Search results for "electroencephalography"
showing 10 items of 779 documents
Wertheim’s hypothesis on ‘highway hypnosis’: empirical evidence from a study on motorway and conventional road driving
2003
This paper aims to study the phenomenon known as 'highway hypnosis' or 'driving without attention mode', which has been defined as a state showing sleepiness signs and attention slip resulting from driving a motor vehicle for a long period in a highly predictable environment with low event occurrence, this being the case with motorways and very familiar roads [Highway hypnosis: a theoretical analysis. In: Gale, A.G., Brown, I.D., Haslegrave, C.M., Moorhead, I., Taylor, S. (Eds.), Vision in Vehicles-III. Elsevier, North-Holland, pp. 467-472]. According to Wertheim's hypothesis on 'highway hypnosis', long-term driving on motorways and conventional roads, e.g. main roads, secondary roads--impl…
Driving on the motorway: the effect of alternating speed on driver's activation level and mental effort
2002
When most of the driving tasks are performed automatically, a driver's level of alertness may decline, as has been pointed out in the study of the phenomenon called 'highway hypnosis'. One possible countermeasure is to periodically vary the speed (Wertheim 1978), but the authors have not found any studies that directly assess the effectiveness of this countermeasure. The objective of our study has been to provide empirical evidence regarding the effects of this strategy on the level of driver activation on a motorway route in real traffic. In the present study activation level as indexed by a relative measure based on slow EEG activity tended to be significantly higher when speed was modifi…
Learning by heart : cardiac cycle reveals an effective time window for learning
2018
Cardiac cycle phase is known to modulate processing of simple sensory information. This effect of the heartbeat on brain function is likely exerted via baroreceptors, the neurons sensitive for changes in blood pressure. From baroreceptors, the signal is conveyed all the way to the forebrain and the medial prefrontal cortex. In the two experiments reported, we examined whether learning, as a more complex form of cognition, can be modulated by the cardiac cycle phase. Human participants ( experiment 1) and rabbits ( experiment 2) were trained in trace eyeblink conditioning while neural activity was recorded. The conditioned stimulus was presented contingently with either the systolic or dias…
Contrast-enhanced transcranial Doppler ultrasonography in the diagnosis of brain death
2013
The diagnosis of brain death (BD) is based on clinical criteria including deep coma, brain stem areflexia and apnoea. Depending on different local guidelines, confirmatory technical tests are sometimes mandatory.1 Since the 1990s, transcranial Doppler sonography (TCD) has found its place in these circumstances and fulfils most of the criteria of an ‘ideal test’ in confirming BD. To confirm intracranial circulatory arrest (CA) with Doppler sonography, typical flow patterns must be recorded in bilateral intracranial and extracranial brain-supplying arteries.2 A completely absent intracranial flow signal is not a reliable sign to determine CA because this can be due to transmission problems. I…
Anterior limbic alpha-like activity: a low resolution electromagnetic tomography study with lorazepam challenge
2005
Summary Objective To verify findings of an independently regulated anterior limbic alpha band source. Methods In a randomised cross-over study, the spontaneous EEG was recorded in nine healthy subjects after i.v. lorazepam or placebo. Intracerebral current densities within classical frequency bands were estimated with low resolution electromagnetic tomography [LORETA] and compared between groups with t -statistical parametric mapping [SPM{ t }]. A region-of-interest [ROI] based method was used to compare frontal and occipital alpha band activity changes. Results Irrespective of treatment group, local maxima of alpha band power were localised both in the occipital lobe, Brodman area [BA] 18,…
Latency of interictal epileptiform discharges in long-term EEG recordings in epilepsy patients.
2015
AbstractPurposeTo assess the latency of interictal epileptiform discharges (IED) and seizures in long-term EEG recordings of patients with epilepsy.MethodIED latency was measured in 210 consecutive patients (mean (SD) age 38.6±13.9 years) with active epilepsy and the relationship to clinical variables was analyzed retrospectively. Median duration of EEG recording was 101.5h (95% confidence interval [CI] 92 to 117h).ResultsIEDs were absent in 45 (21.4%) and present in 165 (78.6%) patients who had a longer duration (p<0.001) and early onset (p<0.01) of epilepsy and more often had IEDs in prior standard EEGs (p<0.01), a structural etiology (OR 2.4, CI: 2.1–2.7), or temporal lobe epilepsy (OR 9…
Encoding, storage, and response preparation-Distinct EEG correlates of stimulus and action representations in working memory.
2019
Working memory (WM) allows for the active storage of stimulus- and higher level representations, such as action plans. This electroencephalography (EEG) study investigated the specific electrophysiological correlates dissociating action-related from stimulus-related representations in WM using three different experimental conditions based on the same stimulus material. In the experiment, a random sequence of single numbers (from 1 to 6) was presented and participants had to indicate whether the current number (N0 condition), the preceding number (N-1 condition), or the sum of the current and the preceding number (S-1 condition) was odd or even. Accordingly, participants had to store a stimu…
Meaningful physical changes mediate lexical-semantic integration: top-down and form-based bottom-up information sources interact in the N400
2011
Models of how the human brain reconstructs an intended meaning from a linguistic input often draw upon the N400 event-related potential (ERP) component as evidence. Current accounts of the N400 emphasise either the role of contextually induced lexical preactivation of a critical word (Lau, Phillips,& Poeppel, 2008) or the ease of integration into the overall discourse context including a wide variety of influencing factors (Hagoort & van Berkum, 2007). The present ERP study challenges both types of accounts by demonstrating a contextually independent and purely form-based bottom-up influence on the N400: the N400 effect for implausible sentence-endings was attenuated when the critical sente…
Cognitive control after distraction: event-related brain potentials (ERPs) dissociate between different processes of attentional allocation.
2008
Attentional reallocation after a distracting event is an important function of cognitive control. This process is tapped by the reorienting negativity (RON) event-related brain potential. It was argued that the RON reflects orientation of attention to relevant information in working memory. To test this hypothesis participants performed an auditory duration discrimination task. The stimuli were presented in a frequent standard or a rare deviant pitch with deviants resulting in behavioral distraction. Participants accomplished this task under two conditions: In the refocus condition participants were asked to respond to every stimulus; in the reorient condition participants were instructed t…
Bodily self-relatedness in vicarious touch is reflected at early cortical processing stages.
2019
Studies have suggested that there is a strong link between the bodily self and the mechanisms underlying vicarious representations. Here, we used somatosensory ERPs to investigate the temporal dynamics of vicarious touch for stimuli that are more or less related to one's own body (human hands vs. rubber gloves). We found that vicarious touch effects were restricted to self-relatable events (human hands) at early implicit stages of somatosensory processing (P45). At later more cognitive stages of processing (late positive complex, LPC), the vicarious touch effect was stronger for self-relatable events (touch on human hands) than nonself-relatable events (touch on rubber gloves) but present f…