Biomedical subjects

W F McDaniel

Publications and source records attributed to W F McDaniel.

28 records · Page 2Linked to original sources

PubMed1992

A rapid technique for visualizing cerebral arteries in rat.

Intracardiac perfusion with cresyl violet acetate dissolved in 0.9% isotonic saline and dimethyl sulfoxide (DMSO) allows one to visualize the arterial blood supply to the central hemispheres. This technique is especially useful in demonstrating the ramifications of and areas supplied by the middle cerebral artery. Many individual differences in the course traversed by the artery and the distal areas supplied were observed. This technique could prove to be a useful adjunct to neurohistological techniques in studies investigating rodent models of stroke.

Animals↗

PubMed1992

ORG 2766 fails to improve visual functions in rats with occipital lesions.

Adult rats were trained on a white versus black card discrimination in a circular water tank. Three independent variables were manipulated: lesion (sham, lateral occipital, medial occipital), dose of ORG 2766 administered (0 or 25 micrograms in saline on alternate days for 18 days), and time of administration (during the post-surgical recovery interval or during post-operative testing). Both visual cortical lesions produced a prominent retention deficit and defective pattern vision. Neither post-surgical nor concurrent administration of ORG 2766 improved visual functions. These results, along with a growing body of evidence, challenge the generality of the positive influences of ORG 2766 upon behavioral recovery observed in animals with limbic lesions.

Adrenocorticotropic Hormone↗

PubMed1992

A behavioral study of bilateral middle cerebral artery hemorrhagic ischemia in rats.

The middle cerebral artery was severed bilaterally (bMCA) in adult rats, and controls experienced sham operations. Tactile sensorimotor and gross locomotor functions, measured by the tape test and a rod walking test, were initially impaired in the injured animals. However, these deficits had resolved within 9 and 30 days respectively. The animals were trained in a multiple T water maze task to find the location of a hidden escape platform at the rate of one trial per day for 30 days. Analyses of the number of errors committed and latency to find the escape platform revealed that the bMCA injured rats suffered deficient reference memory, but no decline in working memory. These data support further the use of the bMCA preparation as a model of stroke.

Animals↗

PubMed1991

Medial frontal lesions, postoperative treatment with an ACTH(4-9) analog, and acquisition of a win-shift spatial strategy.

Forty adult rats of both genders were randomly assigned to one of four factorial groups and prepared with either medial frontal or sham lesions. On the day of surgery osmotic mini-pumps that had been prepared to deliver either 12.5 micrograms of ACTH(4-9) analog per 24 h or saline for the next 14 days were installed in a subcutaneous location. One month following surgery, these animals were studied in an avoidance conditioning experiment. Four to 6 months later their abilities to learn a water maze win-shift spatial strategy was investigated. The brain-damaged rats were found to be deficient on all behavioral measures examined: errors to criterion, days to criterion, and perseverative errors. Although post-neurosurgical administration of the ACTH 4-9 analog has been shown to improve behavioral recovery from brain damage in some studies, the peptide failed to improve the behaviors examined here.

Adrenocorticotropic Hormone↗

PubMed1991

The behavioral effects of bilateral middle cerebral artery hemorrhagic ischemia in rat.

After learning position discrimination in a T-maze water escape task, rats had either a 2 mm section of the middle cerebral artery removed bilaterally (bMCA) or they received a sham operation. Beginning on the day of surgery either total brain gangliosides (50 mg kg-1) or saline were administered daily for five days. Of the several measures of neurological function that were tested, only a temporary deficit in grasping with the front paws was observed in bMCA damaged rats. Ganglioside treatment normalized this practical function. Memory of the preoperative habit was not influenced by bMCA damage, but acquisition of a reversal of this habit was compromised. Ganglioside treatment did not influence this deficit. Acquisition of a spatial alternation strategy was influenced by neither the bMCA lesion nor the ganglioside treatment. The preservation that accompanies bMCA interruption might serve as a useful model of the functional declines that accompany stroke and frontal lobe damage.

Animals↗

PubMed1989

ACTH 4-9 analog can retard spatial alternation learning in brain damaged and normal rats.

Thirty adult male hooded rats (Long-Evans strain) were assigned randomly to one of three lesion groups (n = 10) and prepared with medial frontal, posterior parietal, or sham neocortical injuries. Following a recovery interval of 10-12 days, access to water was limited to 30 min per day and the rats were shaped to traverse a T-maze for a reward of sweetened water. After a pretraining criterion was attained, osmotic minipumps (Alzet 2002) were installed subcutaneously. The minipumps delivered chronically for the next 14 to 15 days either 0 or 1.2 micrograms of ACTH 4-9 dissolved in bacteriostatic saline per day while the rats were trained on a reinforced spatial alternation task. Analysis of the number of errors made to a criterion of at least 80% correct alternations in two consecutive training sessions, or a ceiling of 62 errors (attained by two rats with parietal lesions), revealed that learning was impaired in the rats with parietal injuries. Contrary to our hypothesis, animals receiving ACTH 4-9 committed more errors than their counterparts receiving only saline.

Adrenocorticotropic Hormone↗

PubMed1982

A comparison of lateral peristriate and striate neocortical ablations in the rat.

The effects of striate, lateral peristriate and sham ablations upon the post-operative reacquisition of visual discriminations were studied in two experiments. The results of Experiment 1 indicated that lesions restricted to the lateral peristriate neocortex rendered the rat incapable of resolving an oblique stripe discrimination. Seven of the 9 rats with striate ablations were unable to form the discrimination. The histological findings indicated that the deficit following lateral peristriate injury was not due to interruption of the geniculostriate system. However, the behavioral impairment in destriate rats corresponded to the degree of unintentional injury in lateral peristriate neocortex, but not medial peristriate tissue. In Experiment 2, the effects of these lesions were studied upon the post-operative reacquisition of either a non-reversal or reversal of a preoperatively acquired brightness discrimination. Animals with striate damage demonstrated considerable savings on the non-reversed brightness discrimination, and they acquired the reversal at a rate equal to that seen in animals with sham ablations. Rats with peristriate ablations showed no savings on the non-reversed brightness habit, and they required more extensive training than both the striate and sham groups on the reversal. These findings suggest that the frequently reported loss of a preoperative brightness habit following large posterior neocortex ablations is due to damage in the lateral peristriate neocortex rather than damage of the geniculostriate system. These results, taken with other literature, suggest an important role of the lateral peristriate neocortex in visuospatial sensory function.

Animals↗

PubMed1980

Failure of B6 deficiency to affect performance of aging rats in a passive avoidance task.

Male Fischer-344 rats from three age groups (6-7, 15-16, and 27-29 months) were given either a pyridoxine deficient diet or control diet for five weeks. Differences in body weight produced by the diets were evident in the youngest age groups but not in the oldest group in which all animals tended to lose weight. There was no evidence that diet or age affected performance during passive avoidance learning.

Aging↗

PubMedDate not supplied

Arginine vasopressin 4-9 retards spatial alternation learning.

Thirty adult male rats were randomly divided into three groups and prepared with either posterior parietal, medial frontal or sham neocortical injuries. After a 10-12 day recovery interval, access to water was restricted to a 30-min period per day and the rats were trained to run in a T-maze for a reward of sweetened water. After reaching a pre-training criterion, osmotic mini-pumps (Alzet 2002) were installed subcutaneously. For the next 14 to 15 days, the pumps delivered chronically either 0 or 1.2 micrograms of arginine vasopressin 4-9 (AVP 4-9) dissolved in bacteriostatic saline while the animals were trained on a reinforced spatial alternation task. Analysis of variance on the number of errors committed to a criterion of at least 80% correct alternations in two consecutive training sessions, or a ceiling of 50 errors (attained by two rats with parietal lesions), revealed a significant retardation in animals administered AVP 4-9 during training. These results demonstrate that this centrally active metabolite of vasopressin can interfere with the acquisition of a cognitive learning task when administered concomitantly with training.

Animals↗

PubMedDate not supplied

A strategy for screening memory functions in individuals with mental retardation.

In an attempt to develop a protocol for evaluating mentally retarded clients from a neurobehavioral perspective, a strategy for screening complex verbal, simple verbal, simple visual, and spatial working memory was developed. This strategy results in numeric values on each of the aspects of memory, and it can contribute to a "global index" of memory function. The strategy is described so that it might be adopted by other practitioners interested in screening their client's ability to store and retrieve newly acquired information. Descriptive data for 125 persons carrying diagnoses of mild, moderate, and severe mental retardation are presented. The procedure was found to discriminate well between the various levels of mental retardation, correlate reasonably well with IQ, and possess relatively good test-retest reliability.

Adolescent↗