An integrated brain-behavior model for working memory.

Working memory (WM) is a central construct in cognitive neuroscience because it comprises mechanisms of active information maintenance and cognitive control that underpin most complex cognitive behavior. Individual variation in WM has been associated with multiple behavioral and health features including demographic characteristics, cognitive and physical traits and lifestyle choices. In this context, we used sparse canonical correlation analyses (sCCAs) to determine the covariation between brain imaging metrics of WM-network activation and connectivity and nonimaging measures relating to sensorimotor processing, affective and nonaffective cognition, mental health and personality, physical health and lifestyle choices derived from 823 healthy participants derived from the Human Connectome Project. We conducted sCCAs at two levels: a global level, testing the overall association between the entire imaging and behavioral-health data sets; and a modular level, testing associations between subsets of the two data sets. The behavioral-health and neuroimaging data sets showed significant interdependency. Variables with positive correlation to the neuroimaging variate represented higher physical endurance and fluid intelligence as well as better function in multiple higher-order cognitive domains. Negatively correlated variables represented indicators of suboptimal cardiovascular and metabolic control and lifestyle choices such as alcohol and nicotine use. These results underscore the importance of accounting for behavioral-health factors in neuroimaging studies of WM and provide a neuroscience-informed framework for personalized and public health interventions to promote and maintain the integrity of the WM network.

Does Bowel Preparation for Colonoscopy Affect Cognitive Function?

Colonoscopy is a common procedure used in the diagnosis and treatment of a range of bowel disorders. Prior preparation involving potent laxatives is a necessary stage to ensure adequate visualization of the bowel wall. It is known that the sedatives given to most patients during the colonoscopy cause a temporary impairment in cognitive function; however, the potential for bowel preparation to affect cognitive function has not previously been investigated. To assess the effect of bowel preparation for colonoscopy on cognitive function. This was a prospective, nonrandomized controlled study of cognitive function in patients who had bowel preparation for colonoscopy compared with those having gastroscopy and therefore no bowel preparation. Cognitive function was assessed using the Modified Mini Mental State Examination (MMMSE) and selected tests from the Cambridge Neuropsychological Test Automated Battery. Individual test scores and changes between initial and subsequent tests were compared between the groups. Age, gender, and weight were also compared. Forty-three colonoscopy and 25 gastroscopy patients were recruited. The 2 groups were similar for age and gender; however, patients having gastroscopy were heavier. MMMSE scores for colonoscopy and gastroscopy groups, respectively, were 28.6 and 29.5 (P = 0.24) at baseline, 28.7 and 29.8 (P = 0.32) at test 2, 28.1 and 28.5 (P = 0.76) at test 3. Motor screening scores for colonoscopy and gastroscopy groups, respectively, were 349.3 and 354.1 (P = 0.97) at baseline, 307.5 and 199.7 (P = 0.06) at test 2, 212.0 and 183.2 (P = 0.33) at test 3. Spatial working memory scores for colonoscopy and gastroscopy groups, respectively, were 14.4 and 6.7 (P = 0.29) at baseline, 9.7 and 4.3 (P = 0.27) at test 2, 10 and 4.5 (P = 0.33) at test 3. Digit Symbol Substitution Test scores for colonoscopy and gastroscopy groups, respectively, were 36.3 and 37.8 (P = 0.84) at baseline, 36.4 and 40.0 (P = 0.59) at test 2, 38.6 and 40.8 (P = 0.76) at test 3.This study did not find evidence of cognitive impairment resulting from administration of bowel preparation before colonoscopy.

Implicit and explicit cognitive sexual processes in survivors of childhood sexual abuse.

INTRODUCTION: Women with a history of childhood sexual abuse (CSA) exhibit higher rates of sexual dysfunction than nonabused women. AIM: Because sexual responses are affected by cognitive processes, this study investigated the implicit and explicit cognitive processing of sexual stimuli in women with a history of CSA. METHODS: Women with (CSA; N = 34) and without (no history of abuse [NSA]; N = 22) a history of CSA participated in a quasi-experimental study. MAIN OUTCOME MEASURE: Implicit processes, described as involuntary or unintentional responses to stimuli, were assessed using the Implicit Association Test (IAT). Explicit processes, described as intentional, voluntary, or effortful processing of sexual stimuli, were assessed through a self-reported questionnaire (Sexual Self-Schema Scale). RESULTS: Results showed initial evidence of between group differences in the cognitive processing of sexual stimuli. Regarding the implicit processes, women in the NSA group showed that sexual pictures were more strongly associated with positive valence (pleasure) than nonsexual pictures. For the CSA group, neutral and sexual pictures were similarly associated with pleasure. Conversely, for both groups, romantic pictures were more strongly associated with positive valence than sexual pictures. Moreover, sexual satisfaction was predicted by both implicit and explicit processes, suggesting that the sexuality of women is affected by both processes independently. CONCLUSIONS: These results fit within the larger body of literature suggesting that implicit and explicit processes independently predict different aspects of behavior.

University students' notebook computer use: lessons learned using e-diaries to report musculoskeletal discomfort.

The objective of this pilot study was to identify if notebook accessories (ergonomic chair, desktop monitor and notebook riser) combined with a wireless keyboard, mouse and participatory ergonomics training would have the greatest impact on reducing self-reported upper extremity musculoskeletal discomfort in university students. In addition to pre-post computing and health surveys, the Ecological Momentary Assessment was used to capture change in discomfort over time using a personal digital assistant (PDA) as the e-diary. The PDA was programmed with a survey containing 45 questions. Four groups of university students were randomised to either intervention (three external computer accessories) or to control. Participants reported less discomfort with the ergonomic chair and notebook riser based on the pre-post survey data and the e-diary/PDA ANOVA analysis. However, the PDA data, adjusted for the effect of hours per day of computer use, showed no benefit of the chair and limited benefit from the riser. Statement of Relevance:University students' use of notebook computers has increased. This study found evidence of a positive effect of an adjustable chair or notebook riser when combined with ergonomic training on reducing discomfort. Daily notebook computer use of 4 h was confirmed as a risk factor. Without some form of ergonomic intervention, these students are likely to enter the workforce with poor computing habits, which places them on the road to future injuries as technology continues to play a dominant role in their lives.

Modeling the vagus nerve system with the Unified Modeling Language.

Traditionally, the means of describing anatomical and physiological structures of the autonomic nervous system is natural language, drawings and images as represented in the scientific literature. In behavioral studies of this system, mathematical and electrical models and computer simulation tools are in use. In this article, we propose the use of the Unified Modeling Language to describe and specify the anatomical and physiological structures and indicate how these can be enriched to capture the behavioral view as well. Using the metamodel facilities of the language, we propose a domain specific language that captures the domain concepts, their relationships and constraints. Application of the language is demonstrated by modeling the vagus nerve in part.

A scenario guideline for designing new teletreatments: a multidisciplinary approach.

Lack of user acceptance of telemedicine services is an important barrier to deployment and stresses the need for involving users, i.e. medical professionals. However, the involvement of users in the service development process of telemedicine services is difficult because of (a) the knowledge gap between the expertise of medical and technical experts; (b) the language gap, i.e. the use of different terminologies between the medical and the technical professions; and (c) the methodological gap in applying requirement methods to multidisciplinary scientific matters. We have developed a guideline in which the medical and technical domains meet. The guideline can be used to develop a scenario from which requirements can be elicited. In a retrospective analysis of a myofeedback-based teletreatment service, the technically-oriented People-Activities-Context-Technology (PACT) framework and medically-oriented principles of evidence-based medicine were incorporated into a guideline. The guideline was developed to construct the content of a scenario which describes the new teletreatment service. This allows the different stakeholders to come together and develop the service. Our approach provides an arena for different stakeholders to take part in the early stages of the design process. This should increase the chance of user acceptance and thus adoption of the service being developed.

The myofeedback-based teletreatment system and its evaluation.

The myofeedback-based teletreatment system allows patients to receive tactile and/or visual feedback on muscle activity and muscle relaxation times. Health-care professionals can analyse muscle activity and muscle relaxation times and provide guidance to the patient on the course of treatment. The system was evaluated in a small clinical trial. Qualitative data were obtained by interviews and visual inspection of graphical patient data during the trial. Quantitative data were based on post-trial data analysis. We used a revised version of the information systems success model to evaluate the teletreatment system, and focused on the success categories of system use and user satisfaction. The evaluation found good input data quality, system quality and information quality. Both system use and user satisfaction were good. Thus the teletreatment system appears suitable for small scale clinical deployment. However, the sensory components suffered from heavy use and embedded software problems which made them unreliable. Large scale deployment requires improvement in terms of durability and reliability of the system's sensors.

Chronic cough in patients with sleep-disordered breathing.

Chronic cough can be the sole presenting symptom for patients with obstructive sleep apnoea. We investigated the prevalence, severity and factors associated with chronic cough in patients with sleep-disordered breathing (SDB). We invited 108 consecutive patients who had been referred for evaluation of SDB to complete a comprehensive questionnaire on respiratory and sleep health, which included the Leicester Cough Questionnaire (cough specific quality of life; LCQ), Epworth Sleepiness Scale (ESS) and the Mayo Clinic gastro-oesophageal questionnaire. Chronic cough was defined as cough for a duration of >2 months. 33% of patients with SDB reported a chronic cough. Patients with a chronic cough had impaired cough related-quality of life affecting all health domains (mean+/-sem LCQ score 17.7+/-0.7; normal = 21). Patients with SDB and chronic cough were predominantly females (61% versus 17%; p<0.001) and reported more nocturnal heartburn (28% versus 5%; p = 0.03) and rhinitis (44% versus 14%; p = 0.02) compared to those without SDB. There were no significant differences in ESS, respiratory disturbance index, body mass index, or symptoms of breathlessness, wheeze, snoring, dry mouth and choking between those with cough and those without. Chronic cough is prevalent in patients with SDB and is associated with female sex, symptoms of nocturnal heartburn and rhinitis. Further studies are required to investigate the impact of continuous positive airway pressure therapy on cough associated with SDB to explore the mechanism of this association.

Immunomodulation does not alter histology in resected Crohn's disease.

BACKGROUND: The use of immunomodulators (Azathioprine, 6-Mercaptopurine and Methotrexate) and biological agents (Infliximab and adalimumab) for the treatment of Crohn's disease (CD) has increased in the recent years with the aim of treating the inflammatory component of the disease and hoping to change the natural history of the disease. The aim of this study was to determine if the use of immunomodulators or biological agents in the 2 years prior to resection affects the histopathological characteristics of the patient's disease. METHODS: A retrospective review was conducted over a 10-year period (1996-2005) of patients who underwent resection for CD. Clinical case notes and histology specimens were reviewed. Patients treated with Azathioprine, 6-Mercaptopurine, Methotrexate or Infliximab for more than 3 months within the 2 years preceding surgery were deemed to have been immunomodulated. The results were also analysed by Montreal phenotype. RESULTS: A total of 165 patients were identified. 52 patients had been treated with either immunomodulator or biological agent. Of 20 histological features examined, only muscular hypertrophy approached significance (P = 0.05), Montreal A and Montreal L phenotypes were the same regardless on immunomodulators, however, there was a significant difference (P = 0.03) with regard to Montreal B in patients with stricturing disease being more likely to have received an immunomodulator. CONCLUSIONS: In this cohort of patients requiring resection for CD, those with stricturing disease were more likely to receive immunomodulators or biologics than those without stricturing disease. However, there were no significant histological differences in the resected specimens between those who did and those who did not receive these drugs.

Criterial noise effects on rule-based category learning: the impact of delayed feedback.

Variability in the representation of the decision criterion is assumed in many category-learning models, yet few studies have directly examined its impact. On each trial, criterial noise should result in drift in the criterion and will negatively impact categorization accuracy, particularly in rule-based categorization tasks, where learning depends on the maintenance and manipulation of decision criteria. In three experiments, we tested this hypothesis and examined the impact of working memory on slowing the drift rate. In Experiment 1, we examined the effect of drift by inserting a 5-sec delay between the categorization response and the delivery of corrective feedback, and working memory demand was manipulated by varying the number of decision criteria to be learned. Delayed feedback adversely affected performance, but only when working memory demand was high. In Experiment 2, we built on a classic finding in the absolute identification literature and demonstrated that distributing the criteria across multiple dimensions decreases the impact of drift during the delay. In Experiment 3, we confirmed that the effect of drift during the delay is moderated by working memory. These results provide important insights into the interplay between criterial noise and working memory, as well as providing important constraints for models of rule-based category learning.

Cognitive complexity effects in perceptual classification are dissociable.

It has been proposed that a procedural-based classification system mediates the learning of information-integration categories, whereas a hypothesis-testing system mediates the learning of rule-based categories. Ashby, Ell and Waldron (2003) provided support for this claim by showing that a button switch introduced during classification transfer adversely affected information-integration but not rule-based performance. Nosofsky, Stanton and Zaki (2005) showed that increasing "cognitive complexity" can lead to button switch costs on rule-based performance. They argue that "cognitive complexity," and not the existence of separable classification systems, accounts for Ashby et al.'s empirical dissociation. The present study shows that experimental manipulations that increase "cognitive complexity" often have dissociable effects on information-integration and rule-based classification that are predicted a priori from the processing characteristics associated with the procedural-based and hypothesis-testing systems. These results suggest that manipulations of "cognitive complexity" can be dissociated, suggesting that "cognitive complexity" in not a unitary construct that affects a single psychological process.

Characterizing rule-based category learning deficits in patients with Parkinson's disease.

Parkinson's disease (PD) patients and normal controls were tested in three category learning experiments to determine if previously observed rule-based category learning impairments in PD patients were due to deficits in selective attention or working memory. In Experiment 1, optimal categorization required participants to base their decision on a single stimulus dimension and ignore irrelevant variation on another dimension, thus emphasizing selective attention processes. In Experiment 2, optimal categorization required participants to base their decision on both stimulus dimensions using a conjunction of unidimensional decisions. Thus, this task placed less emphasis on selective attention and more on working memory. In Experiment 3, optimal categorization again required participants to base their decision on both stimulus dimensions using a disjunction of two unidimensional decisions in which an additional verbal operation was needed, thereby placing even greater emphasis on working memory. Results indicated that PD patients were impaired in the unidimensional rule-based condition, but not the other two rule-based conditions. These results are consistent with previous studies that demonstrate that PD patients are impaired in learning rule-based categories when selective attention demands are greatest, whereas these patients are normal in learning rule-based tasks when working memory demands are emphasized. Overall, these findings help to delineate the conditions under which PD patients display rule-based category learning deficits.

Neural correlates of rule-based and information-integration visual category learning.

An emerging theory of the neurobiology of category learning postulates that there are separate neural systems supporting the learning of categories based on verbalizeable rules (RB) or through implicit information integration (II). The medial temporal lobe (MTL) is thought to play a crucial role in successful RB categorization, whereas the posterior regions of the caudate are hypothesized to support II categorization. Functional neuroimaging was used to assess activity in these systems during category-learning tasks with category structures designed to afford either RB or II learning. Successful RB categorization was associated with relatively increased activity in the anterior MTL. Successful II categorization was associated with increased activity in the caudate body. The dissociation observed with neuroimaging is consistent with the roles of these systems in memory and dissociations reported in patient populations. Convergent evidence from these approaches consistently reinforces the idea of multiple neural systems supporting category learning.

Stimulus modality interacts with category structure in perceptual category learning.

Two experiments were conducted that examined information integration and rule-based category learning, using stimuli that contained auditory and visual information. The results suggest that it is easier to perceptually integrate information within these sensory modalities than across modalities. Conversely, it is easier to perform a disjunctive rule-based task when information comes from different sensory modalities, rather than from the same modality. Quantitative model-based analyses suggested that the information integration deficit for across-modality stimulus dimensions was due to an increase in the use of hypothesis-testing strategies to solve the task and to an increase in random responding. The modeling also suggested that the across-modality advantage for disjunctive, rule-based category learning was due to a greater reliance on disjunctive hypothesis-testing strategies, as opposed to unidimensional hypothesis-testing strategies and random responding.

The impact of irrelevant dimensional variation on rule-based category learning in patients with Parkinson's disease.

This study examined the impact of irrelevant dimensional variation on rule-based category learning in patients with Parkinson's disease (PD), older controls (OC), and younger controls (YC). Participants were presented with 4-dimensional, binary-valued stimuli and were asked to categorize each into 1 of 2 categories. Category membership was based on the value of a single dimension. Four experimental conditions were administered in which there were zero, 1, 2, or 3 randomly varying irrelevant dimensions. Results indicated that patients with PD were impacted to a greater extent than both the OC and YC participants when the number of randomly varying irrelevant dimensions increased. These results suggest that the degree of working memory and selective attention requirements of a categorization task will impact whether PD patients are impaired in rule-based category learning, and help to clarify recent discrepancies in the literature.

Patients with gastro-oesophageal reflux disease and cough have impaired laryngopharyngeal mechanosensitivity.

BACKGROUND: Laryngopharyngeal sensitivity (LPS) is important in preventing pulmonary aspiration and may be impaired by anaesthesia and stroke. It has been suggested that gastro-oesophageal reflux disease (GORD) may also impair LPS, although the underlying mechanism is unclear. The aim of this study was to compare LPS in patients with chronic cough and GORD with healthy subjects and to determine the effect of laryngopharyngeal infusions of both acid and normal saline on LPS. METHODS: Fifteen patients with chronic cough and GORD and 10 healthy subjects without GORD underwent LPS testing using the fibreoptic endoscopic evaluation of swallowing with sensory testing (FEESST) technique. LPS, as measured by the lowest air pressure required to elicit the laryngeal adductor reflex (LAR), was determined both before and after laryngopharyngeal infusions of normal saline and 0.1 N hydrochloric acid performed on separate days. RESULTS: The mean baseline LAR threshold of the patient group was significantly higher (9.5 mm Hg, range 6.0-10.0) than in normal subjects (3.68 mm Hg, range 2.5-5.0; p<0.01). Retest thresholds were not significantly different. In normal subjects LAR thresholds were significantly raised after acid but not after saline infusion (p = 0.005). There were no complications associated with the procedure. CONCLUSIONS: Patients with cough and GORD have significantly reduced LPS to air stimuli compared with healthy subjects which could potentially result in an increased risk of aspiration. Exposure to small amounts of acid significantly impaired the sensory integrity of the laryngopharynx.

Cortical and subcortical brain regions involved in rule-based category learning.

The brain regions contributing to rule-based category learning were examined using fMRI. Participants categorized single lines that varied in length and orientation into one of two categories. Category membership was based on the length of the line. Results indicated that left frontal and parietal regions were differentially activated in those participants who learned the task as compared to those who did not. Further, the head of the caudate displayed relative decreases in activation on incorrect trials relative to correct trials. The involvement of this latter structure is likely related to (1) processing an error signal, or (2) volitional switching between potential category rules. Results are consistent with theories suggesting that a frontal-striatal circuit is involved in rule-based category learning.

Delayed feedback disrupts the procedural-learning system but not the hypothesis-testing system in perceptual category learning.

W. T. Maddox, F. G. Ashby, and C. J. Bohil (2003) found that delayed feedback adversely affects information-integration but not rule-based category learning in support of a multiple-systems approach to category learning. However, differences in the number of stimulus dimensions relevant to solving the task and perceptual similarity failed to rule out 2 single-system interpretations. The authors conducted an experiment that remedied these problems and replicated W. T. Maddox et al.'s findings. The experiment revealed a strong performance decrement for information-integration but not rule-based category learning under delayed feedback that was due to an increase in the number of observers using hypothesis-testing strategies to solve the information-integration task, and lower accuracy rates for the few observers using information-integration strategies.

Idiopathic cough, prevalence and underlying mechanisms.

A number of authors have reported a significant percentage of patients whose cause of cough remains undetermined despite a systematic evaluation as recommended in a number of International Guidelines. This subset of patients, which may be regarded as having an idiopathic cough, are often female and of peri or postmenopausal age. Sex hormones may influence the cough reflex in disease or contribute to the chronic lymphocytic airway inflammation seen in some cases and to the association with organ specific autoimmune disease reported. This paper seeks to investigate some of the possible causes of idiopathic cough.