Threshold tracking for assessment of long-term adaptation and sensitization in pain perception

To assess temporal variations in the perception of "phasic" heat pain stimuli a psychophysical tracking procedure was developed that enables repeated assessment of the pain threshold at short intervals. This "double-tracking" procedure produces two tracking curves simultaneously, one that approaches the pain threshold gradually from above, the other from below. The threshold for phasic heat pain was measured in 80 tracking trials with stimuli at temperatures near the pain threshold. Concurrently, the threshold for "tonic" heat pain was determined after every 20 tracking trials with a stimulus adjustment procedure. Eleven healthy subjects (age: 26.4 yr. +/- 6.0) participated in 2 sessions each. Phasic stimulation near the pain threshold did not produce any trends in either of the two threshold measures. Hence there was no long-term adaptation or sensitization. However, there were random variations (random walks) in the tracking curves, which we interpret as resulting from a stochastic relationship between stimulus and sensation. In agreement with other reports, discrimination seemed to be better at painful than at nonpainful temperatures.     

Decision time and movement time in depression: differential effects of practice before and after clinical improvement

Choice reaction time involves, at least two components of response latency, decision time and movement time. Studies of choice reaction time usually provide values of these two components averaged over a given number of trials. The aim of the present study of depressed subjects was to investigate changes across practice on Decision Time (DT) and Movement Time (MT) before and after clinical improvement. 19 depressed subjects were given two sessions of 50 trials each, one before treatment (Di) and one after recovery (Df). Decision time and movement time exhibited quite different patterns. Decision time significantly decreased with clinical improvement. No significant variation across trials was found, in either session. Movement time values varied across trials but the variations observed on Di and Df were significantly different, whereas before treatment latencies recorded at the end of the session were greater than those scored at the start, the contrary was observed after clinical recovery. No significant difference was found between values of movement time scored at the start of the two sessions.     

On the logic of causally necessary and sufficient conditions: Towards a theory of motive-explanations of human actions

Research carried out under the auspices of the Bank of Sweden. Tercentenary Foundation project RJ 86/183: Basic Concepts of Procedural Law in the Light of Present-Day Philosophy of Language and Linguistics.     

Alcoholism: etiologies proposed and therapeutic approaches tried

Alcohol, probably the most popular mood-altering drug, has frightening consequences when abused. Genetic factors and sociocultural influences contribute to alcoholic behavior. Study of endocrines, neurotransmitters, and neuropeptides may reveal biological markers to help identify those at risk for alcoholism. Drinking patterns are often based on the expectation of alcohol's mood-altering quality. The focus of treatment has expanded to include not only drinking behavior but also emotional, social, and vocational adjustment. Controlled drinking has proved effective for some, so that complete abstinence is no longer the sole goal of therapy. Behavioral, martial, group and individual, outpatient and inpatient therapy, and drugs as adjuncts, all help some alcoholics, but none is a cure for all. Answers still lag behind questions but researchers have registered some advances that challenge therapists to enlarge therapeutic approaches to fit the multifaceted picture of alcoholism.     

Aggressive behavior inhibition by serotonin and quipazine injected into the amygdala in the rat

The effects on aggressive behavior, open-field activity, and pain threshold of bilateral microinjections of serotonin (20 micrograms) and quipazine (20 micrograms), the direct serotonergic receptor agonist, into the cortico-medial amygdala were investigated in Wistar rats. Both drugs significantly prolonged the attack latency in isolated killer rats (predatory aggression model), and suppressed the incidence of aggressive postures/attacks in shock-induced fighting test (affective aggression). The only difference in the open-field behavior was the lower number of central square entries in drug-treated compared to saline-injected rats. None of the substances produced any significant change in jump threshold. It is concluded that stimulation of serotonin receptors within the amygdala produces inhibition of affective and muricidal behavior in isolated rats. The effect does not seem to be dependent on changes in general activity and pain sensitivity.     

Mechanisms used by young children in the making of empathic judgments

Forty-four preschool children ranging from three to five years of age received a series of stones in which the protagonists experience happiness, sadness, or fear These protagonists were portrayed as either similar or dissimilar to the child, and the situations depicted were either familiar or unfamiliar to him/her as well The children's task was to infer the emotions experienced by the protagonists Results indicate that children were more accurate in judging the emotions of similar target persons than they were for dissimilar ones Familiarity with the situation, on the other hand, had no effect on accuracy Children were more accurate in identifying happiness and sadness than they were in judging fear, and age was positively related to judgmental accuracy for the former two but not for the latter These results help to resolve the controversy arising from earlier studies of empathy development which failed to disentangle the similarity and familiarity dimensions     

Frequency of neurologic-psychiatric findings in the late phase following minor and medium severe blunt craniocerebral injuries

The authors present a short review of the pertinent literature and report on their own neuropsychiatric findings following internal craniocerebral injuries, at the same time drawing attention to the necessity of psychological examination. Statistical comparisons with the international literature are complicated owing to the different classifications used for craniocerebral injuries.