Electrical Sources of P300 Event-Related Brain Potentials Revealed by Low Resolution Electromagnetic Tomography

Anderer, P.; Saletu, B.; Hv, Semlitsch; Rd, Pascual-Marqui

doi:10.1159/000026473

Cited by 25 publications

(13 citation statements)

References 25 publications

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“…An involvement of frontal structures in P300 generation has recently been claimed by studies on ERPs using low-resolution electromagnetic tomography (LORETA) to draw the corresponding cerebral sources from waves recorded on the scalp surface. 2,45 In building a dipolar model, at least two criteria should be satisfied. The first is that the location of the dipolar sources should conform to current physiological and anatomical concepts.…”

Section: Discussionmentioning

confidence: 99%

“…The cerebral area representing the P300 source has been investigated by topographic and intracerebral recordings and, more recently, by neuroradiological techniques. 2,9,14,30,33,37,42,51,52,54,55 The lack of general agreement on the P300 generator can be explained by the possibility that several cerebral areas are involved.19 Indeed, according to Johnson's triarchic model, the P300 topography is largely influenced by three factors: subjective probability; stimulus meaning; and proportion of the overall stimulus information delivered to the subject. The P300 cerebral sources are differently activated on the basis of the contribution of each factor in the selected task; therefore, the P300 topography is variable.…”

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confidence: 99%

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Dipolar source modeling of the P300 event‐related potential after somatosensory stimulation

Valeriani

Fraioli

Ranghi³

et al. 2001

Muscle and Nerve

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The cerebral generators of the P300 potential evoked by somatosensory stimuli were investigated. Event-related potentials elicited by an oddball paradigm were recorded in 15 healthy subjects by 19 scalp electrodes. Nontarget and target electric stimuli were delivered on the anterior surface of the left elbow and of the wrist, respectively. Target traces showed an N140 potential followed by a widely distributed P300 response. Dipolar source modeling of target traces resulted in a six-dipole model. In the earlier latency range (up to 200 ms), one dipole in the contralateral perirolandic region and two dipoles in the parasylvian cortex of both hemispheres were activated. Two dipolar sources located bilaterally in the medial temporal region (MTR) showed their maximal activity at the P300 latency. Finally, a dipole in the contralateral frontal lobe was activated both at the latency of the N140 response and after 200 ms. It was found that two symmetrical MTR sources and a frontal dipole contributed to P300 generation.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Dipolar source modeling of the P300 event‐related potential after somatosensory stimulation

Valeriani

Fraioli

Ranghi³

et al. 2001

Muscle and Nerve

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“…Recurrent processing is assumed to then further sharpen the visual representation [51][52][53]. Finally, depending on the exact task, after about 300 milliseconds, activation reaches fronto-parietal areas [54][55][56]. In contrast to perception, imagery is caused by internal signals from (working) memory.…”

Section: Temporal Dynamicsmentioning

confidence: 99%

Shared Neural Mechanisms of Visual Perception and Imagery

Dijkstra

Bosch

Gerven

2019

Trends in Cognitive Sciences

258

169

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For decades, the extent to which visual imagery relies on similar neural mechanisms as visual perception has been a topic of debate. Here, we review recent neuroimaging studies comparing these two forms of visual experience. Their results suggest that there is large overlap in neural processing during perception and imagery: neural representations of imagined and perceived stimuli are similar in visual, parietal and frontal cortex. Furthermore, perception and imagery seem to rely on similar top-down connectivity. The most prominent difference is the absence of bottom-up processing during imagery. These findings fit well with the idea that imagery and perception rely on similar emulation or prediction processes. Externally and internally generated visual experience A large part of our sensory experience is visual. When walking down the street, we are bombarded with different colors, shapes and textures. Also when thinking about future or past events, most people tend to experience a rapid stream of detailed images [1]. Visual experience can be triggered externally, by events in the outside world that change the light that falls unto our retinas, such as during perception (see Glossary); or internally, by information from memory via a process known as mental imagery (see Box 1 on the relationship between imagery and working memory). Generally, these are seen as two distinct phenomena. However, they are phenomenologically similar which can sometimes lead us to question whether we really saw something or whether it was just our imagination. The question to what extent visual imagery relies on the same neural mechanisms as perception has been a topic of debate for decades. Originally, the debate was centered around the question whether imagery, like perception, relied on depictive, picture-like representations, or on symbolic, language-like representations [2-5]. Due to imagery's inherently private nature, for a long time it was impossible to address this question. Neuroimaging studies on the involvement of the primary visual cortex during imagery have now largely resolved this debate in favor of the depictive view [6]. However, a broader perspective, addressing the involvement and interaction of brain regions beyond the primary visual cortex, has been missing. The current review explores to what extent externally and internally generated visual experiences rely on similar neural mechanisms. We discuss the findings with respect to visual areas which are important in the depictivism-versus-symbolism debate, but we also focus on the involvement of parietal and frontal areas. Next, we focus on the temporal dynamics of neural processing during both forms of visual experience. After that, we discuss the overlap in directional connectivity between perception and imagery. We finish by concluding that perception and imagery are in fact highly similar and we discuss the issues and questions raised by this conclusion.

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“…Already the first version of LORETA, which modeled the brain volume in a solution space with 1,153 voxels (8.385 mm length) uniformly distributed in a half-sphere, succeeded in correctly localizing auditory N1 sources in the left and right auditory cortices [7,25,70]. This was confirmed by the new version of LORETA restricting the solution space to cortical gray matter volume in the Talairach domain, which resulted in 2,394 voxels with a length of 7 mm [31,71].…”

Section: Localization Of Auditory Standard N1 and P2 As Well As Targementioning

confidence: 99%

“…In the first pharmaco-ERP LORETA study, Anderer et al [33] reported increased parietal P300 source strength after acute, subacute and superimposed infusions of Actovegin -a protein-free metabolically active hemoderivate improving oxygen and glucose utilization -in patients with age-associated memory impairment. This increase may reflect an improved availability of cognitive processing resources in an area that on the one hand plays an important role in fundamental aspects of attention [34][35][36] and on the other hand has been found to be functionally impaired in dementia [37,38].…”

Section: Introductionmentioning

confidence: 99%

Brain Regions Activated during an Auditory Discrimination Task in Insomniac Postmenopausal Patients before and after Hormone Replacement Therapy: Low-Resolution Brain Electromagnetic Tomography Applied to Event-Related Potentials

Anderer

Saletu²,

Saletu-Zyhlarz³

et al. 2004

Neuropsychobiology

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Electrical sources of auditory event-related potentials (ERPs) determined by means of low-resolution brain electromagnetic tomography (LORETA) in 48 unmedicated insomniac postmenopausal patients aged between 46 and 67 years were compared with those obtained in 48 age-matched normal female controls. Subsequently, the patients were included in a double-blind, placebo-controlled, comparative, randomized 3-arm trial phase – Climodien 2/3 [estradiol valerate (EV) 2 mg + the progestin dienogest 3 mg] was compared with EV 2 mg and placebo – followed by an open-label phase in which all of them received Climodien 2/2 (EV 2 mg + dienogest 2 mg). The double-blind and the open-label phase lasted 2 months. ERPs were recorded from 19 EEG leads in a two-tone oddball paradigm and electrical sources of standard N1 and P2 as well as target N2 and P300 components were estimated. In both patients and controls, LORETA revealed an activation of the superior temporal gyrus [auditory cortex, Brodmann areas (BA) 41, 42, 22] for all four components. For standard P2, an additional activation was observed medially parietally in the precuneus (BA 7, 5). For target N2, also a medial frontal source (BA 9, 10, 32) was identified. Finally, for the target P300 component – in addition to the aforementioned sources – activations in the prefrontal cortex (BA 9, 10, 46, 47), the inferior parietal cortex (supramarginal gyrus, BA 40, 39) and the posterior cingulum (BA 31) were found. Thus, patients and controls did not differ in the structural processes engaged in these fundamental aspects of information processing. However, patients demonstrated significantly reduced source strength – for standard ERP components predominantly in the temporal lobe and for target components predominantly in the frontal lobe, indicating reduced energetic resources available for perceptual and cognitive demands of the discrimination task. While, as compared with placebo, estrogen alone had only minor effects on ERP source strength, Climodien generally increased the impressed current density at the ERP peak latencies, predominantly in the temporal lobe, indicating an increased stimulus-induced cortical arousal in the primary and higher-order auditory cortex. Specifically, Climodien enhanced P300 source strength in the left middle temporal gyrus and in the left superior frontal gyrus, brain regions that on the one hand have been shown to be affected by hormone therapy in positron emission tomography and functional magnetic resonance neuroimaging studies and that on the other hand are among those critical for encoding and memory processes.

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Electrical Sources of P300 Event-Related Brain Potentials Revealed by Low Resolution Electromagnetic Tomography

Cited by 25 publications

References 25 publications

Dipolar source modeling of the P300 event‐related potential after somatosensory stimulation

Dipolar source modeling of the P300 event‐related potential after somatosensory stimulation

Shared Neural Mechanisms of Visual Perception and Imagery

Brain Regions Activated during an Auditory Discrimination Task in Insomniac Postmenopausal Patients before and after Hormone Replacement Therapy: Low-Resolution Brain Electromagnetic Tomography Applied to Event-Related Potentials

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