Objectives: The time series of single trial cortical evoked potentials typically have a random appearance, and their trial-to-trial variability is commonly explained by a model in which random ongoing background noise activity is linearly combined with a stereotyped evoked response. In this paper, we demonstrate that more realistic models, incorporating amplitude and latency variability of the ...

while most tinnitus cases have some degree of hearing impairment, a small percent of the patients admitted to ear, nose and throat clinics or hearing evaluation centers are those who complain of tinnitus despite having normal hearing thresholds. present study was performed in order to better understanding of the probable causes of tinnitus and to investigate possible changes in the cochlear and...

Selective attention decreases trial-to-trial variability in cortical auditory-evoked activity. This effect increases over the course of maturation, potentially reflecting the gradual development of selective attention and inhibitory control. Work in adults indicates that music training may alter the development of this neural response characteristic, especially over brain regions associated wit...

Modern non-invasive brain imaging techniques utilize changes in cerebral blood flow, volume and oxygenation that accompany brain activation. However, stimulus-evoked hemodynamic responses display considerable inter-trial variability even when identical stimuli are presented and the sources of this variability are poorly understood. One of the sources of this response variation could be ongoing ...

Magnetic- and electric-evoked brain responses have traditionally been analyzed by comparing the peaks or mean amplitudes of signals from selected channels and averaged across trials. More recently, tools have been developed to investigate single trial response variability (e.g., EEGLAB) and to test differences between averaged evoked responses over the entire scalp and time dimensions (e.g., SP...

Evoked activity in the mammalian cortex and the resulting behavioral responses exhibit a large variability to repeated presentations of the same stimulus. This study examined whether the variability can be attributed to ongoing activity. Ongoing and evoked spatiotemporal activity patterns in the cat visual cortex were measured with real-time optical imaging; local field potentials and discharge...

Visually evoked responses produced by flickering light stimulation were recorded from the scalp over the occiput in normal subjects and patients with unilateral central visual loss due to various causes. It was necessary to use a digital computer so tluit the small evoked sigmds could be detected from larger extraneous potentials not "time locked" to the stimulus. The signal to noise ratio teas...

The stimulus-evoked response is the principle measure used to elucidate the timing and spatial location of human brain activity. Brain and behavioural responses to pain are influenced by multiple intrinsic and extrinsic factors and display considerable, natural trial-by-trial variability. However, because the neuronal sources of this variability are poorly understood the functional information ...

The conventional approach for processing electric or magnetic evoked brain response data involves averaging of repeated responses to increase the signal to noise ratio of the response of interest. It is recognized however, that evoked responses can vary significantly in amplitude, time course, and spatial distribution. Such variability may encode changes in subject performance or state associat...

INTRODUCTION Spontaneous fluctuations in BOLD signal are used for functional connectivity [1]. It has been suggested that these spontaneous fluctuations may influence trial-to-trial variability of the evoked BOLD response [2]. Taken together, these studies suggest that the amplitude of the spontaneous fluctuation has significance for the strength of the functional connectivity (between symmetri...