Several characteristic phenomena of excitability were found in the cardiac muscle during the relative refractory period when the excitability was studied by electrical stimulations with surface electrodes.According to BROOKS and his associates1,2,15)and subsequently by HOFFMAN et al.7,8),CRANEFIELD et al.3),and VAN Dum et al.20)the characteristic aspects of the excitability of cardiac muscles d...

Developmental dyslexia (decoding-based reading disorder; RD) is a complex trait with multifactorial origins at the genetic, neural, and cognitive levels. There is evidence that low-level sensory-processing deficits precede and underlie phonological problems, which are one of the best-documented aspects of RD. RD is also associated with impairments in integrating visual symbols with their corres...

Phosphene sensation is commonly used to measure cortical excitability during transcranial magnetic stimulation (TMS) of the occipital cortex. However, some individuals lack this perception, and the reason for it is still unknown. In this work, we used functional magnetic resonance imaging (fMRI) to detect brain activation during local TMS of the occipital cortex in twelve healthy subjects. We f...

The development of maximal velocity and power in muscle depends on the ability to transmit action potentials (AP) at very high frequencies up to about 400 Hz. However, for every AP there is a small loss of K(+) to the interstitium, which during intense exercise, may build up to a point where excitability is reduced, thus limiting the intensity of further exercise. It is still unknown how the mu...

Adult-born dentate granule neurons contribute to memory encoding functions of the dentate gyrus (DG) such as pattern separation. However, local circuit-mechanisms by which adult-born neurons partake in this process are poorly understood. Computational, neuroanatomical and electrophysiological studies suggest that sparseness of activation in the granule cell layer (GCL) is conducive for pattern ...

OBJECTIVE To evaluate the effects of several single TMS pulses, delivered at two different inter-trial intervals (ITIs), on corticospinal excitability. METHODS Twelve healthy volunteers participated in two experimental sessions, during which TMS pulses were delivered at random or at fixed ITIs. The TMS single pulse-induced modulation of corticospinal output (motor evoked potential amplitude -...

Small trabeculae of rabbit left atrium immersed in TKBa solution (Tyrode with 10 mM K+ and 1 mM Ba2+) were used to study frequency dependence of "membrane" slow response excitability at long cycle lengths (greater than 1 s). In TKBa, stimuli generate graded, low-amplitude (2-15 mV) subliminal responses of variable long duration (up to 450 ms). A full all-or-none slow response is generated when ...

The role of transcranial magnetic stimulation in epileptology is discussed in this article. Usefulness of TMS are discussed as a diagnostic tool in testing altered cortical excitability in patients with epilepsy and the modes of action of antiepileptic drugs, which are helpful to evaluate the pathophysiology of epilepsy. Also potential therapeutic tool in epilepsy with repetitive transcranial m...

OBJECTIVE To examine visual cortical excitability in persons with migraine using transcranial magnetic stimulation (TMS) over an extrastriate area of the brain, area V5. BACKGROUND Previous studies found that persons with migraine have a lower phosphene threshold than healthy control subjects with TMS delivered over the primary visual cortical area V1. The result suggests that the occipital c...

Prestimulation oscillatory phase and power in particular frequency bands predict perception of at-threshold visual stimuli and of transcranial magnetic stimulation (TMS)-induced phosphenes. These effects may be due to changes in cortical excitability, such that certain ranges of power and/or phase values result in a state in which a particular brain area is more receptive to input, thereby bias...