title: Intelligence-related differences in the asymmetry of spontaneous cerebral activity.
abstract: Recent evidence suggests the spontaneous BOLD signal synchronization of corresponding interhemispheric, homotopic regions as a stable trait of human brain physiology, with emerging differences in such organization being also related to some pathological conditions. To understand whether such brain functional symmetries play a role into higher-order cognitive functioning, here we correlated the functional homotopy profiles of 119 healthy subjects with their intelligence level. Counterintuitively, reduced homotopic connectivity in above average-IQ versus average-IQ subjects was observed, with significant reductions in visual and somatosensory cortices, supplementary motor area, rolandic operculum, and middle temporal gyrus, possibly suggesting that a downgrading of interhemispheric talk at rest could be associated with higher cognitive functioning. These regions also showed an increased spontaneous synchrony with medial structures located in ipsi- and contralateral hemispheres, with such pattern being mostly detectable for regions placed in the left hemisphere. The interactions with age and gender have been also tested, with different patterns for subjects above and below 25 years old and less homotopic connectivity in the prefrontal cortex and posterior midline regions in female participants with higher IQ scores. These findings support prior evidence suggesting a functional role for homotopic connectivity in human cognitive expression, promoting the reduction of synchrony between primary sensory regions as a predictor of higher intelligence levels.
authors.affiliation: Siena-Brain Investigation & Neuromodulation Lab (SiBin), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy.|Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA, USA.|Siena Robotics and Systems Lab (SIRS-Lab), Engineering and Mathematics Department, University of Siena, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Santarnecchi
authors.affiliation: Siena-Brain Investigation & Neuromodulation Lab (SiBin), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Tatti
authors.affiliation: Siena-Brain Investigation & Neuromodulation Lab (SiBin), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Rossi
authors.affiliation: Siena-Brain Investigation & Neuromodulation Lab (SiBin), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy.
authors.forename: Vinicio
authors.initials: V
authors.lastname: Serino
authors.affiliation: Siena-Brain Investigation & Neuromodulation Lab (SiBin), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rossi
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D001921:Brain / Q000254:growth & development / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000254:growth & development / Q000502:physiology; D010100:Oxygen / Q000097:blood; D012146:Rest; D012727:Sex Characteristics; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: brain asymmetry; connectivity; homotopy; individual differences; intelligence; resting state