Cognitive neuroimaging: cognitive science out of the armchair

Cognitive scientists were not quick to embrace the functional neuroimaging technologies that emerged during the late 20th century. In this new century, cognitive scientists continue to question, not unreasonably, the relevance of functional neuroimaging investigations that fail to address questions of interest to cognitive science. However, some ultra-cognitive scientists assert that these experiments can never be of relevance to the study of cognition. Their reasoning reflects an adherence to a functionalist philosophy that arbitrarily and purposefully distinguishes mental information-processing systems from brain or brain-like operations. This article addresses whether data from properly conducted functional neuroimaging studies can inform and subsequently constrain the assumptions of theoretical cognitive models. The article commences with a focus upon the functionalist philosophy espoused by the ultra-cognitive scientists, contrasting it with the materialist philosophy that motivates both cognitive neuroimaging investigations and connectionist modelling of cognitive systems. Connectionism and cognitive neuroimaging share many features, including an emphasis on unified cognitive and neural models of systems that combine localist and distributed representations. The utility of designing cognitive neuroimaging studies to test (primarily) connectionist models of cognitive phenomena is illustrated using data from functional magnetic resonance imaging (fMRI) investigations of language production and episodic memory.     

Effect of manipulating the risetime of an acoustic stimulus on two protective reflexes: cardiac defense and motor startle

Effect of manipulating the risetime of an acoustic stimulus on two protective reflexes: cardiac defense and motor startle. The risetime is a parametric characteristic of the eliciting stimulus frequently used to differentiate among psychophysiological reflexes. The aim of the present study was to examine the effect of manipulating the risetime of an acoustic stimulus on two protective reflexes: cardiac defense and motor startle. 100 participants underwent a psychophysiological reactivity test to five presentations of an intense acoustic stimulus (105 dB white noise) under one of five risetime conditions: 0, 24, 48, 96, and 240 ms. Total energy of the stimulus was controlled by increasing the base duration of the stimulus (1000 ms) by one third of the risetime. Results showed that risetime significantly affected motor startle but not cardiac defense. Startle amplitude decreased linearly with increasing risetime after 24 ms. On the other hand, repetition of the stimulus significantly affected cardiac defense but not motor startle. These results question the traditional differentiation between startle and defense based on risetime.     

Partial support from a non-replication: comment on Roma, Silberberg, Ruggiero, and Suomi (2006)

A purported replication by P. G. Roma, A. Silberberg, A. M. Ruggiero, and S. J. Suomi of the authors' previous study claims to contradict their finding that capuchin monkeys (Cebus apella) refuse to exchange with an experimenter if their partner receives a superior reward. Roma et al. used no exchange task, however, or any other task. Roma et al. offered frustration as explanation of their findings, yet failed to statistically prove that the effect of frustration is stronger than that of inequity. They also misrepresented the dependent measure of the authors' study. Reanalysis of the authors' own data indicated no role of frustration, that is, no effect of previous experience with a superior reward. The authors conclude that Roma et al.'s study is not a replication and does not disprove the authors' findings.     

A questionnaire to assess school social climate

A questionnaire to assess the school social climate (CECSCE) made from items of The California School Climate and Safety Survey is presented. The CECSCE displays a stable factorial Oblimin structure in two social climate factors: 1) relative to the school and 2) relative to the teaching staff. Both factors present a correlation that oscillates between 0.42 and 0.48; and they explain 54,2% and 45,6% of the variance, respectively. Its reliability test-retest is acceptable (r= 0.61) after 9 months. Both factors present gender differences in favour of girls. They also differentiate at the educational level, displaying in 2 masculine course higher means in both factors than in 3 masculine course. The second factor correlates positively with the factors that measure social competence in the Merrell School Social Behaviour Scales and negatively with those that measure antisocial and non adapted behaviour.     

Empathy in children aged 10 to 12 years

The objectives of this research were: 1) to determine whether there were differences in empathy according to gender; 2) to analyze the relationships between empathy and social behaviour, self-concept, emotional stability, social interaction strategies, capacity to analyze emotions, intelligence, and creativity; and 3) to identify predicting variables of empathy. The sample consisted of 139 participants aged 10 to 12 years. ANOVA results showed gender differences in empathy, with significantly higher scores in females. Pearson coefficients suggest that participants with high empathy showed many positive social behaviours (prosocial, assertive, consideration, self-control, leadership), few negative social behaviors (passive, aggressive, antisocial, withdrawal) and many assertive strategies of social interaction; that they were named as prosocial classmates; and that they had high self-concept, high capacity to analyze negative emotions, high emotional stability and many behaviors and traits of creative personality. Multiple regression analyses permitted identification of the following predicting variables of empathy: high level of prosocial behaviour, low level of aggressive behaviour and high self-concept.     

A Chilean version of the Efficient Personality Questionnaire for Adolescents

This investigation aims at adapting the test for Efficient Personality in educational contexts to Chilean reality. This instrument measures the construct efficient personality , made up of four levels of the self: strengths, requests, challenges and relationships. The original version has 58 items. In order to adapt it to our reality, 30 items were modified. The instrument was applied to a sample of 594 third and fourth secondary level students from four educational institutions of Vi?a del Mar. The new version of the instrument (23 items) presents a .85 reliability coefficient. The factorial analysis shows a structure of four basic factors which explain 50.42 % of the total variance. These factors, which are very similar those proposed in the original instrument, are named as academic self realization, social self realization, solving efficiency, and self steem. The second order factors analysis reveals a single factors structure that explains 43,28 % of the total variance, thus confirming the presence of the only factor that would correspond to the efficient personality construct presented.     

Different parameters support generalization and discrimination learning in Drosophila at the flight simulator

We have used a genetically tractable model system, the fruit fly Drosophila melanogaster to study the interdependence between sensory processing and associative processing on learning performance. We investigated the influence of variations in the physical and predictive properties of color stimuli in several different operant-conditioning procedures on the subsequent learning performance. These procedures included context and stimulus generalization as well as color, compound, and conditional discrimination (colors and patterns). A surprisingly complex dependence of the learning performance on the colors' physical and predictive properties emerged, which was clarified by taking into account the fly-subjective perception of the color stimuli. Based on estimates of the stimuli's color and brightness values, we propose that the different tasks are supported by different parameters of the color stimuli; generalization occurs only if the chromaticity is sufficiently similar, whereas discrimination learning relies on brightness differences.     

Conditioned and unconditioned fear organized in the periaqueductal gray are differentially sensitive to injections of muscimol into amygdaloid nuclei

The lateral and basolateral nuclei of the amygdala (LaA and BLA, respectively) serve as a filter for unconditioned and conditioned aversive information that ascends to higher structures from the brainstem, whereas the central nucleus of the amygdala (CeA) is considered to be the main output for the defense reaction. It has been shown that the dorsal periaqueductal gray (dPAG) is activated by threatening stimuli and has important functional links with the amygdala through two-way anatomical connections. In this work, we examined the influence of chemical inactivation of these nuclei of amygdala on the freezing and escape responses induced by electrical stimulation through electrodes implanted in the dPAG of Wistar rats. Each rat also bore a cannula implanted in the LaA, BLA or CeA for injections of muscimol (0.5 microg/0.5 microL) or its vehicle. The duration of freezing behavior that outlasts electrical stimulation of the dPAG was also measured. On the following day, these animals were submitted to a contextual fear-conditioning using foot shocks as unconditioned stimulus. Conditioned freezing to contextual cues previously associated with foot shocks was also inhibited by injections of muscimol into these amygdaloid nuclei. The contextual conditioned freezing behavior is generated in the neural circuits of conditioned fear in the amygdala. The data obtained also show that injections of muscimol into the three amygdaloid nuclei did not change the aversive threshold of freezing, but disrupted the dPAG post-stimulation freezing. Previous findings that the latter freezing results directly from dPAG stimulation and that it is not sensitive to a context shift suggest that it is unconditioned in nature. Thus, the amygdala can affect some, but not all, aspects of unconditioned freezing. Post-stimulation freezing may reflect the process of transferring aversive information from dPAG to higher brain structures.