Enhanced amygdala-anterior cingulate white matter structural connectivity in Sahaja Yoga Meditators.

OBJECTIVE: To study the white matter connections between anterior cingulate cortex, anterior insula and amygdala as key regions of the frontal-limbic network that have been related to meditation. DESIGN: Twenty experienced practitioners of Sahaja Yoga Meditation and twenty nonmeditators matched on age, gender and education level, were scanned using Diffusion Weighted Imaging, using a 3T scanner, and their white matter connectivity was compared using diffusion tensor imaging analyses. RESULTS: There were five white matter fiber paths in which meditators showed a larger number of tracts, two of them connecting the same area in both hemispheres: the left and right amygdalae and the left and right anterior insula; and the other three connecting left anterior cingulate with the right anterior insula, the right amygdala and the left amygdala. On the other hand, non-meditators showed larger number of tracts in two paths connecting the left anterior insula with the left amygdala, and the left anterior insula with the left anterior cingulate. CONCLUSIONS: The study shows that long-term practice of Sahaja Yoga Meditation is associated with larger white matter tracts strengthening interhemispheric connections between limbic regions and connections between cingulo-amygdalar and cingulo-insular brain regions related to top-down attentional and emotional processes as well as between top-down control functions that could potentially be related to the witness state perceived through the state of mental silence promoted with this meditation. On the other hand, reduced connectivity strength in left anterior insula in the meditation group could be associated to reduced emotional processing affecting top-down processes.

Contribution of Brain Cortical Features to the Psychological Risk Profile of Juvenile Offenders

Objectives: This study contributes to the neuroscience of offending behavior by addressing two aims: a) to examine differences in the cortical features in a group of male serious juvenile offenders (21 OG), versus controls (28 CG), both ranging from 18 to 21 years old; and b) to determine to what extent the differential cortical features and the risk psychological profile discriminate between the two groups. Method: Besides cortical measures, demographics, executive functioning, childhood trauma, psychopathic traits, psychopathological symptoms, and antisocial and delinquent behavior were assessed. Results: Whole-brain analysis of the cortical mantle identified increased cortical thickness in the cluster comprising the right middle temporal gyrus and a smaller surface area in the lateral orbitofrontal cortex for the OG compared to the CG. The discriminant function correctly classified 100% of cases of the CG and 94.7% of the OG. Right temporal cluster, childhood trauma, callousness and symptoms of interpersonal sensitivity, psychoticism, depression, phobic anxiety, and obsessive-compulsive behavior contributed to the OG. In turn, the lateral orbitofrontal cluster, psychopathic traits of grandiosity, unemotionality, and thrill seeking, and working memory contributed to the CG. Conclusions: The increased right middle temporal gyrus of the OG could be indicative of impaired brain development in social cognition processes since it appeared in combination with the higher risk profile. The reduced orbitofrontal cortex could be indicative of immature brain development in emotional control processes since it appeared in combination with the normative psychological profile in adolescence. Based on these novel findings, areas of potential improvement for research and intervention are suggested. (AU)

Objetivos: Este estudio contribuye a la neurociencia de la conducta delictiva abordando dos objetivos: a) examinar las diferencias en las características corticales en un grupo de delincuentes juveniles de sexo masculino (21 GD), frente a los controles (28 GC), ambos con edades comprendidas entre los 18 y los 21 años; y b) determinar hasta qué punto las características corticales diferenciales y el perfil psicológico de riesgo discriminan entre los dos grupos. Método: Además de las medidas corticales, se evaluaron los datos demográficos, el funcionamiento ejecutivo, el trauma infantil, los rasgos psicopáticos, los síntomas psicopatológicos y el comportamiento antisocial y delictivo. Resultados: El análisis del manto cortical de todo el cerebro mostró un mayor grosor cortical en el clúster que comprende la circunvolución temporal media derecha y una menor superficie en la corteza orbitofrontal lateral para el GD con respecto al GC. La función discriminante clasificó correctamente el 100% de los casos del GC y el 94,7% del GD. El clúster temporal derecho, el trauma infantil, la insensibilidad y los síntomas de sensibilidad interpersonal, psicoticismo, depresión, ansiedad fóbica y comportamiento obsesivo-compulsivo contribuyeron al GD. Por su parte, el clúster orbitofrontal lateral, los rasgos psicopáticos de grandiosidad, impasibilidad y búsqueda de emociones y la memoria de trabajo contribuyeron al GC. Conclusiones: La alteración temporal media derecha del GD podría ser indicativa de un desarrollo cerebral alterado en los procesos de cognición social, ya que este rasgo cortical apareció en combinación con el perfil de mayor riesgo. La reducción en el área orbitofrontal podría ser indicativa de un desarrollo cerebral inmaduro en los procesos de control emocional, ya que apareció en combinación con el perfil psicológico normativo en la adolescencia. A partir de estos hallazgos novedosos, se proponen áreas posibles de mejora para la investigación y la intervención. (AU)

Crystallized and fluid intelligence are predicted by microstructure of specific white-matter tracts.

Studies of the neural basis of intelligence have focused on comparing brain imaging variables with global scales instead of the cognitive domains integrating these scales or quotients. Here, the relation between mean tract-based fractional anisotropy (mTBFA) and intelligence indices was explored. Deterministic tractography was performed using a regions of interest approach for 10 white-matter fascicles along which the mTBFA was calculated. The study sample included 83 healthy individuals from the second wave of the Cuban Human Brain Mapping Project, whose WAIS-III intelligence quotients and indices were obtained. Inspired by the "Watershed model" of intelligence, we employed a regularized hierarchical Multiple Indicator, Multiple Causes model (MIMIC), to assess the association of mTBFA with intelligence scores, as mediated by latent variables summarizing the indices. Regularized MIMIC, used due to the limited sample size, selected relevant mTBFA by means of an elastic net penalty and achieved good fits to the data. Two latent variables were necessary to describe the indices: Fluid intelligence (Perceptual Organization and Processing Speed indices) and Crystallized Intelligence (Verbal Comprehension and Working Memory indices). Regularized MIMIC revealed effects of the forceps minor tract on crystallized intelligence and of the superior longitudinal fasciculus on fluid intelligence. The model also detected the significant effect of age on both latent variables.

Anatomical connections underlying personally-familiar face processing.

Familiar face processing involves face specific regions (the core face system) as well as other non-specific areas related to processing of person-related information (the extended face system). The connections between core and extended face system areas must be critical for face recognition. Some studies have explored the connectivity pattern of unfamiliar face responding area, but none have explored those areas related to face familiarity processing in the extended system. To study these connections, diffusion weighted imaging with probabilistic tractography was used to estimate the white-matter pathways between core and extended system regions, which were defined from functional magnetic resonance imaging responses to personally-familiar faces. Strong white matter connections were found between occipitotemporal face areas (OFA/FFA) with superior temporal sulcus and insula suggesting the possible existence of direct anatomical connections from face-specific areas to frontal nodes that could underlay the processing of emotional information associated to familiar faces.

Inferior fronto-temporo-occipital connectivity: a missing link between maltreated girls and neglectful mothers.

The neurobiological alterations resulting from adverse childhood experiences that subsequently may lead to neglectful mothering are poorly understood. Maternal neglect of an infant's basic needs is the most prevalent type of child maltreatment. We tested white matter alterations in neglectful mothers, the majority of whom had also suffered maltreatment in their childhood, and compared them to a matched control group. The two groups were discriminated by a structural brain connectivity pattern comprising inferior fronto-temporo-occipital connectivity, which constitutes a major portion of the face-processing network and was indexed by fewer streamlines in neglectful mothers. Mediation and regression analyses showed that fewer streamlines in the right inferior longitudinal fasciculus tract (ILF-R) predicted a poorer quality of mother-child emotional availability observed during cooperative play and that effect depended on the respective interactions with left and right inferior fronto-occipital fasciculi (IFO-R/L), with no significant impact of psychopathological and cognitive conditions. Volume alteration in ILF-R but not in IFO-L modulated the impact of having been maltreated on emotional availability. The findings suggest the altered inferior fronto-temporal-occipital connectivity, affecting emotional visual processing, as a possible common neurological substrate linking a history of childhood maltreatment with maternal neglect.

Testing the connections within face processing circuitry in Capgras delusion with diffusion imaging tractography.

Although Capgras delusion (CD) patients are capable of recognizing familiar faces, they present a delusional belief that some relatives have been replaced by impostors. CD has been explained as a selective disruption of a pathway processing affective values of familiar faces. To test the integrity of connections within face processing circuitry, diffusion tensor imaging was performed in a CD patient and 10 age-matched controls. Voxel-based morphometry indicated gray matter damage in right frontal areas. Tractography was used to examine two important tracts of the face processing circuitry: the inferior fronto-occipital fasciculus (IFOF) and the inferior longitudinal (ILF). The superior longitudinal fasciculus (SLF) and commissural tracts were also assessed. CD patient did not differ from controls in the commissural fibers, or the SLF. Right and left ILF, and right IFOF were also equivalent to those of controls. However, the left IFOF was significantly reduced respect to controls, also showing a significant dissociation with the ILF, which represents a selective impairment in the fiber-tract connecting occipital and frontal areas. This suggests a possible involvement of the IFOF in affective processing of faces in typical observers and in covert recognition in some cases with prosopagnosia.