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981.
Previous data suggest that overtraining can overcome fear conditioning deficits in rats with lesions of the basolateral complex of the amygdala (BLA). We have previously shown that the central nucleus of the amygdala (CEA) is essential for the acquisition and expression of conditional fear to both contextual and auditory conditioned stimuli (CSs) after overtraining. This provides strong evidence that the CEA can compensate for the loss of the BLA. Another brain area that may compensate for the loss of the BLA is the bed nucleus of the stria terminalis (BNST). We explored this possibility by examining the consequences of lesions or reversible inactivation of the BNST on the expression of overtrained fear in rats with BLA lesions. We demonstrate that lesions or inactivation of the BNST block the expression of freezing to the conditioning context, but not to an auditory conditional stimulus. These results reveal that the BNST has a critical role in the expression of contextual fear, but not fear to an auditory CS, and is therefore not the essential locus of compensation for fear learning in the absence of the BLA. 相似文献
982.
It has been suggested that reduced infralimbic (IL) cortical activity contributes to impairments of fear extinction. We therefore explored whether pharmacological activation of the IL would facilitate extinction under conditions it normally fails (i.e., immediate extinction). Rats received auditory fear conditioning 1 h before extinction training. Immediately prior to extinction, rats received microinfusions into the IL of the GABA(A) receptor antagonist, picrotoxin, or the NMDA receptor partial agonist, D-cycloserine. Although neither drug facilitated extinction, they both facilitated the subsequent re-extinction of fear when animals were trained in a drug-free state, suggesting that activating the IL primes behavioral extinction. 相似文献
983.
Stephen J. McKinney 《Journal of Beliefs & Values》2011,32(3):360-362
984.
Elizabeth Nicholls Catriona M. E. Ryan Catherine M. L. Bryant Stephen E. G. Lea 《Animal cognition》2011,14(1):21-34
Two experiments examined whether pigeons discriminate polymorphous categories on the basis of a single highly predictive feature
or overall similarity. In the first experiment, pigeons were trained to discriminate between categories of photographs of
complex real objects. Within these pictures, single features had been manipulated to produce a highly salient texture cue.
Either the picture or the texture provided a reliable cue for discrimination during training, but in probe tests, the picture
and texture cues were put into conflict. Some pigeons showed a significant tendency to discriminate on the basis of the picture
cue (overall similarity or family resemblance), whereas others appeared to rely on the manipulated texture cue. The second
experiment used artificial polymorphous categories in which one dimension of the stimulus provided a completely reliable cue
to category membership, whereas three other dimensions provided cues that were individually unreliable but collectively provided
a completely reliable basis for discrimination. Most pigeons came under the control of the reliable cue rather than the unreliable
cues. A minority, however, came under the control of single dimensions from the unreliable set. We conclude that cue salience
can be more important than cue reliability in determining what features will control behavior when multiple cues are available. 相似文献
985.
Previous research has demonstrated that both emotional valence and arousal can influence the subjective experience of time. The current research extends this work by (1) identifying how quickly this emotional modulation of time perception can occur and (2) examining whether valence and arousal have different effects at different stages of perception. These questions were addressed using a temporal bisection task. In each block of this task, participants are trained to distinguish between two different exposure durations. Participants are then shown stimuli presented at a number of durations that fall between the two learned times, and are asked to indicate whether the test stimulus was closer in duration to the shorter or longer learned item. In the current study, participants completed blocks of trials in which the durations were "Short" (100-300 ms) or "Long" (400-1600 ms). Stimuli consisted of neutral photographs as well as four categories of emotional images: high-arousal negative, high-arousal positive, low-arousal negative, and low-arousal positive. In Short blocks, arousing and nonarousing negative images were judged to have been shown for shorter durations than they actually were (i.e., the duration was underestimated); this effect occurred at durations as brief as 133 ms. In Long blocks, the display time for highly arousing negative items was overestimated, whereas durations were underestimated for highly arousing positive items and less arousing negative items. These data suggest that arousal and valence have different effects at different stages of perception, possibly due to the different neural structures involved at each stage of the emotional modulation of time perception. 相似文献
986.
Previous studies examining event-related potentials and evaluative priming have been mixed; some find evidence that evaluative priming influences the N400, whereas others find evidence that it affects the late positive potential (LPP). Three experiments were conducted using either affective pictures (Experiments 1 and 2) or words (Experiment 3) in a sequential evaluative priming paradigm. In line with previous behavioral findings, participants responded slower to targets that were evaluatively incongruent with the preceding prime (e.g., negative preceded by positive) compared to evaluatively congruent targets (e.g., negative preceded by negative). In all three studies, the LPP was larger to evaluatively incongruent targets compared to evaluatively congruent ones, and there was no evidence that evaluative incongruity influenced the N400 component. Thus, the present results provide additional support for the notion that evaluative priming influences the LPP and not the N400. We discuss possible reasons for the inconsistent findings in prior research and the theoretical implications of the findings for both evaluative and semantic priming. 相似文献
987.
Colautti LA Fuller-Tyszkiewicz M Skouteris H McCabe M Blackburn S Wyett E 《Body image》2011,8(4):315-321
The present study evaluated whether the strength of relationship between contextual cues (presence of company and mood) and state body dissatisfaction varied as a function of individual differences in key trait measures (body shame, body surveillance tendencies, internalization of appearance standards, and trait affect) which have been linked to trait body dissatisfaction. Fifty-five undergraduate women completed a questionnaire containing the trait-based measures and then carried a Personal Digital Assistant (PDA) for a 7-day period. The PDA prompted participants six times daily to self-report their current mood and state body dissatisfaction. Multi-level modeling revealed that individual differences in body shame predicted inter-individual variability in the strength of the relationships between presence of company and state body dissatisfaction, and positive mood and state body dissatisfaction. Trait positive affect also explained variance in the positive mood state-body dissatisfaction relationship. The implications of the findings for prevention of body image disturbances are discussed. 相似文献
988.
Stephen R. Jackson Amy Parkinson Valentina Manfredi Guy Millon Chris Hollis Georgina M. Jackson 《Journal of Neuropsychology》2013,7(1):29-44
Tourette syndrome (TS) is a neuro‐developmental disorder characterized by the occurrence of motor and vocal tics: involuntary, repetitive, stereotyped behaviours that occur with a limited duration, often typically many times in a single day. Previous studies suggest that children and adolescents with TS may undergo compensatory, neuroplastic changes in brain structure and function that help them gain control over their tics. In the current study we used single‐pulse and dual‐site paired‐pulse transcranial magnetic stimulation (TMS), in conjunction with a manual choice reaction time task that induces high levels of inter‐manual conflict, to investigate this conjecture in a group of children and adolescents with TS, but without co‐morbid Attention Deficit Hyperactivity Disorder (ADHD). We found that performance on the behavioural response‐conflict task did not differ between the adolescents with TS and a group of age‐matched typically developing individuals. By contrast, our study demonstrated that cortical excitability, as measured by TMS‐induced motor‐evoked potentials (MEPs), was significantly reduced in the TS group in the period immediately preceding a finger movement. This effect is interpreted as consistent with previous suggestions that the cortical hyper‐excitability that may give rise to tics in TS is actively suppressed by cognitive control mechanisms. Finally, we found no reliable evidence for altered patterns of functional inter‐hemispheric connectivity in TS. These results provide evidence for compensatory brain reorganization that may underlie the increased self‐regulation mechanisms that have been hypothesized to bring about the control of tics during adolescence. 相似文献
989.
Stephen Kosslyn William Thompson Jennifer Shephard Giorgio Ganis Deborah Bell Judith Danovitch 《Journal of Cognitive Psychology》2013,25(5):696-716
The present study was designed to discover whether variations in normalised regional cerebral blood flow (rCBF) in different brain areas predict variations in performance of different imagery tasks. Positron emission tomography (PET) was used to assess brain activity as 16 participants performed four imagery tasks. These tasks were designed so that performance was particularly sensitive to the participant's ability to form images with high resolution, to generate images from distinct segments, to parse imaged forms into parts while inspecting them, or to transform (rotate) images. Response times and error rates were recorded. Multiple regression analyses revealed that variations in most brain areas predicted variations in performance of only one task, thus demonstrating that the four tasks tap largely independent imagery processes. However, we also found that some underlying processes were recruited by more than one task, particularly those implemented in the occipito‐parietal sulcus, the medial frontal cortex, and Area 18. 相似文献
990.