Reference memory

Short-term memory tasks increase high-affinity uptake of acetylcholine, whereas long-term reference memory tasks cause an acute increase followed by a long-lasting decrease and inhibition (Decker et al. 1988). In contrast, the drug scopolamine creates amnestic effects by blocking muscarinic receptors and decreasing acetylcholine levels. Thus, at... 

Similarly, intrahippocampal injections of 8-OH-DPAT induced no change in performance levels of the rat trained to run in a radial maze (Buhot et al. 1995). However, the intrahippocampal injection of the 5-HTjg receptor agonist CP-93,129 [3-(l,2,5,6-tetrahydropyrid-4-yl] pyrrolo [3,2-6] pyrid-5-one] induced a higher frequency of reference memory errors than of working memory. It was concluded that stimulation of 5-HT,g receptors in the CAl field of the dorsal hippocampus impairs performance of rats in a spatial learning task. 

Administration of scopolamine to rats induces amnesia in passive avoidance learning. EGb administered intraperitoneally 30 mm before the initial trial at doses of 150-500 mg/kg significantly attenuated the amnesic effects of scopolamine on step-through latencies in a retention trial 4 hours after training for the passive avoidance test in rats [107]. Hoyer et d. showed that, using an animal model of in tracer ebroventricular streptozotocin treatment, EGb treatment compensated for deterioration in working memory, reference memory and passive... 

Fig. 19.1. Learning acquisition in the spatial reference memory version of a water maze test of mixed background C3B6 mice in two different animal colonies. Mice in the colony A were kept in a quiet room with appropriate for behavioral experiments husbandry practices, while the colony B had increased noise level and sub-optimal for behavioral studies conditions. The mice trained in the colony A showed a significant improvement in finding a hidden platform location during training (their search path was on average about 5 m shorter at the end of training as compared to at the beginning of training). On the other hand, the mice in colony B showed no improvement (the rate of improvement between day 1 and day 5 was about 1 m). See text for further details.

Morris Water Maze (Spatial Learning and Reference Memory)... 

Long-term or reference memory can also be assessed by having a restricted number of arms baited, but always the same. The animal must visit only the baited arms during a test session. 

The principal variant to the radial maze procedure described above is the inclusion of a reference memory component, by baiting only some of the arms (Beatty Bierley 1985). In addition to remembering which arms were visited during a particular session... 

Another approach to reference memory is to use the radial maze task as a repeated acquisition task with different arms being baited during each test session (Levin et al. 1998). In this way the task can be modified to evaluate exclusively reference memory. As with repeated passive avoidance sessions, this use of the radial maze is very time-consuming, and we do not recommend it for safety pharmacology purposes. 

Beatty WW, Bierley RA (1985) Scopolamine degrades working memory but spares spatial reference memory dissimilarity of cholinergic effect and restriction of distal visual cues. Pharmacol Biochem Behav 23 1-6 Cassel JC, Kelche C (1989) Scopolamine treatment and fimbria-fomix lesions mimetic effects on radial maze performance. Physiol Behav 46 347-353 Levin ED, Bettegowda C, Weaver T, Christopher NC (1998) Nicotine-dizocilpine interactions and working and reference memory performance in rats in the radial-arm maze. Pharmacol Biochem Behav 61 335-340 Magni S, Krekule I, Bures J (1979) Radial maze type as a determinant of the choice behavior of rats. J Neurosci Meth 1 343-352... 

Sloan HL, Good M, Dunnett SB. 2006. Double dissociation between hippocampal and prefrontal lesions on an operant delayed matching task and a water maze reference memory task. Behav Brain Res 171 116-126. 

Behavioural studies described age-dependent cognitive deficits assessed by using a Morris water maze. This behavioural test measures spatial reference memory. In these transgenic APP mice, both their acquisition of hidden platform locations and their retention of spatial reference information are affected (Table 1). 

Korsakoff s psychosis is considered by some to represent a progression of WE. It is characterized by a striking loss of working memory with relatively little loss of reference memory. Prompt treatment of Wernicke s syndrome with thiamine is believed to prevent the development of Korsakoffs syndrome, but the latter responds little if at all to treatment with thiamine. 

Memory, or remembering, is behavioral recall (i.e., the preservation of learned behavior over time). A distinction is often made between what is referred to as short-term or working memory, occurring over relatively short delay periods, and long-term or reference memory, considered more permanent memory. Obviously, the temporal parameters associated... 

Chronic exposure to high serum levels of corticosterone induced a significant impairment of inhibitory avoidance learning in rats. In another study, corticosterone elevated over a period of 21 days impaired the formation of a longer-term form of memory, most likely reference memory. Impairments in spatial working memory were seen only after longer durations of corticosterone administration. 

RJR-2403 has been described as equal to or better than nicotine as a cognitive enhancer in behavioral assays (274). This compound ameliorated scopolamine-induced impairments in passive avoidance as well as working and reference memory impairments in a radial arm maze task caused by NBM lesions in rats... 

In the programmers manner or language listing, cross-reference, memory dump. 

Unexpected was the finding that CBi knockout mice acquired a spatial reference memory task in the water maze normally. This was unexpected since pharmacological studies had predicted that CBi knockout would facilitate learning and memory... 

Gamoh S, Hashimoto M, Sugioka K, Ilossain MS, Hata N, Misawa Y, et al. Chronic administration of docosahexaenoic acid improves reference memory-related learning ability in young rats. Neuroscience 1999 93 237-241. 

The effects of DHA-rich Chlorella oil administration for six weeks on total errors, reference memory errors, and working memory errors regarding radial maze performance in mice were shown Fig.(19). The administration of DHA-rich Chlorella oil significantly decreased the numbers of total errors and working memory errors. These results showed that the intake of DHA-rich Chlorella oil effectively enhances working memory in maze performance. 

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