title: Sex-Specific Automatic Responses to Infant Cries: TMS Reveals Greater Excitability in Females than Males in Motor Evoked Potentials.
abstract: Neuroimaging reveals that infant cries activate parts of the premotor cortical system. To validate this effect in a more direct way, we used event-related transcranial magnetic stimulation (TMS). Here, we investigated the presence and the time course of modulation of motor cortex excitability in young adults who listened to infant cries. Specifically, we recorded motor evoked potentials (MEPs) from the biceps brachii (BB) and interosseus dorsalis primus (ID1) muscles as produced by TMS delivered from 0 to 250 ms after sound onset in six steps of 50 ms in 10 females and 10 males. We observed an excitatory modulation of MEPs at 100 ms from the onset of infant cry specific to females and to the ID1 muscle. We regard this modulation as a response to natural cry sounds because it was attenuated to stimuli increasingly different from natural cry and absent in a separate group of females who listened to non-cry stimuli physically matched to natural infant cries. Furthermore, the 100-ms latency of this response is not compatible with a voluntary reaction to the stimulus but suggests an automatic, bottom-up audiomotor association. The brains of adult females appear to be tuned to respond to infant cries with automatic motor excitation.
authors.affiliation: Department of Philosophy, Sociology, Education and Applied Psychology, University of Padua Padua, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Messina
authors.affiliation: Center for Mind/Brain Sciences, University of Trento Trento, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Cattaneo
authors.affiliation: Department of Psychology and Cognitive Sciences, University of Trento Trento, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Venuti
authors.affiliation: Department of Psychology and Cognitive Sciences, University of Trento Trento, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: de Pisapia
authors.affiliation: Department of Psychology and Cognitive Sciences, University of Trento Trento, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Serra
authors.affiliation: Department of Psychology and Cognitive Sciences, University of TrentoTrento, Italy; Division of Psychology, School of Humanities and Social Sciences, Nanyang Technological UniversitySingapore, Singapore.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Esposito
authors.affiliation: Department of Psychology and Cognitive Sciences, University of Trento Trento, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Rigo
authors.affiliation: Department of Education, Free University of Bolzano Bolzano, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Farneti
authors.affiliation: Child and Family Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development Bethesda, MD, USA.
authors.forename: Marc H
authors.initials: MH
authors.lastname: Bornstein
keywords: MEPS; TMS; baby cries; parenting; sex differences