Cortical mapping with navigated transcranial magnetic stimulation in low-grade glioma surgery

Transcranial magnetic stimulation (TMS) is a promising method for both investigation and therapeutic treatment of psychiatric and neurologic disorders and, more recently, for brain mapping. This study describes the application of navigated TMS for motor cortex mapping in patients with a brain tumor located close to the precentral gyrus. Materials and methods: In this prospective study, six patients with low-grade gliomas in or near the precentral gyrus underwent TMS, and their motor responses were correlated to locations in the cortex around the lesion, generating a functional map overlaid on three-dimensional magnetic resonance imaging (MRI) scans of the brain. To determine the accuracy of this new method, we compared TMS mapping with the gold standard mapping with direct cortical electrical stimulation in surgery. The same navigation system and TMS-generated map were used during the surgical resection procedure. Results: The motor cortex could be clearly mapped using both methods. The locations corresponding to the hand and forearm, found during intraoperative mapping, showed a close spatial relationship to the homotopic areas identified by TMS mapping. The mean distance between TMS and direct cortical electrical stimulation (DES) was 4.16 +/- 1.02 mm (range: 2.56-5.27 mm). Conclusion: Preoperative mapping of the motor cortex with navigated TMS prior to brain tumor resection is a useful presurgical planning tool with good accuracy.

Characterization of the motor performance in infants with a diagnosis of Cerebral Palsy in process of rehabilitation: the importance of the proactivity of caregivers

Introduction: The progress in technology, associated to the high survival rate in premature newborn infants in neonatal intensive care units, causes an increase in morbidity. Individuals with CP present complex motor alterations, with primary deficits of abnormal muscle tone affecting posture and voluntary movement, alteration of balance and coordination, decrease of force, and loss of selective motor control with secondary problems of contractures and bone deformities. Objective: The aim of this work is to describe the spontaneous movement and strategies that lead infants with cerebral palsy to move. Methods: Seven infants used to receive assistance at the Essential Stimulation Center of CIAM (Israeli Center for Multidisciplinary Support - Philanthropic Institution), with ages ranging between six and 18 months with diagnosis of Cerebral Palsy (CP) were assessed. Results: The results show the difficulty presented by the infants with respect to the spontaneous motor functions and the necessity of help from the caregiver in order to perform the functional activity (mobility). Prematurity prevails as the major risk factor among the complications. Conclusion: The child development can be understood as a product of the dynamic interactions involving the infant, the family, and the context. Thus, the social interactions and family environment in which the infant live may encourage or limit both the acquisition of skills and the functional independence.

Increased variability of motor cortical excitability to transcranial magnetic stimulation in migraine: a new clue to an old enigma

Increased, decreased or normal excitability to transcranial magnetic stimulation (TMS) has been reported in the motor (M1) and visual cortices of patients with migraine. Light deprivation (LD) has been reported to modulate M1 excitability in control subjects (CS). Still, effects of LD on M1 excitability compared to exposure to environmental light exposure (EL) had not been previously described in patients with migraine (MP). To further our knowledge about differences between CS and MP, regarding M1 excitability and effects of LD on M1 excitability, we opted for a novel approach by extending measurement conditions. We measured motor thresholds (MTs) to TMS, short-interval intracortical inhibition, and ratios between motor-evoked potential amplitudes and supramaximal M responses in MP and CS on two different days, before and after LD or EL. Motor thresholds significantly increased in MP in LD and EL sessions, and remained stable in CS. There were no significant between-group differences in other measures of TMS. Short-term variation of MTs was greater in MP compared to CS. Fluctuation in excitability over hours or days in MP is an issue that, until now, has been relatively neglected. The results presented here will help to reconcile conflicting observations.

The meristematic activity of the endodermis and the pericycle and its role in the primary thickening of stems in monocotyledonous plants

Background: It had long been thought that a lateral meristem, the so-called primary thickening meristem (PTM) was responsible for stem thickening in monocotyledons. Recent work has shown that primary thickening in the stems of monocotyledons is due to the meristematic activity of both the endodermis and the pericycle. Aims: The aim of this work is to answer a set of questions about the developmental anatomy of monocotyledonous plants: (1) Do the stem apices of monocots have a special meristematic tissue, the PTM? (2) Are the primary tissues of the stem the same as those of the root? (3) Is there good evidence for the formation of both the cortex and the vascular tissue from a single meristem, the PTM, in the shoot and from two distinguishable meristems in the root? (4) If the PTM forms only the cortex, what kind of meristem forms the vascular tissue? Methods: Light microscopy was used to examine stem and root anatomy in 16 species from 10 monocotyledonous families. Results: It was observed that radially aligned cortical cells extend outwards from endodermal initial cells in the cortex of the roots and the stems in all the species. The radial gradation in size observed indicates that the cortical cells are derivatives of a meristematic endodermis. In addition, perfect continuity was observed between the endodermis of the root and that of the stem. Meristematic activity in the pericycle gives rise to cauline vascular bundles composed of metaxylem and metaphloem. Conclusion: No evidence was obtained for the existence in monocotyledons of a PTM. Monocotyledons appear to resemble other vascular plants in this respect.