Effects of stress and sex on acquisition and consolidation of human fear conditioning

We examined the relationship between stress hormone (cortisol) release and acquisition and consolidation of conditioned fear learning in healthy adults. Participants underwent acquisition of differential fear conditioning, and consolidation was assessed in a 24-h delayed extinction test. The acquisition phase was immediately followed by an 11-min psychosocial stress period (arithmetic test combined with a public speech). Salivary cortisol was sampled at various time points before and after acquisition and retention of fear conditioning. Results showed two effects of endogenous cortisol. Post-acquisition cortisol correlated with fear acquisition in male but not female participants. In addition, post-acquisition cortisol correlated with consolidation of fear but only in those participants with high cortisol levels. We conclude that in the short term, a robust and sexually dimorphic relationship exists between fear learning and stress hormone levels. For those participants whose fear learning is accompanied by high stress hormone levels, a long-term relationship exists between cortisol release and memory consolidation. These short-term and long-term effects may relate to the differential involvement of mineralocorticoid and glucocorticoid receptor subtypes, respectively. The findings have implications for understanding the role of stress, sex, and hormones in different stages of fear learning and memory.     

Effects of hearing the past, present, or future during music performance

Three experiments were performed to explore the effects of mismatches between actions (key-presses) and the contents of auditory feedback (pitch events) during music performance. Pianists performed melodies from memory during altered auditory feedback that was synchronized with key-presses but matched the pitch of other sequence events. Feedback direction was manipulated by presenting pitches that matched events intended for the past (delays; Experiments 1 and 3) or the future (prelays; Experiments 2 and 3). Feedback distance was manipulated by varying the absolute separation between the current event and the location of the feedback pitch. All alterations disrupted the accuracy of performance (pitch errors) more so than timing. Serial-ordering errors indicated confusions among proximal and metrically similar events, consistent with the predictions of an incremental planning model (Palmer & Pfordresher, 2003). Patterns of serial-ordering errors suggested that performers compensate for the disruptive effects of altered feedback by changing event activations during planning.     

Auditory feedback in music performance: the role of melodic structure and musical skill

Five experiments explored whether fluency in musical sequence production relies on matches between the contents of auditory feedback and the planned outcomes of actions. Participants performed short melodies from memory on a keyboard while musical pitches that sounded in synchrony with each keypress (feedback contents) were altered. Results indicated that altering pitch contents can disrupt production, but only when altered pitches form a sequence that is structurally similar to the planned sequence. These experiments also addressed the role of musical skill: Experiments 1 and 3 included trained pianists; other experiments included participants with little or no musical training. Results were similar across both groups with respect to the disruptive effects of auditory feedback manipulations. These results support the idea that a common hierarchical representation guides sequences of actions and the perception of event sequences and that this coordination is not acquired from learned associations formed by musical skill acquisition.     

Race and General Cognitive Ability: The Myth of Diminishing Returns to Education

The impact of education on racial differences in general cognitive ability was assessed using data from the National Longitudinal Survey of Youth. To control for attrition during the educational process, we compared the scores of individuals who ultimately attained the same level of education but who were tested at different points in their educational careers. Multiple regression analyses revealed that education can have a strong positive effect on cognitive ability in both whites and blacks. Whites benefited more from education than blacks during the high school years, but blacks benefited much more than whites from a college education, substantially narrowing the gap between the races. These findings contradict the hypothesis that racial differences in intelligence are relatively immutable, in part because of the diminishing returns from increases in education.     

White Counselor Self-Awareness: A Prerequisite for Developing Multicultural Competence

This review of the literature examines White counselor self-awareness as an important variable in developing multicultural competence. The self-dimension discussed in this article includes worldview, cultural values, and racial identity. It is suggested that counselor self-awareness is a prerequisite to developing multicultural competence and that an in-depth understanding of these factors may improve the delivery of mental health services to culturally diverse client populations.     

The relationship of structural ischemic brain damage to neurobehavioural deficit: the effect of postischemic MK-801

Global cerebral ischemia is well known to cause neuronal necrosis in selectively vulnerable sectors of the hippocampus. Since the hippocampus of the rat is involved in spatial navigation, learning, and memory, selective deficits in these abilities may arise from ischemic brain damage. Previous studies have shown (a) a detectable neurobehavioural deficit due to ischemic brain damage limited to half of the CA1 sector of the hippocampus and (b) a reduction of ischemic neuronal necrosis with the noncompetitive N-methyl-D-Aspartate (NMDA) antagonist MK-801. This study was designed to determine the relationship between the improvement in structural brain damage in postischemically treated rats and any improvement in neurobehavioural performance, using a learning-set water task. Seventeen male Wistar rats received 10.5 min of forebrain ischemia induced by carotid clamping and hypotension. Brain temperature was estimated with probes in the temporalis muscle. Ten of these animals received no therapy (controls), and seven animals received 5 mg/kg MK-801 iv, 20 min postischemia. Six additional rats underwent a sham operation. Postischemic hypothermia was prevented with heating lamps. Four controls and one MK-801 treated animal died. The survivors were then tested on a place learning-set task in a swimming pool paradigm, and quantitative histopathologic analysis of their entire brains was done. The learning-set task revealed defects in spatial navigation, reflected as increased errors and latency in the performance of the untreated control rats. The performance of the MK-801 treated group progressively approached that of sham-operated rats over the course of testing and was significantly better than controls. Importantly, no long-term detrimental effect of MK-801 on the learning-set task performance was seen. Quantitative neuropathology revealed significantly less damage in the MK-801 treated group in all major brain regions. In the hippocampus, MK-801 treated animals showed hippocampal damage limited to the vulnerable portion of the pyramidal cell band comprising 48.8% of the CA1 pyramidal cells, as opposed to 72.4% in untreated controls. Extra-hippocampal damage was evident only in untreated control animals. MK-801 totally prevented neuronal necrosis in both the cerebral cortex and striatum and also prevented infarction in the neocortex and thalamus. Three conclusions emerge from the study. First, postischemic MK-801 mitigates structural brain damage in several brain regions in the absence of concomitant hypothermia. Second, neurobehavioural performance appears to be improved by MK-801 when performance trends are examined, but is somewhat less sensitive than quantitated histopathology due to compounding interanimal variation in performance abilities.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effects of cognition on the psychophysical function

Previous investigation of the deterministic-sensory and the probability-sensory-learning models of psychophysical relationships have featured the manipulation of a single cognitive cue. The present study sought to expand these findings through the manipulation of multiple cognitive cues. Subjects made magnitude estimations of skin-area contact for each of two sets which varied identically in surface area but differed in that one set also varied in accelerative force. Within sets, three treatments featured systematic variation in the presentation of cognitive cues. Power functions were obtained for all treatments and the results supported the deterministic-sensory model. It was suggested, however, that resolution of the perception versus cognition issue must await the identification of innate and conditioned correlates of the subjective response to specific sensory stimuli.     

Effects of television modeling on residential energy conservation

A combination of social marketing, communications, social learning (particularly modeling), and behavior analysis may provide an effective framework for behavior change via films and television. We used this approach in developing special television programs about residential energy conservation. The programs were tailored and directed to preselected middle-class homeowners (N = 150), and delivered over a public access channel of a cable TV system. The results indicated that after one program exposure (about 20 minutes), viewers adopted simple strategies modeled in the programs which led to savings of approximately 10% on their home energy use for a substantial part of the cooling and heating season. Although the potential benefits to costs of large-scale media efforts seemed great, institutional barriers for such programs were identified. Less expensive, more local programs seem more viable.