The what, when, whether model of intentional action

The question of how we can intentionally control our behavior has an enduring fascination for philosophers, psychologists, and neurologists. Brain imaging techniques such as functional MRI have recently provided new insights into the functional and brain mechanisms involved in intentional action. However, the literature is rather contradictory and does not reveal a consistent picture of the functional neuroanatomy of intentional action. Here the authors argue that this confusion arises partly because intentional action has been treated as a unitary concept within neuroscience, even though experimental studies may focus on any of a number of different aspects of intentional action. To provide a heuristic framework for the investigation of intentional action, the authors propose a model that distinguishes three major components: a component related to the decision about which action to execute (what component), a component that is related to the decision about when to execute an action (when component), and finally the decision about whether to execute an action or not (whether component). Based on this distinction, the authors review some key findings on intentional action and provide neuroscientific evidence for the What, When, Whether (WWW) model of intentional action.     

Urinary organic acid excretion during feeding of medium-chain or long-chain triglyceride diets in patients with non-insulin-dependent diabetes mellitus

Medium-chain triglycerides (MCTs) are absorbed and metabolized differently from long-chain triglycerides (LCTs). Recent data indicate that MCTs may be useful as a dietary substitute in a variety of clinical disorders. The current studies were undertaken to characterize urinary organic acid excretion in patients with non-insulin-dependent diabetes mellitus during 4 d of an LCT or MCT diet. Urinary excretion of the dicarboxylic acids adipic, suberic, and 3-hydroxysebacic and the (omega-1) hydroxylation products 5-hydroxyhexanoic acid and 7-hydroxyoctanoic acid, was increased during MCT feeding as compared with LCT feeding. Urinary suberic and 7-hydroxyoctanoic acid excretions were increased 55- and 30-fold, respectively, during the MCT-substituted diet. Urinary organic acid profiles provide information on the fate of lipids during MCT feeding and may also be useful in assessing complicance during clinical trials employing MCT-substituted diets.     

Untersuchungen über den Gehalt des menschlichen Plasmas an antidiuretischem Hormon mit einer verbesserten Methode zum Hormonnachweis

Ohne ZusammenfassungMit Unterstützung der Deutschen Forschungsgemeinschaft.     

A study of twins and stroke.

BACKGROUND AND PURPOSE: Although there are strong genetic contributions to coronary artery disease, only a few studies have considered heritable influences on stroke. METHODS: We investigated the role of genetic factors in stroke using the Twin Registry maintained by the National Academy of Sciences-National Research Council. The registry includes 15,948 male twin pairs born between 1917 and 1927. In 1985, 9,475 twins responded to a mailed questionnaire, which covered vascular risk factors, cardiac events, and stroke. RESULTS: Analysis of twin pairs in which both responded to the questionnaire, and a question on stroke, indicated proband concordance rates of 17.7% for monozygotic pairs and 3.6% for dizygotic pairs (relative risk = 4.3; chi 2 = 4.94, df = 1; p less than 0.05). CONCLUSIONS: This nearly fivefold increase in the prevalence of stroke among the monozygotic compared with the dizygotic twin pairs suggests that genetic factors are involved in the etiology of stroke. The twin study paradigm holds considerable promise for identifying both genetic and environmental influences on stroke.     

Localized proton NMR observation of [3-13C]lactate in stroke after [1-13C]glucose infusion.

To assess whether elevated lactate in stable stroke is being actively produced from blood glucose localized 1H NMR stimulated echo spectra were obtained from a patient in the region of a 32-day-old cortical infarct before and 60-100 min after infusion of [1-13C]glucose. Prior to the infusion the spectrum from the region of the infarct contained an elevated resonance from C3 lactate and a greatly reduced resonance from N-acetyl groups relative to an unaffected contralateral region. After the infusion two additional resonances were observed at 62 and -64 Hz relative to the unlabeled resonance of C3 lactate which were assigned on the basis of chemical shift and relative intensity to [3-13C]lactate. The [3-13C]lactate fractional enrichment in the infarct region was measured to be 32% which is within error one-half the average [1-13C]plasma glucose enrichment during the postinfusion NMR measurement. The result suggests that the stroke lactate pool was completely derived from infused glucose.