Linguistic meaning related differences in evoked potential topography: English, Swiss-German, and imagined

Functionally different neural populations for processing different categories of word meaníng are suggested by the topography of event-related EEG scale-field distributions. Noun and verb meanings of English and Swiss-German homophones produced differences in anterior-posterior topography during the first 300 to 350 msec of the response. Similar results were found for a degraded-speech stimulus when subjects imagined noun and verb meanings. Anterior—posterior scalp-field differences appeared both in an analysis of the positions of field maximal and minimal values; and in principal component analysis of ERPs.     

Response and associative phase components of elaborative prompt effects in children's noun-pair learning

The effects of aural and pictorial elaborative prompts were estimated separately for response and associative phase components of children's nounpair learning. A 20-item list of noun pairs was administered individually to 200 second- and third-grade children by the method of paired-associates. Indices of response learning (free verbal recall and pictorial identification) revealed equivalent effects among prompt conditions whereas measures of associative learning (multiple-choice pictorial-recognition tests) demonstrated substantial performance facilitation as a function of both aural and pictorial elaborative prompts. This outcome was regarded as an unequivocal identification of the locus of elaborative prompt effects in children's nounpair learning.     

The relation of esteem and vocational counseling to range of incorporation scores

Range of incorporation scores is a potential outcome measure of vocational counseling. Post-test analysis was used to examine the relation of vocational counseling and esteem to 69 Vietnam veterans' ranges of incorporation scores. Measures of esteem and incorporation for eight professions were obtained from 36 veterans who had just completed 10 hr of group counseling and 33 who were just beginning counseling. ANOVA of the ranges of the incorporation scores indicated that high-esteem veterans had higher ranges than low-esteem veterans (p <.05), and suggested that counseled veterans had higher ranges than noncounseled veterans (p ? .10).     

Spatial learning in the holeboard impairs an early phase of long-term potentiation in the rat hippocampal CA1-region

Long-term potentiation (LTP) and depression (LTD) are considered as cellular models for learning and memory. We studied the impact of holeboard training on LTP in the rat CA1 hippocampal region. In 7-week-old Wistar rats a recording electrode was chronically implanted into the hippocampal pyramidal cell layer of the CA1 of the right hemisphere and a stimulation electrode into the contralateral CA3 region.Two groups of animals received a spatial holeboard training of 10 or 15 trials over 2 days on a fixed pattern of baited holes. The last trial was performed 15 min after a primed burst stimulation of the contralateral CA3, which resulted in LTP in the ipsilateral CA1. A pseudo-trained group that received a 10 trial training with changing patterns of baited holes after each trial and a group that remained in the recording chambers during the experiments served as controls. Experimental rats significantly improved their spatial performance with increasing numbers of trials, indicated by decreasing times to pick up all food pellets and by decreasing numbers of reference memory errors. A learning-related impairment of CA1-LTP measured in both the population-spike amplitude as well as the fEPSP could be noted. These results show that specific (pattern-training), but not unspecific (pseudo-training) spatial information processing prior to electrical stimulation can severely affect LTP in hippocampal area CA1.     

Mirror,mirror on the wall … Comments on the chimeric face task used by Roszkowski and Snelbecker (1982)

A critique is presented of the chimeric face task used as a measure of cerebral laterality by M. J. Roszkowski and G. E. Snelbecker (1982, Brain and Cognition, 1, 404–409). Problems arise because the faces used are not true mirror images of each other, but in fact differ in facial details. Data are presented to illustrate that the earlier results are not caused by cerebral laterality but by the fact that the two drawings are not equally happy—even when placed in the same left-right orientation.     

Semantic categorization and event-related potentials

The N400 component of the event-related brain potential (ERP) was examined by presenting subjects with a series of words belonging to the same category and a series of declarative sentences. Half of the word series ended with a semantically unrelated word, while half of the sentences ended with a semantically inappropriate word. In the first experiment, subjects were instructed to read the word series and sentences, while in the second experiment they were instructed to indicate whether the word series or sentences ended appropriately or not with a button-press response. Word series and sentences with semantically incongruous endings produced a robust negative component at 400 msec followed by a positive-going wave for both the reading and decision tasks. When the subjects were required to categorize the word series and sentences endings, the negative component was followed by a robust P3 in both conditions. Analysis of scalp amplitude distributions for each task taken in conjunction with previous findings suggests that the semantically induced N400 component is most likely a "generic" N2. The relationship between the N2, N400, and P3 is discussed.     

Research note: The accuracy of group majorities for disjunctive and conjunctive decision tasks

For complex group decision tasks which can be described in terms of establishing the truth value of conjunctive (and) or disjunctive (or) composite propositions, the advantage for group judgmental accuracy of disaggregating the decision task into separate individual evaluations of the truth value of each component atomic proposition in the composite is investigated. For true propositions it is shown that disaggregation is preferable for conjunctive tasks, but not for disjunctive tasks; while the reverse is true for false propositions.