Neuronal activation of cerebellum functional circuits in motor and non-motor functions in mice.

The cerebellum is involved in the control of balance, movement and the acquisition of motor skills. Scientific and technological advances have shown that the cerebellum also participates in non-motor functions, such as emotional control, memory and language. However, which cerebellar areas and functional circuits are predominantly activated in these different functions is not known. The current study analyzed the neuronal activation of cerebellar areas and other brain structures (e.g., hippocampus, amygdala, prelimbic cortex and infralimbic cortex) after exposure to rotarod and inhibitory avoidance behavioral models to establish possible neuronal circuits for motor and non-motor functions. Naïve male Swiss albino mice weighing 25 to 35 g were used. The animals were subjected to three conditions for behavioral evaluation: inhibitory avoidance, which is a model used to infer emotional memory; rotarod, which assesses motor performance and motor learning; and housing box/control. The mice remained in their housing box in Condition 1. Mice in Condition 2 were exposed to the inhibitory avoidance box for 2 days, and mice in Condition 3 were exposed to the rotarod for 3 days. The animals were euthanized after the last exposure to the apparatus then perfused with paraformaldehyde. Brains were extracted and sectioned for immunofluorescence analysis of c-Fos protein in pre-established structures. Images of the brain structures were obtained, and neuronal activation was analyzed microscopically. One-way analysis of variance was used, followed by Tukey's post-hoc test. There was no significant difference in c-Fos expression in lobe VI of the cerebellum between the different conditions. Differences in c-Fos expression were observed in the basolateral amygdala, infralimbic cortex and prelimbic cortex, which are relevant to emotional processes, after exposure to the evaluation apparatuses. Pearson's r correlation coefficient test showed a positive correlation between the variables of structures related to emotional processes. We concluded that there was no significant difference in c-Fos expression in lobe VI of the cerebellum after exposure of the animals to the evaluation apparatus. However, there was a difference in c-Fos expression in other brain structures related to emotional processes after exposure of animals to the apparatus.

Joint position sense is bilaterally reduced for shoulder abduction and flexion in chronic hemiparetic individuals.

BACKGROUND: The stroke is the leading cause of adult disability in the world. One of the main complaints of individuals post-stroke refers to the loss of function of the upper limb, as evidenced during the performance of activities of daily living. This difficulty may be related to an important component of sensorimotor control, joint position sense, a submodality of proprioception. OBJECTIVES: To investigate whether the proprioception of both shoulders of chronic hemiparetic patients is altered during abduction and flexion. METHODS: Thirteen subjects with chronic hemiparesis due to ischemic stroke and 13 healthy subjects matched for gender and age was included. The joint sense position was assessed using a dynamometer. Absolute error for shoulder abduction and flexion at the 30 and 60° was calculated. RESULTS: No difference was found between the paretic and non-paretic limbs in movements at both 30 and 60°. Higher values of absolute error for both paretic and non-paretic limbs compared to the control were observed during abduction at 30 and at 60°. CONCLUSIONS: Chronic ischemic post-stroke patients have bilateral proprioceptive deficits in the shoulder during abduction and flexion. But these deficits are dependent on the movement performed and the angle tested. The results demonstrate the need to include bilateral exercises and/or visual feedback in the rehabilitation program.

Intrinsic properties and functional changes in spastic muscle after application of BTX-A in children with cerebral palsy: systematic review.

OBJECTIVE: This article aimed to review the literature to verify the effect of botulinum toxin type A (BTX-A) on the intrinsic properties of spastic muscles and functionality in children with cerebral palsy (CP). METHODS: A literature search was conducted in the following databases: CINAHL, SCOPUS, Web of Science and PubMed. Database searches were limited to the period from January 1993 to March 2014. RESULTS: A total of 2182 papers were identified, and 17 met the inclusion criteria. Only one study analyzed the effect of the toxin on muscle intrinsic properties and others analyzed the effect on functionality. CONCLUSION: BTX-A application demonstrated no changes in the passive stiffness of spastic muscle. In relation to functional level, the evidence of BTX-A effect was controversial. These studies showed methodological quality limitations that restrict the interpretation of the results for the entire CP population, which justifies the need for further randomized controlled trials.

Muscle atrophy, voluntary activation disturbances, and low serum concentrations of IGF-1 and IGFBP-3 are associated with weakness in people with chronic stroke.

BACKGROUND: The muscle weakness that is exhibited poststroke is due to a multifactorial etiology involving the central nervous system and skeletal muscle changes. Insulinlike growth factor 1 (IGF-1) and IGF binding protein 3 (IGFBP-3) have been described as biomarkers of neuromuscular performance in many conditions. However, no information about these biomarkers is available for people with chronic hemiparesis. OBJECTIVE: The purpose of this study was to investigate possible factors involved in muscle weakness, such as IGF-1 and IGFBP-3 serum concentrations, muscle volume, and neuromuscular performance of the knee flexors and extensors, in people with chronic hemiparesis poststroke. DESIGN: This was a cross-sectional study. METHODS: A cross-sectional study was performed on 14 individuals poststroke who were paired with healthy controls. Mobility, function, balance, and quality of life were recorded as outcome measures. Knee flexor and extensor muscle volumes and neuromuscular performance were measured using nuclear magnetic resonance imaging, dynamometry, and electromyography. The serum concentrations of IGF-1 and IGFBP-3 were quantified by enzyme-linked immunosorbent assay (ELISA). RESULTS: The hemiparetic group had low serum concentrations of IGF-1 (25%) and IGFBP-3 (40%); reduced muscle volume in the vastus medialis (32%), vastus intermedius (29%), biceps femoris (16%), and semitendinosus and semimembranosus (12%) muscles; reduced peak torque, power, and work of the knee flexors and extensors; and altered agonist and antagonist muscle activation compared with controls. CONCLUSIONS: Low serum concentrations of IGF-1 and IGFBP-3, deficits in neuromuscular performance, selective muscle atrophy, and decreased agonist muscle activation were found in the group with chronic hemiparesis poststroke. Both hemorrhagic and ischemic stroke were considered, and the data reflect a chronic poststroke population with good function.