Electrophysiologic analysis of the representation of the somatosensory system in the dogfish midbrain tectum

Evoked responses in the dogfish tectum opticum were studied during electrical stimulation of the spinal cord, its dorsal roots and ramus ophthalmicus of the facial nerve. Recordings were obtained from different depth as well as from different points on the tectum surface. Evoked responses could be detected mainly on the contralateral side of the tectum opticum either as slow positive (spinal cord stimulation) or negative-positive (facial stimulation) waves which were preceeded by one or two fast, probably, presynaptic deflections and followed by a very slow low-amplitude negative wave. The evoked responses possessed the properties of tectal postsynaptic responses, being somatotopically distributed on the surface and reversely represented in the inner part of the tectal lamina. Projections of different inputs were widely overlapped, but specific areas of maximal activity were presented. These findings evidence that the tectum opticum performs a double function: a primary projecting and an integrative centre.     

Effect of non-catecholic 2-aminotetralin derivatives on dopamine metabolism in the rat striatum

The concentrations of dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured in the striatum of rats after i.p. injection of dipropyl-2-aminotetralin and the four positional isomers of monohydroxy-dipropyl-2-aminotetralin. All compounds except 8-OH dipropylaminotetralin caused a decrease in DOPAC- and HVA-concentrations. In addition, 5-OH-dipropylaminotetralin produced a small elevation in DA concentrations. In contrast, 7-OH dipropylaminotetralin, in doses of 100 mumol/kg and more, decreased DA to 50% and initially increased HVA and DOPAC to about 200%, after which the concentrations of the metabolites fell to 30% or less. The 5-OH isomer was found to be the most potent compound, decreasing HVA concentrations to 70% at a dose of 0.14 mumol/kg. The potencies are compared to those of catechol-group containing DA-agonists such as apomorphine and N,N-dipropyl-5,6-dihydroxy-2-aminotetralin. In addition, a comparison is made with reported behavioural data. It is suggested that the more active N-alkylated 2-aminotetralins have a conformation which corresponds to that of the alpha rotamer of dopamine.     

Analysis of a multi-criteria project crashing model

The purpose of this paper is to report on the model formulation and results of a multi-criteria time-cost (crashing) CPM project network. In the project of interest (the installation of a bank paper processing system), multiple and conflicting objectives concerning both time and cost must be incorporated into the decision analysis. The project network is, therefore, formulated as a goal programming model, including the various managerial objectives as goal constraints and associated priorities.     

Reflex conditioning in a spinal man.

A 40-yr-old man with a completely transected spinal cord and a spastic neurogenic bladder was conditioned to void upon the presentation of an external stimulus. A classical conditioning paradigm was employed in which strong abdominal shock (UCS) was paired with an initially neutral mild electrical stimulation of the thigh (CS). After the pairing trials, a reliable conditioned response of urination was elicited by the CS alone. The conditioned response did not extinguish over time, and the procedure left the bladder with clinically safe residual amounts of urine. Practical implications of the conditioning technique for the treatment of spastic neurogenic bladder conditions in spinally injured patients are discussed, as is the theoretical significance of conditioning at the reflex level in the absence of cortical involvement. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Le laser a impulsions pour le denombrement en fluorescence de Escherichia coli enteropathogene sur membrane filtrante

Reproducible results in fluorescence are obtainable with a pulsed dye laser as the excitation source for the enumeration of enteropathogenic E. coli directly on a membrane filter; an electronic detection and recording system is used and the technique may be completely automated.