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High-density event-related potentials (ERPs) were used to understand the effect of aging on the neural correlates of the picture superiority effect. Pictures and words were systematically varied at study and test while ERPs were recorded at retrieval. Here, the results of the word-word and picture-picture study-test conditions are presented. Behavioral results showed that older adults demonstrated the picture superiority effect to a greater extent than younger adults. The ERP data helped to explain these findings. The early frontal effect, parietal effect, and late frontal effect were all indistinguishable between older and younger adults for pictures. In contrast, for words, the early frontal and parietal effects were significantly diminished for the older adults compared to the younger adults. These two old/new effects have been linked to familiarity and recollection, respectively, and the authors speculate that these processes are impaired for word-based memory in the course of healthy aging. The findings of this study suggest that pictures allow older adults to compensate for their impaired memorial processes, and may allow these memorial components to function more effectively in older adults. 相似文献
23.
Christopher Malone Rebecca G. Deason Rocco Palumbo Nadine Heyworth Michelle Tat Andrew E. Budson 《Journal of clinical and experimental neuropsychology》2019,41(2):204-218
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that presents predominantly with impairments in learning and memory. Patients with AD are also susceptible to false memories, a clinically relevant memory distortion where a patient remembers an incorrect memory that they believe to be true. The use of cognitive strategies to improve memory performance among patients with AD by reducing false memories has taken on added importance given the lack of disease-modifying agents for AD. However, existing evidence suggests that cognitive strategies to reduce false memories in patients with AD are of limited effectiveness, although these strategies may be useful at earlier stages of the disease. The purpose of this review is to examine experimental findings of false memories and associated memory processes in patients with mild cognitive impairment due to AD and mild AD dementia. Cognitive strategies to reduce false memories in these patient populations are also reviewed. Approaches to clinically relevant future research are suggested and discussed. 相似文献
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Daffner KR Ryan KK Williams DM Budson AE Rentz DM Scinto LF Holcomb PJ 《Neurobiology of aging》2005,26(9):1283-1295
Previous research on age-related changes in ERP components in response to novel and target stimuli has not carefully controlled for differences in level of cognitive status between age groups, which may have contributed to the common findings of increased P3 latency, decreased P3 amplitude, and altered P3 scalp distribution. Here, cognitively high-performing (top third based on published norms) old, middle-aged, and young adults matched for IQ, education, and gender participated in a novelty oddball paradigm. There were no age-associated differences in P3 latency. Older adults had a larger, more anteriorly distributed P3 amplitude to all stimulus types, even repetitive standards, suggesting they may rely on increased resources and effortful frontal activity to successfully process any kind of visual stimulus. However, after controlling for this non-specific age-related processing difference, the amplitude and scalp distribution of the P3 component to novel and target stimuli were comparable across age groups, indicating that for cognitively high functioning elders there may be no age-related differences specific to the processing of novel and target events as indexed by the P3 component. 相似文献
27.
Patients with mild Alzheimer's disease (AD) were compared with age-matched control subjects on an associative recognition task. Subjects studied pairs of unrelated words and were later asked to distinguish between these same studied pairs (intact) and new pairs that contained either rearranged studied words (rearranged) or non-studied words (non-studied). Studied pairs were presented either once or 3 times. Repetition increased hits to intact pairs in both groups, but repetition increased false alarms to rearranged pairs only in patients. This latter pattern indicates that repetition increased familiarity of the rearranged pairs, but only the control subjects were able to counter this familiarity by recalling the originally studied pairs (a recall-to-reject process). AD impaired this recall-to-reject process, leading to more familiarity based false alarms. These data support the idea that recollection-based monitoring processes are impaired in mild AD. 相似文献
28.
The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis 总被引:5,自引:0,他引:5
Maheshwar MM; Cheadle JP; Jones AC; Myring J; Fryer AE; Harris PC; Sampson JR 《Human molecular genetics》1997,6(11):1991-1996
Tuberous sclerosis is an autosomal dominant trait in which the
dysregulation of cellular proliferation and differentiation results in the
development of hamartomatous growths in many organs. The TSC2 gene is one
of two genes determining tuberous sclerosis. Inactivating germline
mutations of TSC2 in patients with tuberous sclerosis and somatic loss of
heterozygosity at the TSC2 locus in the associated hamartomas indicate that
TSC2 functions as a tumour suppressor gene and that loss of function is
critical to expression of the tuberous sclerosis phenotype. The TSC2
product, tuberin, has a region of homology with the GTPase activating
protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in
vitro. Here we show that the region of homology between tuberin and human
rap1GAP and the murine GAP mSpa1 is more extensive than previously reported
and spans approximately 160 amino acid residues encoded within exons 34-38
of the TSC2 gene. Single strand conformation polymorphism analysis of these
exons in 173 unrelated patients with tuberous sclerosis and direct
sequencing of variant conformers together with study of additional family
members enabled characterisation of disease associated mutations in 14
cases. Missense mutations, which occurred in exons 36, 37 and 38 were
identified in eight cases, four of whom shared the same recurrent change
P1675L. Each of the five different missense mutations identified was shown
to occur de novo in at least one sporadic case of tuberous sclerosis. The
high proportion of missense mutations detected in the region of the TSC2
gene encoding the GAP-related domain supports its key role in the
regulation of cellular growth.
相似文献
29.
Elastin point mutations cause an obstructive vascular disease, supravalvular aortic stenosis 总被引:7,自引:2,他引:7
Li DY; Toland AE; Boak BB; Atkinson DL; Ensing GJ; Morris CA; Keating MT 《Human molecular genetics》1997,6(7):1021-1028
Supravalvular aortic stenosis (SVAS) is an inherited obstructive vascular
disease that affects the aorta, carotid, coronary and pulmonary arteries.
Previous molecular genetic data have led to the hypothesis that SVAS
results from mutations in the elastin gene, ELN. In these studies, the
disease phenotype was linked to gross DNA rearrangements (35 and 85 kb
deletions and a translocation) in three SVAS families. However, gross
rearrangements of ELN have not been identified in most cases of autosomal
dominant SVAS. To define the spectrum of ELN mutations responsible for this
disorder, we refined the genomic structure of human ELN and used this
information in mutational analyses. ELN point mutations co-segregate with
the disease in four familial cases and are associated with SVAS in three
sporadic cases. Two of the mutations are nonsense, one is a single base
pair deletion and four are splice site mutations. In one sporadic case, the
mutation arose de novo. These data demonstrate that point mutations of ELN
cause autosomal dominant SVAS.
相似文献
30.
AM Innes KM Boycott EG Puffenberger D Redl IM MacDonald AE Chudley C Beaulieu R Perrier T Gillan A Wade JS Parboosingh 《Clinical genetics》2010,78(5):424-431
Innes AM, Boycott KM, Puffenberger EG, Redl D, MacDonald IM, Chudley AE, Beaulieu C, Perrier R, Gillan T, Wade A, Parboosingh JS. A founder mutation in BBS2 is responsible for Bardet‐Biedl syndrome in the Hutterite population: utility of SNP arrays in genetically heterogeneous disorders. Bardet‐Biedl syndrome (BBS) is a multisystem genetically heterogeneous disorder, the clinical features of which are largely the consequence of ciliary dysfunction. BBS is typically inherited in an autosomal recessive fashion, and mutations in at least 14 genes have been identified. Here, we report the identification of a founder mutation in the BBS2 gene as the cause for the increased incidence of this developmental disorder in the Hutterite population. To ascertain the Hutterite BBS locus, we performed a genome‐wide single nucleotide polymorphism (SNP) analysis on a single patient and his three unaffected siblings from a Hutterite family. The analysis identified two large SNP blocks that were homozygous in the patient but not in his unaffected siblings, one of these regions contained the BBS2 gene. Sequence analysis and subsequent RNA studies identified and confirmed a novel splice site mutation, c.472‐2A>G, in BBS2. This mutation was also found in homozygous form in three subsequently studied Hutterite BBS patients from two different leuts, confirming that this is a founder mutation in the Hutterite population. Further studies are required to determine the frequency of this mutation and its role, if any, in the expression of other ciliopathies in this population. 相似文献