Douglas L. Grimsley

Salt seeking by means of food and fluid selection in adrenalectomized rats

An experiment involving several changes in the salt content of food and solutions investigated the generality of salt-seeking behavior in adrenalectomized rats. Salt-solution intake varied as a function of NaCl concentration. The intake of sodium is relatively unaffected by the concentration of NaCl in the food as long as NaCl in solution is available. But when the salt solution is removed, salt seeking and sodium regulation takes place by way of salt in the food.

Bilateral skin temperature, handedness, and the biofeedback control of skin temperature

There are differences in physiological variables when they are recorded from the left and right side of the body simultaneously. In some cases, handedness has been found to have a significant relationship to bilateral differences. The present study examined the relationship between handedness and baseline heart rate and skin temperature, as well as bilateral differences in skin temperature during visual and auditory biofeedback. Subjects were 32 college females, 24 right-handed and 8 left-handed. Recordings of heart rate and skin temperature from both the dominant and the nondominant hand were made during baseline and during the 10-min experimental session while subjects attempted to warm their dominant hand. Both groups showed significantly increased skin temperature during the experimental session. No prominent bilateral differences in skin temperature were found. These results do not support bilateral differences as a generalizable construct.

Pavlov's position on the effects of decortication on conditional reflexes

This paper examined D. Joravsky’s (1989) hypothesis that I.P. Pavlov dogmatically refused to acknowledge that classical conditioning can be mediated by subcortical regions of the large cerebral hemispheres. Decortication literature from 1901 to 1936 was reviewed. The early studies available to Pavlov, who died in 1936, showed that decortication does not allow the establishment of new or retaining of old conditional reflexes (CRs). G.P. Zelenyi’s later experiments(1930) suggested that the establishment of primitive CRs in decorticated dogs was possible. Pavlov never denied this possibility but cautioned that Zelenyi’s experiments could have been methodologically flawed. Although Joravsky’s original hypothesis on Pavlov’s position on the relation between decortication and the establishment of CRs is by and large accepted, it must be stressed that Pavlov’s theory of higher nervous activity was primarily concerned with the function of the brain in the higher organism’s struggle for existence. Within this context the cortical, rather than subcortical, processes play the decisive role in the organism’s adaptation to the changing external environment.

NaCl preference in the gerbil

Gerbil preference levels for salt solutions were determined by using the single-stimulus method. The concentration resulting in the largest acceptance was 0.9%, even though gerbils can utilize salt solutions as high as 6%. Since the single-stimulus method correlates well with other preference measures, these results should generalize to other testing procedures.

Effect of preoperative exposure to salty food on food selection in adrenalectomized rats

Rats that have been adrenalectomized will seek NaCl in food or in a solution, but they show a marked preference to regulate salt balance by drinking rather than eating. The hypothesis that rats do not regulate NaCl by eating because of limited exposure to diets rich in NaCl was tested in the present experiment. Twenty weanling rats were divided into two major groups: (1) experienced animals who were fed lab chow with extra NaCl added for 40 preoperative days, and (2) inexperienced animals that ate plain lab chow preoperatively. Half of each of these groups were adrenalectomized and half were sham operated. All animals had access to both plain and NaCl-enriched food postoperatively. The results showed that the adrenalectomized rats consumed considerably more NaCl-enriched food than did the sham animals, but that preoperative salt experience had no significant effect on intake. Sodium-deficient rats will seek out NaCl in food and regulate their salt need; this behavior occurs with or without preoperative experience with NaCl-enriched foods.

Effects of experience with salty food on salt selection in adrenalectomized rats

Sodium-deficient rats will seek out NaCl in food or solution and regulate their salt need. The question of this study is the extent to which salt-seeking behavior can be modified by long-term exposure to a high NaCl diet. Four female rats were divided into two groups: (1) animals that were fed lab chow with extra NaCl added during breeding, gestation, and until the offspring were weaned, the Experienced group, and (2) animals that ate only plain lab chow until weaning, the Inexperienced group. Food preference was measured in the offspring at age 28–29 and 41–42 days and them about half of each group were adrenalectomized and half sham operated. All animals had access to both plain and NaCl-enriched rood and saline for 10 days postoperatively. The saline solution was removed and intake measured for an additional 8 days. Early experience with the high NaCl diet resulted in greater consumption of the NaCl-enriched food preoperatively and altered the pattern of intake following the removal of the saline solution postoperatively. The results indicate that early exposure to a high salt diet can influence the rats’ later salt-seeking behavior.

Nicotine effects on biofeedback training

Biofeedback involving hand warming has become a frequently used procedure in health and stress management programs. The present research examined the effects of smoking on the ability to learn temperature control during biofeedback training. Three groups of female college students were compared: groups of smokers who smoked prior to the biofeedback session were compared to smokers who did not smoke and to nonsmokers. The results showed that the greatest increase in skin temperature was for nonsmokers, followed by smokers who did not smoke for at least 1 hr before the biofeedback session. The group of smokers who smoked just prior to the biofeedback were not able to increase their skin temperature. The basal skin temperature measured before treatment was higher for smokers than nonsmokers. The results are discussed in terms of the paradoxical physiological arousing effects and the self-reported tranquilizing effects of smoking.

Carotid ligation in the rat

The effects of unilateral carotid ligation on physiological regulation and learning were studied in laboratory rats. Body weight, water intake, and T-maze performance were not significantly different from that of sham-operated animals. Cannulation of the carotid artery is, therefore, a useful laboratory tool with few undesirable side effects.