What is the significance of the withdrawal reflex

The onset period of our design was shorter than that of cocontraction of multiple muscles achieved by functional electrical stimulation [ 20 ]. In this way, successive needle-pricking appears to promote the recovery of lower extremity motor function in a shorter time.

For the MAS, hip flexion was significantly improved in the intervention group than that in the control group after six days of treatment. The improvement of hip flexion is beneficial for patients, as it alleviates extensor spasms and prevents venous thrombosis. The strength of the lower limb muscles has an important impact on the balance and walking function in patients with poststroke hemiplegia [ 21 ].

Hip extension and knee flexion significantly improved in the intervention group compared with the control group at D3 , which conforms to the classic neurodevelopmental theory in that the recovery speed of proximal joints is faster than that of the distal joints. However, manual measurement may result in some error; thus, in further clinical trials, indicators such as electromyography should be added. Safety is a basic principle for clinical therapeutic methods.

Acupuncture is a traditional Chinese medicine practice in which thin needles are inserted into the body. It addresses the energy Qi in the meridian, but from a neurophysiological perspective, it also acts as mechanical stimulation.

Acupuncture has been used for poststroke paralysis. Mounting evidence has demonstrated the safety of acupuncture. In this study, needle-pricking involved inserting the tip of the needle to no more than the subcutaneous level. After the intervention, the acupuncturist strictly sanitised the corresponding irritated part. Patients may occasionally experience petechiae during the course of treatment but do not exhibit more marked adverse events, such as hematoma and numbness caused by effects on the peripheral nerves.

Our study had some limitations. The sample size was small 35 cases. The study period was relatively short and did not include long-term follow-up observations. There was a degree of subjectivity in the measurements conducted by the evaluator. Conventional rehabilitation treatment may have created a certain bias in this study. However, these factors do not affect the rapidity of recovery and the changes in the FMA score of poststroke patients. In conclusion, successive needle-pricking on the plantar and dorsal aspects of the foot is effective for promoting muscle strength, balance ability, and voluntary movement in patients with poststroke hemiplegia.

The results of this study warrant further implementation of this safe and convenient treatment in the clinic. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Article of the Year Award: Outstanding research contributions of , as selected by our Chief Editors. Read the winning articles. Journal overview. Special Issues. Academic Editor: Manel Santafe. Received 17 Jun Revised 09 Aug Accepted 17 Aug Published 31 Aug Abstract The withdrawal reflex is a defensive reaction to nociceptive stimuli and can be used to regulate locomotor gait during rehabilitation. Introduction Stroke is a common cerebrovascular disease, characterised by high disability and mortality; it threatens the health of patients and increases the social burden [ 1 ].

Methods 2. Figure 1. Figure 2. The dotted line represents the direction of the evoked movement. Table 1. Treatment time day U value value After 3 days D3 Table 2. Comparison of the Brunnstrom stage Ueda assessment of the lower limb between the two study groups at D3 and D6. Table 3. Figure 3. Table 4. Figure 4. For hip extension and knee flexion, the contralateral position was used.

Table 5. Table 6. References A. Thrift, T. Thayabaranathan, G. Howard et al. Pundik, J. McCabe, M. Skelly, C. Tatsuoka, and J. Derderian and P. View at: Google Scholar J. Schouenborg and J.

The remaining ganglia were removed from the body cavity to euthanize the animal, and these unneeded ganglia and tissues were discarded. The pins were positioned in the reduced tail preparation to minimize tail contraction following mechanical and electrical stimulation. Tail MN responses to mechanical tail stimulation were monitored before, during, and after habituation training in intact tail-ganglia preparations to determine aging effects.

Three pre-training tests were recorded and the baseline response was calculated from their average. Habituation training consisted of 30 tail taps at 30 s ISI same as described above for behavioral experiment in intact animals. Post-test responses were then evoked at 5, 10, and 15 min after training. The latency between tail shock and initiation of the first evoked AP was measured in mature and aged II preparations. The distance between SN somata and the position of shock delivery on the tail was measured with calipers and used to calculate the approximate conduction velocity in nerve P9.

The pipette solution for intracellular recordings in intact ganglia consisted of 3 M KCl. All reagents were from Sigma-Aldrich St. Significant differences, such as that occurring during habituation training, were determined by one-way within subjects repeated-measures ANOVA. Comparisons of mature and aged II responses were made using 2-sample t -tests. All analyses were performed using the open source R statistical program Vienna, Austria.

The median lifespans of the two cohorts studied were and days. Animals were sexually mature by age 7 months. Morphological and aging characteristics were as described in a previous study Kempsell and Fieber, In our previous studies Kempsell and Fieber, , a , b , we established that baseline TWR amplitude in these cohorts was significantly weaker mature: 8.

Prior studies in Aplysia demonstrated that habituation training results in decreased TWR amplitude and duration Carew et al. Aging significantly affected habituation. In the same animals tested when they reached stage aged II, TWR amplitude and duration did not change significantly from baseline during habituation training or in post-tests. Figure 1. Habituation in the TWR was disrupted during aging. In the same animals at stage aged II, training did not change TWR amplitude during training or in post-tests.

B TWR duration decreased significantly during habituation training in mature animals and remained habituated at 5 and 10 min post-tests. AP duration mature: 3.

AHP amplitude in tail SN also was not different mature: 4. Habituation training was demonstrated to decrease excitability in Aplysia MN Castellucci et al. To determine whether aging affected this phenomenon, MN excitability, quantified as the number of AP fired during ms tail tap, was evaluated in mature and aged II reduced tail preparations before and after habituation training Figure 2A.

Figure 2. Aging affects tail MN response following habituation training. Training in mature preparations reduced response to tail tap, but aged II preparations were unaffected, as summarized in C. B Baseline excitability of tail MN to tail tap decreased significantly during aging. Studies in vertebrate models have shown that conduction velocity, the speed at which AP travel down the axon, decreased during aging in processes of neocortical, cerebellar, and peripheral sensory and motor neurons Rogers et al.

We investigated whether conduction velocity between mechanoreceptive field on the tail and SN soma changed during aging by measuring the latency between tail shock and AP discharge in tail SN. Conduction velocity was 1.

Figure 3. Conduction velocity decreased during aging in tail SN. B The latency between tail shock and initiation of the first evoked AP increased significantly in aged II. C Conduction velocity in nerve P9 decreased significantly during aging. This study focused on age-related memory loss in the Aplysia model that builds on previous studies demonstrating that a SN-MN circuit such as for TWR is useful for understanding aging mechanisms in the nervous system.

Failure to habituate in aged animals is a part of a continuum of aging declines noted in the intact TWR that coincide with concomitant changes in tail SN and MN excitability compared to that of younger sibling animals Fieber et al.

The TWR of intact animals declined in amplitude and slowed in duration during aging, and had related neural correlates. Baseline tail MN excitability was significantly lower in aged animals, both in our prior work and in these experiments, as reported in other animals Landfield and Pitler, ; Kerr et al. This decreased baseline excitability may provide the explanation for habituation failure of TWR, because it might mean that the scope for further synaptic depression in tail MN that should have occurred during habituation was already reached during aging, and could not be further reduced.

The failure of habituation training to induce synaptic depression in aged tail MN also suggests impairment of modulation of the TWR neural circuit responsible for habituation. Conduction velocity in the tail nerve decreased, suggesting that aging negatively affects multiple aspects of tail SN-MN synaptic transmission.

Decreased excitability of both SN and MN as well as reduced transmission between them may underlie the age-related deficits in learning and memory observed in this study and others Kempsell and Fieber, b. The absence of habituation in TWR in aged animals suggested that at least some forms of nonassociative learning are compromised during aging.

Habituation failure in aged Aplysia correlates well with other aging studies in this organism that found changes in habituation of the gill-siphon withdrawal reflex and changes in forms of short-term memory for sensitization in TWR Rattan and Peretz, ; Kempsell and Fieber, b. It was recently reported that cultured SN of aged Aplysia that form synaptic connections with MN have both reduced recovery from synaptic depression and reduced protein kinase C activation after exogenous serotonin Dunn and Sossin, , providing additional evidence of age-related changes in the TWR circuit responsible for habituation of the reflex.

Furthermore, two studies that found that protein kinase activation rescued performance of aged SN and MN in the TWR circuit Dunn and Sossin, ; Kempsell and Fieber, a , suggested age-related impairment of the signal transduction pathway upstream of protein kinase activation.

Conduction velocity in afferent fibers decreased in aged animals, consistent with mammalian studies indicating reduced conduction velocity in processes of neocortical, cerebellar, and peripheral sensory and motor neurons Barnes et al. This increase in the latency of transmission between mechanoreceptive fields on the tail and tail SN may cause impairments in the temporal processing of sensory information during aging, contributing to declines in memory for habituation.

The parallels between Aplysia and vertebrate neurophysiologies support the prospect that Aplysia aging studies may identify molecular targets with therapeutic potential in age-related memory failure.

The connection between behavior and the cellular communication accessible by studies of membrane excitability and receptor physiology is most direct in animal models with simple brains. Habituation training failed to induce behavioral habituation or related depression of tail MN excitability in aged sea hares, suggesting that this form of nonassociative learning is compromised in aged Aplysia , as in other animal models Fraley and Springer, ; Leussis and Bolivar, Loss of modulation of the TWR circuit in aged animals was correlated with failure to habituate.

The study was executed by ATK. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

We gratefully acknowledge assistance from the staff of the University of Miami Aplysia Resource. Aston-Jones, G. Age-impaired impulse flow from nucleus basalis to cortex. Nature , — Barnes, C. Effects of aging on the dynamics of information processing and synaptic weight changes in the mammalian hippocampus.

It is a monosynaptic reflex that provides automatic regulation of skeletal muscle length. When a muscle lengthens, the muscle spindle is stretched and its nerve activity increases. This increases alpha motor neuron activity, causing the muscle fibers to contract and thus resist the stretching.

A secondary set of neurons also causes the opposing muscle to relax. The reflex functions to maintain the muscle at a constant length. The Golgi tendon reflex is a normal component of the reflex arc of the peripheral nervous system. The tendon reflex operates as a feedback mechanism to control muscle tension by causing muscle relaxation before muscle force becomes so great that tendons might be torn. Although the tendon reflex is less sensitive than the stretch reflex, it can override the stretch reflex when tension is great, making you drop a very heavy weight, for example.

Like the stretch reflex, the tendon reflex is ipsilateral. The sensory receptors for this reflex are called Golgi tendon receptors, and lie within a tendon near its junction with a muscle. In contrast to muscle spindles, which are sensitive to changes in muscle length, tendon organs detect and respond to changes in muscle tension that are caused by a passive stretch or muscular contraction.

Jendrassik maneuver : The Jendrassik maneuver is a medical maneuver wherein the patient flexes both sets of fingers into a hook-like form and interlocks those sets of fingers together note the hands of the patient in the chair. This maneuver is used often when testing the patellar reflex, as it forces the patient to concentrate on the interlocking of the fingers and prevents conscious inhibition or influence of the reflex. The crossed extensor reflex is a withdrawal reflex. The reflex occurs when the flexors in the withdrawing limb contract and the extensors relax, while in the other limb, the opposite occurs.

An example of this is when a person steps on a nail, the leg that is stepping on the nail pulls away, while the other leg takes the weight of the whole body. The crossed extensor reflex is contralateral, meaning the reflex occurs on the opposite side of the body from the stimulus. To produce this reflex, branches of the afferent nerve fibers cross from the stimulated side of the body to the contralateral side of the spinal cord.

There, they synapse with interneurons, which in turn, excite or inhibit alpha motor neurons to the muscles of the contralateral limb. The withdrawal reflex nociceptive or flexor withdrawal reflex is a spinal reflex intended to protect the body from damaging stimuli.

It is polysynaptic, and causes the stimulation of sensory, association, and motor neurons. When a person touches a hot object and withdraws his hand from it without thinking about it, the heat stimulates temperature and danger receptors in the skin, triggering a sensory impulse that travels to the central nervous system.

The sensory neuron then synapses with interneurons that connect to motor neurons. Some of these send motor impulses to the flexors to allow withdrawal. Some motor neurons send inhibitory impulses to the extensors so flexion is not inhibited—this is referred to as reciprocal innervation. Although this is a reflex, there are two interesting aspects to it:. Golgi tendon organ : The Golgi tendon organ, responsible for the Golgi tendon reflex, is diagrammed with its typical position in a muscle left , neuronal connections in spinal cord middle , and expanded schematic right.