Search results for "motor cortex"

Neuromodulation of chronic headaches: position statement from the European Headache Federation

2013

The medical treatment of patients with chronic primary headache syndromes (chronic migraine, chronic tension-type headache, chronic cluster headache, hemicrania continua) is challenging as serious side effects frequently complicate the course of medical treatment and some patients may be even medically intractable. When a definitive lack of responsiveness to conservative treatments is ascertained and medication overuse headache is excluded, neuromodulation options can be considered in selected cases.Here, the various invasive and non-invasive approaches, such as hypothalamic deep brain stimulation, occipital nerve stimulation, stimulation of sphenopalatine ganglion, cervical spinal cord sti…

P 56 tDCS shows no effects on motor cortex excitability at rest

2017

Introduction Transcranial direct current stimulation (tDCS) is a widely used technique in research and clinics. However, the underlying physiological mechanisms are not yet clear. Modeling studies suggest that the electric field during tDCS is dominated by a tangential component which predominantly modifies active synaptic connections ( Radman et al., 2007 ). We have previously shown that tDCS with an increased tangential compared to the conventional montage introduced by Nitsche and Paulus (2000) , suppresses the effects of paired associative stimulation of the supplementary motor area and the primary motor cortex (PASSMA-M1) independent of tDCS polarity (Faber et al., under submission). H…

Transcranial Magnetic Stimulation as a Tool to Study the Role of the Motor Cortex in Human Muscle Function

2010

Meta-analytical definition and functional connectivity of the human vestibular cortex.

2012

Contrary to most other sensory systems, no consensus has been reached within the scientific community about the exact locations and functions of human cortical areas processing vestibular information. Metaanalytical modelling using activation likelihood estimation (ALE) for the integration of neuroimaging results has already been successfully applied to several distinct tasks, thereby revealing the cortical localization of cognitive functions. We used the same algorithm and technique with all available and suitable PET and fMRI studies employing a vestibular stimulus. Most consistently across 28 experiments vestibular stimuli evoked activity in the right hemispheric parietal opercular area …

Modulation of cortical motor outputs by the symbolic meaning of visual stimuli

2010

The observation of an action modulates motor cortical outputs in specific ways, in part through mediation of the mirror neuron system. Sometimes we infer a meaning to an observed action based on integration of the actual percept with memories. Here, we conducted a series of experiments in healthy adults to investigate whether such inferred meanings can also modulate motor cortical outputs in specific ways. We show that brief observation of a neutral stimulus mimicking a hand does not significantly modulate motor cortical excitability (Study 1) although, after prolonged exposure, it can lead to a relatively nonspecific modulation (Study 2). However, when such a neutral stimulus is preceded b…

Suppression of extinction with TMS in humans: from healthy controls to patients.

2006

We review a series of studies exemplifying some applications of single-pulse and paired-transcranial magnetic stimulation (TMS) in the study of spatial attention and of its deficits. We will focus primarily on sensory extinction, the failure to consciously perceive a contralesional sensory stimulus only during bilateral stimulation of homologous surfaces. TMS studies in healthy controls show that it is possible either to interfere or modulate the excitability of the parietal cortex during sensory (i.e. tactile and visual) attentional tasks, thus reproducing a condition of virtual extinction. TMS studies in patients with unilateral (mainly right) brain damage show that the modulation of the …

Weakness and focal sensory deficits in the postictal state.

2010

Postictal motor deficits may occur in patients following partial and generalized tonic-clonic seizures. Frequency is unclear, epidemiology being hampered by heterogeneous populations and variable methods of detection. Postictal paresis may affect any body part, may be bilateral, and may occur more frequently in seizures involving the sensorimotor cortex. Duration varies depending on the precise mode of testing from a few minutes to 36 hours. Sensory deficits following seizures have been rarely reported but may be missed if not specifically tested for. The lateralizing value of postical paresis is high (>90%), pointing to a seizure origin in the opposite frontal lobe. Postictal paresis often…

Topical Review: Functional Anatomy of Human Hippocampal Formation and Related Structures

1996

Data on the internal organization, and neuronal connections of the human hippocampal formation and related structures of the limbic system are briefly reviewed. In the healthy brain, somatosensory, visual, and auditory input proceeds through neocortical core and belt fields to a variety of association areas, and from here the data is transported via long cortico-cortical pathways to the extended prefrontal association cortex. Tracts generated from this highest organizational level of the brain guide the data via the frontal belt (premotor cortex) to the frontal core (primary motor area). The striatal and cerebellar loops provide the major routes for this data transfer. The main components o…

Continuous Theta-Burst Stimulation Intensity Dependently Facilitates Motor-Evoked Potentials Following Focal Electrical Stimulation of the Rat Motor …

2020

Although theta-burst stimulation (TBS) is known to differentially modify motor cortical excitability according to stimulus conditions in humans, whether similar effects can be seen in animals, in particular rats, remains to be defined. Given the importance of experimental rat models for humans, this study explored this stimulation paradigm in rats. Specifically, this study aimed to explore corticospinal excitability after TBS in anesthetized animals to confirm its comparability with human results. Both inhibition-facilitation configurations using paired electrical stimulation protocols and the effects of the TBS paradigm on motor-evoked potentials (MEPs) in rat descending motor pathways wer…

Extremely Low Frequency Magnetic Fields Do Not Affect LTP-Like Plasticity in Healthy Humans.

2020

Introduction: Several studies explored, in vitro, the biological effects of extremely low-frequency magnetic fields (ELF-MFs) and reported the induction of functional changes in neuronal activity. In particular, ELF-MFs can influence synaptic plasticity both in-vitro and in animal models. Indeed, some studies reported an increase in long-term potentiation (LTP) whereas others suggested its reduction. However, no specific study has investigated such effect in humans. Aims: To evaluate whether ELF-MFs affect the propensity of the human cortex to undergo LTP-like plasticity. Methods: We designed a randomized, single-blind, sham-controlled, cross-over study on 10 healthy subjects. Cortical plas…