Interference effects from divided attention during retrieval in younger and older adults.

The authors examined how retrieval, under divided attention (DA) conditions, is affected by the type of material in a concurrent task, and whether aging produces larger interference effects on memory. Young and old adults studied a list of unrelated words under full attention, and recalled them while performing either an animacy decision task to words or an odd-digit identification task to numbers. The animacy-distracting task interfered substantially with retrieval, and the size of the effect was not amplified in older compared with younger adults. DA using the odd-digit task did not produce as large an interference effect. These findings support the component-process model of memory, and pose problems for resource models of interference from DA at retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal and spatial context memory in patients with focal frontal, temporal lobe, and diencephalic lesions

Patients with focal frontal, temporal lobe, or diencephalic lesions were investigated on measures of temporal (recency) and spatial (position) context memory, after manipulating exposure times to match recognition memory for targets (pictorial stimuli) as closely as possible. Patients with diencephalic lesions from an alcoholic Korsakoff syndrome showed significant impairment on the temporal context (recency) task, as did patients with frontal lesions penetrating the dorsolateral frontal cortex, according to MRI (and PET) evidence. Patients with temporal lobe lesions showed only a moderate (non-significant) impairment on this task, and patients with medial frontal lesions, or large frontal lesions not penetrating the dorsolateral cortical margins, performed as well as healthy controls at this task. On the spatial context memory task, patients with lesions in the temporal lobes showed significant impairment, and patients with right temporal lesions performed significantly worse than patients with left temporal lesions. Patients with diencephalic lesions showed only a modest (non-significant) impairment on this task, and the frontal lobe group performed normally. When a group of patients with temporal lobe lesions resulting from herpes encephalitis were examined separately, an identical pattern of results was obtained, the herpes group being significantly impaired on spatial memory and showing a trend towards impairment for temporal context memory. There were strong correlations between anterograde memory quotients and context memory performance (despite the use of an exposure time titration procedure) and a weak association in the frontal group with one frontal/executive task [corrected] (card-sorting perservations). It is predicted that correlations between temporal context memory and frontal/executive tasks will be greater in samples of patients all of whom have frontal lesions invading the dorsolateral cortical margin.     

Frequency judgements of abstract designs by patients with diencephalic, temporal lobe or frontal lobe lesions

Patients with diencephalic, temporal lobe or frontal lobe lesions were compared with healthy controls on a frequency judgement task. The three patient groups were disproportionately impaired at estimating how often a series of abstract designs had been presented relative to controls. Diencephalic and temporal lobe patients did not differ from each other. It is argued that the results may reflect a 'core' memory deficit in the temporal lobe patients. The impairment in the frontal patients may reflect their difficulty in making an organised search in memory for multiple traces of an item, while the deficit shown by the diencephalic patients (particularly those with Korsakoff syndrome) may be due to the combined effects of a generally poor memory and superimposed frontal pathology.     

Prospective memory: A neuropsychological study.

To examine the neuropsychology of prospective remembering, older adults were divided preexperimentally into 4 groups on the basis of their scores on 2 composite measures: one assessing frontal lobe function and the other assessing medial temporal lobe function. The groups reflected the factorial combination of high and low functioning for each neuropsychological system, and they were tested on an event-based laboratory prospective memory task. High-functioning frontal participants showed better prospective remembering than low-functioning frontal participants. There was no significant difference in prospective memory performance attributable to medial temporal functioning. The results support the theoretical notion that frontal lobe processes play a key role in prospective remembering. Discussion focuses on the particular components of prospective memory performance that frontal lobes might mediate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Process-specific interference effects during recognition of spatial patterns and words.

The authors examined recognition memory for words or visuospatial patterns under full (FA) or divided attention (DA) conditions with a distracting task requiring either phonological (rhyme) or visuospatial (curved-line) processing of letters, in 72 young adults. The authors found an interaction such that the curved-line distracting task had a more detrimental effect on corrected recognition, and discriminability measured by d′, for spatial patterns than did the rhyme distracting task, whereas the reverse was true for memory of words. There was also a general effect of DA on response bias such that C increased under DA relative to FA conditions, regardless of the distracting task, and type of information being remembered. Results suggest memory interference from DA at retrieval is process-specific, and that DA at retrieval leads to a more conservative response strategy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overestimation and unreliability in "feeling-of-doing" judgements about temporal ordering performance: impaired self-awareness following frontal lobe damage

"Feeling-of-doing" accuracy in a temporal ordering task in 33 patients with frontal lobe lesions and a matched control group was investigated. The temporal ordering task used word lists that had high, medium, or no semantic interrelatedness. Patients with frontal lobe lesions showed an impairment in temporal ordering across all three word lists. Both groups performed better on the lists with higher semantic interrelatedness. Patients with frontal lobe lesions overestimated their ability to order words accurately. On the less semantically interrelated lists, metamemory judgment in patients with frontal lesions did not correlate with their performance. These results indicate that both temporal order judgment and metacognitive decisions about temporal order judgment are subserved by the prefrontal cortex and further clarifies the role of the frontal lobes in behavioral monitoring.     

Impaired generation and use of strategy in schizophrenia: evidence from visuospatial and verbal tasks

BACKGROUND: The aim of this study was to investigate mnemonic strategic deficits in schizophrenic patients. METHODS: Analogous tasks were used that required the self-generation of an efficient strategy and its implementation in two domains: visuospatial and verbal. The tasks were given to 20 IQ preserved schizophrenics and 20 matched normal controls. A number of different scores was derived from each task including strategy, short-term memory capacity and perseveration. RESULTS: Overall, the schizophrenic patients were significantly impaired in their ability to generate effective mnemonic strategies on both tasks. In addition, on the visuospatial task there was no difference between the groups on the memory scores, but the schizophrenic patients made significantly more perseverative errors than controls. They were disproportionately worse on the verbal strategy task, showing impairment on memory as well as on strategy scores and were also impaired at semantically classifying the words. Performance was similar to the deficit seen in patients with frontal lobe excisions and Parkinson's disease, in terms of the inability to generate an effective strategy. The deficit on the verbal task was similar to patients with temporal lobe excisions who show impaired verbal memory. However, the pattern differed in the sense that the temporal lobe patients were able to generate effective strategies, unlike the patients with schizophrenia. CONCLUSIONS: High functioning schizophrenic patients are impaired in utilizing visuospatial and verbal mnemonic strategies. By comparing the results with those of neurosurgical excision patients, further evidence is provided for both frontal and temporal lobe involvement in schizophrenia.     

Effects of bilingualism, aging, and semantic relatedness on memory under divided attention.

We examined how encoding and retrieval processes were affected by manipulations of attention, and whether the degree of semantic relatedness between words in the memory and distracting task modulated these effects. We also considered age and bilingual status as mediating factors. Monolingual and bilingual younger and older adults studied a list of words from a single semantic category presented auditorily, and later free recalled them aloud. During either study or retrieval, participants concurrently performed a distracting task requiring size decisions to words from either the same or a different semantic category as the words in the memory task. The greatest disruptions of memory from divided attention (DA) were for encoding rather than retrieval. The effect of semantic relatedness was significant only for DA at encoding. Older age and bilingualism were associated with lower recall scores in all conditions, but these factors did not influence the magnitude of memory interference. The results suggest that encoding is more sensitive to semantic similarity in a distracting task than is retrieval. The role of attention at encoding and retrieval is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationships between normal aging, frontal lobe function, and memory for temporal and spatial information.

Young and old participants were evaluated on tests of frontal lobe function, recognition memory, and memory for temporal and spatial information. Older participants showed significant impairments on memory for temporal order, and this impairment was found to correlate with deficits on frontal lobe tests measuring spontaneous flexibility but not reactive flexibility. However, spatial memory showed no evidence of an age effect. An interpretation of this latter finding based on the differential availability of contextual cues is ruled out because similar results were obtained when spatial memory was assessed in a different context to that used during learning. The researchers concluded that memory for temporal order and spatial memory are affected differentially by age. Theoretical interpretations of this difference are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Double dissociation between item and source memory.

The present experiment provides evidence for a double dissociation between item and source memory, thereby strengthening the claim that the 2 kinds of memory rely on different brain structures. Elderly participants were divided preexperimentally into 2 groups on the basis of their scores on a composite measure of frontal lobe function. In a subsequent test of sentence memory, the 2 groups did not differ; on a test of memory for the voice in which sentences were spoken, participants with high-frontal function outperformed those with low-frontal function. When the same participants were divided according to a composite measure of medial temporal lobe function, the high-functioning adults outperformed the low-functioning adults on memory for the sentence, but the groups did not differ on memory for voice. Results focus on different theories of frontal lobe function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive resources and dual-task interference effects at retrieval in normal people: The role of the frontal lobes and medial temporal cortex.

Conducted 3 experiments to examine the hypothesis that concurrent secondary tasks at retrieval will interfere more with long-term, episodic memory functions involving the frontal lobes than those involving the medial temporal lobes hippocampus (MTL/H). The rationale is that strategic retrieval processes mediated by the frontal lobes place greater demands on cognitive resources than do relatively automatic associative retrieval processes (ecphory) mediated by the temporal lobes. In Exps 1 and 2, sequential finger tapping was performed at encoding, at retrieval, at both, or at neither. Recall of a categorized list of 16 words from the California Verbal Learning Test in Exp 1, and release from proactive inhibition (PI) in Exp 2, both being tests that involve the frontal lobes, were impaired if normal Ss tapped at both encoding and retrieval. Concurrent tapping had little effect on rate of learning in Exp 1 and on total words recalled during the buildup of PI in Exp 2, both of which are indices that are affected more by MTL/H than by frontal lesions. In Exp 3, tapping by normal Ss affected letter fluency, a test more sensitive to frontal lobe than temporal lobe damage, but not category fluency, for which the reverse is true. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distribution of the Rhesus haplotype frequencies in the Düsseldorf administrative center (North Rhine-Westphalia)

Patients with medically intractable epilepsy and either hippocampal sclerosis or frontal lobe lesions were compared with healthy controls, to investigate a possible neuroanatomical correlate of a component of working memory: the central executive. Patients were tested on a short-term memory task which comprised visuo-spatial and verbal components, in single and concurrent trials. Differences were found between the patient groups for dual-task capacity, despite being equated on single-task trials. Patients with frontal lobe damage were the most affected by the demands of attention division. The results of this study do not support the thesis of a hippocampal role in the working memory component examined, but point to a frontal lobe focus for this janusian cognitive function. An unexpected finding of an increment in performance over the trials of visuo-spatial assessment, in patients with hippocampal sclerosis, is presented.     

Subjective memory evaluations in patients with focal frontal, diencephalic, and temporal lobe lesion

This paper examines subjective memory evaluations and their correlates in patients with focal frontal, diencephalic, or temporal lobe lesions. Although all patient groups showed significantly lower subjective memory evaluations than healthy subjects, the temporal lobe group rated themselves significantly lower than the frontal lobe or diencephalic groups despite comparable severity of amnesia, implying more severely impaired 'insight' in the latter two groups. There was a 'temporal gradient' such that patients rated their memory for 'old' (premorbid) items better than their memory for 'new' (recent) or prospective items. As in previous studies, subjective memory evaluations were not correlated with measures of 'objective' anterograde memory performance, but the present study suggests that subjective evaluations are not randomly determined. It seemed to be the site of lesion (frontal and/or diencephalic), rather than underlying aetiology, which produced a particularly severe loss of 'insight'. Whether the earliest remote or autobiographical memories were preserved or not appeared to be an important correlate of current subjective memory evaluations, and patients who had been memory-disordered for longer were more likely to evaluate their memory as poor than those with a more recent onset.     

Rates of forgetting in organic amnesia following temporal lobe, diencephalic, or frontal lobe lesions.

Forgetting rates were examined in patients with diencephalic, temporal lobe, or frontal lesions. No significant differences were found in short-term forgetting of verbal and nonverbal material; in recognition memory for pictures, words, or designs over delays between 1 min and 20 or 30 min; or on a measure of explicit cued recall for words, calculated in terms of the process dissociation procedure. Significantly faster forgetting was found in the diencephalic and the temporal lobe groups in the free recall of pictures of objects, although there was no difference between these 2 groups. It is concluded that the major deficit in amnesic patients' memory processes is in the initial acquisition of information but that there is a subtler deficit in retention over specific delays, detectable only on measures of free recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive function, cardiovascular reactivity, and behavior in boys at high risk for alcoholism.

Boys (average age?=?12.1 years) from families with an extensive history of paternal alcoholism differed from controls of similar age and IQ on measures of cognitive function, cardiovascular reactivity, and parent-rated conduct problems. High-risk boys performed most poorly on neuropsychological tests of frontal lobe function. According to tests of temporal organization and conditional associate learning, control over working memory was the frontal subfunction primarily affected. A mental arithmetic task also elicited greater heart rate increases and peripheral vasoconstriction among high-risk boys than among controls. After controlling for group status, significant correlations remained between frontal lobe test scores and disruptive behavior and between cardiovascular hyperreactivity and anxiety levels. The possible contribution of these findings to alcohol abuse was discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working Memory and Perseveration in Verbal Fluency.

Letter and semantic fluency tasks are often used in neuropsychological assessment and are sensitive to many conditions. Performance is assessed by correct responses and errors, including perseverations. Healthy young adults performed letter and semantic fluency tasks. One group performed these tasks in the conventional manner; 2 other groups performed them while maintaining memory loads. The memory loads consisted either of words from the same category as the fluency task or of words from a different category. The results showed little effect of memory loads on correct responses but significant effects of memory load on perseveration rates: Same-category loads resulted in higher rates, especially in letter fluency. The results are discussed in terms of frontal lobe function in verbal fluency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strategic processing and memory for temporal order in patients with frontal lobe lesions.

This study evaluated whether deficits in memory for temporal order in patients with frontal lobe lesions result from impaired automatic encoding of temporal information or are secondary to deficits in effortful processes, such as the use of organizational strategies and control of interference. Patients with lesions in the dorsolateral prefrontal cortex and control participants were tested on temporal order reconstruction of semantically related and unrelated word lists learned under intentional or incidental conditions. Memory for temporal order in patients with frontal lobe lesions was sensitive to semantic relatedness but not to intention to learn. Tests of item free recall and recognition using similar encoding manipulations indicated that order performance in these patients was dissociable from item memory. Results indicate that automatic processing of temporal information is intact in patients with frontal lobe lesions but that strategic processing of this information is impaired. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An application of prefrontal cortex function theory to cognitive aging.

The purpose of this review is to extend the existing application of the frontal lobe hypothesis of cognitive aging beyond the limited work on inhibitory control (F. N. Dempster, see record 1992-22951-001) to include memory processes supported by the prefrontal cortex. To establish a background for this analysis, I review existing models of prefrontal cortex function and present a synthesized model that includes a general function of temporal integration, supported by 4 specific processes: prospective memory, retrospective memory, interference control, and inhibition of prepotent responses. I found the frontal lobe hypothesis to perform well, with the exception of an inability to account for age-related declines in item recall and recognition memory, possibly a result of age-related declines in medial temporal function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

True memory, false memory, and subjective recollection deficits after focal parietal lobe lesions.

Objective: There is mounting evidence that the posterior parietal cortex (PPC) plays an important role in episodic memory. We previously found that patients with PPC damage exhibit retrieval-related episodic memory deficits. Here we assess whether parietal lobe damage affects episodic memory on a different task: the Deese–Roediger–McDermott (DRM) false-memory paradigm. Methods: Two patients with bilateral PPC damage and a group of matched controls were tested. In Experiment 1, the task was to remember words; in Experiment 2 the task was to remember pictures of common objects. Prior studies have shown that normal participants have high levels of false memory to words, low levels to pictures. Results: The patients exhibited significantly lower levels of false memory to words. One patient showed significantly elevated levels of false memory to pictures. The patients' false memories were accompanied by reduced levels of recollection, as tested by a Remember/Know procedure. Conclusions: PPC damage causes decreased levels of false memories and an abnormal Remember/Know profile. Their false memory rate is similar to the rate exhibited by patients with medial temporal lobe damage. These results support the view that portions of the PPC play a critical role in objective and subjective aspects of recollection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Forms of memory failure in schizophrenia.

Examined effortful and automatic memory task performances in 36 schizophrenic patients and 18 normal controls. Tasks included free recall, recognition, and frequency estimation. Patients demonstrated impairment in recall, in recognition, in semantic encoding, and in frequency estimation. Deficits were observed across tasks despite differences in attentional demands. Results suggest a basic compromise of memory function, which is consistent with recent neuroimaging evidence of structural or physiological abnormalities in frontal and temporal lobe structure in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)