Psychophysiology
1540-5958
0048-5772
Anh Quốc
Cơ quản chủ quản: Wiley-Blackwell Publishing Ltd , WILEY
Lĩnh vực:
Experimental and Cognitive PsychologyDevelopmental NeuroscienceCognitive NeuroscienceEndocrine and Autonomic SystemsNeuroscience (miscellaneous)Biological PsychiatryPhysiology (medical)NeurologyNeuropsychology and Physiological PsychologyPhysiologyDevelopmental and Educational Psychology
Các bài báo tiêu biểu
The N1 Wave of the Human Electric and Magnetic Response to Sound: A Review and an Analysis of the Component Structure ABSTRACT This paper reviews the literature on the Nl wave of the human auditory evoked potential. It concludes that at least six different cerebral processes can contribute to (he negative wave recorded from the scalp with a peak latency between 50 and 150 ms: a component generated in the auditory‐cortex on the supratemporal plane, a component generated in the association cortex on the lateral aspect of the temporal and parietal cortex, a component generated in the motor and premotor cortices, the mismatch negativity, a temporal component of the processing negativity, and a frontal component of the processing negativity, The first three, which can be considered ‘true’ N1 components, are controlled by the physical and temporal aspects of the stimulus and by the general state of the subject. The other three components are not necessarily elicited by a stimulus but depend on the conditions in which the stimulus occurs. They often last much longer than the true N1 components that they overlap.
Tập 24 Số 4 - Trang 375-425 - 1987
Removing electroencephalographic artifacts by blind source separation Eye movements, eye blinks, cardiac signals, muscle noise, and line noise present serious problems for electroencephalographic (EEG) interpretation and analysis when rejecting contaminated EEG segments results in an unacceptable data loss. Many methods have been proposed to remove artifacts from EEG recordings, especially those arising from eye movements and blinks. Often regression in the time or frequency domain is performed on parallel EEG and electrooculographic (EOG) recordings to derive parameters characterizing the appearance and spread of EOG artifacts in the EEG channels. Because EEG and ocular activity mix bidirectionally, regressing out eye artifacts inevitably involves subtracting relevant EEG signals from each record as well. Regression methods become even more problematic when a good regressing channel is not available for each artifact source, as in the case of muscle artifacts. Use of principal component analysis (PCA) has been proposed to remove eye artifacts from multichannel EEG. However, PCA cannot completely separate eye artifacts from brain signals, especially when they have comparable amplitudes. Here, we propose a new and generally applicable method for removing a wide variety of artifacts from EEG records based on blind source separation by independent component analysis (ICA). Our results on EEG data collected from normal and autistic subjects show that ICA can effectively detect, separate, and remove contamination from a wide variety of artifactual sources in EEG records with results comparing favorably with those obtained using regression and PCA methods. ICA can also be used to analyze blink‐related brain activity.
Tập 37 Số 2 - Trang 163-178 - 2000
Quantification of Sleepiness: A New Approach ABSTRACT The Stanford Sleepiness Scale (SSS) is a self‐rating scale which is used to quantify progressive steps in sleepiness. The present study investigated whether the SSS cross‐validates with performance on mental tasks and whether the SSS demonstrates changes in sleepiness with sleep loss. Five college student S s were given a brief test of memory and the Wilkinson Addition Test in 2 test sessions and The Wilkinson Vigilance Test in 2 other sessions spaced throughout a 16‐hr day for 6 days. S s made SSS ratings every 15 min during their waking activities. On night 4, S s underwent all night sleep deprivation. On all other nights, S s were allowed only 8 hrs in bed. Mean SSS ratings correlated r = .68 with performance on the Wilkinson Tests. Discrete SSS ratings correlated r = .47 with performance on the memory test. Moreover, mean baseline SSS ratings were found to be significantly lower than corresponding ratings of the deprivation period.
Tập 10 Số 4 - Trang 431-436 - 1973
A Solution for Reliable and Valid Reduction of Ocular Artifacts, Applied to the P300 ERP ABSTRACT The P300 ERP was measured in 10 subjects each for 9 days. The selection of instructions for subjects, the recording technique, the elimination of a few single trials significantly contaminated by eye movements, and the use of a correction procedure for ocular artifacts with calculable reliability and validity resulted in a set of data, in which 94% of the single trials were suitable for further analysis. The correction procedure relies on regression analysis. To reduce coherence between eyeblink activity and ongoing EEG, VEOG and EEG are averaged on eyeblinks. This yields a high reliability and validity of regression factors, determined per day, subject, and lead. In addition, this correction procedure allows for an estimation of the maximal error that must be taken into account. The efficiency of the procedure is demonstrated for single trials and averaged potentials.
Tập 23 Số 6 - Trang 695-703 - 1986
Guidelines for using human event‐related potentials to study cognition: Recording standards and publication criteria Event‐related potentials (ERPs) recorded from the human scalp can provide important information about how the human brain normally processes information and about how this processing may go awry in neurological or psychiatric disorders. Scientists using or studying ERPs must strive to overcome the many technical problems that can occur in the recording and analysis of these potentials. The methods and the results of these ERP studies must be published in a way that allows other scientists to understand exactly what was done so that they can, if necessary, replicate the experiments. The data must then be analyzed and presented in a way that allows different studies to be compared readily. This paper presents guidelines for recording ERPs and criteria for publishing the results.
Tập 37 Số 2 - Trang 127-152 - 2000
A Bio‐Informational Theory of Emotional Imagery ABSTRACT A theory of emotional imagery is described which conceives the image in the brain to be a conceptual network, controlling specific somatovisceral patterns, and constituting a prototype for overt behavioral expression. Evidence for the hypothesis that differentiated efferent activity is associated with type and content of imaginal activity is considered. Recent work in cognitive psychology is described, which treats both the generation of sensory imagery and text comprehension and storage as examples of the processing of propositional information. A similar propositional analysis is applied to emotional imagery as it is employed in the therapeutic context. Experiments prompted by this view show that the conceptual structure of the image and its associated efferent outflow can be modified directly through instructions and through shaping of reports of image experience. The implications of the theory for psychopathology are considered, as well as its relevance to therapeutic behavior change.
Tập 16 Số 6 - Trang 495-512 - 1979
The pupil as a measure of emotional arousal and autonomic activation Abstract Pupil diameter was monitored during picture viewing to assess effects of hedonic valence and emotional arousal on pupillary responses. Autonomic activity (heart rate and skin conductance) was concurrently measured to determine whether pupillary changes are mediated by parasympathetic or sympathetic activation. Following an initial light reflex, pupillary changes were larger when viewing emotionally arousing pictures, regardless of whether these were pleasant or unpleasant. Pupillary changes during picture viewing covaried with skin conductance change, supporting the interpretation that sympathetic nervous system activity modulates these changes in the context of affective picture viewing. Taken together, the data provide strong support for the hypothesis that the pupil's response during affective picture viewing reflects emotional arousal associated with increased sympathetic activity.
Tập 45 Số 4 - Trang 602-607 - 2008
On the utility of P3 amplitude as a measure of processing capacity The present review focuses on the utility of the amplitude of P3 of as a measure of processing capacity and mental workload. The paper starts with a brief outline of the conceptual framework underlying the relationship between P3 amplitude and task demands, and the cognitive task manipulations that determine demands on capacity. P3 amplitude results are then discussed on the basis of an extensive review of the relevant literature. It is concluded that although it has often been assumed that P3 amplitude depends on the capacity for processing task relevant stimuli, the utility of P3 amplitude as a sensitive and diagnostic measure of processing capacity remains limited. The major factor that prompts this conclusion is that the two principal task variables that have been used to manipulate capacity allocation, namely task difficulty and task emphasis, have opposite effects on the amplitude of P3. I suggest that this is because, in many tasks, an increase in difficulty transforms the structure or actual content of the flow of information in the processing systems, thereby interfering with the very processes that underlie P3 generation. Finally, in an attempt to theoretically integrate the results of the reviewed studies, it is proposed that P3 amplitude reflects activation of elements in a event‐categorization network that is controlled by the joint operation of attention and working memory.
Tập 38 Số 3 - Trang 557-577 - 2001
Electrophysiological correlates of feature analysis during visual search Abstract Event‐related brain potentials (ERPs) were recorded from normal young adults during visual search tasks in which the stimulus arrays contained either eight identical items (homogeneous arrays) or seven identical items and one deviant item (pop‐out arrays). Four experiments were conducted in which different classes of stimulus arrays were designated targets and the remaining stimulus arrays were designated nontargets. In Experiments 1 and 2, both target and nontarget pop‐out stimuli elicited an enhanced anterior N2 wave and a contralaterally larger posterior P1 wave, but Experiments 3 and 4 demonstrated that these components do not reflect fully automatic pop‐out detection processes. In all four experiments, target pop‐outs elicited enlarged anterior P2, posterior N2, occipital P3, and parietal P3 waves. The target‐elicited posterior N2 wave contained a contralateral subcomponent (N2pc) that exhibited a focus over occipital cortex in maps of current source density. The overall pattern of results was consistent with guided search models in which preattentive stimulus information is used to guide attention to task‐relevant stimuli.
Tập 31 Số 3 - Trang 291-308 - 1994
Prestimulus Effects on Human Startle Reflex in Normals and Schizophrenics ABSTRACT Graham (1975) demonstrated that a weak prestimulus could effectively inhibit or facilitate the eyeblink component of the startle reflex in humans, depending on the temporal duration of the prestimulus. This study had three goals: 1) to replicate the findings of Graham, 2) to establish the reliability of this phenomenon by a test‐retest comparison, and 3) to compare the eyeblink reflex response of normal subjects with schizophrenic subjects. Seven prestimulus durations of continuous tone (from 0 to 2000 msec) were presented to 20 normal subjects and the results confirmed that maximal inhibition of eyeblink amplitude occurred in the 120 msec prestimulus condition. Increased amplitude occurred nonsignificantly when the prestimulus lasted for 2000 msec. On retest, 14 normal subjects showed a significant degree of reliability. When 20 normal subjects were compared to 12 schizophrenic subjects, significant differences in eyeblink response were found for blink amplitude and latency in the 60 msec prestimulus condition. This change is consistent with information processing “overload” theories of sensory overstimulation in schizophrenia. The blink reflex is a rather stable phenomenon and is probably altered in schizophrenia and/or by antipsychotic medication.
Tập 15 Số 4 - Trang 339-343 - 1978