Role of cortical excitatory/inhibitory imbalance in autism spectrum disorders from a symptom severity trajectories framework: a study protocol.

BACKGROUND: There is considerable evidence reporting an excitatory/inhibitory (E/I) cortical imbalance in autism spectrum disorders (ASD). However, previous findings on the direction of this imbalance and its relationship to ASD symptomatology are heterogeneous. Some factors contributing to these mixed results might be the methodological differences between studies assessing the E/I ratio and the intrinsic variability within the autistic spectrum. Studying the evolution of ASD symptoms and the factors that modulate it might help to explain and reduce this variability. Here we present a study protocol to explore the longitudinal role of E/I imbalance in ASD symptoms, combining different approaches to measure the E/I ratio and using the trajectories of symptom severity as a framework. METHODS: This observational two time-point prospective study assesses the E/I ratio and the evolution of the behavioural symptoms in a sample of at least 98 participants with ASD. Participants are enrolled at 12 to 72 months of age and followed from 18 to 48 months after. A comprehensive battery of tests is applied to evaluate ASD clinical symptoms. The E/I ratio is approached from electrophysiology, magnetic resonance, and genetics. We will calculate the individual change for the main ASD symptoms and, based on that, we will define the trajectories of symptom severity. Then, we will investigate the correlation between measures of excitation/inhibition balance and autistic symptomatology cross-sectionally, as well as the ability of these measurements to predict changes in symptoms over time. DISCUSSION: This study presents a robust multisystemic approach to the E/I imbalance theory in autism and its relation to divergent symptom trajectories. That setting will allow us to relate and compare the neurobiological information coming from different sources and its impact on behavioural symptoms while accounting for the high variability in ASD. The findings derived from this study could contribute to the ASD biomarkers research and might provide valuable evidence for the development of more personalized treatments in ASD.

Surgery and Radiosurgery in Autism: A Retrospective Study in 10 Patients.

INTRODUCTION: A subgroup of patients with autism spectrum disorder (ASD) show self or heteroaggression, dyscontrol episodes, and others are of obsessive-compulsive disorder (OCD) profile; some of them are resistant to medical and behavioural treatment. We describe the long-term outcome in a group of these patients, treated with radiofrequency brain lesions or combined stereotactic surgery and Gamma Knife (GK) radiosurgery. METHODS: We reviewed the medical records of 10 ASD patients with pathological aggressiveness and OCD, who had undergone radiofrequency lesions and/or radiosurgery with GK in our institution. RESULTS: The 10 patients had a significant reduction of their symptoms (PCQ 39.9 and 33, OAS 11.8 and 5, CYBOCS-ASD 30.4 and 20), preoperatively and in the last follow-up, respectively; p < 0.005 (in all cases), although all but 2 needed more than 1 treatment to maintain this improvement. CONCLUSIONS: We observed a marked improvement in behaviour, quality of life, and relationship with the environment in all our 10 patients after the lesioning treatments, without long-lasting side effects.

Small temporal pole encephalocele: A hidden cause of "normal" MRI temporal lobe epilepsy.

OBJECTIVE: Small temporal pole encephalocele (STPE) can be the pathologic substrate of epilepsy in a subgroup of patients with noninformative magnetic resonance imaging (MRI). Herein, we analyzed the clinical, neurophysiologic, and radiologic features of the epilepsy found in 22 patients with STPE, and the frequency of STPE in patients with refractory focal epilepsy (RFE). METHODS: We performed an observational study of all patients with STPE identified at our epilepsy unit from January 2007 to December 2014. Cases were detected through a systematic search of our database of RFE patients evaluated for surgery, and a prospective collection of patients identified at the outpatient clinic. The RFE database was also employed to analyze the frequency of STPE among the different clinical subgroups. RESULTS: We identified 22 patients with STPE (11 women), including 12 (4.0%) of 303 patients from the RFE database, and 10 from the outpatient clinic. The median age was 51.5 years (range 29-75) and the median age at seizure onset was 38.5 years (range 15-73). Typically, 12 (80%) of 15 patients with left STPE reported seizures with impairment of language. Among the RFE cases, STPE were found in 9.6% of patients with temporal lobe epilepsy (TLE), and in 0.5% of those with extra-TLE (p = 0.0001). STPEs were more frequent in TLE patients with an initial MRI study reported as normal (23.3%) than in those with MRI-visible lesions (1.4%; p = 0.0002). Stereo-electroencephalography was performed in four patients, confirming the localization of the epileptogenic zone at the temporal pole with late participation of the hippocampus. Long-term seizure control was achieved in four of five operated patients. SIGNIFICANCE: STPE can be a hidden cause of TLE in a subgroup of patients with an initial report of "normal" MRI. Early identification of this lesion may help to select patients for presurgical evaluation and tailored resection.

Subcortical regional morphology correlates with fluid and spatial intelligence.

Neuroimaging studies have revealed associations between intelligence and brain morphology. However, researchers have focused primarily on the anatomical features of the cerebral cortex, whereas subcortical structures, such as the basal ganglia (BG), have often been neglected despite extensive functional evidence on their relation with higher-order cognition. Here we performed shape analyses to understand how individual differences in BG local morphology account for variability in cognitive performance. Structural MRI was acquired in 104 young adults (45 men, 59 women, mean age = 19.83, SD = 1.64), and the outer surface of striatal structures (caudate, nucleus accumbens, and putamen), globus pallidus, and thalamus was estimated for each subject and hemisphere. Further, nine cognitive tests were used to measure fluid (Gf), crystallized (Gc), and spatial intelligence (Gv). Latent scores for these factors were computed by means of confirmatory factor analysis and regressed vertex-wise against subcortical shape (local displacements of vertex position), controlling for age, sex, and adjusted for brain size. Significant results (FDR < 5%) were found for Gf and Gv, but not Gc, for the right striatal structures and thalamus. The main results show a relative enlargement of the rostral putamen, which is functionally connected to the right dorsolateral prefrontal cortex and other intelligence-related prefrontal areas.

Reversed hierarchy in the brain for general and specific cognitive abilities: a morphometric analysis.

Intelligence is composed of a set of cognitive abilities hierarchically organized. General and specific abilities capture distinguishable, but related, facets of the intelligence construct. Here, we analyze gray matter with three morphometric indices (volume, cortical surface area, and cortical thickness) at three levels of the intelligence hierarchy (tests, first-order factors, and a higher-order general factor, g). A group of one hundred and four healthy young adults completed a cognitive battery and underwent high-resolution structural MRI. Latent scores were computed for the intelligence factors and tests were also analyzed. The key finding reveals substantial variability in gray matter correlates at the test level, which is substantially reduced for the first-order and the higher-order factors. This supports a reversed hierarchy in the brain with respect to cognitive abilities at different psychometric levels: the greater the generality, the smaller the number of relevant gray matter clusters accounting for individual differences in intelligent performance.

Social dysfunction relates to shifts within socioaffective brain systems among Schizophrenia and Alzheimer's disease patients.

Social dysfunction represents one of the most common signs of neuropsychiatric disorders, such as Schizophrenia (SZ) and Alzheimer's disease (AD). Perturbed socioaffective neural processing is crucially implicated in SZ/AD and generally linked to social dysfunction. Yet, transdiagnostic properties of social dysfunction and its neurobiological underpinnings remain unknown. As part of the European PRISM project, we examined whether social dysfunction maps onto shifts within socioaffective brain systems across SZ and AD patients. We probed coupling of social dysfunction with socioaffective neural processing, as indexed by an implicit facial emotional processing fMRI task, across SZ (N = 46), AD (N = 40) and two age-matched healthy control (HC) groups (N = 26 HC-younger and N = 27 HC-older). Behavioural (i.e., social withdrawal, interpersonal dysfunction, diminished prosocial or recreational activity) and subjective (i.e., feelings of loneliness) aspects of social dysfunction were assessed using the Social Functioning Scale and De Jong-Gierveld loneliness questionnaire, respectively. Across SZ/AD/HC participants, more severe behavioural social dysfunction related to hyperactivity within fronto-parieto-limbic brain systems in response to sad emotions (P = 0.0078), along with hypoactivity of these brain systems in response to happy emotions (P = 0.0418). Such relationships were not found for subjective experiences of social dysfunction. These effects were independent of diagnosis, and not confounded by clinical and sociodemographic factors. In conclusion, behavioural aspects of social dysfunction across SZ/AD/HC participants are associated with shifts within fronto-parieto-limbic brain systems. These findings pinpoint altered socioaffective neural processing as a putative marker for social dysfunction, and could aid personalized care initiatives grounded in social behaviour.

Neuroanatomic overlap between intelligence and cognitive factors: morphometry methods provide support for the key role of the frontal lobes.

Evidence from neuroimaging studies suggests that intelligence differences may be supported by a parieto-frontal network. Research shows that this network is also relevant for cognitive functions such as working memory and attention. However, previous studies have not explicitly analyzed the commonality of brain areas between a broad array of intelligence factors and cognitive functions tested in the same sample. Here fluid, crystallized, and spatial intelligence, along with working memory, executive updating, attention, and processing speed were each measured by three diverse tests or tasks. These twenty-one measures were completed by a group of one hundred and four healthy young adults. Three cortical measures (cortical gray matter volume, cortical surface area, and cortical thickness) were regressed against psychological latent scores obtained from a confirmatory factor analysis for removing test and task specific variance. For cortical gray matter volume and cortical surface area, the main overlapping clusters were observed in the middle frontal gyrus and involved fluid intelligence and working memory. Crystallized intelligence showed an overlapping cluster with fluid intelligence and working memory in the middle frontal gyrus. The inferior frontal gyrus showed overlap for crystallized intelligence, spatial intelligence, attention, and processing speed. The fusiform gyrus in temporal cortex showed overlap for spatial intelligence and attention. Parietal and occipital areas did not show any overlap across intelligence and cognitive factors. Taken together, these findings underscore that structural features of gray matter in the frontal lobes support those aspects of intelligence related to basic cognitive processes.

Changes in resting-state functionally connected parietofrontal networks after videogame practice.

Neuroimaging studies provide evidence for organized intrinsic activity under task-free conditions. This activity serves functionally relevant brain systems supporting cognition. Here, we analyze changes in resting-state functional connectivity after videogame practice applying a test-retest design. Twenty young females were selected from a group of 100 participants tested on four standardized cognitive ability tests. The practice and control groups were carefully matched on their ability scores. The practice group played during two sessions per week across 4 weeks (16 h total) under strict supervision in the laboratory, showing systematic performance improvements in the game. A group independent component analysis (GICA) applying multisession temporal concatenation on test-retest resting-state fMRI, jointly with a dual-regression approach, was computed. Supporting the main hypothesis, the key finding reveals an increased correlated activity during rest in certain predefined resting state networks (albeit using uncorrected statistics) attributable to practice with the cognitively demanding tasks of the videogame. Observed changes were mainly concentrated on parietofrontal networks involved in heterogeneous cognitive functions.

Grapheme-color synesthetes show peculiarities in their emotional brain: cortical and subcortical evidence from VBM analysis of 3D-T1 and DTI data.

Grapheme-color synesthesia is a neurological phenomenon in which viewing achromatic letters/numbers leads to automatic and involuntary color experiences. In this study, voxel-based morphometry analyses were performed on T1 images and fractional anisotropy measures to examine the whole brain in associator grapheme-color synesthetes. These analyses provide new evidence of variations in emotional areas (both at the cortical and subcortical levels), findings that help understand the emotional component as a relevant aspect of the synesthetic experience. Additionally, this study replicates previous findings in the left intraparietal sulcus and, for the first time, reports the existence of anatomical differences in subcortical gray nuclei of developmental grapheme-color synesthetes, providing a link between acquired and developmental synesthesia. This empirical evidence, which goes beyond modality-specific areas, could lead to a better understanding of grapheme-color synesthesia as well as of other modalities of the phenomenon.

Is a neutral expression also a neutral stimulus? A study with functional magnetic resonance.

Although neutral faces do not initially convey an explicit emotional message, it has been found that individuals tend to assign them an affective content. Moreover, previous research has shown that affective judgments are mediated by the task they have to perform. Using functional magnetic resonance imaging in 21 healthy participants, we focus this study on the cerebral activity patterns triggered by neutral and emotional faces in two different tasks (social or gender judgments). Results obtained, using conjunction analyses, indicated that viewing both emotional and neutral faces evokes activity in several similar brain areas indicating a common neural substrate. Moreover, neutral faces specifically elicit activation of cerebellum, frontal and temporal areas, while emotional faces involve the cuneus, anterior cingulated gyrus, medial orbitofrontal cortex, posterior superior temporal gyrus, precentral/postcentral gyrus and insula. The task selected was also found to influence brain activity, in that the social task recruited frontal areas while the gender task involved the posterior cingulated, inferior parietal lobule and middle temporal gyrus to a greater extent. Specifically, in the social task viewing neutral faces was associated with longer reaction times and increased activity of left dorsolateral frontal cortex compared with viewing facial expressions of emotions. In contrast, in the same task emotional expressions distinctively activated the left amygdale. The results are discussed taking into consideration the fact that, like other facial expressions, neutral expressions are usually assigned some emotional significance. However, neutral faces evoke a greater activation of circuits probably involved in more elaborate cognitive processing.

Higher glutamate to glutamine ratios in occipital regions in women with migraine during the interictal state.

BACKGROUND: Glutamate (Glu) and glutamine (Gln) are strongly compartmentalized (in neurons for Glu and in astrocytes for Gln). The visual cortex is the brain region with a higher neuron/astrocyte ratio (the highest neuronal density and the relatively lowest density of astrocytes). Elevations in extracellular Glu or potassium above certain thresholds are likely candidates to be the final common steps in the multiple distinct processes that can lead to cortical spreading depression. Astrocytes play a key role in this phenomenon, by acting as a sink for extracellular Glu and potassium, as well as generally acting as a buffer for the ionic and neurochemical changes that initiate and propagate cortical spreading depression. OBJECTIVE: The purpose of this study was to quantify Glu and Gln to generate Glu/Gln ratios in women with migraine during the interictal state compared with healthy control women. METHODS: Twenty-seven patients with migraine (8 with aura and 19 without aura) and 19 matched healthy controls were included in the study. We performed proton magnetic resonance spectroscopy in the anterior paracingulate cortex and occipital cortex (OC). Spectral analysis was performed by LCModel, allowing a separation of Glu and Gln using a 3T machine. RESULTS: The main result was a significantly higher Glu/Gln ratio in the OC of migraine patients compared with healthy control subjects (4.87 for migraineurs [standard deviation (SD) = 2.74] and 3.42 for controls [SD = 1.52], P = .042). We also observed higher Glu levels (6.98 for migraineurs [SD = 0.85] and 6.22 for controls [SD = 0.97], P = .007) and Glu/creatine + phosphocreatine ratio (1.18 for migraineurs [SD = 0.18] and 1.00 for controls [SD = 0.16], P = .001) in anterior paracingulate cortex in migraine patients but saw no differences in Glu/Gln ratio (2.79 for migraineurs [SD = 1.11] and 2.63 for controls [SD = 1.61], P = .68). CONCLUSION: These findings are consistent with glutamatergic differences in migraine patients during the interictal period compared with healthy controls. We hypothesize that an increased Glu/Gln ratio could arise from neuronal-glial coupling of glutamatergic metabolism differences or an increased neuron/astrocyte ratio in the OC.

An effective environmental intervention for management of the 'mirror sign' in a case of probable Lewy body dementia.

The term 'mirror sign' refers to the inability to recognize the reflection of oneself in a mirror, while the ability to recognize others' faces often remains intact. In this article, we present a case of an 85-year-old woman, with probable Lewy body dementia, who stably exhibited a delusional 'mirror sign' for a period of 9 months. Following a straightforward, ecological, non-pharmacological intervention, her 'mirror sign' delusion was no longer present.

Hippocampal structure and human cognition: key role of spatial processing and evidence supporting the efficiency hypothesis in females.

Here we apply a method for automated segmentation of the hippocampus in 3D high-resolution structural brain MRI scans. One hundred and four healthy young adults completed twenty one tasks measuring abstract, verbal, and spatial intelligence, along with working memory, executive control, attention, and processing speed. After permutation tests corrected for multiple comparisons across vertices (p < .05) significant relationships were found for spatial intelligence, spatial working memory, and spatial executive control. Interactions with sex revealed significant relationships with the general factor of intelligence (g), along with abstract and spatial intelligence. These correlations were mainly positive for males but negative for females, which might support the efficiency hypothesis in women. Verbal intelligence, attention, and processing speed were not related to hippocampal structural differences.

Seizure and developmental outcomes after hemispherectomy in children and adolescents with intractable epilepsy.

PURPOSE: The aim of this study is to describe a series of pediatric hemispherectomies, reviewing pathologic substrate, epilepsy characteristics and seizure outcome as well as developmental profiles, before and after surgery, in different domains. METHODS: Seventeen patients with full pre-surgical work-up, minimum follow-up of 12 months, and at least one post-surgical neuropsychological evaluation were selected. Three had Rasmussen encephalitis (RE), five hemispheric malformations of cortical development (MCD), and nine hemispheric vascular lesions. RESULTS: At latest follow-up, all patients with RE and 66.7 % of those with vascular lesions are in Engel's class I; in the latter group, pre-surgical independent contralateral EEG discharges statistically correlated with a worse seizure outcome. Patients with MCD showed the worst seizure outcome. Pre-surgical language transfer to the right hemisphere was confirmed in a boy with left RE, operated on at 6 years of age. Patients with MCD and vascular lesions already showed severe global developmental delay before surgery, which persists afterwards. A linear correlation was found between earlier age at surgery and better outcome in personal-social, gross motor, and adaptive domains, in the vascular lesions group. The case with highest cognitive improvement had continuous spike and wave during sleep on pre-surgical EEG. CONCLUSIONS: Pathologic substrate was the main factor related with seizure outcome. In children with MCD and vascular lesions, although developmental progression is apparent, significant post-surgical improvements are restricted by the severity of pre-surgical neuropsychological disturbances and a slow maturation. Early surgery assessment is recommended to enhance the possibilities for a better quality of life in terms of seizure control, as well as better autonomy and socialization.

The correlation between white-matter microstructure and the complexity of spontaneous brain activity: a difussion tensor imaging-MEG study.

The advent of new signal processing methods, such as non-linear analysis techniques, represents a new perspective which adds further value to brain signals' analysis. Particularly, Lempel-Ziv's Complexity (LZC) has proven to be useful in exploring the complexity of the brain electromagnetic activity. However, an important problem is the lack of knowledge about the physiological determinants of these measures. Although a correlation between complexity and connectivity has been proposed, this hypothesis was never tested in vivo. Thus, the correlation between the microstructure of the anatomic connectivity and the functional complexity of the brain needs to be inspected. In this study we analyzed the correlation between LZC and fractional anisotropy (FA), a scalar quantity derived from diffusion tensors that is particularly useful as an estimate of the functional integrity of myelinated axonal fibers, in a group of sixteen healthy adults (all female, mean age 65.56±6.06 years, intervals 58-82). Our results showed a positive correlation between FA and LZC scores in regions including clusters in the splenium of the corpus callosum, cingulum, parahipocampal regions and the sagittal stratum. This study supports the notion of a positive correlation between the functional complexity of the brain and the microstructure of its anatomical connectivity. Our investigation proved that a combination of neuroanatomical and neurophysiological techniques may shed some light on the underlying physiological determinants of brain's oscillations.

Photoreactivity of the occipital cortex measured by functional magnetic resonance imaging-blood oxygenation level dependent in migraine patients and healthy volunteers: pathophysiological implications.

BACKGROUND: The brain of migraineurs is hyperexcitable, particularly the occipital cortex, which is probably hypersensitive to light. Photophobia or hypersensitivity to light may be accounted for by an increased excitability of trigeminal, the visual pathways, and the occipital cortex. OBJECTIVE: To study light sensitivity and photophobia by assessing the response to light stimuli with functional magnetic resonance imaging-blood oxygenation level dependent (fMRI-BOLD) of the occipital cortex in migraineurs and in controls. Also, to try to decipher the contribution of the occipital cortex to photophobia and whether the cortical reactivity of migraineurs may be part of a constitutional (defensive) mechanism or represents an acquired (sensitization) phenomenon. METHODS: Nineteen patients with migraine (7 with aura and 12 without aura) and 19 controls were studied with fMRI-BOLD during 4 increasing light intensities. Eight axial image sections of 0.5 cm that covered the occipital cortex were acquired for each intensity. We measured the extension and the intensity of activation for every light stimuli. Photophobia was estimated according to a 0 to 3 semiquantitative scale of light discomfort. RESULTS: Migraineurs had a significantly higher number of fMRI-activated voxels at low (320.4 for migraineurs [SD = 253.9] and 164.3 for controls [SD = 102.7], P = .027) and medium-low luminance levels (501.2 for migraineurs [SD = 279.5] and 331.1 for controls [SD = 194.3], P = .034) but not at medium-high (579.5 for migraineurs [SD = 201.4] and 510.2 for controls [SD = 239.5], P = .410) and high light stimuli (496.2 for migraineurs [SD = 216.2] and 394.7 for controls [SD = 240], P = .210). No differences were found with respect to the voxel activation intensity (amplitude of the BOLD wave) between migraineurs and controls (8.98 [SD = 2.58] vs 7.99 [SD = 2.57], P = .25; 10.82 [SD = 3.27] vs 9.81 [SD = 3.19], P = .31; 11.90 [SD = 3.18] vs 11.06 [SD = 2.56], P = .62; 11.45 [SD = 2.65] vs 10.25 [SD = 2.22], P = .16). Light discomfort was higher in the group of migraineurs at all the intensities tested, but there was no correlation with the number of activated voxels in the occipital cortex and photophobia. Repetitive light stimuli failed to demonstrate a lack of habituation in migraineurs. CONCLUSIONS: Migraineurs during interictal periods showed hyperxcitability of the visual cortex with a wider photoresponsive area, the underlying mechanism probably being dual: constitutional-defensive and acquired-sensitizating.

Pascual-Castroviejo type II syndrome (P-CIIS). Importance of the presence of persistent embryonic arteries.

INTRODUCTION: Cutaneous hemangioma and vascular malformation are two vascular abnormalities frequently associated with absence or hypoplasia of one or both carotid and/or vertebral arteries, presence of persistent embryonic arteries, especially the trigeminal, cerebellar malformations, and coarctation of the aortic arch and/or congenital cardiopathy. This disease is known as Pascual-Castroviejo type II syndrome (P-CIIS) and by the acronym PHACE. MATERIAL AND METHODS: Three patients (two females and one male) with facial hemangioma are studied during the first years of age by magnetic resonance angiography (MRA) and their vascular evolution to adult age followed through several MRA controls. RESULTS: All the three patients showed persistence of the trigeminal artery associated to other intra- and extracranial vascular abnormalities of type hemangioma or hemangiomatous arteries that presented progressive involution with decreased arterial caliber without appearing cerebrovascular stroke or hypoxic zones because, at the same time, collateral vascularization appeared through connections between the embryonic arteries and the peripheral branches of the internal carotids or connections between branches of the external and internal carotids. Only one patient had obstruction of a branch of the left middle cerebral artery after 3 days, with gastroenteritis with elevated fever at 17 months of life that caused parenchymal infarct in the left cerebral region supplied by the obstructed artery. CONCLUSIONS: The presence of embryonic arteries, especially the trigeminal, and connections between branches of the internal and external carotids, mainly through the internal maxillary and ophthalmic arteries, ensure the cerebral supply in the P-CIIS despite the progressive involvement of the cerebral arteries.

Brain resilience across the general cognitive ability distribution: Evidence from structural connectivity.

Resting state functional connectivity research has shown that general cognitive ability (GCA) is associated with brain resilience to targeted and random attacks (TAs and RAs). However, it remains to be seen if the finding generalizes to structural connectivity. Furthermore, individuals showing performance levels at the very high area of the GCA distribution have not yet been analyzed in this regard. Here we study the relation between TAs and RAs to structural brain networks and GCA. Structural and diffusion-weighted MRI brain images were collected from 189 participants: 60 high cognitive ability (HCA) and 129 average cognitive ability (ACA) individuals. All participants completed a standardized fluid reasoning ability test and the results revealed an average HCA-ACA difference equivalent to 33 IQ points. Automated parcellation of cortical and subcortical nodes was combined with tractography to achieve an 82 × 82 connectivity matrix for each subject. Graph metrics were derived from the structural connectivity matrices. A simulation approach was used to evaluate the effects of recursively removing nodes according to their network centrality (TAs) versus eliminating nodes at random (RAs). HCA individuals showed greater network integrity at baseline and prior to network collapse than ACA individuals. These effects were more evident for TAs than RAs. The networks of HCA individuals were less degraded by the removal of nodes corresponding to more complex information processing stages of the PFIT network, and from removing nodes with larger empirically observed centrality values. Analyzed network features suggest quantitative instead of qualitative differences at different levels of the cognitive ability distribution.

Neocortical Age and Fluid Ability: Greater Accelerated Brain Aging for Thickness, but Smaller for Surface Area, in High Cognitive Ability Individuals.

Biological (BA) and chronological (CA) age may or may not fit. The available evidence reveals remarkable individual differences in the overlap/mismatch between BA and CA. Increased mismatch can be interpreted as delayed (BA/CA < 1) or accelerated biological aging (BA/CA > 1). Body and brain health are correlated and both predict aging outcomes associated with physical and mental fitness. Moreover, research has shown that older brain age at midlife correlates negatively with cognitive ability measured in early childhood, which suggests early life predisposition to accelerated aging in adulthood. Under this framework, here we test if increased cognitive ability is associated with delayed brain aging, analyzing structural MRI data of 188 individuals, sixty of whom were recruited from MENSA, an association comprising individuals who obtained cognitive ability scores in the top 2 percent of the population. These high ability individuals (HCA) showed an average advantage of 33 IQ points, on a fluid reasoning test they completed for this research, over those other recruited because of their average cognitive ability (ACA). Next, brain age was computed at the individual level for two distinguishable neocortical features (thickness and surface area) according to models trained in an independent large-scale sample of 2377 individuals. Results revealed a stronger pattern of accelerated brain aging in HCA compared to ACA individuals for thickness, while the opposite pattern was suggested for surface area. The findings align well with the greater relevance of individual differences in cortical surface area for enhancing our understanding of cognitive differences at the brain level.

Cognitive deficits and clinical symptoms in patients with treatment-refractory obsessive-compulsive disorder: The role of slowness in information processing.

Patients with Obsessive-Compulsive Disorder (OCD) present neuropsychological deficits across different cognitive domains, especially in executive functioning and information processing speed. Some studies have even suggested that speed deficits may underlie poor neuropsychological performance. However, this hypothesis remains unanswered in both OCD general population and OCD refractory subgroup. In addition, it is not clear whether such deficits are secondary to the clinical symptoms or may constitute a primary deficit. The aim of this study was to explore the speed of processing hypothesis in treatment-refractory OCD patients, and to clarify to what extent slowness is related to psychopathological symptoms. Both clinical and neuropsychological examination was conducted to assess 39 OCD refractory patients candidates for neurosurgery and 39 healthy matched individuals. Principal component analysis revealed a three-component structure in the neuropsychological battery being used, including a speed of processing, working memory, and conflict monitoring components. Group comparisons revealed that OCD patients performed significantly worse than healthy individuals in speed measures, but no differences were found in executive tests not influenced by time. Correlation analyses revealed a lack of association between neuropsychological and clinical measures. The results suggest that treatment-refractory OCD patients exhibit a primary deficit in information processing speed independent of clinical symptoms.