Thomas J. Koehnle

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Recognizing a deficiency of indispensable amino acids (IAAs) for protein synthesis is vital for dietary selection in metazoans, including humans. Cells in the brain's anterior piriform cortex (APC) are sensitive to IAA deficiency, signaling diet rejection and foraging for complementary IAA sources, but the mechanism is unknown. Here we report that the(More)
Pseudoreplication is one of the most influential methodological issues in ecological and animal behavior research today. At its inception, the idea of pseudoreplication highlighted important concerns about the design and analysis of experiments in ecology. The doctrine purported to provide a unified view of experimental design and analysis, wherein precise(More)
Omnivores must obtain diets balanced with respect to amino acids to support growth and protein synthesis. The standard paradigm used to study behavioral responses to amino acid deficiency combines deficient diets with dietary novelty. The objective of this study was to examine the effects of amino acid deficiency on the first meal of rats without the(More)
We have investigated the axonal transport of neurofilament protein in cultured neurons by constricting single axons with fine glass fibers. We observed a rapid accumulation of anterogradely and retrogradely transported membranous organelles on both sides of the constrictions and a more gradual accumulation of neurofilament protein proximal to the(More)
The anterior piriform cortex (APC) functions as a chemosensor for indispensable amino acid deficiency and responds to this deficiency with increased activity, as indicated by observations including averaged evoked-potentials and c-fos expression in the APC. Little is known of the intracellular signaling mechanisms that mediate this deficiency-related(More)
Diets deficient in an indispensable amino acid have long been known to suppress food intake in rats. Detection of dietary deficiency takes place in the anterior piriform cortex (APC). Recent studies showed that the response to amino acid deficiency takes as little as 15 min to develop, but few data exist to correlate the concentration of amino acids in the(More)
Interoceptive signals have a powerful impact on the motivation and emotional learning of animals during stressful experiences. However, current insights into the organization of interoceptive pathways stem mainly from observation and manipulation of adults, and little is known regarding the functional development of viscerosensory signaling pathways. To(More)
Numerous clinical reports indicate that thyroid hormones can influence mood, and a change in thyroid status is an important correlate of depression. Moreover, thyroid hormones have been shown to be effective as adjuncts for traditional antidepressant medications in treatment-resistant patients. In spite of a large clinical literature, little is known about(More)
The present study examined whether manipulation of the early life experience of rat pups might alter the later ability of an interoceptive challenge to recruit central neural circuits that receive visceral sensory signals and generate stress responses. For this purpose, litters were exposed to daily maternal separation for either 15min (MS-15) or 180min(More)