Time-dependent changes in cognitive flexibility performance during intermittent social stress: Relevance for motivation and reward-seeking behavior

Repeated exposure to stress produces cognitive impairments that can lead to psychiatric disorders. How and when these cognitive impairments occur during repeated exposure to stress is not well understood. The present study investigates the time course effects of the exposure to intermittent episodes of social stress on cognitive flexibility performance. Male rats were trained to perform a cognitive flexibility (set-shifting) task. Then they were submitted to intermittent social defeat stress, which consisted of exposing animals to social defeat once every three days for ten days (four stress episodes). Set-shifting performance was evaluated before and in between social stress episodes, and up to ten days after the end of the stress protocol. Plasma levels of corticosterone after tail-pinch were also measured after the last set-shifting session. Intermittent exposure to social stress did not impair cognitive flexibility but produced short-and long-term changes in set-shifting performance. After the third social defeat episode, stressed animals required significantly more time to respond to cues (instrumental action) and to poke in the food-trough when no food pellet was delivered. These effects were reversed ten days after stress and suggest a decrease in motivation to pursue rewards. In contrast, stressed animals responded more accurately to light cues that predicted rewards. This effect, which emerged ten days after stress, suggests an increase in the reactivity to salient cues in the long-term. These time-dependent behavioral changes might help to understand the transition from social stress to stress-related disorders including drug abuse.

Sonographic diagnosis of a liver cell adenoma

As shown by the case we have reported, ultrasonography should be the first imaging method used in a young woman with pain in the right upper quadrant and a history of contraceptive use. Possible biliary system abnormalities, a more common cause of pain in the right upper quadrant, can be simultaneously evaluated.

A strategy for the biological assessment of addiction

Substances and drugs with powerful psychotropic effects have come into common use during the past decade. Involvement with these substances can range from benign to tragic experiences. Such use may include: experimental, social or recreational use, long-term habituation, toxic reactions, medical-psychologic complications, overdose, and death. Although clinicians tend to analyze and explain many patterns of drug use in terms of various psychodynamic, sociologic and behavioral theories, all of these perspectives begin with the biological and pharmacological effects produced by the various drugs. During the assessment process, the clinician can avoid much confusion by learning to differentiate between the direct pharmacological effects and the diverse psychological and behavioral effects of the drug(s) or substances(s) in question. In order to make these distinctions, a foundation in the "biological basics" is essential. This paper presents a strategy for learning the direct tropic effects produced by various drugs. This approach organizes commonly used drugs into six basic categories reflecting the primary action of each: narcotics and related analgesics; sedative-hypnotics (including barbiturates, non-barbiturate sedatives, minor tranquilizers and alcohol); stimulants (including amphetamines, cocaine, and others); hallucinogens; and others like phencyclidine, cannabis and inhalants, which do not readily fit the other categories.

Diagnosis in the addictions I: Conceptual problems

A crisis of categories exists in the body of knowledge associated with the phenomenon of the addictions. This crisis is characterized by (a) the absence of an accepted paradigm for integrating the knowledge in the field; (b) the consequent paucity of facts; and (c) the lack of integration between research, theory and practice. The problem of diagnosis has been brought into focus by (a) the growth of empirical and theoretical knowledge in the field; (b) the emergence of new patterns of substance use; and (c) changes in socio-cultural values and attitudes. Specifically, the categorical concept of dependence has become confusing and unworkable. A recent attempt at reformulation of diagnostic terminology of the field by the World Health Organization is reviewed and two conceptual schemes for identifying, gathering, and ordering the clinical data necessary to support a multidimensional diagnosis of drug dependence and the specification of drug-related disabilities are examined.

Choledochal cyst: sonographic evaluation of an unusual case

The preeminence of sonography in the diagnosis of obstructive jaundice has already been established. Earlier reports have described a variety of radiologic modalities used to establish the diagnosis of choledochal cyst. Our case illustrates the usefulness of sonography in differential consideration, though either transhepatic or operative cholangiography is necessary to further define the point and nature of the obstructive process and to determine that the cyst communicates with the common bile duct.

A perspective for pediatric surgeons: chronic idiopathic intestinal pseudoobstruction

Chronic idiopathic intestinal pseudoobstruction (CIIP) is a disorder of alimentary tract motility with onset of symptoms in adolescence or young adulthood, characterized by recurring attacks of abdominal pain, distention, vomiting, and constipation often leading to malnutrition and death. Starting with an adolescent patient, treated for a succession of life-threatening attacks of pseudoobstruction, the authors have identified CIIP in four generations of a Virginia family. Studies show characteristic dilation and diminished motility of the esophagus and intestine. Surgery's role in CIIP is palliative, and operation should only be offered when medical measures have failed to control symptoms.