Conditioned fear is modulated by D2 receptor pathway connecting the ventral tegmental area and basolateral amygdala

Excitation of the mesocorticolimbic pathway, originating from dopaminergic neurons in the ventral tegmental area (VTA), may be important for the development of exaggerated fear responding. Among the forebrain regions innervated by this pathway, the amygdala is an essential component of the neural circuitry of conditioned fear. The functional role of the dopaminergic pathway connecting the VTA to the basolateral amygdala (BLA) in fear and anxiety has received little attention. In vivo microdialysis was performed to measure dopamine levels in the BLA of Wistar rats that received the dopamine D(2) agonist quinpirole (1 μg/0.2 μl) into the VTA and were subjected to a fear conditioning test using a light as the conditioned stimulus (CS). The effects of intra-BLA injections of the D(1) antagonist SCH 23390 (1 and 2 μg/0.2 μl) and D(2) antagonist sulpiride (1 and 2 μg/0.2 μl) on fear-potentiated startle (FPS) to a light-CS were also assessed. Locomotor performance was evaluated by use of open-field and rotarod tests. Freezing and increased dopamine levels in the BLA in response to the CS were both inhibited by intra-VTA quinpirole. Whereas intra-BLA SCH 23390 did not affect FPS, intra-BLA sulpiride (2 μg) inhibited FPS. Sulpiride's ability to decrease FPS cannot be attributed to nonspecific effects because this drug did not affect motor performance. These findings indicate that the dopamine D(2) receptor pathway connecting the ventral tegmental area and the basolateral amygdala modulates fear and anxiety and may be a novel pharmacological target for the treatment of anxiety.     

Parental Influences on Elite Aesthetic Athletes’ Body Image Dissatisfaction and Disordered Eating

Although different forms of parental influences on adolescents’ body image and eating disturbances have been studied, this relationship is nearly uninvestigated within the population of aesthetic athletes, a risk group for the development of eating disorders. The present study examined the role of specific family variables on the body image dissatisfaction (BID) and disordered eating (DE) of elite aesthetic athletes (n = 85) and controls (n = 142). Adolescents (M = 14.87 years, SD = 2.22) completed measures of direct influences (concern with thinness and weight teasing by parents), perceived quality of relationship with each parent and the overall family environment, BID and DE. Participants’ parents (223 mothers and 198 fathers) also completed measures of BID and DE. In general, parents of athletes do not present higher levels of BID or DE than do controls’ parents. Interesting differences were found between athletes’ and controls’ BID and DE predictors. Among athletes, direct parental influences are the only significant predictive family variable, which can reinforce the pressure to be thin found within elite-aesthetic contexts. The study’s findings highlight not only the importance of critical parental comments in athletes’ expression of BID and DE, but also of maternal modeling among adolescents in the general population. Such parental behavior may be an appropriate target in different prevention efforts.     

Relationship between dispositional optimism/pessimism and stress coping strategies

Recent studies confirm that dispositional pessimism is related with a worse state of physical health, in comparison with dispositional optimism . The efficacy of stress coping strategies has been considered as a mediating mechanism in this relationship. The aim of the present study is to analyze in a sample of university students (n = 200) the association between dispositional optimism/pessimism and different categories of self-reported somatic symptoms , and evaluate the possible mediation of the stress coping strategies in this relationship. The results indicate that: 1) pessimism is positively related with the report of physical symptoms, whereas optimism is negatively associated to somatic complaints; and 2) this relationship can be mainly explained by the differential utilization of the coping strategy denominated self-criticism (characteristic of pessimism).     

Why do people change in therapy? A preliminary study

Why do people change in therapy? A preliminary study. This work represents the beginning of a new way to study the processes that can explain the therapeutic change. The method used is the observation and analysis of therapeutic sessions directly recorded and developed inside a behavioural approach. The category system tries to carry out a functional analysis of the therapist-client interaction which enables the identification of learning processes that work in clinical setting and explain success in therapy. Outcomes are provisional but show the utility of this initial trend of investigation to the comprehension of clinical phenomenon. Conclusions also emphasize the importance of associative learning processes on the therapeutic change.     

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.     

On the facilitatory effects of cognate words in bilingual speech production

There is a growing body of evidence showing that a word's cognate status is an important dimension affecting the naming performance of bilingual speakers. In a recent article, Kohnert extended this observation to the naming performance of an aphasic bilingual (DJ). DJ named pictures with cognate names more accurately than pictures with non-cognate names. Furthermore, having named the pictures in Spanish helped the subsequent retrieval (with a delay of one week between the two tests) of the same pictures' names in English, but only for pictures with cognate names. That is, there was a language transfer but only for those translation words that were phonologically similar. In this article we first evaluate the conclusions drawn from these results by Kohnert, and second we discuss the theoretical implications of the facilitatory effects of cognate words for models of speech production in bilingual speakers.     

Outcome additivity and outcome maximality influence cue competition in human causal learning

Recent research suggests that outcome additivity pretraining modulates blocking in human causal learning. However, the existing evidence confounds outcome additivity and outcome maximality. Here the authors present evidence for the influence of presenting information about outcome maximality (Experiment 1) and outcome additivity (Experiment 2) on subsequent forward blocking. The results of Experiment 3 confirm that, with outcome maximality controlled, outcome additivity affects backward blocking but not release from overshadowing. Finally, the results of Experiment 4 demonstrate that information about outcome additivity has a similar effect on forward blocking if presented after the blocking training instead of before. The results are compatible with the idea that blocking results from inferential processes at the time of testing and not from a failure to acquire associative strength during training.     

Categorizing facial identities, emotions, and genders: attention to high- and low-spatial frequencies by children and adults

Three age groups of participants (5-6 years, 7-8 years, adults) matched faces on the basis of facial identity. The procedure involved either low- or high-pass filtered faces or hybrid faces composed from two faces associated with different spatial bandwidths. The comparison stimuli were unfiltered faces. In the three age groups, the data indicated a significant bias for processing of low-pass information in priority. In a second task, participants were asked to identify the emotion (smiling or grimacing) or gender (male or female) of hybrid high-pass/low-pass faces. Opposite results emerged in the two tasks irrespective of the age group; the gender discrimination task indicated a bias for low-pass information, and the emotion task indicated a bias for high-pass information. These differences suggest independent processing routes for functionally different types of information such as emotion, gender, and identity. These routes are already established by 5 years of age.     

Activation of adenosine receptors in the posterior cingulate cortex impairs memory retrieval in the rat

Adenosine A1 and A2A receptor agonists and antagonists have been reported to alter learning and memory. The aim of our study was to investigate the involvement of adenosinergic system in memory retrieval into posterior cingulate cortex (PCC) of Wistar rats. To clarify this question, we tested specifics agonist and antagonists of adenosine A1 and A2A receptors in rats submitted to a one-trial inhibitory avoidance task. The stimulation of adenosine A1 and A2A receptors by CPA and CGS21680, respectively, impaired memory retrieval for inhibitory avoidance task, into PCC. These findings provide behavioral evidence for the role of adenosinergic system in the memory retrieval into PCC.