PubMed Health⌕ Search

Biomedical subjects

S A Ferguson

Publications and source records attributed to S A Ferguson.

12 recordsLinked to original sources
PubMed1992

Acute effects of chlorpromazine in a monkey operant behavioral test battery.

The effects of acute chlorpromazine treatment were assessed using a complex operant test battery (OTB) containing five tasks thought to depend upon processes associated with short-term memory and attention [delayed-matching-to-sample (DMTS)], color and position discrimination [conditioned position responding (CPR)], motivation [progressive ratio (PR)], time perception [temporal response differentiation (TRD)], and learning [incremental repeated acquisition (IRA)]. Adult male rhesus monkeys were tested 15 min after IV injection of saline or chlorpromazine (0.010, 0.030, 0.100, or 0.175 mg/kg). Behavioral endpoints measured included percent task completed, response rate or latency, and response accuracy. The order of task sensitivity to disruption by chlorpromazine was TRD = PR = IRA = DMTS = CPR in which sensitivity was defined as a significant alteration in any aspect of task performance. Chlorpromazine slowed response rates in all tasks except TRD but did decrease accuracy in that task. These effects were similar to those noted in previous studies of acute chlorpromazine treatment. Specific motoric effects suggested decreased task initiation at doses that left general motor ability intact. This finding is similar to that noted in parkinsonism caused by chronic chlorpromazine treatment.

Animals↗
PubMed1992

Age differences in using source-relevant cues.

Subjects heard words originating from 2 speakers and later decided which of the 2 speakers said the words. Older adults had difficulty with source monitoring when perceptual cues from 2 sources were similar (2 female speakers), but this difficulty was overcome when perceptual cues were distinctive (a male and a female speaker) and were the only salient cues to source. Older adults also benefited from distinctive spatial cues when these were the only salient cues to source. Older adults, however, experienced difficulties in using multiple cues (both perceptual and spatial) to source effectively, whereas younger adults were able to use multiple cues to enhance their source-monitoring performance. It is suggested that age differences in source monitoring result from differential cue utilization.

Adult↗
PubMed1991

Clinical utility of high-resolution portal films.

We have evaluated the film quality and overall clinical utility of a unique high-resolution portal film system which utilizes high contrast graphics art film. A total of 127 unselected patients had their conventional portal films and high-resolution films of the same site, compared and graded subjectively for a variety of parameters by an independent panel of radiotherapists and radiographers. Although consistent improvements in most aspects of image quality were noted, improved overall clinical usefulness of the high-resolution portal film system in comparison to the conventional films, when subjected to multiple regression analysis, was confined to lateral neck views only. High-resolution portal film utility was also found to depend significantly on field size with areas less than 110 cm2 having a markedly worse clinical utility score.

Humans↗
PubMed1988

Behavioral effects of developmental lead exposure in rhesus monkeys.

Postnatal lead exposure has been found to cause long-term learning and memory deficits in monkeys. Pulse-chronic exposure, consisting of acute high-level exposure followed by chronic lower-level exposure, has been particularly effective in causing these impairments. We investigated possible antecedents of lead-induced cognitive dysfunction by evaluating the behavioral effects of pulse-chronic lead exposure in rhesus monkeys during the first 6 months of postnatal life. Blood lead concentrations in the monkeys reached a peak of 55.8 +/- 7.8 ug/dl during week 5 after birth and then averaged between 33.1 and 42.9 ug/dl during the rest of the first 6 months after birth. Zinc protoporphyrin levels were increased by lead exposure, but hematocrits were unaffected. Significant lead-related effects were detected on a visual exploration test and a neonatal behavioral assessment battery. Lead-treated monkeys exhibited decreased looking behavior on the visual exploration test and decreased muscle tonus and increased arousal or agitation on the behavioral assessment battery. No effects were seen on a Piagetian object permanence task and no toxic effects on health or growth were detected. In addition to providing indices of behavioral dysfunction during postnatal lead exposure, performance on these early behavioral tests may predict later lead-induced cognitive dysfunction.

Animals↗
PubMed1988

Data-driven and conceptually driven processes in partial-word identification and recognition.

Three experiments examined priming in partial-word identification (Warrington & Weiskrantz, 1968) and its relation to recognition memory. The results showed that changes in modality of presentation between study and test reduced performance on both identification and recognition. In contrast, changes in elaborative processing enhanced recognition but had no effect on identification. Furthermore, when explicit memory instructions were given, identification was changed to a cued recall test and was consequently affected by elaborative processing. We also found that the time course of forgetting in priming was different from that in recognition; priming in identification did not change over a 24-hr interval, whereas recognition declined rapidly during this interval. Overall, these results suggest that identification relies primarily on data-driven processing, whereas recognition can rely on both data-driven and conceptually driven processing.

Adult↗
PubMedDate not supplied

A nonhuman primate version of the open field test for use in behavioral toxicology and teratology.

As reviewed here, little work has been done on testing nonhuman primates individually in open field paradigms. Hence, normative data from three studies of rhesus monkeys are presented. Important criteria for describing the pattern of activity exhibited by monkeys in the open field are introduced and the effects of gender and differences in rearing are assessed. Differences between this nonhuman primate version of the open field and that typically used with rodents are discussed, including reasons for differences in the variability of behavior between monkeys and rodents and a comparison of coefficients of detection (as an index of the power of the test to detect group differences). Overall, the use of the nonhuman primate version of the open field in behavioral toxicology and teratology is feasible and may fill a significant niche not presently well represented.

Animals↗
PubMedDate not supplied

Effects of postnatal lead exposure on open field behavior in monkeys.

Nursery-reared rhesus monkeys were treated with either no lead or moderate levels of lead from day eight or nine until day 365 after birth. All subjects were at or below 5 micrograms/dl blood lead levels for at least 1.5 years by the time of the present study conducted at 4 years of age. Data were collected in a primate version of the open field test which proved sensitive to several behavioral alterations in the lead-treated monkeys. These significant differences included a failure to habituate as evidenced by number of sectors entered, increased durations of activity and environmental exploration, and a longer latency to enter the open field. Most of these effects were compatible with a hypothesis of hippocampal dysfunction in the lead-treated monkeys and appeared to indicate enduring lead-induced alterations. These results provide further support for a correlation between early lead exposure and hippocampal dysfunction. Additionally, the utility of a primate version of the open field test for behavioral toxicological studies is substantiated.

Animals↗
PubMedDate not supplied

Effects of arecoline and scopolamine on open field behavior of adult monkeys treated with lead during the first year postpartum.

Nursery-reared rhesus monkeys were treated with no or moderate levels of lead during the first year postpartum. Previously, the lead-treated monkeys exhibited behaviors in the nonhuman primate version of the open field (10) resembling those caused by hippocampal lesions. The current study investigated the mechanism(s) underlying these lead-related effects using a cholinergic agonist (arecoline) and antagonist (scopolamine) as pharmacological probes that were administered prior to open field testing at 5 and 6 years of age, respectively. Arecoline decreased locomotion and number of sectors entered. Scopolamine decreased defecation frequency. Neither drug interacted with prior lead treatment, indicating limited cholinergic involvement in the expression of these alterations. The lead-treated subjects continued to exhibit alterations as previously reported (10); specifically, a longer latency to enter the open field, increased frequency and duration of environmental exploration and, at 5 years of age, decreased duration of inactivity in the open field. These effects were seen four and five years after lead treatment ended and nearly three and four years after blood lead levels had declined to less than or equal to 5 micrograms/dL. Although latency to enter and duration of inactivity seem to be approaching control levels, the increased exploration does not.

Animals↗
PubMedDate not supplied

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on behavior of monkeys in peer groups.

Adult female rhesus monkeys were fed diets containing 0, 5, or 25 ppt 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for approximately 4 years. They were bred to unexposed males during TCDD exposure (Experiment 1) and again after TCDD exposure ended (Experiment 2). Offspring from both experiments were weaned at 4 months and socialized for 1.5 h/day in groups of four monkeys each beginning at approximately 8 months of age. Each social group contained both control and TCDD-exposed monkeys. In Experiment 2, the offspring were later placed in new social groups containing only monkeys from the same TCDD exposure condition. The TCDD-exposed offspring born concurrent with maternal TCDD exposure (Experiment 1) initiated more rough-tumble play, retreated less during play bouts, and were less often displaced from preferred positions in the playroom. They also engaged in more self-directed behaviors. The behavior of offspring born after maternal TCDD exposure ended (Experiment 2) was not altered when they were socialized with control monkeys. However, some behavioral changes did emerge when they were placed in social groups containing only TCDD-exposed monkeys.

Animals↗
PubMedDate not supplied

Quantification of back motion during asymmetric lifting.

The objective of this study was to determine how trunk motion characteristics (in all three planes of the trunk) change as a free dynamic lifting task becomes more asymmetric. Trunk motion characteristics included range of motion, velocity (peak and average), and acceleration. Previous studies have shown that trunk motion characteristics affect trunk strength as well as the action of the trunk musculature. These trunk motion characteristics were quantified as a function of seven task asymmetries and three task weights. The experimental task required the subject to lift materials in positions commonly seen in the workplace. The range of motion, peak velocity, average velocity, and peak acceleration in each plane of the body were documented during the tasks. Generally, trunk motion characteristics in all three planes increased with an increase in task asymmetry. However, with an increase in task weight all the sagittal plane parameters and one transverse plane parameter decreased. Models were constructed to predict trunk motion characteristics given a task asymmetry and weight. When these motion components were compared to dynamic strength estimates from previous studies it was found that dynamic asymmetric lifts could reduce available strength up to 21% of maximum static strength. The results provide new insight into factors associated with the risk of developing low back disorders.

Adult↗