From the reward network to whole-brain metrics: structural connectivity in adolescents and young adults according to body mass index and genetic risk of obesity.

BACKGROUND: Obesity is a multifactorial condition. Genetic variants, such as the fat mass and obesity related gene (FTO) polymorphism, may increase the vulnerability of developing obesity by disrupting dopamine signaling within the reward network. Yet, the association of obesity, genetic risk of obesity, and structural connectivity of the reward network in adolescents and young adults remains unexplored. We investigate, in adolescents and young adults, the structural connectivity differences in the reward network and at the whole-brain level according to body mass index (BMI) and the FTO rs9939609 polymorphism. METHODS: One hundred thirty-two adolescents and young adults (age range: [10, 21] years, BMI z-score range: [-1.76, 2.69]) were included. Genetic risk of obesity was determined by the presence of the FTO A allele. Whole-brain and reward network structural connectivity were analyzed using graph metrics. Hierarchical linear regression was applied to test the association between BMI-z, genetic risk of obesity, and structural connectivity. RESULTS: Higher BMI-z was associated with higher (B = 0.76, 95% CI = [0.30, 1.21], P = 0.0015) and lower (B = -0.003, 95% CI = [-0.006, -0.00005], P = 0.048) connectivity strength for fractional anisotropy at the whole-brain level and of the reward network, respectively. The FTO polymorphism was not associated with structural connectivity nor with BMI-z. CONCLUSIONS: We provide evidence that, in healthy adolescents and young adults, higher BMI-z is associated with higher connectivity at the whole-brain level and lower connectivity of the reward network. We did not find the FTO polymorphism to correlate with structural connectivity. Future longitudinal studies with larger sample sizes are needed to assess how genetic determinants of obesity change brain structural connectivity and behavior.

Understanding social cognition in children with cerebral palsy: exploring the relationship with executive functions and the intervention outcomes in a randomized controlled trial.

Children with Cerebral Palsy (CP) experience Social Cognition (SC) difficulties, which could be related to executive functioning. While motor interventions are common, there is limited knowledge about the impact of cognitive interventions on SC in this population. This study examined the relationship between SC and Executive Function (EF) skills and the effectiveness of an EF intervention that included some SC tasks for improving SC in children with CP. SC and EF domains were assessed in 60 participants with CP (30 females; 8-12 years). The relationship between SC and EF baseline scores was analyzed by bivariate correlations and contingency tables. Participants were matched by age, sex, motor ability, and intelligence quotient and randomized into intervention or control groups. The intervention group underwent a 12-week home-based computerized EF intervention. Analysis of covariance was used to examine differences in SC components between groups at post-intervention and 9 months after. Significant positive correlations were found between the SC and EF scores. The frequencies of impaired and average scores in SC were distributed similarly to the impaired and average scores in EFs. The intervention group showed significant improvements in Affect Recognition performance post-intervention, which were maintained at the follow-up assessment, with a moderate effect size. Long-term improvements in Theory of Mind were observed 9 months after. CONCLUSIONS: This study highlights the association between SC and EFs. A home-based computerized cognitive intervention program improves SC in children with CP. Including SC tasks in EF interventions may lead to positive short- and long-term effects for children with CP. CLINICAL TRIAL REGISTRATION: NCT04025749 retrospectively registered on 19 July 2019. WHAT IS KNOWN: • Executive functions and social cognition are associated with social and community participation in people with cerebral palsy. • A home-based computerized cognitive intervention can improve the executive functioning of children with cerebral palsy. WHAT IS NEW: • Social cognition performance is related to core and higher-order executive functions. • A home-based computerized executive function intervention, including social cognition tasks, has positive short- and long-term effects on social cognition skills in children with cerebral palsy.

Interventions with an Impact on Cognitive Functions in Cerebral Palsy: a Systematic Review.

This systematic review aimed at investigating those interventions that impact on cognitive functioning in children and adults with cerebral palsy (CP). A systematic database search was conducted and twenty-eight studies suitable for inclusion were identified, of which only nine were randomized controlled trials (RCTs). Among all the studies included, ten were multi-modal (cognitive and physical tasks), eleven physical, five cognitive, and two alternative and augmentative communication interventions. The evidence suggests that multi-modal and physical interventions improve general cognitive functioning. Multi-modal and cognitive interventions have an impact on visual perception. Both interventions, together with physical interventions have an effect on a specific executive function domain (inhibitory control), and only cognitive interventions improved other executive function domains such as working memory. However, no RCT assessed the effects of all executive function domains. Few studies have looked at interventions to improve memory and language, and there is a scarcity of long-term research. Future RCTs must be of higher quality and better account for age and sex differences, as well as the clinical heterogeneity of CP. To date, there is evidence that multi-modal, cognitive or physical interventions have an impact on general cognitive functioning, visual perception and executive functions in children with CP, which may support their cognitive development.The protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO): CRD42020152616.

A randomized controlled trial of a home-based computerized executive function intervention for children with cerebral palsy.

Children with cerebral palsy (CP) often show executive function (EF) impairments that are key to quality of life. The aim of this study was to assess whether a home-based computerized intervention program improves executive functions (EFs) compared to usual care. Sixty participants (30 females) with CP (8-12 years old) were paired by age, sex, motor ability, and intelligence quotient score and then randomized to intervention and waitlist control groups. The intervention group received a 12-week home-based computerized EF intervention (5 days/week, 30 min/day, total dose 30 h). Core and higher-order EFs were assessed before, immediately after, and 9 months after completing the intervention. The intervention group performed better than the waitlist control group in the three core EFs (immediately and 9 months after the intervention): inhibitory control (F = 7.58, p = 0.13 and F = 7.85, p = 0.12), working memory (F = 8.34, p = 0.14 and F = 7.55, p = 0.13), and cognitive flexibility (F = 4.87, p = 0.09 and F = 4.19, p = 0.08). No differences were found between the groups in higher-order EFs or EF manifestations in daily life. CONCLUSIONS: A home-based computerized EF intervention improved core EFs in children with CP, but further research is needed to identify strategies that allow the transfer of these improvements to everyday life. TRIAL REGISTRATION: NCT04025749 retrospectively registered on 19 July 2019. WHAT IS KNOWN: • One in two children with cerebral palsy has an intellectual impairment. Visual perception and executive functions are the most reported specific cognitive deficits. • The majority of interventions for cerebral palsy focus on motor impairments, but only a few randomized controlled trials have explored the effect of interventions on executive functions. WHAT IS NEW: • A home-based computerized cognitive intervention can improve the core executive functions of children with cerebral palsy. • Short- and long-term effects on core executive functions have been found.

Alterations in Brain Network Organization in Adults With Obesity as Compared With Healthy-Weight Individuals and Seniors.

OBJECTIVE: Life expectancy and obesity rates have drastically increased in recent years. An unhealthy weight is related to long-lasting medical disorders that might compromise the normal course of aging. The aim of the current study of brain connectivity patterns was to examine whether adults with obesity would show signs of premature aging, such as lower segregation, in large-scale networks. METHODS: Participants with obesity (n = 30, mean age = 32.8 ± 5.68 years) were compared with healthy-weight controls (n = 33, mean age = 30.9 ± 6.24 years) and senior participants who were stroke-free and without dementia (n = 30, mean age = 67.1 ± 6.65 years) using resting-state magnetic resonance imaging and graph theory metrics (i.e., small-world index, clustering coefficient, characteristic path length, and degree). RESULTS: Contrary to our hypothesis, participants with obesity exhibited a higher clustering coefficient compared with senior participants (t = 5.06, p < .001, d = 1.23, 95% CIbca = 0.64 to 1.88). Participants with obesity also showed lower global degree relative to seniors (t = -2.98, p = .014, d = -0.77, 95% CIbca = -1.26 to -0.26) and healthy-weight controls (t = -2.92, p = .019, d = -0.72, 95% CIbca = -1.19 to -0.25). Regional degree alterations in this group were present in several functional networks. CONCLUSIONS: Participants with obesity displayed greater network clustering than did seniors and also had lower degree compared with seniors and individuals with normal weight, which is not consistent with the notion that obesity is associated with premature aging of the brain. Although the cross-sectional nature of the study precludes causal inference, the overly clustered network patterns in obese participants could be relevant to age-related changes in brain function because regular networks might be less resilient and metabolically inefficient.

Effect of the catechol-O-methyltransferase Val 158 Met polymorphism on theory of mind in obesity.

Obesity is often accompanied with psychosocial adjustment problems, such as difficulties in social interactions and social withdrawal. A key aspect of social cognition is theory of mind, which allows inferring mental states, feelings, motivations, and beliefs of others and to use this information to predict their future behaviour. Theory of mind is highly dependent on prefrontal dopaminergic neurotransmission, which is regulated by catechol-O-methyltransferase (COMT) activity. We aimed at determining whether theory of mind is altered in obesity and if this ability is modulated by COMT. Fifty patients with obesity and 47 normal-weight individuals underwent the Reading the Mind in the Eyes Test, the Wisconsin Card Sorting Test, and the Vocabulary subscale of the Wechsler Adult Intelligence Scale. The genotype for the COMT Val 158 Met functional polymorphism was determined for all subjects. Patients with obesity obtained significantly lower scores in the negative items of the Reading the Mind in the Eyes Test than normal-weight subjects. Further, an interaction effect was observed between group and COMT genotype. Specifically, the presence of the Met allele was associated to a better identification of negative mental states only in patients with obesity. Our results indicate that obesity is accompanied with difficulties in theory of mind and that this ability is influenced by the COMT genotype.

[Fetal alcohol spectrum disorder. An underdiagnosed neuro-development disorder of uncertain prognosis]. / Trastorno del espectro alcohólico fetal. Un trastorno del neurodesarrollo infradiagnosticado y de pronóstico incierto.

Prenatal exposure to alcohol is the cause of cognitive and behavioural disorders grouped under the term fetal alcohol spectrum disorders (FASD). The long-term evolution of subjects with FASD is often unfavourable, especially in social and academic fields. Executive dysfunction is a hallmark deficit for children with FASD with increased rates of externalizing behaviours, such as aggressiveness and frequently delinquency in adolescence and adulthood. Deficits in social skills, empathy and communication ability are frequent observed among FASD. Prenatal exposure to alcohol is the most frequent cause of acquired and preventable neurodevelopmental disorder.

La exposición prenatal al alcohol es causa de alteraciones somáticas, cognitivas y conductuales que se agrupan bajo el término de trastorno del espectro alcohólico fetal (TEAF). La evolución a largo plazo de los sujetos afectados a menudo es desfavorable, especialmente a nivel académico y adaptativo social. En el perfil neuropsicológico es característica la disfunción ejecutiva a menudo asociada a trastornos de la conducta que evolucionan en muchos casos hacia la delincuencia a partir de la adolescencia y en la edad adulta. Se han descrito también déficits de las habilidades sociales y la empatía. La exposición prenatal al alcohol constituye la causa más frecuente de trastorno del neurodesarrollo adquirido y prevenible.

COVID-19 severity is related to poor executive function in people with post-COVID conditions.

Patients with post-coronavirus disease 2019 (COVID-19) conditions typically experience cognitive problems. Some studies have linked COVID-19 severity with long-term cognitive damage, while others did not observe such associations. This discrepancy can be attributed to methodological and sample variations. We aimed to clarify the relationship between COVID-19 severity and long-term cognitive outcomes and determine whether the initial symptomatology can predict long-term cognitive problems. Cognitive evaluations were performed on 109 healthy controls and 319 post-COVID individuals categorized into three groups according to the WHO clinical progression scale: severe-critical (n = 77), moderate-hospitalized (n = 73), and outpatients (n = 169). Principal component analysis was used to identify factors associated with symptoms in the acute-phase and cognitive domains. Analyses of variance and regression linear models were used to study intergroup differences and the relationship between initial symptomatology and long-term cognitive problems. The severe-critical group performed significantly worse than the control group in general cognition (Montreal Cognitive Assessment), executive function (Digit symbol, Trail Making Test B, phonetic fluency), and social cognition (Reading the Mind in the Eyes test). Five components of symptoms emerged from the principal component analysis: the "Neurologic/Pain/Dermatologic" "Digestive/Headache", "Respiratory/Fever/Fatigue/Psychiatric" and "Smell/ Taste" components were predictors of Montreal Cognitive Assessment scores; the "Neurologic/Pain/Dermatologic" component predicted attention and working memory; the "Neurologic/Pain/Dermatologic" and "Respiratory/Fever/Fatigue/Psychiatric" components predicted verbal memory, and the "Respiratory/Fever/Fatigue/Psychiatric," "Neurologic/Pain/Dermatologic," and "Digestive/Headache" components predicted executive function. Patients with severe COVID-19 exhibited persistent deficits in executive function. Several initial symptoms were predictors of long-term sequelae, indicating the role of systemic inflammation and neuroinflammation in the acute-phase symptoms of COVID-19." Study Registration: www.ClinicalTrials.gov , identifier NCT05307549 and NCT05307575.

Factors Related to Quality of Life in Children With Cerebral Palsy.

BACKGROUND: We investigated the influence of relevant demographic, clinical, neuropsychological, and psychosocial variables on the proxy-reported quality of life (QOL) of children with cerebral palsy (CP). METHODS: The proxy-reported Cerebral Palsy Quality of Life-Child questionnaire (CP QOL-Child) was completed by 58 children with CP (mean age 10.22 years, SD 1.67). Relationships between QOL scores and demographic, clinical, neuropsychological, and psychosocial variables were assessed. CP QOL scores and other variables that correlated significantly were introduced into a multiple linear regression model. RESULTS: Executive functioning and motor functional status were explanatory variables for the CP QOL total score. Executive functions explained three specific QOL domains: Social Wellbeing and Acceptance, Feelings about Functioning, and Emotional Wellbeing and Self-esteem. Parental stress also explained Social Wellbeing and Acceptance. Motor functional status and visual perception were explanatory variables for the Access to Services domain. Finally, autism spectrum disorder (ASD) traits were an explanatory variable for the Participation and Physical Health domain. CONCLUSION: Executive functioning and motor functional status importantly influence QOL of children with CP. Visual perception, ASD symptoms, and parental stress variables are related with specific QOL domains. These findings demonstrate that interventions targeting cognitive functions in children with CP may positively influence QOL.

Body mass index, systemic inflammation and cognitive performance in adolescents: A cross-sectional study.

BACKGROUND: Excessive body weight has been related to lower cognitive performance. One of the mechanisms through which excess body weight may affect cognition is inflammation. HYPOTHESIS: Our hypothesis is that both body mass index (BMI) and circulating levels of inflammatory biomarkers will be negatively related to cognitive performance. DESIGN: Cross-sectional study. SETTING: Users of the public health centres of the Consorci Sanitari de Terrassa (Terrassa, Spain) between 2010 and 2017 aged 12-21 years. PARTICIPANTS: One hundred and five adolescents (46 normoweight, 18 overweight, 41 obese). MEASUREMENTS: Levels of high sensitivity C-reactive protein, interleukin 6, tumour necrosis factor α (TNFα) and fibrinogen were determined from blood samples. Cognitive performance was evaluated and six cognitive composites were obtained: working memory, cognitive flexibility, inhibitory control, decision-making, verbal memory, and fine motor speed. A single multivariate general lineal model was used to assess the influence of the four inflammatory biomarkers, as well as participants' BMI, sex, and age on the 6 cognitive indexes. RESULTS: An inverse relationship between BMI and inhibitory control (F = 5.688, p = .019; ß = -0.212, p = .031), verbal memory (F = 5.404, p = .022; ß = -0.255, p = .009) and fine motor speed (F = 9.038, p = .003; ß = -0.319, p = .001) was observed. Levels of TNFα and fibrinogen were inversely related to inhibitory control (F = 5.055, p = .027; ß = -0.226, p = .021) and verbal memory (F = 4.732, p = .032; ß = -0.274, p = .005), respectively. LIMITATIONS: The cross-sectional nature of the study, the use of cognitive tests designed for clinical purposes, and the use of BMI as a proxy for adiposity are limitations of our study that must be taken into account when interpreting results. CONCLUSIONS: Our data indicate that some components of executive functions, together with verbal memory, are sensitive to specific obesity-related inflammatory agents at early ages.

Improving Reading Skills Using a Computerized Phonological Training Program in Early Readers with Reading Difficulties.

In the last years, there has been a big effort to identify risk factors for reading difficulties and to develop new methodologies to help struggling readers. It has been shown that early intervention is more successful than late intervention, and that intensive training programs can benefit children with reading difficulties. The aim of our study is to investigate the effectiveness of an intensive computerized phonological training program designed to improve reading performance in a sample of children with reading difficulties at the early stages of their reading learning process. Thirty-two children with reading difficulties were randomly assigned to one of the two intervention groups: RDIR (children with reading difficulties following a computerized intensive remediation strategy) (n = 20) (7.01 ± 0.69 years), focused on training phonemic awareness, decoding and reading fluency through the computational training; and RDOR (children with reading difficulties following an ordinary remediation strategy) (n = 12) (6.92 ± 0.82 years), which consisted of a reinforcement of reading with a traditional training approach at school. Normal readers (NR) were assigned to the control group (n = 24) (7.32 ± 0.66 years). Our results indicate that both the RDIR and RDOR groups showed an increased reading performance after the intervention. However, children in the RDIR group showed a stronger benefit than the children in the RDOR group, whose improvement was weaker. The control group did not show significant changes in reading performance during the same period. In conclusion, results suggest that intensive early intervention based on phonics training is an effective strategy to remediate reading difficulties, and that it can be used at school as the first approach to tackle such difficulties.

Neuropsychological impairment in post-COVID condition individuals with and without cognitive complaints.

One of the most prevalent symptoms of post-COVID condition is cognitive impairment, which results in a significant degree of disability and low quality of life. In studies with large sample sizes, attention, memory, and executive function were reported as long-term cognitive symptoms. This study aims to describe cognitive dysfunction in large post-COVID condition individuals, compare objective neuropsychological performance in those post-COVID condition individuals with and without cognitive complaints, and identify short cognitive exams that can differentiate individuals with post-COVID symptoms from controls. To address these aims, the Nautilus project was started in June 2021. During the first year, we collected 428 participants' data, including 319 post-COVID and 109 healthy controls (18-65 years old) from those who underwent a comprehensive neuropsychological battery for cognitive assessment. Scores on tests assessing global cognition, learning and long-term memory, processing speed, language and executive functions were significantly worse in the post-COVID condition group than in healthy controls. Montreal Cognitive Assessment, digit symbol test, and phonetic verbal fluency were significant in the binomial logistic regression model and could effectively distinguish patients from controls with good overall sensitivity and accuracy. Neuropsychological test results did not differ between those with and without cognitive complaints. Our research suggests that patients with post-COVID conditions experience significant cognitive impairment and that routine tests like the Montreal Cognitive Assessment, digit symbol, and phonetic verbal fluency test might identify cognitive impairment. Thus, the administration of these tests would be helpful for all patients with post-COVID-19 symptoms, regardless of whether cognitive complaints are present or absent. Study registration: www.ClinicalTrials.gov, identifiers NCT05307549 and NCT05307575.

Functional connectivity alterations associated with literacy difficulties in early readers.

The link between literacy difficulties and brain alterations has been described in depth. Resting-state fMRI (rs-fMRI) has been successfully applied to the study of intrinsic functional connectivity (iFc) both in dyslexia and typically developing children. Most related studies have focused on the stages from late childhood into adulthood using a seed to voxel approach. Our study analyzes iFc in an early childhood sample using the multivariate pattern analysis. This facilitates a hypothesis-free analysis and the possible identification of abnormal functional connectivity patterns at a whole brain level. Thirty-four children with literacy difficulties (LD) (7.1 ± 0.69 yr.) and 30 typically developing children (TD) (7.43 ± 0.52 yr.) were selected. Functional brain connectivity was measured using an rs-fMRI acquisition. The LD group showed a higher iFc between the right middle frontal gyrus (rMFG) and the default mode network (DMN) regions, and a lower iFc between the rMFG and both the bilateral insular cortex and the supramarginal gyrus. These results are interpreted as a DMN on/off routine malfunction in the LD group, which suggests an alteration of the task control network regulating DMN activity. In the LD group, the posterior cingulate cortex also showed a lower iFc with both the middle temporal poles and the fusiform gyrus. This could be interpreted as a failure in the integration of information between brain regions that facilitate reading. Our results show that children with literacy difficulties have an altered functional connectivity in their reading and attentional networks at the beginning of the literacy acquisition. Future studies should evaluate whether or not these alterations could indicate a risk of developing dyslexia.

Is cognitive training an effective tool for improving cognitive function and real-life behaviour in healthy children and adolescents? A systematic review.

Computerised cognitive training (CCT) has been applied to improve cognitive function in pathological conditions and in healthy populations. Studies suggest that CCT produces near-transfer effects to cognitive functions, with less evidence for far-transfer. Newer applications of CTT in adults seem to produce certain far-transfer effects by influencing eating behaviour and weight loss. However, this is more unexplored in children and adolescents. We conducted a systematic review of 16 studies with randomised controlled design to assess the impact of CCT on cognitive functioning and real-life outcomes, including eating behaviour, in children and adolescents with typical development (PROSPERO registration number: CRD42019123889). Results show near-transfer effects to working memory, with inconsistent results regarding far-transfer effects to other cognitive functions and real-life measures. Long-term effects show the same trend. Far-transfer effects occurred after cue-related inhibitory control and attentional training, although effects seem not to last. CCT may be a potential weight-loss treatment option but more research is needed to determine the specific characteristics to enhance treatment outcomes.

Corpus callosum and prefrontal functions in adolescents with history of very preterm birth.

Very preterm (VPT) birth can account for thinning of the corpus callosum and poorer cognitive performance. Research findings about preterm and VPT adolescents usually describe a small posterior corpus callosum, although our research group has also found reductions of the anterior part, specifically the genu. The aim of the present study was to investigate the functional implications of this concrete reduction. Fifty-two VPT adolescents were compared with 52 adolescents born at term; there were no significant differences in age and gender, and socioeconomic status was similar between the groups. All participants underwent a magnetic resonance imaging (MRI) study and assessment of prefrontal functioning and vocabulary. The VPT group showed significant reductions of the genu, isthmus and splenium, as well as a significantly worse performance on category verbal fluency, executive functions, everyday memory and vocabulary. Although several parts of the corpus callosum correlated with some prefrontal functions, the genu was the part which principally explained these correlations. The subtest Vocabulary only correlated with the splenium. The relationship between genu and prefrontal functions and between splenium and vocabulary may be due to the fact that these parts of the corpus callosum connect prefrontal and posterior parietal cortex, respectively. The work presented here provides evidence of specific associations between reductions in the anterior corpus callosum (genu) and lower prefrontal functioning in VPT adolescents.

Cerebral activation in children and adolescents with obsessive-compulsive disorder before and after treatment: a functional MRI study.

BACKGROUND: Structural and functional fronto-striatal abnormalities are involved in the pathophysiology of obsessive-compulsive disorder (OCD). The aims of the present study were: (a) to investigate possible regional brain dysfunction in premotor cortico-striatal activity in drug-naïve children and adolescents with OCD; (b) to correlate brain activation with severity of obsessive-compulsive symptomatology; and (c) to detect possible changes in brain activity after pharmacological treatment. METHOD: Twelve children and adolescents (age range 7-18 years; seven male, five female) with DSM-IV obsessive-compulsive disorder and twelve healthy subjects matched for age, sex and intellectual level were studied. Functional magnetic resonance imaging data were obtained during the performance of simple and complex sequences. RESULTS: Comparing the complex motor condition with the simple control condition, both patients and controls showed a pattern of cerebral activation involving the fronto-parietal cortex and basal ganglia. Compared with controls, OCD patients presented significantly higher brain activation bilaterally in the middle frontal gyrus. After 6 months of pharmacological treatment and with clear clinical improvement, activation in the left insula and left putamen decreased significantly. CONCLUSION: In a paediatric OCD sample that was treatment naïve and without another psychiatric disorder we showed hyperactivation of the circuits that mediate symptomatic expression of OCD. The cerebral activation decreases after treatment and clinical improvement.

Proton magnetic resonance spectroscopy reveals medial temporal metabolic abnormalities in adolescents with history of preterm birth.

Prematurity is associated with volumetric reductions in specific brain areas such as the hippocampus and with metabolic changes that can be detected by spectroscopy. Short echo time (35 ms) Proton magnetic resonance spectroscopy (1H MRS) was performed to assess possible medial temporal lobe metabolic abnormalities in 21 adolescents with preterm birth (mean age: 14.8, SD: 1.3) compared with an age-matched control sample (mean age: 14.8, SD: 1.6). 1H MRS spectra were analyzed with linear combination model fitting, obtaining the absolute metabolite concentrations for Creatine (Cr), and myo-inositol (Ins). In addition, the following metabolite sums were measured: total Cho (glycerophospho-choline + phosphocholine), total N-acetyl-aspartate + N-acetyl-aspartylglutamate (NA), and total Glx (glutamate + glutamine). A stereological analysis was performed to calculate hippocampal volume. Absolute Cr, and total NA values were decreased in the preterm group (p = 0.016; p = 0.002, respectively). The preterm also showed a hippocampal reduction (p < 0.0001). Significant relationships were found between gestational age and different metabolites and the hippocampal volume. Moreover, hippocampal volume correlated with brain metabolites in the whole sample. Results demonstrate that prematurity affects medial temporal lobe metabolites, and that the alteration is related to structural changes, suggesting that the cerebral changes persist until adolescence.

Left posterior hippocampal density reduction using VBM and stereological MRI procedures in schizophrenia.

Structural deficits in the hippocampus have been implicated in the pathophysiology of schizophrenia. However the role played by structural impairments in the hippocampus in the memory deficits of schizophrenic patients remains unclear. Magnetic resonance imaging was used in this study to investigate left, right, anterior and posterior hippocampal volume and density in 28 schizophrenic patients and 33 normal controls. Voxel-based morphometry analysis showed that schizophrenics had significantly lower density in the right and posterior hippocampus than controls. MRI stereological analysis revealed significant differences in left posterior hippocampus than controls. MRI stereological analysis revealed significant differences in anterior and posterior on both sides, with the left posterior region predominating. Schizophrenics showed significant impairments in verbal learning and long term retention (P<0.001). The correlation analyses between hippocampal density and memory variables yielded a significant correlation between forgetting and density of the anterior hippocampus. These findings support the hypothesis of a regional atrophy within the hippocampus in schizophrenic patients.

Hormonal and genetic influences on processing reward and social information.

Social neuroscience is an emerging interdisciplinary field that combines tools from cognitive, cellular, and molecular neuroscience to understand the neural mechanisms underlying human interactions, emphasizing the complementary nature of different organization levels in the social and biological domains. Previous studies focused on the molecular/neuronal substrates of a variety of complex behaviors, such as parental behavior and pair bonding. Less is known about the various factors influencing interindividual differences in reward processing and decision making in social contexts, both relying upon the dopaminergic system. This review concerns (1) basic electrophysiological findings and recent neuroimaging findings showing that reward processing and social interaction processes share common neural substrates and (2) genetic and hormonal influences on these processes. Recent research combining molecular genetics, endocrinology, and neuroimaging demonstrated that variations in dopamine-related genes and in hormone levels affect the physiological properties of the dopaminergic system in nonhuman primates and modulate the processing of reward and social information in humans. These findings are important because they indicate the neural influence of genes conferring vulnerability to develop neuropathologies such as drug addiction and pathological gambling. Taken together, the reviewed data start to unveil the relationships between genes, hormones, and the functioning of the reward system, as well as decision making in social contexts, and provide a link between molecular, cellular, and social cognitive levels in humans.