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At least 523 records · Page 29Linked to original sources

PubMed2005

With sadness comes accuracy; with happiness, false memory: mood and the false memory effect.

The Deese-Roediger-McDermott paradigm lures people to produce false memories. Two experiments examined whether induced positive or negative moods would influence this false memory effect. The affect-as-information hypothesis predicts that, on the one hand, positive affective cues experienced as task-relevant feedback encourage relational processing during encoding, which should enhance false memory effects. On the other hand, negative affective cues are hypothesized to encourage item-specific processing at encoding, which should discourage such effects. The results of Experiment 1 are consistent with these predictions: Individuals in negative moods were significantly less likely to show false memory effects than those in positive moods or those whose mood was not manipulated. Experiment 2 introduced inclusion instructions to investigate whether moods had their effects at encoding or retrieval. The results replicated the false memory finding of Experiment 1 and provide evidence that moods influence the accessibility of lures at encoding, rather than influencing monitoring at retrieval of whether lures were actually presented.

Acoustic Stimulation↗

PubMed1995

Acute ethanol impairs spatial memory but not stimulus/response memory in the rat.

The present studies investigate how acutely administered ethanol (ETOH) affects the use of spatial memory. Previous electrophysiological results have shown that acutely administered ETOH alters the firing of hippocampal neurons and that prenatal or chronic exposure to ETOH produces deficits on spatial learning tasks, tasks dependent on the hippocampus. In contrast, it has also been demonstrated that acutely administered ETOH does not impair spatial localization. In the current studies, rats were trained to perform a spatial or stimulus/response task under saline. After training, rats were injected with ETOH, and the use of spatial or stimulus/response memory was tested. Acutely administered ETOH impaired the use of spatial memory, but not the use of stimulus/response memory. Because the use of spatial memory requires an intact hippocampus, the present studies suggest that acutely administered ETOH selectively impairs behaviors dependent on the hippocampus.

Animals↗

PubMed2006

Making memories: a cross-sectional investigation of episodic memory encoding in childhood using FMRI.

In adults, the neural substrate associated with encoding memories connected to a specific time and place include the prefrontal cortex and medial temporal lobe (MTL). Using functional magnetic resonance imaging, this research studied the developmental trajectory of this frontal-MTL system by comparing 7- and 8-year-old children to those who were 10 or older in conditions that promoted episodic encoding. In 1 condition, participants generated verbs from nouns heard; in another, they listened to short stories for comprehension. Regions in which brain activation predicted subsequent recognition memory performance were identified. These included the left prefrontal cortex, but not MTL, in the verb generation condition for both age groups. In the story comprehension condition, activation in left posterior MTL predicted subsequent memory performance in both age groups, and activation in left anterior MTL (including the hippocampus proper) and left prefrontal cortex predicted subsequent memory only for the older children. These results illustrate both similarities and differences in how brain systems interact in development to mediate the formation of episodic memories.

Adolescent↗

PubMed2002

Are false memories more difficult to forget than accurate memories? The effect of retention interval on recall and recognition.

What is the effect of retention interval on accurate and false recollection in the Deese, Roediger, and McDermott (DRM) procedure? Previous research has suggested that false recall is more persistent than accurate recall but the recognition results have been inconsistent. In two parametric studies, we tested recall and recognition for the same DRM lists, over retention intervals that ranged from no delay to a 2-month delay. We found that accurate and false memory were diminished by increases in retention interval, false memory persistence was present for recall and recognition, greater persistence for false memory than for accurate memory was more readily observed for recall than recognition, and the high-threshold (Pr), signal detection (d'), and nonparametric (A') recognition measures differed in their sensitivity for detecting change. The effect of retention interval on accurate and false memory is consistent with expectations from fuzzy trace theory. In the DRM procedure, truth is not more memorable than fiction.

Humans↗

PubMed1991

Effect of true memory impairment on a test of memory complaint validity.

The Fifteen-Item Test (FIT) is designed to detect an exaggerated presentation on memory assessment. This study examines the extent to which poor FIT performance might reflect true - as opposed to exaggerated - memory impairment. Subjects were 60 persons with mild to severe memory impairment who were not involved in litigation or disability proceedings. FIT performance was examined in relation to WAIS, WMS, and AVLT variables. The results show the FIT "failure" can result from true memory impairment, but that severe memory impairment is generally required to "fail." Common qualitative errors in this neurologic population are also described. Clinical implications of these findings are discussed, with caution against use of the FIT in isolation to address possible exaggerated presentation.

Journal Article↗

PubMed2006

Diazepam-induced prospective memory impairment and its relation to retrospective memory, attention, and arousal.

The amnestic effects of benzodiazepines are well documented on a variety of memory tasks. However, prospective memory (PM), or remembering to execute an action at a future time, has not been studied previously. This study examined the effect of diazepam on word list recall, PM, sustained attention, and subjective ratings of arousal. Forty-eight healthy participants, aged 19-35, received an average of 0.19 mg/kg oral diazepam or placebo in a double-blind manner. Retrospective memory and PM were assessed by free recall of unrelated word lists and by instructing participants to request a hidden belonging at the end of the session, respectively. Sustained attention was measured by multiple trials of a digit cancellation task, and subjective arousal was assessed by self-ratings of drowsiness. Diazepam impaired performance on all measures, including PM. Reduced PM performance was associated with decreased subjective arousal in the diazepam group but was unrelated to sustained attention. This is the first report of the effects of benzodiazepines on prospective remembering, and further supports the view that the arousal/attentional system is composed of partially independent subsystems that have differential relationships to memory.

Adult↗

PubMed2001

Short-term memory, working memory, and inhibitory control in children with difficulties in arithmetic problem solving.

The relations between short-term memory, working memory, inhibitory control, and arithmetic word problem solution were studied in children who were poor in arithmetic problem solving (n = 23). The children were compared with a group of good problem solvers (n = 26), matched for vocabulary, age, and gender. The results corroborate the hypothesis of poor problem solvers' general deficit in inhibitory processes. They had lower scores and made more intrusion errors in a series of working memory tasks requiring inhibition of irrelevant information. The results showed that problem solving performance is related to the ability of reducing the accessibility of nontarget and irrelevant information in memory. Span tasks that imply passive storage of information showed that poor problem solvers were impaired when they have to retain numerical information, but they did not differ from children who did not have difficulty with mathematics when the material included words.

Child↗

PubMed1993

Blockade of hippocampal nicotinic receptors impairs working memory but not reference memory in rats.

In a three-panel runway task, intrahippocampal injection of the nicotinic receptor antagonist, mecamylamine (10 and 18 micrograms/side), significantly increased the number of errors (attempts to pass through two incorrect panels of the three panel-gates at four choice points) in a test of working memory. This increase in errors also occurred after rats were given IP mecamylamine (10 mg/kg). Mecamylamine did not affect the number of errors in a test of reference memory whether it was given at doses up to 18 micrograms/side intrahippocampally or up to 10 mg/kg IP. These results suggest that mechanisms mediated by hippocampal nicotinic receptors play a role in working memory but not in reference memory.

Animals↗

PubMed1997

Two circuits to convert short-term memory into long-term memory.

According to a brain model, encoding synapses record presynaptic axonal 'on-off' patterns as memory, and modulating synapses convert short-term memory into long-term memory by helping encoding synapses develop long-term potentiation and depression. Sensory organs conduct sounds and images as series of axonal 'on-off' patterns to encoding synapses of perceptive cortices where the patterns are recorded, computed, and rerouted to mesotemporal lobes, hippocampal formations and higher cortical centers. Mesotemporal lobes and hippocampal formations compute and convey the 'on-off' patterns to dorsomedial thalamic nuclei (circuit A), septal nuclei and mammillary bodies (circuit B), where the patterns are computed and conveyed to prefrontal lobes (circuit A) and anterior thalamic nuclei (circuit B) respectively. Anterior thalamic nuclei project axonal 'on-off' patterns to cingulate gyri that compute and convey the patterns to prefrontal lobes. Finally, prefrontal lobes send modulating axons to encoding synapses of perceptive cortices. Amnesia of Korsakoff's syndrome results from unilateral dysfunction of circuit A and contralateral dysfunction of circuit B, or bilateral dysfunction of either. The fact that there is more severe memory deficit in Alzheimer's disease than in Korsakoff's syndrome suggests that the former has a wider spread of failing synapses besides circuit A and circuit B.

Alcohol Amnestic Disorder↗

PubMed1997

Role of the hippocampus in sex differences in verbal memory: memory outcome following left anterior temporal lobectomy.

The authors examined the neural and cognitive bases for sex differences in verbal memory in 57 patients who underwent left anterior temporal lobectomy (ATL) for the treatment of intractable seizures. On the California Verbal Learning Test (D. C. Delis, J. H. Kramer, E. Kaplan, & B. A. Ober, 1987), women recalled more words than men both before and after surgery, regardless of the extent of hippocampal damage. Extent of hippocampal sclerosis was related to memory loss in both men and women. Women's superiority in verbal memory appears to result in part from their use of an efficient encoding strategy. Women were more likely than men to use semantic clustering both before and after ATL, and sex differences in word recall were attenuated after scores were adjusted for semantic clustering. There was no effect of ATL on semantic clustering. Taken together, these results suggest that sex differences in verbal memory are not due to differences in the integrity of the left hippocampus.

Adult↗

PubMed1975

Memory for speech and speech for memory.

Thirty kindergarteners, 15 who substituted /w/ for /r/ and 15 with correct articulation, received two perception tests and a memory test that included /w/ and /r/ in minimally contrastive syllables. Although both groups had nearly perfect perception of the experimenter's productions of /w/ and /r/, misarticulating subjects perceived their own tape-recorded w/r productions as /w/. In the memory task these same misarticulating subjects committed significantly more /w/-/r/ confusions in unspoken recall. The discussion considers why people subvocally rehearse; a developmental period in which children do not rehearse; ways subvocalization may aid recall, including motor and acoustic encoding; an echoic store that provides additional recall support if subjects rehearse vocally, and perception of self- and other- produced phonemes by misarticulating children-including its relevance to a motor theory of perception. Evidence is presented that speech for memory can be sufficiently impaired to cause memory disorder. Conceptions that restrict speech disorder to an impairment of communication are challenged.

Analysis of Variance↗

PubMed1998

Comparison between a "traditional" memory test and a "behavioral" memory battery in Spanish patients.

The main objective of this study was to compare a "traditional" test of memory, the Wechsler Memory Scale-Revised (WMS-R; Wechsler, 1987) with a behavioral evaluation test, the Rivermead Behavioural Memory Test (RBMT; Wilson, Cockburn, & Baddeley, 1985). Eighty volunteers participated in the study and were divided into four groups: 20 older adults with memory problems, 20 patients with temporal lobe epilepsy, 20 patients with Alzheimer' s disease, and 20 controls. A Spanish translation and adaptation of the WMS-R and a Spanish version of the RBMT were used. The results indicated that the RBMT was as robust as the WMS-R in differential discrimination of patients.

Aged↗

PubMed1997

Amsterdam Short-Term Memory test: a new procedure for the detection of feigned memory deficits.

The validity of two malingering tests, the newly developed Amsterdam Short-Term Memory (ASTM) test and the Distraction test (Baker, Hanley, Jackson, Kimmance, & Slade, 1993) was examined in a group of patients with closed-head injury (CHI), a normal control group, and a control group with instruction to feign memory deficits. Both control groups consisted of first-degree relatives of the patients. The ASTM test is a forced-choice verbal memory test, based on the technique of symptom validity testing. Stimulus material was chosen from category norms and chance level is not transparent. The CHI and normal control groups scored near ceiling on the ASTM test, whereas the feigned deficit group scored significantly worse. The ASTM test classified all subjects correctly. Contrary to expectation, the Distraction test appeared to be invalid. The score profiles of the CHI and feigning groups on conventional memory and concentration tests were indistinguishable from each other. Thus, the ASTM test may be very useful for the detection of malingering and other kinds of less than optimal performance. The test may readily be constructed in any language for which category norms are available.

Adult↗

PubMedDate not supplied

Memory scores in middle-aged rats predict later deficits in memory, paradoxical sleep, and blood glucose regulation in old age.

Age-related deficits in memory are correlated with deficits in paradoxical sleep and poor glucose tolerance in rats. The present experiment used a longitudinal design to determine whether memory or glucose tolerance in middle-aged rats could predict deficits in memory, sleep, and glucose tolerance in old age. Correlations were obtained between spontaneous alternation scores and glucose tolerance levels in middle age (14 months) and inhibitory avoidance, daytime sleep, and glucose tolerance levels in old age (24 months). Spontaneous alternation scores, but not glucose tolerance levels, predicted performance on all 3 behavioral and biological measures in old age. Measures of functional integrity, such as memory, may be sensitive predictors of subsequent age-related change in specific cognitive and neurobiological systems.

Aging↗

PubMed2006

Memory performance profile in occupational chronic solvent encephalopathy suggests working memory dysfunction.

This pilot study characterizes memory functioning of 11 men with occupational chronic solvent encephalopathy (CSE). Pattern (PRM) and spatial recognition (SRM), spatial span (SSP), spatial working memory (SWM), and paired associate learning (PAL) from Cambridge Neuropsychological Test Automated Battery were performed twice. The most sensitive variables to show impairment were PAL trials, SRM total correct, and SWM number of between-search errors. The majority of the CSE patients demonstrated mild deficits. The most persistent dysfunction was in tasks demanding working memory processing, which predicted well the CSE status. Qualitatively, the memory deficits resemble those seen in moderate or severe Parkinson's disease.

Association Learning↗

PubMed2003

The roles of verbal short-term memory and working memory in the acquisition of grammar by children with Williams syndrome.

The roles of verbal short-term and working memory were examined in a sample of children with Williams syndrome (mean chronological age 10 years, 2 months) and a sample of grammar-matched children who are developing normally. Forward digit span, nonword repetition, and backward span were all found to be correlated with receptive grammatical ability in the sample of children with Williams syndrome, but not in the sample of children who are developing normally. The relation between working memory, as measured by backward digit span, and grammatical ability was found to be significantly stronger in children with Williams syndrome than in the control group. This finding highlights the possibility that children with Williams syndrome may rely on their working memory to a greater extent than children who are developing normally to learn grammar. Hierarchical regression analyses indicated receptive vocabulary may mediate the relations among forward digit span, backward digit span, and grammatical ability for the children with Williams syndrome. Phonological short-term memory, however, contributed independently to grammatical ability even after receptive vocabulary was taken into account.

Adolescent↗

PubMedDate not supplied

Roles of attention, memory, and motor preparation in modulating human brain activity in a spatial working memory task.

Neuronal activity of the human brain was studied with magnetoencephalography (MEG) in a spatial working memory task similar to those commonly used with nonhuman primates. The subject was required to remember target positions for 3 s and make a same-different judgement with a finger lift comparing the position of the probed target with the probe or to execute a memory-guided saccade to the probed target. In this type of task single-unit studies have shown attention- and memory-related activities independent of movement type during the retention interval in a large number of cortical areas of the primates, including the parietal and prefrontal areas. Consistent with these results, there were strong stimulus-driven transient and sustained responses and modulations of oscillatory activity during the retention period. Although we did not determine the source locations, coarse estimates of the currents responsible for the MEG signals showed activity over a wide area of the cortex, most prominently over the Rolandic, parietal and occipital areas, but also over the frontal area. Some of the activities in these cortical areas reflect processes that may be identified with attention and memory, while others were related to preparation of the overt movements.

Adult↗

PubMedDate not supplied

Novel lists of 7 +/- 2 known items can be reliably stored in an oscillatory short-term memory network: interaction with long-term memory.

This paper proposes a model for the short-term memory (STM) of unique lists of known items, as, for instance, a phone number. We show that the ability to accurately store such lists in STM depends strongly on interaction with the preexisting long-term memory (LTM) for individual items (e.g., digits). We have examined this interaction in computer simulations of a network based on physiologically realistic membrane conductances, synaptic plasticity processes, and brain oscillations. In the model, seven STMs can be kept active, each in a different gamma-frequency subcycle of a theta-frequency oscillation. Each STM is maintained and timed by an activity-dependent ramping process. LTM is stored by the strength of synapses in recurrent collaterals. The presence of preexisting LTM for an item greatly enhances the ability of the network to store an item in STM. Without LTM, the precise timing required to keep cells firing within a given gamma subcycle cannot be maintained and STM is gradually degraded. With LTM, timing errors can be corrected and the accuracy and order of items is maintained. This attractor property of STM storage is remarkable because it occurs even though there is no LTM that identifies which items are on the list or their order. Multiple known items can be stored in STM, even though their representation is overlapping. However, multiple, identical memories cannot be stored in STM, consistent with the psychophysical demonstration of repetition blindness. Our results indicate that meaningful computation (memory completion) can occur in the millisecond range during an individual gamma cycle.

Computer Simulation↗