, 2011). Evidence also indicates dysfunctional resting-state oscillations in adult subjects with ASDs. Murias et al. (2007) examined resting-state EEG data in 20 subjects

with ASDs and found increased theta activity in the left hemisphere and reduced long-range coherence in the low alpha band (8–10 Hz). Similar evidence for a shift toward increased local connectivity has been observed in the delta band by Barttfeld and colleagues (2011), suggesting a dysbalance between local and global processing. This is consistent with pathophysiological theories that postulate increased connectivity CT99021 mouse in local and reduced connectivity in long-range circuits (Geschwind and Levitt, 2007). Further evidence for abnormal gamma-band activity comes from studies in first-degree relatives of children with ASDs. Similar to the findings in children with ASDs, both the power and phase locking of gamma-band oscillations to selleck kinase inhibitor auditory 40 Hz stimulation are reduced in the left hemisphere in first-degree relatives (Rojas et al., 2011), suggesting that dysfunctions in sensory-driven gamma-band activity may represent an intermediate endophenotype. The pronounced alterations of gamma-band oscillations suggest that changes in the E/I balance of

cortical networks may be a pervasive feature not only in schizophrenia but also in ASDs (Gogolla et al., 2009a; Rubenstein and Merzenich, 2003). Several lines of evidence support this possibility. ASD is associated with a high incidence of epilepsy (Tuchman and Rapin, 2002), altered expression of various GABA-receptor subtypes (Fatemi et al., 2002; Oblak et al., 2010), and dysfunctions in glutamatergic neurotransmission (Choudhury et al., 2012). Studies

with larger samples, however, aminophylline are required to further characterize the nature and extent of these changes. Investigations of risk factors and genes involved in the development of ASDs have revealed changes in PV interneurons. Prenatal exposure to Valproic Acid (VPA), an antiepileptic drug, leads to a 7- to 10-fold increase in relative risk for ASDs (Moore et al., 2000) and mice prenatally treated with VPA show a dramatic reduction of PV interneurons in adulthood in the neocortex (Gogolla et al., 2009b). The reduction of PV interneurons is consistent with a recent study that has examined the effect of prenatal VPA exposure on gamma-band activity in mice (Gandal et al., 2010). VPA-exposed mice demonstrated selective behavioral alterations related to ASDs as well as reduced phase locking of 30–50 Hz oscillations to auditory stimulation. Paralleling the findings from the animal model, children with ASDs showed a similar decrease in phase-locked gamma-band activity in both hemispheres.