Temporomandibular Disorder in Brazilian Patients: A Preliminary Study

The objective of the current study was to evaluate disease-related beliefs, adherence to treatment, quality of life, coping strategies and cognitive status in a group of Brazilian patients with Temporomandibular Disorder (TMD). Thirty patients were evaluated with a semi-directed interview, the Coping Strategies Inventory, and a Mini-Mental State Examination. Although half (50%) of the patients had known their diagnosis long term, 40% of the sample were not correctly following proposed treatment. All patients had a similar pattern of pain behavior related to TMD, while disease-related beliefs, quality of life and coping strategies were variable. Expectations about treatment also had significant association with treatment adherence. The findings of this study suggest that a more thorough understanding of individual differences in TMD is warranted.     

The Quality of Home Environment in Brazil: An Ecological Model

Based on Bronfenbrenner's (1999) ecological perspective, a longitudinal, prospective model of individual differences in the quality of home environment (Home Observation for Measurement of the Environment—HOME) was tested in a sample of 179 Brazilian children and their families. Perinatal measures of family socioeconomic status (SES) and child birth weight had direct effects on HOME at preschool age. As either family SES or child birth weight increased, HOME also increased through diminished emotional distress in the mother a month following childbirth. SES had a negative effect on number of children in the household, which in turn had a long-term negative impact on HOME. Compared to mothers who had reported not to plan their pregnancy, those who did were more likely to have fewer children, to report more spouse support during childbearing, and to show less emotional distress a month after childbirth, all of which also influenced HOME at preschool age. These findings are discussed in light of the broader socio-ecological Brazilian context, with direct implications to clinical practice aimed at improving the quality of home environment.     

Effects of trophic poisoning with methylmercury on the appetitive elements of the agonistic sequence in fighting-fish (Betta splendens)

The aggressive display in Betta splendens is particularly prominent, and vital to its adaptation to the environment. Methylmercury is an organic variation of Hg that presents particularly pronounced neuro-behavioral effects. The present experiments aim to test the effect of acute and chronic poisoning with methylmercury on the display in Bettas. The animals were poisoned by trophic means in both experiments (16 ug/kg in acute poisoning; 16 ug/kg/day for chronic poisoning), and tested in agonistic pairs. The total frequency of the display was recorded, analyzing the topography of the agonistic response. The methylmercury seems to present a dose- and detoxification-dependent effect on these responses, with a more pronounced effect on motivity in acute poisoning and on emotionality in the chronic poisoning. It is possible that this effect could be mediated by alteration in the mono-amino-oxidase systems.     

Choice, experience, and the generalized matching law

Five pigeons were exposed to different pairs of concurrent variable-interval, variable-interval schedules on nine experimental conditions of 30 sessions each. For every session, the parameters of the generalized matching equation were computed for the first five, six, seven, eight, and nine experimental conditions. The exponent a, both for response and time distribution, tended to decrease with increases in number of experimental conditions and to increase with number of sessions per condition, but values of k (bias) varied unsystematically. When the subjects were exposed to five new pairs of schedules, with 55 sessions per condition, the findings were confirmed. Data from the literature on the generalized matching law suggest that the variability of exponent values may be explained in part by the use of naive or experienced subjects in different investigations and by the variability in number of experimental conditions and in number of sessions per condition.     

Performance of Faller and Nonfaller Older Adults on a Motor–Motor Interference Task

Typically, falls in older adults occur when 2 tasks are performed simultaneously, due to the increased motor demand required to maintain stability and attention to perform the other task. The authors' purpose was to investigate walking while grasping, transporting, and placing a dowel on a predetermined target while manipulating difficulty levels of the manual task. Faller and nonfaller older adults performed a walking block (manual tasks combined with gait) and a stationary block (upright stance combined with manual tasks). The manual task involved grasping, transporting, and placing the dowel over a target. The results showed that fallers underperformed when compared with nonfallers in the task of placing the dowel over the target. The main difference observed between the groups was found in the condition that required allocation of attention between tasks and greater accuracy in the final placement of the object. Fallers showed gait stability similar to the nonfallers, but fallers were less accurate than nonfallers in the object placement task, especially for the highest level of difficulty. Thus, fallers seem to use a stability-first strategy. Fallers had problems in executing the manual tasks, which suggests a more global change in motor behavior rather than specific changes to balance control.     

Representational momentum in dynamic facial expressions is modulated by the level of expressed pain: Amplitude and direction effects

Humans have developed a specific capacity to rapidly perceive and anticipate other people’s facial expressions so as to get an immediate impression of their emotional state of mind. We carried out two experiments to examine the perceptual and memory dynamics of facial expressions of pain. In the first experiment, we investigated how people estimate other people’s levels of pain based on the perception of various dynamic facial expressions; these differ both in terms of the amount and intensity of activated action units. A second experiment used a representational momentum (RM) paradigm to study the emotional anticipation (memory bias) elicited by the same facial expressions of pain studied in Experiment 1. Our results highlighted the relationship between the level of perceived pain (in Experiment 1) and the direction and magnitude of memory bias (in Experiment 2): When perceived pain increases, the memory bias tends to be reduced (if positive) and ultimately becomes negative. Dynamic facial expressions of pain may reenact an “immediate perceptual history” in the perceiver before leading to an emotional anticipation of the agent’s upcoming state. Thus, a subtle facial expression of pain (i.e., a low contraction around the eyes) that leads to a significant positive anticipation can be considered an adaptive process—one through which we can swiftly and involuntarily detect other people’s pain.     

Predator (cat hair)-induced enhancement of hippocampal long-term potentiation in rats: involvement of acetylcholine

Extensive literature has demonstrated that arousal and fear modify memory acquisition and consolidation. Predator hair and odors increase arousal in rats and, therefore, may influence information encoding and synaptic plasticity in the rodent nervous system. In behavioral experiments, we confirm that laboratory-bred Long Evans rats avoid cat hair. Electrophysiological work in vivo showed that long-term potentiation (LTP) in the dentate gyrus induced by perforant path stimulation was enhanced for 5-7 days when LTP induction occurred in the presence of cat hair relative to fake hair. The muscarinic receptor antagonist scopolamine (i.p.) reversed the cat hair-elicited LTP enhancement without affecting weaker LTP elicited in the presence of fake hair. Thus, exposure to a predator stimulus elicits a cholinergically-dependent state of heightened plasticity that may serve to facilitate information storage in hippocampal circuits.     

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.