Cortical Activation in Mental Rotation and the Role of the Corpus Callosum: Observations in Healthy Subjects and Split-Brain Patients

none6The mental rotation (MR) is an abstract mental operation thanks to which a person imagines rotating an object or a body part to place it in an other position. The ability to perform MR was belived to belong to the right hemisphere for objects, and to the left for one’s ownbody images. Mental rotation is considered to be basic for imitation with the anatomical perspective, which in turn is needed for social interactions and learning. Altered imitative performances have been reported in patients with resections or microstructure alterations of the corpus callosum (CC). These patients also display a reduced MR ability compared to control subjects, as shown in a recent behavioral study. The difference was statistically significant, leading us to hypothesize a role of the CC to integrate the two hemispheres’ asymmetric functions. The present study was designed to detect, by means of a functional MRI, the cortical activation evoked during an MR task in healthy control subjects and callosotomized patients. The results suggest that performing MR requires activation of opercular cortex and inferior parietal lobule in either hemispheres, and likely the integrity of the CC, thus confirming that the main brain commissure is involved in cognitive functions.openPierpaoli, Chiara; Ghoushi, Mojgan; Foschi, Nicoletta; Lattanzi, Simona; Fabri, Mara; Polonara, GabrielePierpaoli, Chiara; Ghoushi, Mojgan; Foschi, Nicoletta; Lattanzi, Simona; Fabri, Mara; Polonara, Gabriel

White Matter and Cognition in Adults Who Were Born Preterm

BACKGROUND AND PURPOSE: Individuals born very preterm (before 33 weeks of gestation, VPT) are at risk of damage to developing white matter, which may affect later cognition and behaviour. METHODS: We used diffusion tensor MRI (DT-MRI) to assess white matter microstructure (fractional anisotropy; FA) in 80 VPT and 41 term-born individuals (mean age 19.1 years, range 17-22, and 18.5 years, range 17-22 years, respectively). VPT individuals were part of a 1982-1984 birth cohort which had been followed up since birth; term individuals were recruited by local press advertisement. General intellectual function, executive function and memory were assessed. RESULTS: The VPT group had reduced FA in four clusters, and increased FA in four clusters relative to the Term group, involving several association tracts of both hemispheres. Clusters of increased FA were associated with more severe neonatal brain injury in the VPT group. Clusters of reduced FA were associated with lower birth weight and perinatal hypoxia, and with reduced adult cognitive performance in the VPT group only. CONCLUSIONS: Alterations of white matter microstructure persist into adulthood in VPT individuals and are associated with cognitive function

Is the Imitative Competence an Asymmetrically Distributed Function?

This study reconsiders behavioral and functional data from studies investigating the anatomical imitation (AI) and the related mental rotation (MR) competence, carried out by our group in healthy subjects, with intact interhemispheric connections, and in split-brain patients, completely or partially lacking callosal connections. The results strongly point to the conclusion that AI and MR competence requires interhemispheric communication, mainly occurring through the corpus callosum, which is the largest white matter structure in the human brain. The results are discussed in light of previous studies and of future implications

Functional topography of the corpus callosum investigated by DTI and fMRI

This short review examines the most recent functional studies of the topographic organization of the human corpus callosum, the main interhemispheric commissure. After a brief description of its anatomy, development, microstructure, and function, it examines and discusses the latest findings obtained using diffusion tensor imaging (DTI) and tractography (DTT) and functional magnetic resonance imaging (fMRI), three recently developed imaging techniques that have significantly expanded and refined our knowledge of the commissure. While DTI and DTT have been providing insights into its microstructure, integrity and level of myelination, fMRI has been the key technique in documenting the activation of white matter fibers, particularly in the corpus callosum. By combining DTT and fMRI it has been possible to describe the trajectory of the callosal fibers interconnecting the primary olfactory, gustatory, motor, somatic sensory, auditory and visual cortices at sites where the activation elicited by peripheral stimulation was detected by fMRI. These studies have demonstrated the presence of callosal fiber tracts that cross the commissure at the level of the genu, body, and splenium, at sites showing fMRI activation. Altogether such findings lend further support to the notion that the corpus callosum displays a functional topographic organization that can be explored with fMRI

Non-Destructive Testing for the In Situ Assessment of the Ionic Flux in Cementitious Materials

The study deals with the design, calibration and testing of a diffusive sampling probe for in situ assessment of ion mobility in binder-based matrix. In parallel, leaching texts were conducted to compare the ions release obtained under equilibrium condition with the dynamic flux induced by the diffusive sampling probe. The probe contains an ionic exchange resin that acts as sink, causing a re-supply of ions from the solid to the solution phase, and inducing diffusion fluxes from the mortar through a thin diffusion chamber. The flux depends on the quantity of mobile ions in the solid phase and on the exchanging rate from solid phase to solution. By means of the in situ sampling with this diffusive probe, information about the interaction of materials with the environment can be obtained. This information is very useful for the environmental impact assessment of the material and its durability

Non-destructive testing for the in situ assessment of the ionic flux in cementitious materials

none4noTittarelli, Francesca; Pierpaoli, Mattia; Giosuè, Chiara; Letizia Ruello, MariaTittarelli, Francesca; Pierpaoli, Mattia; Giosue', Chiara; Ruello, Maria Letizi

Appraisal of a Multitasking Air Cleaner Process Based on Multiple Combined Techniques

Nowadays there is an amplified interest in maintaining suitable Indoor Air Quality (IAQ). Besides a wide range of available interventions, air cleaners are considered a valuable tool since based on inexpensive and easily implementing technologies to improve IAQ. The purpose of this work is to combine the TiO2-photocatalysis with the electrostatic and adsorptive processes, in order to improve efficiency and selectivity. A TiO2-photocatalytic oxidation combined with an electrostatic filter has been studied. Nitrogen oxide reduction and degradation of many Volatile Organic Compounds over different catalyst support were monitored jointly with CO and CO2 production. The choice of materials with diversified adsorptive characteristics plays an important role in the observed efficiency and selectivity