Chromatic specificity of the visual evoked response.

The temporal alternation of red and green stripes in a structured field produces successive contrast, which can elicit cortical potentials recorded from the scalp. Amplitudes of the major frequency components of the potentials correspond to the relative intensities of red and green producing the contrast. The amplitude variations are color-specific, since total luminance and structure are held constant.

Brain potentials during sentence verification: late negativity and long-term memory strength.

Subjects decided whether self-referential statements were true or false. Event-related potentials (ERPs) associated with final words creating false statements displayed a late negativity (N340) relative to ERPs for true completions. The size of this difference between true and false statements was greater for highly familiar statements (e.g. "My name is Ira") than for less familiar ones (e.g. "I go to bed late") even after all the statements had been practised a number of times. The late negativity appears to be associated with a discrepancy between presented and remembered information, and its magnitude reflects the long-term familiarity or strength of the remembered information.

Postdoctoral education and training for clinical service providers in health psychology.

It was recommended by the 1983 National Working Conference on Education and Training in Health Psychology (Stone, 1983) that 2 years of postdoctoral education and training be mandated for future licensed health service providers in health psychology. The background for requiring this postdoctoral training, a model for education, criteria for developing programs, issues of funding, and a rationale for accepting this mandate are presented. Highlighted are the stable and consistent growth of health psychology, the need to expand the period of clinical training to meet the many advances in the field, and the challenges that exist for the fully trained clinical health service provider.

Event-related potentials: a critical review of methods for single-trial detection.

The analysis of ERP data has followed several lines over the last 20 years. The most prevalent method is simply to average ERPs for a given class of stimuli. The ERPs are compared for differences across classes of stimuli. Little other special data processing is used. The ERP comparisons are usually performed using visual examination of the wave-shapes. Sometimes statistics are calculated such as means, variances, and confidence limits. Linear filtering is used to reduce interference. Another approach is to model or analyze the ERP as a sequence of vectors or frames of data samples. These samples may be of the ERP time waveform or they may be of the frequency transform of the ERP waveform. The frames of data vary in length from the entire ERP waveform (500 to 1000 msec) to frames as short as ten sample points (100 msec). Recognition of an event in the ERP is achieved by computing a distance measure between parameter vectors for one class of stimuli and corresponding parameter vectors for another class of stimuli. Recognition is achieved by selecting the ERP with the lowest distance score. This approach is "pattern matching" and relies on two assumptions: adjacent frames of data are uncorrelated, and the variability of the data can be accounted for by the distance measured for all stimuli in the classes presented. Subject variability is generally not accounted for, other than to assume it is the same for all classes of stimuli. The data are clustered into a variety of reference patterns that represent particular manifestations of a particular stimulus. Another approach is "feature-based" recognition. The idea is to identify and automatically extract features of the data that can provide a characterization of stimuli. The features selected may be abstract. They are calculated from the data or transforms of the data.

Brain potentials during sentence verification: automatic aspects of comprehension.

College students learned a set of facts relating fictitious people and their occupations (e.g. 'Matthew is a lawyer'). Event-related brain potentials (ERPs) were recorded while they subsequently viewed a series of such statements presented in segments (e.g. 'Matthew/is a/dentist'). ERPs to occupations completing statements falsely were significantly more negative than those to true statements in an interval 200-420 msec poststimulus (peak N320), whether subjects were required to make a decision about each statement or passively view the presented segments (Experiments 1 and 2). A later ERP positivity was observed during 'response' trials that was of longer latency for false than true completions; but this positive component was greatly attenuated during 'no-response' trials. The enhanced N320 for false completions was not affected by requiring subjects on some trials to respond incorrectly (Experiment 3). It is concluded that attending to a presented word results in an automatic analysis of its meaning in the context of a preceding verbal input, and that ERPs can indicate the nature of the output of that analysis.

Brain potentials related to seeing one's own name.

Subjects were assigned an assumed name and then shown a series of statements of the form, "My name / is / X", where X was the assumed name, their own first name, or one of a set of other false names. Their task was to respond positively to the "assumed" name and reject as false all other names, including their own. An N380 feature of the averaged task-related brain potentials, considered to be inversely related to the degree of contextual priming, was greatly enhanced for the false names compared to the assumed name. The N380 to one's own name was more similar to that of the false than the assumed name, indicating that the sentence context's priming of various names was under the subjects' attentional control, and that the late negativity could be modulated by this attention. In contrast, a large P510 feature distinguished one's own name from the false name, and this difference was unaffected by practice. Even in cases, then, where the context allows anticipation of one verbal event (here, the assumed name), a highly overlearned and salient stimulus such as one's own name continues to produce a distinctive neural response.

A Yudin-type short form of the WISC-R: two aspects of validation.

Provided validity data for a Yudin-type short form of the WISC-R for N equal to 70 middle-class children (34 males and 36 females, X age equal to 7.6 years, SD equal to 2.58 months) of above-average intelligence (means: VIQ equal to 115.55, PIQ equal to 122.27, FIQ equal to 121.02). Short- to long-form validity coefficients were all above .90 for Verbal, Performance, and Full Scale IQ scores. Highly similar predictive validity coefficients were found for the short and long forms of the WISC-R when compared with the Metropolitan Achievement and Otis Lennon Mental Ability tests. In contrast, little support was found for the validity of the short-form profile data as assessed by Cattell's rp coefficient of profile similarity.