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Probe Trials (probe + trials)
Selected AbstractsMale and female Fmr1 knockout mice on C57 albino background exhibit spatial learning and memory impairmentsGENES, BRAIN AND BEHAVIOR, Issue 6 2010K. B. Baker Impaired spatial learning is a prominent deficit in fragile X syndrome (FXS). Previous studies using the Fmr1 knockout (KO) mouse model of FXS have not consistently reported a deficit in spatial learning. Fmr1 KO mice bred onto an albino C57BL/6J- Tyrc-Brd background showed significant deficits in several primary measures of performance during place navigation and probe trials in the Morris water maze. Fmr1 KO mice were also impaired during a serial reversal version of the water maze task. We examined fear conditioning as an additional cognitive screen. Knockout mice exhibited contextual memory deficits when trained with unsignaled shocks; however, deficits were not found in a separate group of KO mice trained with signaled shocks. No potentially confounding genotypic differences in locomotor activity were observed. A decreased anxiety-like profile was apparent in the open field, as others have noted, and also in the platform test. Also as previously reported, startle reactivity to loud auditory stimuli was decreased, prepulse inhibition and social interaction increased in KO mice. Female Fmr1 KO mice were tested along with male KO mice in all assays, except for social interaction. The female and male KO exhibited very similar impairments indicating that sex does not generally drive the behavioral symptoms of the disorder. Our results suggest that procedural factors, such as the use of albino mice, may help to reliably detect spatial learning and memory impairments in both sexes of Fmr1 KO mice, making it more useful for understanding FXS and a platform for evaluating potential therapeutics. [source] Handling and environmental enrichment do not rescue learning and memory impairments in ,CamKIIT286A mutant miceGENES, BRAIN AND BEHAVIOR, Issue 3 2003A. C. Need Environmental enrichment and postnatal handling have been shown to improve learning and memory in the Morris water maze, and to rescue impairments caused by genetic modification, age or genetic background. Mice with a targeted point mutation that prevents autophosphorylation at threonine-286 of the ,-isoform of the Ca2+/calmodulin-dependent kinase II have impaired hippocampus-dependent and -independent strategy learning and memory in the water maze. We have investigated whether these impairments can be rescued with a combination of postnatal handling and environmental enrichment in a hybrid genetic background. Severe impairments were seen in acquisition and probe trials in both enriched and nonenriched mutants, indicating that enrichment did not rescue the learning and memory impairments. However, enrichment did rescue a specific performance deficit; enhanced floating behaviour, in the mutants. In summary, we have shown the lack of autophosphorylation of the ,-isoform of the Ca2+/calmodulin-dependent kinase II prevents enrichment-induced rescues of strategy learning and memory impairments. Furthermore, we have established that there are enrichment mechanisms that are independent of this autophosphorylation. [source] Selective hippocampal damage in rhesus monkeys impairs spatial memory in an open-field test,HIPPOCAMPUS, Issue 7 2004Robert R. Hampton Abstract The hippocampus is critical for remembering locations in a wide variety of species, including humans. However, recent findings from monkeys following selective hippocampal lesions have been equivocal. To approximate more closely the situations in which rodents and birds are tested, we used a spatial memory task in which rhesus monkeys (Macaca mulatta) moved about freely in a large room, on a tether. We used MRI-guided stereotaxic surgery to produce selective hippocampal lesions in five monkeys, and retained five unoperated control monkeys. In the study phase of each trial of the matching-to-location task, monkeys found food in one site in an array of identical foraging sites. During the test, which occurred after a delay, monkeys could return to the site where the food had been found during study to obtain more food. In Experiment 1, normal monkeys showed a small significant tendency to return directly to a site where they had previously found food that day. Operated monkeys showed no such matching tendency. In Experiment 2, further training produced reliable matching-to-location performance in both groups at short delays, but monkeys with selective hippocampal lesions rapidly forgot the location of the food. In Experiment 3, we tested whether monkeys used a "cognitive map" to encode the location of the hidden food, by requiring them to relocate the food from a starting location different from that used during study. As a group, monkeys were more accurate than expected by chance, indicating that they did encode the rewarded location with respect to allocentric landmarks; however, both groups of monkeys were significantly worse at relocating the food when required to approach from a different location. In Experiment 4, probe trials using symmetrical test arrays found no evidence for egocentric coding of the rewarded location. © 2004 Wiley-Liss, Inc. [source] Speed of Processing and Face Recognition at 7 and 12 MonthsINFANCY, Issue 4 2002Susan A. Rose This research examined developmental and individual differences in infants' speed of processing faces and the relation of processing speed to the type of information encoded. To gauge processing speed, 7- and 12-month-olds were repeatedly presented with the same face (frontal view), each time paired with a new one, until they showed a consistent preference for the new one. Subsequent probe trials assessed recognition of targets that either preserved configural integrity (Study 1: 3/4 profile and full profile poses) or disrupted it while preserving featural information (Study 2: rotations of 160° or 200° and fracturings). There were developmental differences in both speed and in infants' appreciation of information about faces. Older infants took about 60% fewer trials to reach criterion and had more mature patterns of attention (i.e., looks of shorter duration and more shifts of gaze). Whereas infants of both ages recognized the familiar face in a 3/4 pose, the 12-month-olds also recognized it in profile and when rotated. Twelve-month-olds who were fast processors additionally recognized the fractured faces; otherwise, processing speed was unrelated to the type of information extracted. At 7 months then, infants made use of some configural information in processing faces; at 12 months, they made use of even more of the configural information, along with part-based or featural information. [source] | ||||||||||