The Rapid Access Memory Program for Addressing Concerns of Incipient Dementia in Academic Primary Care Settings.

BACKGROUND: Expedient diagnosis of incipient dementia is often hindered by time constraints in primary care visits, shortage of dementia specialists, and extended waitlists for comprehensive neuropsychological evaluations. METHODS: We developed the Rapid Access Memory Program (RAMP) to improve access of neuropsychological services for older adults presenting to our institutional primary care clinics with concerns of cognitive decline. RAMP provides abbreviated neurocognitive assessment, same-day patient feedback, expedited reporting to referring providers, and is financially self-supported. Here, we describe development of RAMP and clinical outcomes from the first 3 years. RESULTS: Of 160 patients seen, dementia was diagnosed in 30% and Mild Cognitive Impairment in 50%; Alzheimer's disease was the most common suspected etiology. New psychiatric diagnosis was made in about one-third (n = 54). Most frequent recommendations involved medication adjustments (initiating cholinesterase inhibitors, deprescribing anticholinergics), safety (driving, decision-making), and specialist referrals. Additionally, 27 (17%) subsequently enrolled in local research. CONCLUSIONS: Results support feasibility and utility of RAMP for connecting older adults in primary care with neuropsychological services.

Neurophysiology of predictable unpleasant event processing in pre-adolescents and early adolescents, part II: Reflex and event-related potential markers of defensive reactivity and peripheral attention modulation.

The ability to anticipate and process predictable unpleasant events, while also regulating emotional reactivity, is an adaptive skill. The current article and a companion in this issue test for potential changes in predictable event processing across the childhood-to-adolescence transition, a key developmental period for biological systems that support cognitive/ emotional abilities. While the companion article focuses on neurophysiology of predictable event processing itself, the present article examines peripheral emotional response regulation and attention modulation that coincides with event processing. A total of 315 third-, sixth-, or ninth-grade individuals saw 5-s cues predicting "scary," "every day," or uncertain pictures, and here, blink reflexes and brain event-related potentials (ERPs) elicited by peripheral noise probes are analyzed. During the cue, blink reflexes and probe ERP (P200) amplitudes were increased when the cue predicted scary, compared to everyday, content. After picture onset, reflex enhancement by scary content then disappeared for predictable images, whereas ERP modulation was similar regardless of predictability. Patterns are similar to those in adults and suggest (1) sustained defensive response priming and enhancement of peripheral attention during aversive anticipation, and (2) an ability, even in pre-adolescents, to downregulate defensive priming while maintaining attentional modulation once an awaited predictable aversive event occurs.

Neurophysiology of predictable unpleasant event processing in preadolescents and early adolescents, part I: Event-related potential markers of unpleasant image anticipation and processing.

The ability to anticipate and process predictable unpleasant events, while also regulating emotional reactivity, is an adaptive skill. The current article and a companion in this issue test for potential changes in predictable event processing across the childhood-to-adolescence transition, a key developmental period for biological systems that support cognitive/emotional abilities. While the companion article focuses on emotion regulation and peripheral attention modulation in predictable unpleasant contexts, the current paper presents neurophysiological markers of predictable event processing itself. 315 third-, sixth-, or ninth-grade individuals saw 5-s cues predicting "scary," "every day," or uncertain image content; in this paper, cue- and picture-locked event-related potentials (ERPs) are analyzed. During the cue, early ERP positivities were increased and later slow-wave negativities were reduced when predicted content was scary as compared with mundane. After picture onset, a picture processing-related positivity was then increased for scary compared with everyday images regardless of predictability. Cue-interval data suggest enhanced processing of scary cues and reduced anticipatory processing of scary images-opposite to adults. After event onset, meanwhile, emotional ERP enhancement regardless of predictability is similar to adults and suggests that even preadolescent individuals maintain preferential engagement with unpleasant events when they are predictable.

Network Analysis of Intrinsic Functional Brain Connectivity in Male and Female Adult Smokers: A Preliminary Study.

Background: The goal of this study was to conduct a preliminary network analysis (using graph-theory measures) of intrinsic functional connectivity in adult smokers, with an exploration of sex differences in smokers. Methods: Twenty-seven adult smokers (13 males; mean age = 35) and 17 sex and age-matched controls (11 males; mean age = 35) completed a blood oxygen level-dependent resting state functional magnetic resonance imaging experiment. Data analysis involved preprocessing, creation of connectivity matrices using partial correlation, and computation of graph-theory measures using the Brain Connectivity Toolbox. Connector hubs and additional graph-theory measures were examined for differences between smokers and controls and correlations with nicotine dependence. Sex differences were examined in a priori regions of interest based on prior literature. Results: Compared to nonsmokers, connector hubs in smokers emerged primarily in limbic (parahippocampus) and salience network (cingulate cortex) regions. In addition, global influence of the right insula and left nucleus accumbens was associated with higher nicotine dependence. These trends were present in male but not female smokers. Conclusions: Network communication was altered in smokers, primarily in limbic and salience network regions. Network topology was associated with nicotine dependence in male but not female smokers in regions associated with reinforcement (nucleus accumbens) and craving (insula), consistent with the idea that male smokers are more sensitive to the reinforcing aspects of nicotine than female smokers. Implications: Identifying alterations in brain network communication in male and female smokers can help tailor future behavioral and pharmacological smoking interventions. Male smokers showed alterations in brain networks associated with the reinforcing effects of nicotine more so than females, suggesting that pharmacotherapies targeting reinforcement and craving may be more efficacious in male smokers.

Communicating with Sensation Seekers: An fMRI Study of Neural Responses to Antidrug Public Service Announcements.

This study examined the neural basis of processing high- and low-message sensation value (MSV) antidrug public service announcements (PSAs) in high (HSS) and low sensation seekers (LSS) using fMRI. HSS more strongly engaged the salience network when processing PSAs (versus LSS), suggesting that high-MSV PSAs attracted their attention. HSS and LSS participants who engaged higher level cognitive processing regions reported that the PSAs were more convincing and believable and recalled the PSAs better immediately after testing. In contrast, HSS and LSS participants who strongly engaged visual attention regions for viewing PSAs reported lower personal relevance. These findings provide neurobiological evidence that high-MSV content is salient to HSS, a primary target group for antidrug messages, and additional cognitive processing is associated with higher perceived message effectiveness.

Modulation of meso-limbic reward processing by motivational tendencies in young adolescents and adults.

Adolescence is a particularly vulnerable period for the onset of substance use disorders and other psychopathology. Individual variability in motivational tendencies and temperament and significant changes in functional brain organization during adolescence are important factors to consider in the development of substance use and dependence. Recent conceptualizations suggest that sensitivity to reward is heightened in adolescence and that this motivation tendency may precipitate subsequent substance abuse. The present study examined the role of personality traits in mesolimbic neurobehavioral response on a monetary incentive delay (MID) task in young adolescents (11-14 years) and emerging adults (18-25 years) using functional magnetic resonance imaging. As a group, adolescents were not more sensitive to gains than losses compared to adults during either anticipatory and feedback phases; instead, compared to adults they showed less sensitivity to incentive magnitude in mesolimbic circuitry during anticipation and feedback stages. However, personality modulated this response such that adolescents high in impulsivity or low in avoidance tendencies showed greater gain sensitivity and adolescents high in avoidance showed greater loss sensitivity during cue anticipation. In adults, mesolimbic response was modulated by the impulsivity construct such that high-impulsive adults showed reduced magnitude sensitivity during both anticipation and feedback compared to low impulsive adults. The present findings suggest that impulsive personality significantly modulates mesolimbic reward response during both adolescence and adulthood but avoidance and approach tendencies also modulate this response in adolescents. Moreover, personality modulated incentive valence in adolescents but incentive magnitude in adults. Collectively, these findings suggest that mesolimbic reward circuitry function is modulated by somewhat different parameters in adolescence than in adulthood.

Lower subcortical gray matter volume in both younger smokers and established smokers relative to non-smokers.

Although established adult smokers with long histories of nicotine dependence have lower neural tissue volume than non-smokers, it is not clear if lower regional brain volume is also observed in younger, less established smokers. The primary goal of this study was to investigate neural tissue volume in a large group of smokers and non-smokers, with a secondary goal of measuring the impact of age on these effects. We used voxel-based morphometry to compare regional gray matter volume in 118 individuals (59 smokers, 59 age- and gender-matched non-smokers). Younger smokers had significantly lower gray matter volume in the left thalamus and the left amygdala than their non-smoking peers (family-wise error-corrected clusters, P < 0.05). There was no correlation between smoking use variables and tissue volume among younger smokers. Established smokers had significantly lower gray matter volume than age-matched non-smokers in the insula, parahippocampal gyrus and pallidum. Medial prefrontal cortex gray matter volume was negatively correlated with pack-years of smoking among the established smokers, but not the younger smokers. These data reveal that regional tissue volume differences are not limited exclusively to established smokers. Deficits in young adults indicate that cigarette smoking may either be deleterious to the thalamus and amygdala at an earlier age than previously reported, or that pre-existing differences in these areas may predispose individuals to the development of nicotine dependence.

Impact of obstructive sleep apnea syndrome on cognition in early postmenopausal women.

PURPOSE: Obstructive sleep apnea syndrome (OSAS) has a higher prevalence in postmenopausal women who are not on hormone replacement therapy (HRT), as compared to premenopausal women. Cognitive impairment (CI) is associated with OSAS and the early postmenopausal state. We hypothesized that compared to postmenopausal women at low risk for OSAS, postmenopausal women at high risk for OSAS would report worse cognitive function. METHODS: Early postmenopausal women not on HRT between the ages of 45 and 60 years, within 5 years of natural menopause, were enrolled. Participants completed a REDCap survey which collected information on demographics and risk factors, Berlin questionnaire to screen subjects for OSAS risk, and the Mail-In Cognitive Function Screening Instrument (MCFSI) score which was used to assess CI. RESULTS: Of 381 respondents, 127 were omitted due to missing/duplicate data or not meeting inclusion criteria. One hundred fifty-four women were classified as high risk for OSAS (OSAS+), and 100 were classified as low risk for OSAS (OSAS-). OSAS- women reported lifetime smoking, lifetime drinking, and recreational drug use more often than OSAS+ women, while OSAS+ women reported a depression diagnosis more often. The mean MCFSI score in the OSAS+ group was significantly higher (worse cognition) than in the OSAS- group after controlling for covariates (5.59, 95 % CI 5.08-6.11 vs. 4.29, 95 % CI 3.64-4.93, p < 0.05). CONCLUSION: Early postmenopausal women at high risk for OSAS report more CI than those at low risk for OSAS. Future studies should identify biomarkers of this CI and define the degree of reversibility of CI with OSAS treatment.

Structural similarity exerts opposing effects on perceptual differentiation and categorization: an FMRI study.

We manipulated the degree of structural similarity between objects that had to be matched either according to whether they represented the same object (perceptual matching) or belonged to the same category (conceptual matching). Behaviorally, performance improved as a linear function of increased structural similarity during conceptual matching but deteriorated as a linear function of increased structural similarity during perceptual matching. These effects were mirrored in fMRI recordings where activation in several ventral posterior areas exhibited a similar interaction between match type and structural similarity. Our findings provide direct support for the notion that structural similarity exerts opposing effects on classification depending on whether objects are to be perceptually differentiated or categorized-a notion that has been based on rather circumstantial evidence. In particular, the finding that structural similarity plays a major role in categorization of instances according to taxonomy challenges the view that the organization of superordinate categories is not driven by shared structural features.

Influence of neurobehavioral incentive valence and magnitude on alcohol drinking behavior.

The monetary incentive delay (MID) task is a widely used probe for isolating neural circuitry in the human brain associated with incentive motivation. In the present functional magnetic resonance imaging (fMRI) study, 82 young adults, characterized along dimensions of impulsive sensation seeking, completed a MID task. fMRI and behavioral incentive functions were decomposed into incentive valence and magnitude parameters, which were used as predictors in linear regression to determine whether mesolimbic response is associated with problem drinking and recent alcohol use. Alcohol use was best explained by higher fMRI response to anticipation of losses and feedback on high gains in the thalamus. In contrast, problem drinking was best explained by reduced sensitivity to large incentive values in mesolimbic regions in the anticipation phase and increased sensitivity to small incentive values in the dorsal caudate nucleus in the feedback phase. Altered fMRI responses to monetary incentives in mesolimbic circuitry, particularly those alterations associated with problem drinking, may serve as potential early indicators of substance abuse trajectories.

Sex differences in development of functional connections in the face processing network.

BACKGROUND AND PURPOSE: Understanding sex differences in typical development of the face processing network is important for elucidating disruptions during atypical development in sex-linked developmental disorders like autism spectrum disorder. Based on prior sex difference studies in other cognitive domains, this study examined whether females show increased integration of core and extended face regions with age for face viewing, while males would show increased segregation. METHODS: This study used a cross-sectional design with typically developing children and adults (n = 133) and a functional MRI face localizer task. Psychophysiological interaction (PPI) analysis examined functional connectivity between canonical and extended face processing network regions with age, with greater segregation indexed by decreased core-extended region connectivity with age and greater integration indexed by increased core-extended region connectivity with age. RESULTS: PPI analysis confirmed increased segregation for males-right fusiform face area (FFA) coupling to right inferior frontal gyrus (IFG) opercular when viewing faces and left amygdala when viewing objects decreased with age. Females showed increased integration with age (increased coupling of the right FFA to right IFG opercular region and right occipital face area [OFA] to right IFG orbital when viewing faces and objects, respectively) and increased segregation (decreased coupling with age of the right OFA with IFG opercular region when viewing faces). CONCLUSIONS: Development of core and extended face processing network connectivity follows sexually dimorphic paths. These differential changes mostly occur across childhood and adolescence, with males experiencing segregation and females both segregation and integration changes in connectivity.

Parameter Space and Potential for Biomarker Development in 25 Years of fMRI Drug Cue Reactivity: A Systematic Review.

Importance: In the last 25 years, functional magnetic resonance imaging drug cue reactivity (FDCR) studies have characterized some core aspects in the neurobiology of drug addiction. However, no FDCR-derived biomarkers have been approved for treatment development or clinical adoption. Traversing this translational gap requires a systematic assessment of the FDCR literature evidence, its heterogeneity, and an evaluation of possible clinical uses of FDCR-derived biomarkers. Objective: To summarize the state of the field of FDCR, assess their potential for biomarker development, and outline a clear process for biomarker qualification to guide future research and validation efforts. Evidence Review: The PubMed and Medline databases were searched for every original FDCR investigation published from database inception until December 2022. Collected data covered study design, participant characteristics, FDCR task design, and whether each study provided evidence that might potentially help develop susceptibility, diagnostic, response, prognostic, predictive, or severity biomarkers for 1 or more addictive disorders. Findings: There were 415 FDCR studies published between 1998 and 2022. Most focused on nicotine (122 [29.6%]), alcohol (120 [29.2%]), or cocaine (46 [11.1%]), and most used visual cues (354 [85.3%]). Together, these studies recruited 19 311 participants, including 13 812 individuals with past or current substance use disorders. Most studies could potentially support biomarker development, including diagnostic (143 [32.7%]), treatment response (141 [32.3%]), severity (84 [19.2%]), prognostic (30 [6.9%]), predictive (25 [5.7%]), monitoring (12 [2.7%]), and susceptibility (2 [0.5%]) biomarkers. A total of 155 interventional studies used FDCR, mostly to investigate pharmacological (67 [43.2%]) or cognitive/behavioral (51 [32.9%]) interventions; 141 studies used FDCR as a response measure, of which 125 (88.7%) reported significant interventional FDCR alterations; and 25 studies used FDCR as an intervention outcome predictor, with 24 (96%) finding significant associations between FDCR markers and treatment outcomes. Conclusions and Relevance: Based on this systematic review and the proposed biomarker development framework, there is a pathway for the development and regulatory qualification of FDCR-based biomarkers of addiction and recovery. Further validation could support the use of FDCR-derived measures, potentially accelerating treatment development and improving diagnostic, prognostic, and predictive clinical judgments.

Perceptual specialization and configural face processing in infancy.

Adults' face processing expertise includes sensitivity to second-order configural information (spatial relations among features such as distance between eyes). Prior research indicates that infants process this information in female faces. In the current experiments, 9-month-olds discriminated spacing changes in upright human male and monkey faces but not in inverted faces. However, they failed to process matching changes in upright house stimuli. A similar pattern of performance was exhibited by 5-month-olds. Thus, 5- and 9-month-olds exhibited specialization by processing configural information in upright primate faces but not in houses or inverted faces. This finding suggests that, even early in life, infants treat faces in a special manner by responding to changes in configural information more readily in faces than in non-face stimuli. However, previously reported differences in infants' processing of human versus monkey faces at 9 months of age (but not at younger ages), which have been associated with perceptual narrowing, were not evident in the current study. Thus, perceptual narrowing is not absolute in the sense of loss of the ability to process information from other species' faces at older ages.

Decoding Employee ambidexterity: Understanding drivers, constraints, and performance implications for thriving in the evolving work landscapes - A scoping review.

Employee ambidexterity (EA) is becoming increasingly recognised as a significant factor in enhancing individual and organisational performance across diverse industries. Ambidexterity refers to the capacity to exploit and explore organisational resources simultaneously. Scholars from diverse industry sectors have been motivated to delve deeper into the topic of EA due to its growing popularity. The objective of conducting a scoping review was to scrutinise the existing literature and identify the key drivers and constraints that impact EA to thrive in the changing work landscape. The insights gained from this review can assist decision-makers in formulating effective strategies to cultivate the ambidexterity skills of their workforce and achieve desirable outcomes. This review adheres to the PRISMA-ScR protocol. Articles were obtained from databases including Scopus, Web of Science, and EBSCOhost (Academic Search Complete, Business Source Complete). The body of literature concerning EA is in its nascent stage. 23 articles assessing EA's performance outcomes were identified using targeted search terms and thorough screening. After conducting a thorough thematic analysis using the iterative categorisation (IC) technique, tailored for scoping a review, we successfully identified twenty-nine factors contributing to the enhancement of EA, meticulously organised into five distinct categories: organisational factors, social connectedness, employee behaviour, employee personality, and work environment related factors. Similarly, we discovered four factors that impede EA: functional tenure, team identification, bounded discretion, and conscientiousness. Our findings underscore the profound impact of employee ambidexterity on distinct types of performance. Among the sixteen types of performance reported to be enhanced by EA, ten are linked to individual performance, while six are tied to organisational performance. Notably, our analysis revealed that nearly all studies have relied on cross-sectional research methods except for one. However, we advocate for the exploration of longitudinal studies as they hold the promise of offering a more comprehensive understanding of EA. The paper presents valuable insights into how to cultivate ambidextrous capabilities in the workforce for unparalleled success in today's rapidly evolving work environment. Additionally, it identifies several intriguing avenues for future research that could further elucidate and bridge existing knowledge gaps.

COPE and oxytocin for the treatment of co-occurring PTSD and alcohol use disorder: Design and methodology of a randomized controlled trial in U.S. military veterans.

BACKGROUND: A significant proportion of individuals with alcohol use disorder (AUD) also meet criteria for posttraumatic stress disorder (PTSD). Military veterans are at increased risk for developing co-occurring AUD/PTSD, with prevalence rates 2-4 times higher than the general population. Research is needed to develop more effective treatments for this common comorbidity. The current investigation addresses this need by examining the synergistic effects of a novel pharmacotherapy combined with psychotherapy for co-occurring AUD/PTSD among veterans. Accumulating evidence suggests that the neuropeptide oxytocin (OT) is a promising pharmacotherapy to augment psychotherapy for AUD/PTSD. OT targets neurobiological and behavioral dysregulation common to both AUD and PTSD, in particular, corticolimbic connectivity. Human and animal studies show OT reduces alcohol self-administration, tolerance, and withdrawal; enhances fear extinction; and promotes prosocial behaviors. The current study builds on previous work by examining OT among veterans with AUD/PTSD receiving Concurrent Treatment of PTSD and Substance Use Disorders using Prolonged Exposure (COPE), an evidence-based integrated treatment. METHODS: This paper describes the rationale, design, and methodology of a Stage II, 12-week, double-blind, randomized clinical trial of intranasal OT (40 IU) versus placebo combined with COPE among veterans (N = 180) with current AUD/PTSD. In addition, the effects of treatment on corticolimbic connectivity will be examined using functional magnetic resonance imaging (fMRI) at pre- and post-treatment. CONCLUSIONS: The proposed study will provide new knowledge and mechanistic insights to accelerate research in this understudied area and may lead to improved treatment outcomes for co-occurring AUD/PTSD. CLINICALTRIALS: gov: NCT04523922.

A Double-Blind Randomized Controlled Trial of Doxazosin for Co-Occurring PTSD and Alcohol Use Disorder in Veterans.

Objective: The aim of this study was to determine the efficacy of doxazosin, an α1-adrenergic antagonist, for the treatment of co-occurring posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD).Methods: This 12-week, double-blind, randomized controlled trial of doxazosin (16 mg/d) was conducted between June 2016 and December 2019 at the Ralph H. Johnson VA Medical Center in Charleston, South Carolina. Participants were military veterans (N = 141) who met DSM-5 criteria for current PTSD and AUD and were randomly assigned to receive doxazosin (n = 70) or placebo (n = 71). Primary outcome measures were the Clinician Administered PTSD Scale (CAPS-5), the PTSD Checklist for DSM-5 (PCL-5), and the Timeline Follow-Back (TLFB).Results: Findings from the intent-to-treat analyses revealed that participants in both groups demonstrated statistically significant reductions in CAPS-5 and PCL-5 scores (P < .0001), but, contrary to hypotheses, no significant differences were observed between groups. Percent drinking days and percent heavy drinking days also decreased significantly during treatment, but there were no differences between groups (P < .0001). Abstinence during treatment was significantly higher in the doxazosin versus the placebo group (22% vs 7%, P = .017); however, participants in the doxazosin group consumed a greater number of drinks on drinking days (6.15 vs 4.56, P = .0096). A total of 74.5% of the sample completed the treatment phase, and there were no group differences in retention or adverse events.Conclusions: Doxazosin was safe and tolerable but was not more effective than placebo in reducing PTSD or AUD severity in this dually diagnosed sample. Clinical considerations such as heterogeneity of PTSD and AUD presentation and potential moderators are discussed in the context of future research directions.Trial Registration: ClinicalTrials.gov Identifier: NCT02500602.

Process and domain specificity in regions engaged for face processing: an fMRI study of perceptual differentiation.

The degree to which face-specific brain regions are specialized for different kinds of perceptual processing is debated. This study parametrically varied demands on featural, first-order configural, or second-order configural processing of faces and houses in a perceptual matching task to determine the extent to which the process of perceptual differentiation was selective for faces regardless of processing type (domain-specific account), specialized for specific types of perceptual processing regardless of category (process-specific account), engaged in category-optimized processing (i.e., configural face processing or featural house processing), or reflected generalized perceptual differentiation (i.e., differentiation that crosses category and processing type boundaries). ROIs were identified in a separate localizer run or with a similarity regressor in the face-matching runs. The predominant principle accounting for fMRI signal modulation in most regions was generalized perceptual differentiation. Nearly all regions showed perceptual differentiation for both faces and houses for more than one processing type, even if the region was identified as face-preferential in the localizer run. Consistent with process specificity, some regions showed perceptual differentiation for first-order processing of faces and houses (right fusiform face area and occipito-temporal cortex and right lateral occipital complex), but not for featural or second-order processing. Somewhat consistent with domain specificity, the right inferior frontal gyrus showed perceptual differentiation only for faces in the featural matching task. The present findings demonstrate that the majority of regions involved in perceptual differentiation of faces are also involved in differentiation of other visually homogenous categories.

Influence of estradiol on functional brain organization for working memory.

Working memory is a cognitive function that is affected by aging and disease. To better understand the neural substrates for working memory, the present study examined the influence of estradiol on working memory using functional magnetic resonance imaging. Pre-menopausal women were tested on a verbal n-back task during the early (EF) and late follicular (LF) phases of the menstrual cycle. Although brain activation patterns were similar across the two phases, the most striking pattern that emerged was that estradiol had different associations with the two hemispheres. Increased activation in left frontal circuitry in the LF phase was associated with increased estradiol levels and decrements in working memory performance. In contrast, increased activation in right hemisphere regions in the LF phase was associated with improved task performance. The present study showed that better performance in the LF than the EF phase was associated with a pattern of reduced recruitment of the left-hemisphere and increased recruitment of the right-hemisphere in the LF compared to EF phase. We speculate that estradiol interferes with left-hemisphere working-memory processing in the LF phase, but that recruitment of the right hemisphere can compensate for left-hemisphere interference. This may be related to the proposal that estradiol can reduce cerebral asymmetries by modulating transcallosal communication (Hausmann, 2005).

The changing landscape of functional brain networks for face processing in typical development.

Greater expertise for faces in adults than in children may be achieved by a dynamic interplay of functional segregation and integration of brain regions throughout development. The present study examined developmental changes in face network functional connectivity in children (5-12 years) and adults (18-43 years) during face-viewing using a graph-theory approach. A face-specific developmental change involved connectivity of the right occipital face area. During childhood, this node increased in strength and within-module clustering based on positive connectivity. These changes reflect an important role of the ROFA in segregation of function during childhood. In addition, strength and diversity of connections within a module that included primary visual areas (left and right calcarine) and limbic regions (left hippocampus and right inferior orbitofrontal cortex) increased from childhood to adulthood, reflecting increased visuo-limbic integration. This integration was pronounced for faces but also emerged for natural objects. Taken together, the primary face-specific developmental changes involved segregation of a posterior visual module during childhood, possibly implicated in early stage perceptual face processing, and greater integration of visuo-limbic connections from childhood to adulthood, which may reflect processing related to development of perceptual expertise for individuation of faces and other visually homogenous categories.

Medial temporal lobe epilepsy is associated with neuronal fibre loss and paradoxical increase in structural connectivity of limbic structures.

BACKGROUND: It has been hypothesised that seizure induced neuronal loss and axonal damage in medial temporal lobe epilepsy (MTLE) may lead to the development of aberrant connections between limbic structures and eventually result in the reorganisation of the limbic network. In this study, limbic structural connectivity in patients with MTLE was investigated, using diffusion tensor MRI, probabilistic tractography and graph theory based network analysis. METHODS: 12 patients with unilateral MTLE and hippocampal sclerosis (five left and seven right MTLE) and 26 healthy controls were studied. The connectivity of 10 bilateral limbic regions of interest was mapped with probabilistic tractography, and the probabilistic fibre density between each pair of regions was used as the measure of their weighted structural connectivity. Binary connectivity matrices were then obtained from the weighted connectivity matrix using a range of fixed density thresholds. Graph theory based properties of nodes (degree, local efficiency, clustering coefficient and betweenness centrality) and the network (global efficiency and average clustering coefficient) were calculated from the weight and binary connectivity matrices of each subject and compared between patients and controls. RESULTS: MTLE was associated with a regional reduction in fibre density compared with controls. Paradoxically, patients exhibited (1) increased limbic network clustering and (2) increased nodal efficiency, degree and clustering coefficient in the ipsilateral insula, superior temporal region and thalamus. There was also a significant reduction in clustering coefficient and efficiency of the ipsilateral hippocampus, accompanied by increased nodal degree. CONCLUSIONS: These results suggest that MTLE is associated with reorganisation of the limbic system. These results corroborate the concept of MTLE as a network disease, and may contribute to the understanding of network excitability dynamics in epilepsy and MTLE.