title: Frequency-dependent enhancement of fluid intelligence induced by transcranial oscillatory potentials.
abstract: Everyday problem solving requires the ability to go beyond experience by efficiently encoding and manipulating new information, i.e., fluid intelligence (Gf) [1]. Performance in tasks involving Gf, such as logical and abstract reasoning, has been shown to rely on distributed neural networks, with a crucial role played by prefrontal regions [2]. Synchronization of neuronal activity in the gamma band is a ubiquitous phenomenon within the brain; however, no evidence of its causal involvement in cognition exists to date [3]. Here, we show an enhancement of Gf ability in a cognitive task induced by exogenous rhythmic stimulation within the gamma band. Imperceptible alternating current [4] delivered through the scalp over the left middle frontal gyrus resulted in a frequency-specific shortening of the time required to find the correct solution in a visuospatial abstract reasoning task classically employed to measure Gf abilities (i.e., Raven's matrices) [5]. Crucially, gamma-band stimulation (γ-tACS) selectively enhanced performance only on more complex trials involving conditional/logical reasoning. The present finding supports a direct involvement of gamma oscillatory activity in the mechanisms underlying higher-order human cognition.
authors.affiliation: Department of Medicine, Surgery and Neuroscience, University of Siena, 53100 Siena, Italy. emilianosantarnecchi@gmail.com
authors.forename: Emiliano
authors.initials: E
authors.lastname: Santarnecchi
authors.forename: Nicola Riccardo
authors.initials: NR
authors.lastname: Polizzotto
authors.forename: Marco
authors.initials: M
authors.lastname: Godone
authors.forename: Fabio
authors.initials: F
authors.lastname: Giovannelli
authors.forename: Matteo
authors.initials: M
authors.lastname: Feurra
authors.forename: Laura
authors.initials: L
authors.lastname: Matzen
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rossi
authors.forename: Simone
authors.initials: S
authors.lastname: Rossi
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D003071:Cognition / Q000502:physiology; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D008297:Male; D009483:Neuropsychological Tests; D033281:Nontherapeutic Human Experimentation; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D055815:Young Adult