Search PubMed⌕ Search

Biomedical subjects

D B Adams

Publications and source records attributed to D B Adams.

At least 91 records · Page 5Linked to original sources
PubMed1984

An empirical study of the structure of the patrol/marking motivational system in the rat.

The existence and structure of an hypothesized motivational system of patrol/marking was supported and elucidated by a behavioral study on untrained highly inbred laboratory rats. One rat (the "runner") was placed into a test chamber containing a wire-mesh running wheel flanked by two chambers, one of which contained another rat (the "target"). Four conditions of runners (socially-isolated males, socially-housed males, non-estrous females, and estrous females) were exposed to four types of targets (socially-housed males, non-estrous females, estrous females, and blank targets consisting of any empty target chamber). Also placed in the chamber was a Petri dish containing scent-markings of the target rat. The experiment was designed in a counterbalanced way with 10 replications and repeated two times in two separate years. As predicted from the hypothesis, scent-marking, sniffing the dish, locomotion (number of wheel revolutions), and approach (differential running towards the target) were all correlated with each other and varied in the same way as a function of the hormonal and experiential condition of the runner and the type of target. They were interpreted to reflect motor patterns of a single unitary patrol/marking motivational system. Grooming, on the other hand, did not correlate with the other behaviors and facial gland secretion was, therefore, rejected as a motor pattern of patrol/marking.

Animals↗
PubMed1983

Activity of basal forebrain neurons in the rat during motivated behaviors.

The activity of single neurons in the basal forebrain was recorded in the freely-moving rat with moveable fine-wire electrodes. Neural activity was observed while the water-deprived male rat was exposed to three different types of motivating stimuli that elicit locomotion in a running wheel: an estrous female rat; a drinking tube containing water; and grasping and lifting by the experimenter. The neural activity was also observed when the subject was presented with standardized sensory tests and during single pulse stimulation of other brain structures. A majority of the 76 neurons recorded in the forebrain changed their firing rate during orienting and/or locomotion in general (23 neurons) or during behavior related to only one of the specific motivational contexts: the conspecific female (4 neurons); water (7 neurons); or grasp by the experimenter (8 neurons). Whereas the neurons related to orienting and/or locomotion in general were scattered through various brain structures, those neurons related to specific motivational contexts were concentrated in specific areas: the sexually dimorphic nucleus of the medial preoptic area (conspecific female); lateral septum (water); and lateral preoptic area (water and grasp). The present results, although based on relatively few neurons, are consonant with results of research using other techniques. This indicates that analyses at the level of the single neuron promise to be useful for understanding the role of the basal forebrain in motivational systems.

Animals↗
PubMed1983

Investigation with dexamethasone of the processes which moderate immunity against the nematode, Haemonchus contortus, in sheep.

Treatment of sheep with the corticosteroid, dexamethasone, was used to investigate some properties of the immunoregulatory process which dampens the expression of protective responses against the abomasal nematode, Haemonchus contortus, and which may occur as an adaptation for evasion of host immunity by this parasite. The protective responses released by giving dexamethasone early in infection operated during a series of superimposed infections. Accordingly, they may also operate during field exposure to the parasite. Dexamethasone-released protective responses acted earlier than 7 days after infection. Accordingly, there is no reason to suggest that they are distinct from the responses which usually produce refractoriness to infection. Results from two consecutive but not superimposed infections show that activity of the immunoregulatory process identified by dexamethasone treatment can persist for a month. This implies that there is memory for immunoregulation in infection by H. contortus.

Animals↗
PubMed1983

Chronic pain.

Explore the source record for details and available documents.

Back Pain↗
PubMed1981

Ratio of central nervous system to body metabolism in vertebrates: its constancy and functional basis.

We present and document an hypothesis that healthy adults of most vertebrate species use 2-8% of their basal metabolism for the central nervous system (CNS). This relationship is constant across all classes of vertebrates, as we found by examining data from 42 species, including 3 fish, 3 amphibia, 2 reptiles, 6 birds, and 28 mammals. To explain its constancy, we hypothesize that an optimal functional relationship between the energy requirements of an animal's executor system (muscle metabolism) and its control system (CNS metabolism) was established early in vertebrate evolution. Three types of exceptional cases are discussed in terms of the hypothesis: very large animals, domesticated animals, and primates.

Amphibians↗