Finally as to the question of
Finally, as to the question of when infants acquire native phonological processes and hence show context-sensitive perceptual attunement, the scenario sketched above relies on word segmentation and sensitivity to the clustering of assimilated and non-assimilated word forms within short stretches of speech. Word segmentation abilities emerge between 6 and 12 months of age (for a review, see Nazzi et al. (2013); we therefore cannot exclude that the acquisition of native phonetic categories and of phonological processes proceed simultaneously, such that context-dependent perceptual attunement evidenced here arises at the same age as ‘standard’ perceptual attunement, i.e. before the end of the first year of life. Alternatively, the acquisition of phonological processes might lag behind the acquisition of native phonetic categories. We deem this to be more likely, as it takes time not only to fully develop word segmentation abilities but also to gather enough data on clustered tokens of assimilated and non-assimilated word forms. We therefore predict that 12-month-old French-learning infants behave differently from the 14-month-old ones that we tested, and discriminate native voicing contrasts regardless of the context in which they appear.
Acknowledgements This study was funded by grants from the Agence Nationale de la Recherche (ANR-13-APPR-0012; ANR-10-LABX-0087 IEC; ANR-10-IDEX-0001-02 PSL*) and the Fondation de France. We thank Ghislaine Deheane-Lambertz for comments on analyses and previous versions of this manuscript. We are grateful to the parents and infants who participated in this study, as well as to Anne-Caroline Fievet and Luce Legros for their help in recruiting and testing participants and Michel Dutat for technical support.
Introduction When psychoactive drugs are used during development, there are concerns for interference with order GSK461364 function and development (Oberlander et al., 2009; Shrestha et al., 2014). The selective serotonin reuptake inhibitor (SSRI) fluoxetine was approved by FDA in 2003 for treating major depression (MDD) and obsessive-compulsive disorder (OCD) in children, and continues to maintain a favorable profile for efficacy and safety for these disorders (Hetrick et al., 2007; Henry et al., 2012; Cipriani et al., 2016). Additionally, use has extended to therapy for anxiety disorders, autism, attention deficit hyperactivity disorder (ADHD), and conduct disorders (Strawn et al., 2015; Riggs et al., 2007; Quintana et al., 2007; Williams et al., 2013; Hollander et al., 2005). Due to ethical and practical considerations, there are no human studies of long term effects of childhood fluoxetine use on brain development. The rodent literature with fluoxetine administration at a corresponding lifestage is very limited (Olivier et al., 2011). Using a nonhuman primate model, the rhesus monkey, Shrestha et al. (2014) found that fluoxetine dosing during juvenile brain development, a lifestage parallel to childhood in humans, led to long-term effects on brain serotonin systems when assessed in adulthood. Specifically, serotonin transporter, the primary therapeutic target of SSRIs, was increased in hippocampus and neocortex. In addition, some long-term effects on social behavior were reported. These findings point to the value of a more extensive evaluation of long-term effects of juvenile fluoxetine on brain function in the nonhuman primate model. Several characteristics of nonhuman primates contribute to study designs and outcome measures with translational potential. Nonhuman primates have prolonged cognitive development similar to humans (Goldman-Rakic, 1987; Bachevalier and Vargha-Khadem, 2005; Alvarado et al., 2016; Blue et al., 2013; Zeamer et al., 2010), and also have many genetic polymorphisms parallel to those seen in humans (Miller and Madras, 2005). In addition, the complex life histories of nonhuman primates are subject to gene*environment interactions relevant to brain function that are encountered in humans (Kinnally et al., 2009, 2010; Duncan et al., 2014).