Showing papers by "Michela Gallagher published in 1988"
TL;DR: The notion that hippocampal dysfunction underlies the mild/moderate cognitive decline that often accompanies normal aging is supported, and the spatial learning deficit in aged rodents is a promising model for understanding the effect of age on brain systems that serve a memory function in humans.
260 citations
TL;DR: There is a task-specific engagement of cholinergic function in young animals that does not occur in behaviorally impaired aged animals, a finding that is consistent with a role for cholinergy dysfunction in memory impairments associated with aging.
Abstract: The relation of forebrain cholinergic function to learning and memory was explored by identification and characterization of a training- induced change in high-affinity choline uptake (HACU), an index of cholinergic activity. Young adult rats were trained to find an invisible escape platform in a water tank using environmental cues. After 4 d of this place-training (16 trials), hippocampal HACU was significantly reduced relative to that observed in rats trained to find a visible platform (cue-training), even when cue- and place-trained rats were yoked for swim time. These place- but not cue-trained rats showed significantly lower hippocampal HACU than did naive rats, and no effect of training was noted after only 1 d of training. Similar results were obtained in parietal cortex. These differential training effects on HACU correspond to previous reports that muscarinic blockade impairs place, but not cue, learning. A further experiment revealed that the decrease in HACU in hippocampus, but not in parietal cortex, occurred only during the acquisition phase of learning and was related to the rate of acquisition for individual animals. Hippocampal HACU in naive young and aged (24–27 months) rats did not differ, but the response of the septohippocampal cholinergic system to training was diminished in the aged rats. Old rats displayed impaired place learning and a corresponding dampening of the training-induced change in HACU. These results suggest that there is a task-specific engagement of cholinergic function in young animals that does not occur in behaviorally impaired aged animals, a finding that is consistent with a role for cholinergic dysfunction in memory impairments associated with aging.
124 citations
TL;DR: Results provide evidence for a relationship between the behavioral capacities of aged rats and changes in the status of hippocampal function and sodium-dependent high-affinity choline uptake was used to monitor hippocampalfunction in response to training on a spatial task.
111 citations
TL;DR: The results of these experiments demonstrated that posttraining intraseptal naloxone administration facilitated, whereas posttraining intrusion beta-endorphin administration impaired, the acquisition of criterion performance on a maze task performed in new spatial environments, which indicates that the septal region is a brain site that is sensitive to the effects of opioids on spatial memory in new environments.
Abstract: Recent work has demonstrated that posttraining systemic opioid antagonist administration facilitates the acquisition of a radial arm maze task in new spatial environments. In this study, we examined the effect of posttraining naloxone and beta-endorphin microinjections into the medial septal area on the acquisition of a radial maze task in new spatial environments. The results of these experiments demonstrated that posttraining intraseptal naloxone administration facilitated, whereas posttraining intraseptal beta-endorphin administration impaired, the acquisition of criterion performance on a maze task performed in new spatial environments. Further, intraventricular beta-endorphin administration did not produce effects that were comparable to those observed following intraseptal beta-endorphin administration, which indicates that the septal region is a brain site that is sensitive to the effects of opioids on spatial memory in new environments. Further, posttraining intraseptal beta-endorphin administration had no effect on working memory in a familiar spatial environment, whereas pretraining intraseptal beta-endorphin administration had no effect on the performance of a previously acquired spatial task.
66 citations