Modification of glassy carbon surfaces with synthetic laminin-derived peptides for nerve cell attachment and neurite growth

Working memory and its contribution to performance on strategic memory tests in schizophrenia were studied. Patients (n = 18) and control participants (n = 15), all men, received tests of immediate memory (forward digit span), working memory (listening, computation, and backward digit span), and long-term strategic (free recall, temporal order, and self-ordered pointing) and nonstrategic (recognition) memory. Schizophrenia patients performed worse on all tests. Education, verbal intelligence, and immediate memory capacity did not account for deficits in working memory in schizophrenia patients. Reduced working memory capacity accounted for group differences in strategic memory but not in recognition memory. Working memory impairment may be central to the profile of impaired cognitive performance in schizophrenia and is consistent with hypothesized frontal lobe dysfunction associated with this disease. Additional medial-temporal dysfunction may account for the recognition memory deficit.     

Dual-task information processing in schizotypal personality disorder: Evidence of impaired processing capacity.

Working memory theories heavily rely on the concept of processing resources and the their efficient deployment. Some recent work with schizophrenia-spectrum patients has suggested that many associated cognitive impairments may be reduced to deficits in working memory, possibly related to reductions in information-processing capacity resources. In this study, 38 patients with schizotypal personality disorder (SPD), 22 patients with other personality disorders, and 14 healthy comparison participants performed a dual-task processing assessment that was designed specifically for use in this type of study. Participants recalled lists of digits at their predetermined maximum digit span and performed box-checking tests, first alone and then in a dual-task format. Instructions included equal prioritization of both tasks. SPD patients had significantly shorter digit spans, and they also showed more deterioration on both tasks. Performance operating characteristics curves indicated that SPD patients' reduced performance was not due to abnormal resource allocation strategies leading to strategic failures. The authors discuss the implications of these processing capacity limitations for understanding both the signature of cognitive impairment within the schizophrenia spectrum and general abnormalities in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduced working memory span in Parkinson's disease: Evidence for the role of frontostriatal system in working and strategic memory.

Working and strategic memory were examined in unmedicated patients with Parkinson's disease who had neither depression nor dementia. The patients, relative to control participants, had reduced working memory spans for verbal and arithmetic materials. They also had impairment on strategic memory tests of fee recall, temporal ordering, and self-ordered pointing, but no impairment on tests of recognition memory and semantic memory. Impairments in working memory capacity correlated with impairments in strategic memory and with a measure of perceptual-motor speed, but not with motor speed. It is hypothesized that a frontostriatal memory system, in which dopamine plays a critical role, mediates perceptual-motor processing speed that contributes to working memory capacity, which in turn, contributes to strategic memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Depression does not aggravate the episodic memory deficits associated with Alzheimer's disease.

In a population-based study of persons between 75 and 96 years of age, normal old adults (n?=?296), patients with Alzheimer"s disease (AD; n?=?45), and patients with concomitant AD and depression (AD-D; n?=?9) were compared on free recall and recognition of slowly and rapidly presented words and digit span. With the exception of forward digit span, the normal old group outperformed the 2 AD groups across all tasks. In free recall, only the normal old group performed better as task pacing decreased; however, all groups benefited from more study time in recognition. This suggests that both AD and AD-D patients have deficits in the ability to use more study time for remembering. Of most importance, the 2 AD groups were indistinguishable for all task variables. This lack of comorbidity effects is discussed relative to the view that depression, much like many other individual-difference variables that affect memory performance in normal aging, may be overshadowed by the influence of the process in AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Declarative memory following anterior temporal lobectomy in humans.

Hypothesized that verbal memory decline following anterior temporal lobectomy (ATL) is associated with a lack of significant neuropathology in resected left, but not right, hippocampus and is limited to measures of episodic memory only. Tests of immediate (digit span), semantic (visual naming), and episodic memory as measured by the California Verbal Learning Test (CVLT) were administered before and 6 mo after resection of the anterior left (n?=?36) or right (n?=?26) temporal lobe. There were no effects of hippocampal pathology on measures of immediate or semantic memory for either ATL group or for episodic memory for the right ATL group. Left ATL patients who demonstrated no/mild hippocampal sclerosis exhibited significantly greater postoperative decline in episodic memory compared with those with moderate/marked hippocampal sclerosis on multiple CVLT indices (recall measures, learning characteristics, and contrast measures). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

''Best clinical practice'': assessment of processes of care and of outcomes in the US Military Health Services System

The functioning of working memory in schizophrenic patients according to Baddeley's model was examined in two complementary experiments. Experiment 1 comprised 27 patients and their controls, matched in age and level of education. Of this pool, 20 pairs participated also in Experiment 2. Digit span, reading rate, and immediate serial recall assessed the functioning of the phonological loop. Corsi and pattern span tasks assessed the capacity of visuo-spatial memory. The central executive's ability to monitor two concurrent tasks was evaluated in a dual task paradigm, and its capacity to control action in a random generation task. A preliminary set of analyses showed that the patients' performances were reduced in all tasks explored, except in digit span. This initial pattern changed consistently after controlling for reading rate. While slow and fast reading patients were comparable in demographic and clinical criteria, slow reading patients showed impaired performance in all tasks, whereas fast reading patients exhibited reduced performance in visuo-spatial tasks and in the random generation task only. The state of functioning of working memory in schizophrenia appears, therefore, to vary consistently among the components of the model and is markedly impaired in slow reading patients. The implications of slowness are discussed.     

Endothelin B receptor-mediated vasoconstriction induced by endothelin A receptor antagonist

BACKGROUND: Capacity limitation theories have proved to be surprisingly resilient in characterizing some of the cognitive deficits in schizophrenia. However, this perspective has not generally been applied to short-term verbal memory tasks. We explored this issue by first attempting to ascertain if gross misallocations of processing resources might explain impairments in short-term memory in schizophrenia on a classic digit span task and in a second study by attempting to determine what effects delay and memory set size had on a divided attention short-term verbal memory paradigm. METHODS: In the first study 16 patients with schizophrenia and 21 normal controls received 40 trials of a three digit task and 20 trials of a six digit span task. As the absolute number of digits presented and duration of presentation in two conditions were identical, subjects thus had equivalent 'opportunities' to make errors if distraction, in the sense of misallocation of cognitive resources, were at the root of poor performance. In the second study 15 patients with schizophrenia and 15 normal controls were tested in conditions in which two, four or six words were presented and in which rehearsal was prevented by an interference task (colour naming) for delays of 5, 10 or 15 s. RESULTS: Patients had disproportionate difficulty on the six digit rather than the three digit condition, suggesting that deficits in the verbal working memory short-term store may not be the result of attentional factors. In the second study, patients' performance was differentially worsened by the interference task, by memory set size (i.e. a capacity limitation) and by delay, a measure of decay rate. CONCLUSIONS: In concert, these studies demonstrate that schizophrenia patients have difficulties on verbal short-term memory span tasks not because of misallocation of resources, but rather because of limitations in 'representational capacity' and maintenance of information over delays.     

Working memory, attention, and communication disturbances in schizophrenia.

The authors hypothesized that schizophrenic communication disturbances reflect specific cognitive deficits in the areas of working memory and attention. They examined the cognitive correlates of communication disturbances, as measured by linguistic reference performance, in schizophrenic (n?=?48), bipolar (n?=?24), and nonpsychiatric control (n?=?23) individuals. Reference performance ratings in the schizophrenic patients were associated with scores on tests of working memory and attention and were not related to performance on concept formation or verbal fluency tests. In contrast, in the bipolar and nonpsychiatric individuals, reference performance was associated with concept formation and verbal fluency test scores but was not related to performance on tests of working memory. Implications with respect to the processes underlying schizophrenic communication disturbances are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Patterns of content, contextual, and working memory impairments in schizophrenia and nonamnesic alcoholism.

This study used tests of content memory (item recognition of words and abstract designs), context memory (order recognition of verbal and nonverbal items), and working memory (recognition at a short retention interval) to examine patterns of performance in 27 schizophrenic patients, 52 chronic alcoholic patients, and 66 healthy control participants. When performance was age- and IQ-adjusted the schizophrenia group was significantly impaired in item and order recognition of verbal and nonverbal material; the alcoholic group was impaired only in order recognition for both material types. Item- and order-recognition deficits in the schizophrenia group were greatest at the shortest retention intervals, a pattern previously observed in patients with Parkinson's disease, suggesting a prominence of a working memory deficit in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Output loss or rehearsal loop? Output-time versus pronunciation-time limits in immediate recall for forgetting-matched materials.

Forgetting during recall may be one limit on memory span. Output time and accuracy of immediate serial recall using spoken and keypress responses were measured for digit, letter, and word sets approximately matched in phonemic discriminability and in immediate recognition memory. Nonetheless, the materials differed from one another in recall span, in output time during recall, and in pronunciation time (speech rate). Recall output times accounted precisely and completely for the measured memory span for these matched materials. Pronunciation times are correlated with recall output times, but output time gives a slightly better account of recall accuracy. The output time equivalent to the rule that short-term memory span corresponds to the number of items that can be said in about 1.5–2 s is that span corresponds to the number of items that can be recalled in about 4–6 s. Additional variations in span reflect differential item interference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heterogeneity of auditory verbal working memory in schizophrenia.

The heterogeneity of schizophrenia remains an obstacle for understanding its pathophysiology. Studies using a tone discrimination screening test to classify patients have found evidence for 2 subgroups having either a specific deficit in verbal working memory (WM) or deficits in both verbal and nonverbal memory. This study aimed to (a) replicate in larger samples differences between these subgroups in auditory verbal WM; (b) evaluate their performance on tests of explicit memory and sustained attention; (c) determine the relation of verbal WM deficits to auditory hallucinations and other symptoms; and (d) examine medication effects. The verbal WM and tone discrimination performance did not differ between medicated (n = 45) and unmedicated (n = 38) patients. Patients with schizophrenia who passed the tone screening test (discriminators; n = 60) were compared with those who did not (nondiscriminators; n = 23) and healthy controls (n = 47). The discriminator subgroup showed poorer verbal WM than did controls and a deficit in verbal but not visual memory on the Wechsler Memory Scale–Revised (Wechsler, 1987), whereas the nondiscriminator subgroup showed overall poorer performance on both verbal and nonverbal tests and a marked deficit in sustained attention. Verbal WM deficits in discriminators were correlated with auditory hallucinations but not with negative symptoms. The results are consistent with a verbal memory deficit in a subgroup of schizophrenia having intact auditory perception, which may stem from dysfunction of language-related cortical regions, and a more generalized cognitive deficit in a subgroup having auditory perceptual and attentional dysfunction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive mediation of adult age differences in language performance.

Young (M?=?20 years) and old (M?=?68 years) adults completed language processing tasks, measures of working memory capacity (backward span and the n-back lag task), inhibitory efficiency (Stroop interference), and processing speed (color naming). Regression analyses revealed that each of the resource measures significantly predicted language performance and attenuated variance in language performance that would otherwise be attributed to age. When speed variance was entered into the equation first, the mediating influence of the inhibition and working memory measures remained significant. When speed and inhibition differences were controlled, the working memory measures could not reliably predict language performance. These results suggest that language performance differences may be fundamentally mediated by age differences in processing speed and inhibitory efficiency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brain attack. Acute therapeutic interventions. Free radical scavengers and antioxidants

This study used tests of content memory (item recognition of words and abstract designs), context memory (order recognition of verbal and nonverbal items), and working memory (recognition at a short retention interval) to examine patterns of performance in 27 schizophrenic patients, 52 chronic alcoholic patients, and 66 healthy control participants. When performance was age- and IQ-adjusted the schizophrenia group was significantly impaired in item and order recognition of verbal and nonverbal material; the alcoholic group was impaired only in order recognition for both material types. Item- and order-recognition deficits in the schizophrenia group were greatest at the shortest retention intervals, a pattern previously observed in patients with Parkinson's disease, suggesting a prominence of a working memory deficit in schizophrenia.     

Short-term memory for serial order in schizophrenia: A detailed examination of error types.

Cognitive deficits in schizophrenia have been associated with working memory problems. Schizophrenic patients (n?=?24) and controls (n?=?29) participated in simple short-term memory tasks, recalling a list of letters from the first to last item in the order of presentation. The authors hypothesized that deficient sequential representations would increase movement errors (e.g., ABCD being recalled as ABDC) or intrusion errors (e.g., ABCD being recalled as ABCX), whereas simple trace decay would lead to omission errors (e.g., ABCD being recalled as ABC_). Patients made disproportionately more omissions toward the end of 6-item lists. There were no group differences in movements or intrusions as a function of serial position. Schizophrenic patients' limited short-term memory span may be due to greater forgetting during recall and not to a selective deficit in the mechanisms responsible for maintaining serial order information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

strawberry notch encodes a conserved nuclear protein that functions downstream of Notch and regulates gene expression along the developing wing margin of Drosophila

Although many individuals with traumatic brain injury (TBI) perform well on standard neuropsychological tests, they often exhibit marked functional difficulties. The functions which are impaired seem to be analogous to the role of the central executive system (CES) in Baddeley's [Working Memory, 1986, Oxford University Press, New York] widely accepted model of working memory. The purpose of this study was to investigate CES function in individuals with TBI with a dual-task paradigm. We studied 25 non-demented persons who were at various stages in their recovery from severe TBI and compared their performance on a dual-task paradigm to a group of age-matched controls. Our dual-task paradigm measured performance on a simple visual reaction time task both alone (baseline) and during concurrent tasks of articulation or digit span. Subjects were also assessed with other neuropsychological tests of executive function. TBI patients had slower reaction times on the primary task when performed alone (P < 0.05) and greater decrements in performance during dual-task conditions (P < 0.01). They also exhibited significantly greater deficits than control subjects on other measures of executive function. Although correlations between dual-task performance and other executive measures were quite low, principle components analysis suggested that a common factor does exist between these measures. These findings support the conclusion that TBI patients have a working memory impairment that is due to dysfunction of the CES and which may be related to executive function deficits as measured by standard neuropsychological testing.     

Attention control, memory updating, and emotion regulation temporarily reduce the capacity for executive control.

This research tested the hypothesis that initial efforts at executive control temporarily undermine subsequent efforts at executive control. Four experiments revealed that controlling the focus of visual attention (Experiment 1), inhibiting predominant writing tendencies (Experiment 2), taking a working memory test (Experiment 3), or exaggerating emotional expressions (Experiment 4) undermined performance on subsequent tests of working memory span, reverse digit span, and response inhibition, respectively. The results supported a limited resource model of executive control and cast doubt on competing accounts based on mood, motivation, or task difficulty. Prior efforts at executive control are a significant contextual determinant of the operation of executive processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Familial prevalence and coaggregation of schizotypy indicators: A multitrait family study.

Schizophrenic probands (n?=?17), their 1st-degree relatives (n?=?61), and medically and psychiatrically screened normal control Ss (n?=?18) were studied with structured interviews for Diagnostic and Statistical Manual of Mental Disorders (DSM-III) Axis I disorders and schizotypal personality disorder, questionnaire measures of schizotypy, measures of smooth-pursuit eye movement dysfunction, and attention dysfunction. Schizophrenic Ss scored abnormally on essentially all measures. Relatives differed significantly from control Ss on most measures. Correlational analyses indicate that many characteristics tested in these measures run together in families. The data are consistent with the hypothesis that a single vulnerability dimension or typology, presumably in part genetically transmitted, may account for phenotypically distinct abnormalities. These traits, taken together, may have joint usefulness for identifying persons with a predisposition to schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing acoustically presented time intervals of seconds duration: an expression of the phonological loop of the working memory?

Working memory has been proposed to contribute to the processing of time, rhythm and music; the question which component of working memory is involved is under discussion. The present study tests the hypothesis that the phonological loop component (Baddeley, 1986) is involved in the processing of auditorily presented time intervals of a few seconds' duration. Typical effects well known with short-term retention of verbal material could be replicated with short-term retention of temporal intervals: The immediate reproduction of time intervals was impaired under conditions of background music and articulatory suppression. Neither the accuracy nor the speed of responses in a (non-phonological) mental rotation task were diminished under these conditions. Processing of auditorily presented time intervals seems to be constrained by the capacity of the phonological loop: The immediate serial recall of sequences of time intervals was shown to be related to the immediate serial recall of words (memory span). The results confirm the notion that working memory resources, and especially the phonological loop component, underlie the processing of auditorily presented temporal information with a duration of a few seconds.     

Pupillary responses index overload of working memory resources in schizophrenia.

The authors examined the hypothesis that schizophrenia patients have reduced availability of working memory resources by using pupillary responses as an index of resource overload. Pupillary responses were recorded during a verbal working memory task (digit recall) in 24 schizophrenia patients and 32 normal controls. Pupil size increased with increased processing load (digit-span length) but changed little or declined when processing demands exceeded available resources (overload). The schizophrenia patients showed impaired digit recall and abnormally small pupillary responses during digit presentation only in the higher processing load conditions, but they showed abnormally small pupillary responses during digit retrieval in all processing load conditions. The results suggest reduced availability of slave store and central executive working memory resources in schizophrenia. This study serves as an example of how pupillography methods can be used to test current hypotheses regarding overload of cognitive capacities in schizophrenia patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Effect of Tobacco Abstinence on Recognition Memory, Digit Span Recall, and Attentional Vigilance.

This article examines the effects of tobacco abstinence on recognition memory, digit span recall, and visual attentional vigilance. The results demonstrated that abstinence impaired recognition memory discrimination (ad libitum d' = .85, abstinent d' = .64), recognition memory hit rates (ad libitum = .60, abstinent = .54), accuracy of target detection in attentional vigilance (ad libitum = .99, abstinent = .97), and speed of target detection in attentional vigilance (ad libitum = 662 ms, abstinent = 687 ms). Abstinence did not impair digit span recall (ad libitum = .55, abstinent = .56). These results are consistent with the hypotheses that tobacco abstinence impairs episodic memory and sustained attention. They also suggest that some, but not necessarily all, short-term memory processes may not be influenced by tobacco abstinence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)