Higher Brain Areas Involved in Respiratory Control
Alan D. Miller, Armand L. Bianchi, Beverly P. Bishop in Neural Control of the Respiratory Muscles, 2019
Some of the most common respiratory disorders, such as asthma and obstructive sleep apnea, are characterized by increased resistance to airflow. The motor and afferent activity in brain regions responding to such resistance challenges can be visualized with fMRI techniques. Integration of activity associated with inspiratory loading activates rostral, midbrain, ventral medullary, and cerebellar structures (Figure 3).17 These areas include the putamen, anterior hypothalamus, interpeduncular nucleus, parabrachial and basal pons, locus coeruleus, and distinct portions of the cerebellum (culmen and central portion of vermis, and tuber and uvula of vermis). Brain areas activated by expiratory loading additionally include the ventral medulla, in addition to cerebellar, pontine, and rostral sites.18 Rapid off-transients accompany removal of loads, and reapplication of a load results in accommodation of the signal, i.e., the signal is smaller on reapplication. If the loads are sustained, the fMRI signal progressively decreases. The accommodation of the signal to the load suggests a neural adaptation process.
Specificity of Training Effects on Control Functions and the Connective Tissue
Atko Viru in Adaptation in Sports Training, 2017
Neural adaptation takes place at the level of spinal motoneurons as well as at higher levels of the central nervous system. The existence of neural adaptation explains why (1) the changes in cross-sectional area of muscle fibers are much smaller than the changes in maximal force production,15,18 (2) training-induced increases in voluntary strength may occur without increases in twitch and tetanic tension evoked by electrical stimulation,19 (3) training of one limb causes increases in strength of the contralateral limb (see p. 189–190), and (4) a specificity of training effects exists; increases in voluntary strength are specific to the movement pattern,20,21 joint position,22 contraction type,23,24 and movement velocity20,25,26 used in training.
Clinical Management of Spasticity and Contractures in Spinal Cord Injury
Anand D. Pandyan, Hermie J. Hermens, Bernard A. Conway in Neurological Rehabilitation, 2018
There is more human experimental data supporting the idea that spasticity involves synaptic mechanisms such as recurrent inhibition [25], reduction in Ia-reciprocal inhibition [26,27], and reciprocal inhibition of flexor reflex afferents [28]. In summary, changes of motoneuron and interneuron plasticity are assumed to play a significant role in spinal spasticity, which early after an SCI are thought related to postsynaptic mechanisms such as receptor up-regulation, and later during the recovery phase would be associated primarily with pre-synaptic mechanisms [1,9,29]. However, these changes are not observed immediately after spinal trauma. They evolve with time, suggesting gradual changes of neural adaptation following SCI.
Auditory brainstem responses obtained with randomised stimulation level
Published in International Journal of Audiology, 2023
Marta Martinez, Joaquin T. Valderrama, Isaac M. Alvarez, Angel de la Torre, Jose L. Vargas
The present study also evaluated the hearing comfort of the proposed stimulation strategy. Hearing comfort is a critical variable for the success of the test session, particularly in newborns and infants, since hearing discomfort may prevent them from remaining quiet and still during the test (Diefendorf, 2014). In most instances, the auditory stimulus is found unpleasant when abrupt changes of sound are presented (e.g. the sudden presentation of a high sound level; Pitchforth, 2010); however, the continuous presentation of a particular auditory stimulus pattern is easier to inhibit due to two mechanisms: (i) neural adaptation – a decrease in the activity pattern when a continuous stimulus is presented (Thornton and Coleman, 1975; Gillespie and Muller, 2009); and (ii) habituation – a cognitive process associated with selective attention which enables filtering out non-essential stimuli by decreasing the response to a stimulus after prolonged presentations of that stimulus (Rankin et al., 2009; Thompson, 2009). Since the proposed stimulus paradigm consists of a stimulus pattern repeated all along the test session, we predicted that this auditory stimulus would be easier to inhibit, and that the general population would report higher levels of hearing comfort. Furthermore, we also anticipated that due to the adaptation and habituation mechanisms described in the literature, RSL and the conventional paradigm would elicit auditory evoked potentials of different morphology.
Good Visual Performance Despite Reduced Optical Quality during the First Month of Orthokeratology Lens Wear
Published in Current Eye Research, 2020
Ruijing Xia, Binbin Su, Hua Bi, Jiaze Tang, Zhiyi Lin, Bin Zhang, Jun Jiang
Shape perception is believed to be mediated by a population of curvature-sensitive cells in the V4 area of the visual cortex.59–62 The extreme sensitivity of subjects to these radial deformations (as low as 2–4 arc sec) points to the global pooling of contour information at intermediate levels of form vision.25 RF patterns are an useful stimuli class for studying global integration across all modulation cycles both psychophysically and physiologically.25,63 It is well-known that the maturation of the higher-level visual cortex occurs later than that of the lower cortical areas.64–66 Meanwhile, shape perception ability is decreased by normal aging process in adults.67 Prolonged maturational time course for global visual function may account for the high plasticity and swift neural adaptation. Previous studies have reported neural adaptation to existing or imposed optical aberration in normal adults,68–70 and adults undergoing orthokeratology lens treatment.20 Our results demonstrated that the similar neural adaptation exists in children. Moreover, it is as complete and as swift in adults. In both adults and children, the subjective performance is not different from baseline 7 days after the initial lens wear.
Effects of a 12-month task-specific balance training on the balance status of stroke survivors with and without cognitive impairments in Selected Hospitals in Nnewi, Anambra State, Nigeria
Published in Topics in Stroke Rehabilitation, 2018
Uchenna Prosper Okonkwo, Sam Chidi Ibeneme, Ebere Yvonne Ihegihu, Afamefuna Victor Egwuonwu, Charles Ikechukwu Ezema, Fatai Adesina Maruf
The study explored the efficacy of a TSBT, which is a complex combination of progressive goal-oriented systems to train balance control in a long-term rehabilitation program amongst CI and NCI stroke survivors. The findings of the present study showed that there were significant improvement in the balance control of CI stroke survivors at 4 month, and other time points after TSBT intervention with large effect size of 0.690. Similarly, there were significant improvements in the balance control of NCI stroke survivors at 4th month, 8th month and 12th month after TSBT intervention with large effect size 0.544. Interestingly, the two groups have the highest percentage mean change between the baseline and 4th month and the least percentage mean change between 8th month and 12th month. The results of the study also revealed there were clinically significant improvements within the two groups across all stages of the intervention outcome assessment. This may be explained by a combination of factors such as cortical reorganization and neural adaptation or neuroplasticity. Since all participants of this study were sub-acute (3-6 months duration) stroke survivors before recruitment to the study; thus, the contribution of automatic (physiological responses) recovery to the observed results beyond 6 months is less likely.
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