Nodal GABA facilitates axon spike transmission in the spinal cord

SUMMARYGABA is an inhibitory neurotransmitter that produces both postsynaptic and presynaptic inhibition. We describe here an opposing excitatory action of GABA that facilitates spike transmission at nodes of Ranvier in myelinated sensory axons in the spinal cord. This nodal facilitation results from axonal GABAA receptors that depolarize nodes toward threshold, enabling spike propagation past the many branch points that otherwise fail, as observed in spinal cords isolated from mice or rats. Activation of GABAergic neurons, either directly with optogenetics or indirectly with cutaneous stimulation, caused nodal facilitation that increased sensory transmission to motoneurons without postsynaptically exciting motoneurons. This increased transmission with optogenetic or cutaneous stimulation also occurred in awake mice and humans. Optogenetic inhibition of GABAergic neurons decreased sensory transmission, implying that axonal conduction relies on GABA. The concept of nodal facilitation likely generalizes to other large axons in the CNS, enabling recruitment of selective branches and functional pathways.

Foot sole cutaneous stimulation mitigates neuromuscular fatigue during a sustained plantar flexor isometric task

Cutaneous coupling with lower limb motor neurons has long been known. We set out to establish whether this pathway could serve a purpose other than muscular modulation during standing and walking. We found that during a submaximal contraction of the plantar flexor muscles, the addition of intermittent cutaneous stimulation to the skin of the foot sole resulted in an increase in time to task failure by 15%, which was over a minute longer in duration. We conclude that skin stimulation may serve as a mechanism to mitigate fatigue.

Exploiting evolutionarily conserved pathways to promote plasticity of human spinal circuits

Humans evolved from species that walked on all 4 limbs, which means that experiments in quadrupeds can guide and support experiments in humans. This is particularly helpful for neural rehabilitation because the central nervous system is plastic in nature, meaning that activities promoting central nervous system activity can alter subsequent output properties. This is known as neuroplasticity and can be measured as changes in spinal cord excitability through reflexes as a proxy. By targeting evolutionarily conserved pathways that act on similar interneurons within the spinal cord to either increase or decrease excitability, it may be possible to preferentially modulate spinal cord excitability based on a desirable outcome. For example, rhythmic movement reduces spinal cord excitability whereas brief sensory input to cutaneous afferents increases spinal cord excitability. Alterations in spinal cord excitability have been shown to outlast the activity duration, suggesting that neuroplasticity is not transient. This evidence suggests that both rhythmic movement and sensory input can induce acute neuroplasticity of spinal cord excitability. The overall purpose of this dissertation was 2-fold: (i) to provide reviews of how evolutionarily conserved pathways are studied in humans and how they contribute to human rhythmic movement; and (ii) experimentally examine how these conserved pathways, which converge onto similar interneuron circuitry, can be exploited to cause bidirectional changes in spinal cord excitability. Reviews indicate that humans have retained characteristics of quadrupedal locomotion and, in particular, activity of the arms affects the excitability of the legs, and vice versa. Cutaneous input is integrated throughout the body during locomotion, such that cutaneous sensations elicit neuromechanical responses that are nerve-specific and modulated according to the phase of movement. In experiment 1, there was increased spinal cord excitability following patterned stimulation of cutaneous afferents innervating the bottom of the foot. In experiment 2, stimulation to cutaneous afferents innervating both the top and bottom of the foot amplified voluntary plantar- and dorsiflexion. In experiment 3, cervicolumbar connections were exploited to amplify plasticity in spinal cord excitability induced by rhythmic movement. Finally, in experiment 4, there were interactions of rhythmic movement and fatigue, which both reduce spinal cord excitability, with cutaneous stimulation, which increases spinal cord excitability, such that reductions in spinal cord excitability associated with fatigue were mitigated by cutaneous stimulation. Taken together, these experiments suggest that cutaneous stimulation can increase spinal cord excitability, whereas quadrupedal locomotor activity can decrease spinal cord excitability. These conserved pathways can be exploited to intentionally modify spinal cord excitability in a bidirectional fashion, which provides fruitful information for the exploration of rehabilitation and sport performance practices.

Nursing Process of Postoperative Children With Digestive Surgical Case in Children Surgical Ward

<p><strong>Objective: </strong>This scientific paper is aimed to provide an overview of nursing care post-operation in children with digestive surgery case as well as to provide an overview of the effect of non- pharmacological application of cutaneous stimulation cold application in reducing postoperative wound pain.</p><p><strong>Methods: </strong>One example of pain management interventions that can be done is cutaneous stimulation. This technique aims to divert the child's attention to the tactile stimuli provided and inhibits the transmission process and pain perception so as to decrease the pain scale of the child.</p><p><strong>Results: </strong>There were four nursing problems identified. They were acute pain, an imbalance of nutrients less than the body's needs, the risk of damage to the integrity of the skin, and the risk of infection.</p><p><strong>Conclusion: </strong>The main problem is acute pain. The results of the intervention after five days of treatment concluded that the use of cold application could meet the desired outcome criteria in acute postoperative pain nursing problems.</p><p> </p><p><strong>Keywords: </strong><em>child, digestive surgery, non pharmacologic, pain, postoperative</em></p>