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Query: UMLS:C0233794 (memory impairment)
 7,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In 2 experiments, young and older adults demonstrated modality effects of similar magnitude in perceptual identification tasks. That is, both young and older adults demonstrated more repetition priming when study and test modalities matched than when they were different, suggesting that contextual information was equally available across age. However, when asked explicitly to retrieve modality information, older adults were less accurate than young adults. These results constitute evidence for a dissociation between direct and indirect measures of memory for modality information. They call into question hypotheses that memory impairment in old age is due to deficient encoding of contextual information and challenge current accounts of modality effects in repetition priming.
J Exp Psychol Learn Mem Cogn 1992 Nov
PMID:Direct and indirect measures of memory for modality in young and older adults. 144 52

We have recently studied several natural product constituents which have effects on the CNS. (1) Tetrahydropalmatine (THP) and its analogues were isolated from Corydalis ambigua and various species of Stephania. (+)-THP and (-)-THP possess not only analgesic activity, but also exert sedative-tranquilizing and hypnotic actions. Results of receptor binding assay and their pre- and post-synaptic effects on dopaminergic system indicate that (-)-THP and (-)-stepholidine are dopamine receptor antagonists while (+)-THP is a selective dopamine depletor. (2) 3-Acetylaconitine (AAC) is an alkaloid isolated from Aconitum flavum. The relative potency of analgesic action of AAC was 5.1-35.6 and 1250-3912 times that of morphine and aspirin, respectively. The analgesic effect of AAC was not antagonized by naloxone, but was eliminated by reserpine. In monkeys, after AAC was injected for 92 days, no abstinence syndrome was seen after sudden AAC withdrawal or when challenged with nalorphine. (3) Huperzine A (Hup-A) is an alkaloid isolated from Huperzia serrata which was found to be a selective ChE inhibitor and could improve learning and retrieval processes. Preliminary clinical studies showed that Hup-A improve short- and long-term memory in patients of cerebral arteriosclerosis with memory impairment. (4) Ranamargarin is a new tetradecapeptide isolated from the skin of the Chinese frog Rana margaratae. This peptide may mainly act on NK-1 receptor.
Mem Inst Oswaldo Cruz 1991
PMID:Development of natural products as drugs acting on central nervous system. 184 95

We investigated the ability of amnesic patients to learn new facts (e.g., Angel Falls is located in Venezuela) and also to remember where and when the facts were learned (i.e., source memory). To assess the susceptibility of fact and source memory to retrograde amnesia, patients prescribed electroconvulsive therapy were presented facts prior to the first treatment and were tested after their second treatment. All amnesic patients exhibited marked fact memory impairment. In addition, some amnesic patients exhibited source amnesia (i.e., they recalled a few facts but then could not remember where or when those facts had been learned). Source amnesia was unrelated to the severity of the memory deficit itself, because patients who exhibited source amnesia recalled as many facts as the patients who did not. These results show that the deficit in amnesia includes an impairment in acquiring and retaining new facts. Source amnesia can also occur, but it is dissociable from impaired recall and recognition and appears to reflect difficulty in remembering the specific context in which information is acquired. The findings are discussed in terms of their significance for how memory is organized.
J Exp Psychol Learn Mem Cogn 1987 Jul
PMID:A neuropsychological study of fact memory and source amnesia. 295 56

Immediate posttraining intraperitoneal injection of nonconvulsive doses of insulin (2-20 IU/kg) significantly impaired retention of male Swiss mice tested 24 h after training in a one-trial step-through inhibitory avoidance task. The dose-response curve showed a U-shaped form. However, of the doses tested, only 8 IU/kg was effective. Insulin did not affect response latencies in mice not given the footshock on the training trial, indicating that the actions of insulin on retention performance were not due to nonspecific proactive effects on response latencies. The impairing effects of insulin (8 IU/kg) on retention were time-dependent, which suggests that insulin impaired memory storage. The simultaneous administration of glucose (10-1000 mg/kg) antagonized, in a dose-related manner, the actions of insulin (8 IU/kg) on retention, suggesting that the hormone may have produced a hypoglycemic response leading to a decrease in CNS glucose availability with a subsequent memory impairment. Low subeffective doses of atropine (0.5 mg/kg) or mecamylamine (5 mg/kg), but not methylatropine (0.5 mg/kg) or hexamethonium (5 mg/kg), given immediately after training but 10 min before an ineffective dose of insulin (4 IU/kg), interacted with and impaired retention. The central anticholinesterase physostigmine (35 or 70 micrograms/kg), but not its quaternary analog neostigmine (35 or 70 micrograms/kg), prevented the memory impairment induced by insulin (8 IU/kg). Considered together, these findings are consistent with the view that a decrease in the CNS glucose availability impairs the synthesis and/or release of acetylcholine in brain regions critically involved in memory storage.
Neurobiol Learn Mem 1995 May
PMID:The impairment of retention induced by insulin in mice may be mediated by a reduction in central cholinergic activity. 767 Aug 35

The hypotheses that the medial septal area (MSA) is critical for working memory and that MSA neural activity is positively regulated by cholinergic inputs leads to two testable predictions: (1) working memory can be bidirectionally modulated by muscarinic manipulations of the MSA and (2) muscarinic activation of the MSA can enhance memory under conditions of mnemonic impairment. Memory was assessed by T-maze spatial alternation following intraseptal infusion of muscarinic drugs in rats pretreated with intraperitoneal (IP-) injections of scopolamine. Scopolamine dose-dependently impaired working memory and shifted the hippocampal theta activity to a higher peak frequency. Intraseptal scopolamine mimicked the behavioral effects of IP-scopolamine, and intraseptal carbachol appeared to reverse both the behavioral and physiological effects of IP-scopolamine. The results indicate that the amnestic effect of antimuscarinic drugs may be due to an interaction in the MSA and that conditions of memory impairment may be alleviated by selective muscarinic activation of the MSA.
Neurobiol Learn Mem 1995 May
PMID:Bidirectional modulation of scopolamine-induced working memory impairments by muscarinic activation of the medial septal area. 767 Aug 40

In two experiments, younger and older adults studied three lists of verbal phrases, each of the latter describing a simple action. One list was studied and recalled verbally; one was recalled verbally, but the actions were performed at study [retrospective SPTs (subject-performed tasks)]; and one was studied verbally and the actions were performed at test (prospective SPTs). With long lists, but not with short ones, retrospective-SPT recall exceeded verbal recall and older adults recalled fewer SPTs than did younger adults. Prospective-SPT recall did not exceed verbal recall at either list length, and in each of these prospective-SPT tests, older adults recalled fewer action phrases than did younger adults. Thus, it appears that when retrospective and prospective tasks are equated there are marked age differences that are generally consistent with the view that memory impairment in the elderly is more likely to occur in tasks that make higher attentional processing demands.
Mem Cognit 1994 Jan
PMID:Age differences in memory for prospective compared with retrospective subject-performed tasks. 803 82

The four experiments reported here provide evidence that (1) misleading postevent suggestions can impair memory for details in a witnessed event and (2) subjects sometimes remember suggested details as things seen in the event itself. All four experiments used recall tests in which subjects were warned of the possibility that the postevent information included misleading suggestions and were instructed to report both what they witnessed in the event and what was mentioned in the postevent narrative. Recall of event details was poorer on misled items than on control items, and subjects sometimes misidentified the sources of their recollections. Our results suggest that these findings are not due to guessing or response biases, but rather reflect genuine memory impairment and source monitoring confusions.
Mem Cognit 1994 Jan
PMID:Memory impairment and source misattribution in postevent misinformation experiments with short retention intervals. 803 84

Posttraining administration of the L-enantiomer of the competitive inhibitor of nitric oxide synthase, NG-nitro-L-arginine methyl ester (L-NAME, 3-100 mg/kg, ip), impaired 48-h retention of a one-trial step-through inhibitory shock-avoidance task in male Swiss mice. The effects were dose-dependent and were not observed when the D-enantiomer (D-NAME, 3-100 mg/kg, ip) was injected instead of L-NAME. Retention latencies of mice that had not received a footshock during training were not affected by L-NAME. The memory impairment produced by L-NAME was time-dependent, suggesting an action on memory storage. The effects of L-NAME on memory were overcome by the injection of L-(but not D-)arginine (300 mg/kg, ip) along with the inhibitor. Considered together, these findings suggest that the L-arginine/nitric oxide pathway may be involved in memory storage of an inhibitory avoidance response in mice.
Neurobiol Learn Mem 1996 May
PMID:A nitric oxide synthase inhibitor impairs memory storage in mice. 861 82

The present experiments examined the role of the central cholinergic system in the memory impairment induced by post-training administration of a nitric oxide synthase (NOS) inhibitor in mice. Male Swiss mice received a one-trial inhibitory avoidance training (0.8 mA, 50 Hz, 1-s footshock) followed immediately by an ip injection of the NOS inhibitor L-NG-nitroarginine methyl ester (L-NAME; 100 mg/kg). Retention (cut-off time, 300 s) was tested 48 h after training. The administration of L-NAME results in memory impairment for the inhibitory avoidance task. The effects of L-NAME (100 mg/kg, ip) on retention were reversed in a dose-related manner by the centrally acting anticholinesterase physostigmine (35, 70, or 150 microg/kg, sc) administered 30 min after the NOS inhibitor. Further, L-NAME (100 mg/kg, ip)-induced memory impairment was completely antagonized by the centrally acting muscarinic cholinergic agonist oxotremorine (OTM; 25, 50, or 100 microg/kg, sc) when given 30 min after L-NAME. The peripherally acting anticholinesterase neostigmine (150 microg/kg, sc) did not modify the memory-impairing effects of L-NAME. These findings suggest that the memory impairment following post-training administration of a NOS inhibitor is mediated, at least in part, by a reduction of the activity of central muscarinic cholinergic mechanisms and are consistent with our previous view that nitric oxide may be involved in post-training neural processes underlying the storage of newly acquired information.
Neurobiol Learn Mem 1996 May
PMID:Enhancement of the post-training cholinergic tone antagonizes the impairment of retention induced by a nitric oxide synthase inhibitor in mice. 861 84

The effects of a specific presynaptic cholinergic antagonist, toosendanin, on memory formation following a passive avoidance training experience in day-old chicks was investigated. Bilateral injection of toosendanin into the neostriatal/hyperstriatal region of the chick forebrain produced memory impairment in a dose-dependent manner. Retention deficits were apparent from 20 min following training in chicks treated with toosendanin, regardless of the injection time relative to training. Chicks that received injections of the drug at corresponding times prior to retention tests showed normal retention levels, suggesting that toosendanin has no effect on performance and memory retrieval. These results indicate an involvement of cholinergic transmission during an early stage of memory formation.
Neurobiol Learn Mem 1997 May
PMID:Inhibition of intermediate-term memory following passive avoidance training in neonate chicks by a presynaptic cholinergic blocker. 915 59


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