Carroll W. Hughes

Depressive Syndromes in Children and Adolescents: Diagnosis and Treatment

AbstractMajor depressive disorder (MDD) in children and adolescents has been the focus of much research in the last decade. Findings to date indicate that MDD does exist in children and adolescents and is similar to MDD in adults in terms of phenomenology, family history of MDD, dexamethasone nonsuppression, and response to imipramine pharmacotherapy. These findings are reviewed, with a focus on diagnosis and pharmacological approaches to treatment.

Four indices of domestication in Norway rats

Reactivity to handling by an experimenter was predictably greater in wild rats than in domestic counterparts (Rattus norvegicus); this emotionality also diminished in certain critical aspects for wild rats over time. A second index from the pioneering research by Stone (1932), concealment in a stovepipe maze, also discriminated well but proved impractical and apparently confounded. The third, more objective index was a test involving water consumption. This too discriminated well; the wild rats drank more. A fourth and most contemporary index of domesticity compared the two kinds of rats’ swimming to the edge of a pool. Here again wild rats were more reactive and more efficient in escaping from the water.

On the origin of domesticity: A test of Keeler's "black-gene" hypothesis

In a classic set of papers on psychogenetics published in the 1940s, Clyde Keeler hypothesized that a single black recessive coat-color gene in Norway rats (Rattus norvegicus) was linked to docile, sluggish behavior as well as to reduced brain and adrenal gland size. Discovery of a possible “black-gene” rat in a large population of wild brown Norway rats prompted this test of Keeler’s proposed genetic origin of domesticity. Comparisons included computer-monitored open-field activity, activity wheel performance, water consumption, and physiological measures. Contrary to Keeler’s hypothesis, essentially no differences were found among wild black rats, their offspring, and brown rats on either the behavioral or the physiological measures. Our data would suggest that multigenic mechanisms of domestication, including selections and ontogenetic processes, seem to account best for the origin of domesticity.

A stereotaxic implant technique for the weanling rat

A modified technique for permanently implanted electrodes in the weanling rat is presented. As a reliable and durable technique, long-term stimulation of the juvenile rat is made possible.

Consideration of Physiologic Mechanisms in Animal Models of “Sudden Death”

Animal research of the “sudden death” phenomenon purporting to demonstrate causal psychological states has serious methodologic problems. Neither models nor the definition of the term, “sudden death,” are uniformly adopted; thus, the literature contains many conflicting reports. Further, much of the work has dealt with assumed psychological causation which is nontestable in nonverbal animals and tends to obscure study of quantifiable behavioral and physiological mechanisms.

Altered acetylcholinesterase activity (AChE) and maze performance of developing rats (Rattus norvegicus) following mesencephalic electrical brain stimulation

Cortical arousal was altered by electrical brain stimulation (EBS) to the mesencephalic ascending reticular formation beginning at 27 days of age and administered 2 h/day for either 14 or 28 days. Subjects receiving brain stimulation from 27 to 41 days of age showed a significant decrease in telencephalon AChE activity and weight when compared to controls. These decreases in biochemical and physical parameters corresponded to a marked decrement in maze performance. The advantages and potential uses of the weanling chronic EBS preparation to investigate critical developmental periods are considered.