprocally organized. For instance, a stimulus delivered during the swing phase of the ipsilateral limb normally evoked excitatory responses both in flexor muscles of that limb and in extensor muscles of the contralateral limb. The same stimulus delivered during the stance phase of the ipsilateral limb evoked excitatory responses in ipsilateral extensor muscles and in contralateral flexor muscles. Responses were also observed at the same time in fore- and hindlimbs that were well organized with respect to the locomotor cycle. Seventy-five percent of all responses occurred within 8-20 ms of the onset of the stimulus train. Responses evoked in muscles of the opposing limbs of one girdle (e.g., a flexor of one limb and an extensor of the other) had similar latencies, suggesting that the responses were synchronously organized on both sides of the body rather than one being a consequence of the other. Although the majority of responses in a given muscle were elicited during its period of activity, responses could occasionally be evoked when there was no activity in that muscle or could be absent despite activity in the muscle. The short trains of stimuli were normally potent enough to affect the limb trajectory, which reflected changes in the onset or the offset of the activity of most muscles. Thus the stimuli effectively changed both the duration of the period of activity in these muscles and the overall step cycle. Longer trains of stimuli (200 ms) markedly amplified these changes to the point of completely resetting the locomotor rhythm.(ABSTRACT TRUNCATED AT 400 WORDS)

Asymmetry of the Motor System in the Hermit Crab Pagurus Granosimanus Stimpson

1966 ◽  
Vol 45 (1) ◽  
pp. 65-81
Author(s):  
WILLIAM D. CHAPPLE
Keyword(s):  
Spontaneous Activity ◽  
Motor System ◽  
Sensory Stimulation ◽  
Reciprocal Inhibition ◽  
The Other ◽  
Single Pair ◽  
Flexor Muscles ◽  
Reflex Activation ◽  
Giant Fibres ◽  
The Right

1. The decalcification of the abdomen and the asymmetry of the central flexors is a ‘hydrostatic’ mechanism by which the abdomen is expanded to fit the shell tightly. 2. The single pair of giant fibres is homologous to the medial giants of the crayfish except that no contralateral activation of the flexor muscles was observed. 3. Two kinds of asymmetry in the motor system were observed; (a) loss of motor fibres in the first ganglionic roots of the right side; (b) greater frequency of ‘spontaneous activity’ in the slow flexor branch of the third roots on the left side. 4. Sensory stimulation evoked different sets of fibres in these third root branches; one set fired spontaneously even after total ganglionic isolation, the other, when reflexly activated, reciprocally inhibited the first group. 5. Antidromic and synaptic inputs failed to re-set the spontaneous activity; two kinds of reflex activation, phasic and tonic suggest two different sites for inputs, one to the motoneurons, the other to a pre-synaptic pacemaker. 6. Alternations of the two reflex groups occurred in the totally isolated ganglion; addition of picrotoxin to the saline abolished reciprocal inhibition but variations in the frequency of spontaneous activity persisted. 7. A possible mechanism for this system is proposed.

Assessment of knowledge of oral health hygiene among coastal guards in the port trust of south Tamil Nadu - A public health awareness survey

2020 ◽  
Vol 11 (SPL3) ◽  
pp. 1861-1868
Author(s):  
Bianca Princeton ◽  
Abilasha R ◽  
Preetha S
Keyword(s):  
Lung Cancer ◽  
Oral Health ◽  
Oral Hygiene ◽  
Tamil Nadu ◽  
Asbestos Exposure ◽  
The Other ◽  
Oral Manifestations ◽  
Illegal Activities ◽  
The Right ◽  
Oral Hygiene Habits

Oral hygiene is defined as the practice of keeping the mouth clean and healthy, by brushing and flossing to prevent the occurrence of any gum diseases like periodontitis or gingivitis. The main aim of oral health hygiene is to prevent the buildup of plaque, which is defined as a sticky film of bacteria and food formed on the teeth. The coastal guard is an official who is employed to watch the sea near a coast for ships that are in danger or involved with illegal activities. Coastal guards have high possibilities of being affected by mesothelioma or lung cancer due to asbestos exposure. So, a questionnaire consisting of 20 questions was created and circulated among a hundred participants who were coastal guards, through Google forms. The responses were recorded and tabulated in the form of bar graphs. Out of a hundred participants, 52.4% were not aware of the fact that coastal guards have high chances of developing lung cancer and Mesothelioma. 53.7% were aware of the other oral manifestations of lung cancer other than bleeding gums. Majority of the coastal guards feel that they are given enough information about dental hygiene protocols. Hence, to conclude, oral hygiene habits have to be elaborated using various tools in the right manner to ensure better health of teeth and gums.

JUAL BELI TANAH YANG DILAKUKAN TANPA AKTA PPAT

2018 ◽  
Vol 4 (1) ◽  
pp. 89-107
Author(s):  
Cheri Bayuni Budjang
Keyword(s):  
Everyday Life ◽  
Government Regulation ◽  
Land Rights ◽  
The Other ◽  
Legal Certainty ◽  
Land Registration ◽  
The Future ◽  
The Right ◽  
Laws And Regulations

Buying and selling is a way to transfer land rights according to the provisions in Article 37 paragraph (1) of Government Regulation Number 24 of 1997 concerning Land Registration which must include the deed of the Land Deed Making Official to register the right of land rights (behind the name) to the Land Office to create legal certainty and minimize the risks that occur in the future. However, in everyday life there is still a lot of buying and selling land that is not based on the laws and regulations that apply, namely only by using receipts and trust in each other. This is certainly very detrimental to both parties in the transfer of rights (behind the name), especially if the other party is not known to exist like the Case in Decision Number 42 / Pdt.G / 2010 / PN.Mtp

Visual asymmetries during face encoding Increased dwell time and fixations in the upper and left hemifields

2018 ◽  
Author(s):  
Fatima Maria Felisberti
Keyword(s):  
Face Recognition ◽  
Eye Movements ◽  
Visual Field ◽  
Face Processing ◽  
Dwell Time ◽  
The Other ◽  
Environmental Cues ◽  
Reading Habits ◽  
The Right

Visual field asymmetries (VFA) in the encoding of groups rather than individual faces has been rarely investigated. Here, eye movements (dwell time (DT) and fixations (Fix)) were recorded during the encoding of three groups of four faces tagged with cheating, cooperative, or neutral behaviours. Faces in each of the three groups were placed in the upper left (UL), upper right (UR), lower left (LL), or lower right (LR) quadrants. Face recognition was equally high in the three groups. In contrast, the proportion of DT and Fix were higher for faces in the left than the right hemifield and in the upper rather than the lower hemifield. The overall time spent looking at the UL was higher than in the other quadrants. The findings are relevant to the understanding of VFA in face processing, especially groups of faces, and might be linked to environmental cues and/or reading habits.

Challenges of Media Education Standards in Georgia

2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Marine Vekua
Keyword(s):  
Working Conditions ◽  
Teaching Methods ◽  
International Standards ◽  
The Other ◽  
Historical Background ◽  
Journalism Education ◽  
Education Standards ◽  
Modern Media ◽  
The One ◽  
The Right

The main goal of this research is to determine whether the journalism education of the leading media schools inGeorgia is adequate to modern media market’s demands and challenges. The right answer to this main questionwas found after analyzing Georgian media market’s demands, on the one hand, and, on the other hand, differentaspects of journalism education in Georgia: the historical background, development trends, evaluation ofeducational programs and curricula designs, reflection of international standards in teaching methods, studyingand working conditions.

The Taubman/Golandsky Approach to the Violin

Public Voices ◽  
2016 ◽  
Vol 12 (2) ◽  
pp. 7
Author(s):  
Sophie Till
Keyword(s):  
The Other ◽  
Technical Approach ◽  
Piano Technique ◽  
Pedagogical Approach ◽  
New Developments ◽  
Body Of Knowledge ◽  
Music Making ◽  
Helping Others ◽  
The One ◽  
The Right

Three years ago Sophie Till started working with pianist Edna Golandsky, the leading exponent of the Taubman Piano Technique, an internationally acclaimed approach that is well known to pianists, on the one hand, for allowing pianists to attain a phenomenal level of virtuosity and on the other, for solving very serious piano-related injuries. Till, a violinist, quickly realized that here was a unique technical approach that could not only identify and itemize the minute movements that underlie a virtuoso technique but could show how these movements interact and go into music making at the highest level. Furthermore, through the work of the Golandsky Institute, she saw a pedagogical approach that had been developed to a remarkable depth and level of clarity. It was an approach that had the power to communicate in a way she had never seen before, despite her own first class violin training from the earliest age. While the geography and “look” on the violin are different from the piano, the laws governing coordinate motion specifically in playing the instrument are the same for pianists and violinists. As a result of Till’s work translating the technique for violin, a new pedagogical approach for violinists of all ages is emerging; the Taubman/Golandsky Approach to the Violin. In reflecting on these new developments, Edna Golandsky wrote, “I have been working with the Taubman Approach for more than 30 years and have worked regularly with other instrumentalists. However, Sophie Till was the first violinist who asked me to teach her with the same depth that I do with pianists. With her conceptual and intellectual agility as well as complete dedication to helping others, she has been the perfect partner to translate this body of knowledge for violinists. Through this collaboration, Sophie is helping develop a new ‘language’ for violinist that will prevent future problems, solve present ones and start beginners on the right road to becoming the best they can be. The implications of this new work for violinists are enormous.”

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