Search results for "CORTICAL EXCITABILITY"

Transcranial magnetic stimulation reveals cortical hyperexcitability in episodic cluster headache

2014

Abstract Evidence shows involvement of the cerebral cortex in the pathophysiology of cluster headache (CH). Here we investigated cortical excitability in episodic CH patients by using transcranial magnetic stimulation. In 25 patients with episodic CH and 13 healthy subjects we evaluated the motor cortical response to single-pulse (ie, motor threshold, input-output curves, cortical silent period) and paired-pulse (ie, intracortical facilitation, short intracortical inhibition) transcranial magnetic stimulation in both hemispheres. Thirteen patients were evaluated outside bout and the remaining 12 patients inside bout. Our results showed increased slope of the input-output curves after stimul…

The effects of estradiol levels on crossmodal perception: a study on the sound induced flash illusion in healthy and menstrually related migraine ind…

2023

Abstract Objective The sound-induced flash illusion (SIFI) is a valid paradigm to study multisensorial perception. In the “fission” SIFI, multiple flashes are perceived when observing a single flash paired with two or more beeps. SIFI is largely dependent on visual and acoustic cortex excitability; in migraine, dysfunctional cortical excitability affects SIFI perception. Since estrogen peak occurring during ovulation can increase neuronal excitability, the present study aims to verify whether cortical excitability shifts linked to the menstrual cycle could influence SIFI. Methods In a comparative prospective study, we tested the effect of estrogens on crossmodal perception using the SIFI. W…

Indicaxanthin is able to modulate human motor cortical excitability and plasticity

Modulation of excitatory and inhibitory circuits for visual awareness in the human right parietal cortex.

2005

The balance of specific patterns of excitation and inhibition in critical regions of both hemispheres could be relevant in orienting attention over the extrapersonal space. In the present study a group of normal subjects had to detect small rectangular stimuli presented briefly on a computer screen in three different conditions: unilateral presentation either to left or right visual periphery or bilateral simultaneous presentation. Paired transcranial magnetic stimulation (TMS), was applied over the right parietal cortex 150 ms after the presentation of the visual stimuli with different inter-stimulus intervals (ISIs: 1, 3,5 and 10 ms). When paired TMS was applied 150 ms, but not 100 ms, af…

Cannabinoids, TRPV and nitric oxide: the three ring circus of neuronal excitability

2019

Endocannabinoid system is considered a relevant player in the regulation of neuronal excitability, since it contributes to maintaining the balance of the synaptic ionic milieu. Perturbations to bioelectric conductances have been implicated in the pathophysiological processes leading to hyperexcitability and epileptic seizures. Cannabinoid influence on neurosignalling is exerted on classic receptor-mediated mechanisms or on further molecular targets. Among these, transient receptor potential vanilloid (TRPV) are ionic channels modulated by cannabinoids that are involved in the transduction of a plethora of stimuli and trigger fundamental downstream pathways in the post-synaptic site. In this…

Hyperexcitability of parietal-motor functional connections in the intact left-hemisphere of patients with neglect

2008

Hemispatial neglect is common after unilateral brain damage, particularly to perisylvian structures in the right-hemisphere (RH). In this disabling syndrome, behaviour and awareness are biased away from the contralesional side of space towards the ipsilesional side. Theoretical accounts of this in terms of hemispheric rivalry have speculated that the intact left-hemisphere (LH) may become hyper-excitable after a RH lesion, due to release of inhibition from the damaged hemisphere. We tested this directly using a novel twin-coil transcranial magnetic stimulation (TMS) approach to measure excitability within the intact LH of neglect patients. This involved applying a conditioning TMS pulse ove…

Migraine as a Cortical Brain Disorder

2020

Purpose Migraine is an exclusively human chronic disorder with ictal manifestations characterized by a multifaceted clinical complexity pointing to a cerebral cortical involvement. The present review is aimed to cover the clinical, neuroimaging, and neurophysiological literature on the role of the cerebral cortex in migraine pathophysiology. Overview Converging clinical scenarios, advanced neuroimaging data, and experimental neurophysiological findings, indicate that fluctuating excitability, plasticity, and metabolism of cortical neurons represent the pathophysiological substrate of the migraine cycle. Abnormal cortical responsivity and sensory processing coupled to a mismatch between the …

Orally administered indicaxanthin is able to modulate human motor cortical excitability and plasticity

Opuntia Ficus Indica contains Indicaxanthin (IX), an antinflammatory and antioxidant betalaine pigment. This phytochemical is also able to cross the blood brain barrier (BBB) in rats and modulate neuronal activity. Considering these evidence, we aimed at investigating if orally administered IX could affect human brain tissue. 8 healthy and right-handed male subjects were recruited (20-45 years) with no history or clinical signs of neurological diseases, brain trauma or use of drugs acting on neuronal process, as assessed by a clinical neurologist. Non invasive Brain Stimulation and Neuromodulation (NIBS and NIN) instructions were applied in basal condition (T0) and 2 hours after having assu…

Brain stimulation in migraine

2013

Migraine is a very prevalent disease with great individual disability and socioeconomic burden. Despite intensive research effort in recent years, the etiopathogenesis of the disease remains to be elucidated. Recently, much importance has been given to mechanisms underlying the cortical excitability that has been suggested to be dysfunctional in migraine. In recent years, noninvasive brain stimulation techniques based on magnetic fields (transcranial magnetic stimulation, TMS) and on direct electrical currents (transcranial direct current stimulation, tDCS) have been shown to be safe and effective tools to explore the issue of cortical excitability, activation, and plasticity in migraine. M…

Reward and punishment: investigating cortico-bulbar excitability to disclose the value of goods

2013

A continuing challenge for neuroscientists is to develop new conceptual tools and methodologies for understanding, predicting and modelling the influences of rewarding/punishing outcomes on human behaviour and decision making. Reinforcement shapes behaviours from the most primitive (fight/flight, ingest/regurgitate, approach/avoid) to complex (buy/sell). Understanding the neural processes underlying reinforcement is critical for understanding economic and social decision-making. Moreover, comprehension of deranged processing and responses to reinforcing stimuli is crucial across a range of psychology fields and society as a whole, including psychiatric and neurological illness, eating disor…