Physical exercise and cortical thickness in healthy controls: a pilot study.

OBJECTIVE: Physical exercise has showed potential in improving brain function and increase in cortical size. This study aims to assess the cortical changes that are associated with physical exercise. SUBJECTS AND METHODS: We investigated 45 subjects; 25 of them involved in exercise group and 20 in non-exercise group. The exercise group underwent 6 months of intervention consisting of 40 minutes (min) of aerobic exercise and 20 minutes of anaerobic exercise. Magnetic resonance imaging (MRI) scans were acquired from both groups to measure the thickness of the cortex and was assessed with FreeSurfer software. RESULTS: Exercise group demonstrated significantly increased cortical thickness in the left pericalcarine area, left superior parietal area, right rostral middle frontal and right lateral occipital gyrus compared to non-exercise group. CONCLUSIONS: Regular and continuous physical exercise can enhance brain structures. The current findings have important implications for understanding the effect of physical activity or fitness programs on the brains of healthy individuals and of patients with a range of conditions.

The effect of transcranial direct current stimulation combined with functional task training on motor recovery in stroke patients.

The field of neuromodulation encompasses a wide spectrum of interventional technologies that modify pathological activity within the nervous system to achieve a therapeutic effect. Therapy including transcranial direct current stimulation (tDCS) has all shown promising results across a range of neurological and neuropsychiatric disorders. This article reviews the state-of-the-art of neuromodulation for stroke and discusses the opportunities and challenges available for clinicians and researchers interested in advancing neuromodulation therapy. The annual worldwide incidence of stroke ranges from 27.5 to 63 individuals per 100,000. Stroke, a major cause of adult disability, has devastating effects on patients and their caregivers, which has a tremendous socioeconomic impact on families and healthcare systems around the world. There are only a few treatments available for the improvement of motor function in stroke patients. The majority of these treatments are based on functional motor learning (ML) strategies. Both the mechanisms underlying stroke recovery and the effectiveness of neurorehabilitation interventions still remain poorly understood for widespread implementation, although it strongly depends on the quality of rehabilitation service to reach maximal post-stroke recovery.

Kernohan's notch phenomenon demonstrated by diffusion tensor imaging and transcranial magnetic stimulation.

Kernohan's notch phenomenon is the ipsilateral hemiplegia caused by compression of the contralateral cerebral peduncle against the tentorial edge by a supratentorial mass. Diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS) could be useful for exploring the state of the corticospinal tract (CST). This report attempts to demonstrate Kernohan's notch phenomenon in a patient with subdural haematoma by using DTI and TMS. One patient and six normal control subjects were recruited. The patient showed severe right hemiplegia even though the subdural haematoma was located in the right hemisphere. Brain CT at the time of onset showed right transtentorial herniation, and T2 weighted images at 6 weeks after onset showed a leucomalacic lesion on the left cerebral peduncle. DTI and TMS were performed at 6 weeks after onset. The fractional anisotrophy value of the left midbrain and medulla of the patient was found to be decreased in comparison with that of the control subjects. On fibre tractography for the CST, an interruption was observed in the left midbrain and medulla. The motor evoked potential obtained from the right hand muscle showed delayed latency, low amplitude and a higher excitatory threshold, thus indicating that the CST of the left hemisphere had been damaged. It seems that the CST had been damaged at the left midbrain, although subdural haematoma and transtentorial herniation had occurred in the right hemisphere in this patient. This report demonstrates Kernohan's notch phenomenon in this patient using DTI and TMS.

Variations in meniscofemoral ligaments at anatomical study and MR imaging.

PURPOSE: To demonstrate variations in the meniscofemoral ligaments (ligaments of Wrisberg and Humphrey) at anatomical study and magnetic resonance (MR) imaging. DESIGN: Twenty-eight cadaveric knees were partially dissected for the examination of the meniscofemoral ligaments. One hundred knee MR examinations were reviewed by two experienced musculoskeletal radiologists. Proximal variations in the meniscofemoral ligaments at MR imaging were classified into three types according to the attachment site: type I, medial femoral condyle; type II, proximal half of the posterior cruciate ligament (PCL); type III, distal half of the PCL. Distal variations were classified into vertical or oblique types according to the orientation of the intermediate signal at the interface of the ligament and lateral meniscus. RESULTS: At anatomical study, six cases showed variations in the proximal insertion site of the meniscofemoral ligaments. At MR imaging 93 cases had one or more meniscofemoral ligaments, giving a total of 107 ligaments: 90 ligaments of Wrisberg and 17 ligaments of Humphrey. Forty-one ligaments of Wrisberg were type I, 28 type II, 19 type III, and with two indeterminate type, while 6 ligaments of Humphrey were type I and the remaining 11 were indeterminate. Seven cases showed no meniscofemoral ligament. Of the 107 meniscofemoral ligaments, the distal insertion orientation was of vertical type in 10 ligaments, oblique type in 70 and unidentified in 27. CONCLUSION: An understanding of the high incidence of meniscofemoral ligament variations may help in the interpretation of knee MR studies.

Anatomy and magnetic resonance imaging of the posterolateral structures of the knee.

The purpose of the present study was to provide detailed information of the morphological and radiological characteristics of the posterolateral structures of the knee. Muscles and ligaments of the posterolateral part of the knee were studied by dissections of 50 adult cadaver knees and by Magnetic Resonance Imaging (MRI) before and after dissections for comparisons. Diverse morphological characteristics of the arcuate ligament were found. The fabellofibular ligament was present in 42.1% of the knees dissected, whereas the popliteofibular ligament was found in 37.5%. A ligamentous structure, which could be called the posterior tibial ligament, was found in 31.6% of the cases that originated from the lateral part of the capsule proximally and inserted distally on the mid portion of the proximal tibia. By comparing the cross sections and the dissections of the cadaver knees, the popliteus muscle, the arcuate ligament, the fibular collateral ligament, the popliteofibular ligament, and the fabellofibular ligament could be identified in MRI. Comprehensive understanding of the posterolateral anatomy of the knee and improved identification of the structures in MRI will help clinicians to make a more accurate and noninvasive diagnosis of posterolateral instability.

Tendinous insertion of semimembranosus muscle into the lateral meniscus.

Forty-two cadaver knees were used for morphologic and MRI observations of the tendinous distal expansions of the semimembranosus m. and the posterior capsular structures of the knee. A tendinous branch of the semimembranosus m. inserting into the posterior horn of the lateral meniscus was found in 43.2% of the knees dissected, besides five already known insertional branches; capsular, direct, anterior and inferior, as well as the oblique popliteal ligament. The tendon had three morphologic types; thin, broad and round. All three types moved the lateral meniscus posteriorly when pulled on. Thus, the semimembranosus m. may also have a protective function for the lateral meniscus as well as the already well established function of protecting the medial meniscus in knee flexion. When a semimembranosus tendon attachment to the posterior horn of the lateral meniscus is present, its normal insertion is difficult to differentiate from a lateral meniscus tear in MRI and this may cause misdiagnosis.