A study on the role of the dorsal striatum and the nucleus accumbens in allocentric and egocentric spatial memory consolidation

There is now accumulating evidence that the striatal complex in its two major components, the dorsal striatum and the nucleus accumbens, contributes to spatial memory. However, the possibility that different striatal subregions might modulate specific aspects of spatial navigation has not been completely elucidated. Therefore, in this study, two different learning procedures were used to determine whether the two striatal components could be distinguished on the basis of their involvement in spatial learning using different frames of reference: allocentric and egocentric. The task used involved the detection of a spatial change in the configuration of four objects placed in an arena, after the mice had had the opportunity to experience the objects in a constant position for three previous sessions. In the first part of the study we investigated whether changes in the place where the animals were introduced into the arena during habituation and testing could induce a preferential use of an egocentric or an allocentric frame of reference. In the second part of the study we performed focal injections of the N-methyl-d-aspartate (NMDA) receptors' antagonist, AP-5, within the two subregions immediately after training. The results indicate that using the two behavioral procedures, the animals rely on an egocentric and an allocentric spatial frame of reference. Furthermore, they demonstrate that AP-5 (37.5, 75, and 150 ng/side) injections into the dorsal striatum selectively impaired consolidation of spatial information in the egocentric but not in the allocentric procedure. Intra-accumbens AP-5 administration, instead, impaired animals trained using both procedures.     

Discriminative game-related statistics between basketball starters and nonstarters when related to team quality and game outcome

The aim of the present paper was to examine the differences in game-related statistics between basketball players who are selected for the starting five of the team (starters) and those who are not (nonstarters) when related to game outcome (winning and losing) and team quality (best teams, teams classified for the playoffs; and worst teams, teams who miss playoff classification). Archival data were gathered for all 2002-2003 regular season games from the Portuguese Professional League (N = 156). Discriminant analysis was used to identify the game-related statistics that differentiate between starters and nonstarters and interpreted by the examination of the structure coefficients (SC). When the best teams won the games, results described differences between starters and nonstarters with an emphasis on defensive rebounds (SC = .32), assists (SC = .32) and committed fouls (SC = -.68). When the worst teams won the games, results described differences between starters and nonstarters with an emphasis on 2-point field goals successful (SC = .47) and unsuccessful (SC = .48), defensive rebounds (SC =.39), successful free throws (SC =.32), and committed fouls (SC = -.55). An also important finding was that, in best teams, the nonstarters' performance was worse in the games that the team lost, whereas in worst teams, it was the starters' performance that was worse in the games that the team lost.     

Contents of Volume 20

Volume Contents

Contents of Volume 20     

Culture and egocentric perceptions of fairness in conflict and negotiation

In this article, the authors advanced a cultural view of judgment biases in conflict and negotiation. The authors predicted that disputants' self-serving biases of fairness would be more prevalent in individualistic cultures, such as the United States, in which the self is served by focusing on one's positive attributes to "stand out" and be better than others, yet would be attenuated in collectivistic cultures, such as Japan, where the self is served by focusing on one's negative characteristics to "blend in" (S. J. Heine, D. R. Lehman, H. R. Markus, & S. Kitayama, 1999). Four studies that used different methodologies (free recall, scenarios, and a laboratory experiment) supported this notion. Implications for the science and practice of negotiation are discussed.     

Time course of brain activation during graphemic/phonologic processing in reading: an ERP study

The present study sought to investigate the time course of brain activation during grapheme-to-phoneme conversion and phonologic processing of legal Italian syllables. To this goal, we monitored a group of right-handed native Italian volunteers performing a phonologic decision task (same/different judgments). ERPs were recorded from 28 scalp sites during silent reading. Analysis of ERP latency showed faster responses to same syllables than to different ones as early as 105 ms at left temporal electrode site and 160 ms at frontal sites. The first effect of phonologic/graphemic incongruity on the amplitude of ERPs was observed at lateral occipital/posterior temporal sites (N185), where physiologic responses were enhanced to incongruous syllables.     

Spontaneous attention to word content versus emotional tone: differences among three cultures

A Stroop interference task was used to test the hypothesis that people in different cultures are differentially attuned to verbal content vis-à-vis vocal tone in comprehending emotional words. In Study 1, Americans showed greater difficulty ignoring verbal content than ignoring vocal tone (which reveals an attentional bias for verbal content); but Japanese showed greater difficulty ignoring vocal tone than ignoring verbal content (which reveals a bias for vocal tone). In Study 2, Tagalog-English bilinguals in the Philippines showed an attentional bias for vocal tone regardless of the language used, suggesting that the effect is largely cultural rather than linguistic. Implications for culture-and-cognition research are discussed.     

Patterns of adaptation and personality disorders

Patterns of adaptation to conflict were explored with the Serial Color-Word Test, and personality disorders were assessed by means of the Coolidge Axis II Inventory in a group of 76 nonpsychotic women volunteers in the age range 18-50 yr. (M=29.1 yr., SD=8.3), who attended a psychiatric outpatients unit. Forward multiple regression analyses were performed to investigate whether patterns of adaptation were associated with personality disorders. 10 out of 13 personality scales, as measured by the Coolidge Axis II Inventory, were significantly predicted by adaptive variables. Some predictors were positive and others were negative. The variable R(AD) was a negative predictor of avoidant and dependent personalities, and a positive predictor of Extraversion, Aggressive personality, and Antisocial personality; this finding suggests that R(AD) may represent the regulative counterpart of a continuum from passive introversion to aggressive extraversion. The results encourage further research on nontrait laboratory correlates of personality disorders.     

Biological background knowledge and learning from a drug and alcohol education program

The authors asked whether having a base of relevant biological knowledge put school children in a better position to understand the effects of alcohol and cocaine and to learn about these effects when exposed to a curriculum presenting a physiological theory of drug action. Participants were 337 ethnically diverse 3rd- through 6th-grade students who were pretested, trained, and posttested. Multiple regression analyses revealed that knowledge of the basic functions of the heart, blood, and brain predicted certain drug-knowledge variables. Students with greater biological background knowledge also learned more from instruction, a finding with implications for enhancing drug and other health education programs.