Biomedical subjects

G M Brosvic

Publications and source records attributed to G M Brosvic.

23 records · Page 2Linked to original sources

PubMed1989

Effects of copper and vitamin B-6 deficiency on taste sensitivity in the rat: a signal detection analysis.

The effects of dietary copper and Vitamin B-6 deficiency on NaCl sensitivity in adult male rats were assessed in separate studies using a double-blind protocol, high-precision gustometry, computer-controlled go/no-go operant procedures and signal detection measures of sensitivity and responsivity. The dietary manipulations reduced plasma copper ion content to 40% of baseline levels in the copper deficient group and plasma 5'-pyridoxalphosphate content to 5% of baseline levels in the Vitamin B-6 deficient group and, as expected, altered hematocrit and hemoglobin levels in both groups. These metabolic changes resulted in increased NaCl preference in the Vitamin B-6 deficient group but did not alter sensitivity or responsivity to NaCl, and similar results were obtained in simple and complex taste discrimination tests. The present results demonstrate that dietary copper and Vitamin B-6 deficiencies do not result in altered taste sensitivity in the adult male rat.

Animals↗

PubMed1989

Quality specific differences in human taste detection thresholds as a function of stimulus volume.

Taste detection thresholds for sodium chloride, sucrose, citric acid and quinine sulfate were determined with the Henkin three drop forced-choice method at stimulus volumes 0.05 ml, 0.50 ml, and 0.90 ml, with and without water rinses. Taste thresholds were inversely related to stimulus volume (median rs = -.68 and, within each volume, thresholds did not differ as function of water rinsing. The detection thresholds for sodium chloride (range: 15.06 mM to 6.7 mM), sucrose (range: 24.22 mM to 14.13 mM), citric acid (range: 1.47 mM to 0.5 mM) and quinine sulfate (range: 0.35 mM to 0.12 mM) were similar to those of other investigators using considerably larger stimulus volumes and different psychophysical procedures. The present results demonstrate that the Henkin three drop method provides a more optimal measure of changes in taste sensitivity when stimulus volumes of approximately 1 ml are used in place of the standard 0.05 ml stimulus volume.

Adolescent↗

PubMed1989

No influence of adrenalectomy on measures of taste sensitivity in the rat.

The influence of adrenalectomy on the taste sensitivity and responsivity of Long-Evans rats to sodium chloride and sucrose tastants presented separately and in mixtures was examined using high precision gustometry, computer-controlled go/no-go operant procedures, and nonparametric signal detection measures. Relative to baseline levels, adrenalectomized rats' plasma corticosterone levels decreased by 328% while sodium chloride and water consumption increased by 548% and 165%, respectively. The same measures remained unchanged in sham-operated animals. Taste sensitivity and responsivity to sodium chloride and sucrose did not differ between adrenalectomized and sham-operated animals and discrimination performance remained the same between the groups as well. The present results support and extend previous findings that adrenalectomy and the resultant corticosteroid deficiency does not influence taste sensitivity or responsivity in the rat.

Adrenal Cortex↗

PubMed1988

The horizontal-vertical illusion and knowledge of results.

The Horizontal-Vertical (HV) Illusion was examined in two studies in which subjects adjusted the vertical line in L-shaped and inverted-T figures or produced lines in the vertical and horizontal planes. On the adjustment tasks, vertical lines were made significantly shorter than horizontal comparison lines, especially for the inverted-T figure. On the production tasks, lines drawn in the vertical plane were significantly shorter than lines drawn in the horizontal plane. The adjusted and created lines of subjects receiving intertrial feedback on illusion magnitude were significantly more accurate and less variable than the estimations of control subjects. Performance on either task or figure type did not differ as a function of sex of subject. The present results show that the HV illusion exists in the absence of line bisection or a comparison line and results from the overestimation of vertical lines. These findings further clarify the relative contributions of the structural and strategy mechanisms in the formation of the Horizontal-Vertical Illusion.

Adolescent↗

PubMed1986

Absolute and intensity-difference taste thresholds in the rat: evaluation of an automated multi-channel gustometer.

An operant conditioning procedure is described for assessing taste detection and discrimination in rats. Rats were trained to lick at a 10-barrel stimulus delivery tube for a 0.005-ml sample of a positive (S+) or negative (S-) stimulus and to switch to a water delivery tube after presentation of S+. The system is computer controlled and selection of stimuli can be made interactive with performance. After preliminary training, absolute and intensity-difference thresholds can be determined in 1-2 sessions. Mean absolute thresholds in 10 rats for NaCl, sodium-saccharin, and sucrose were 0.0049%, 0.0012%, and 0.035%, respectively. Intensity-difference thresholds (not reported previously in the rat) for NaCl and saccharin were 16.1% and 12.3%, respectively. With these procedures rats also rapidly acquired 2-tastant discriminations, including those involving taste mixtures.

Animals↗