Fig. 4

The ascending auditory processing pathway with presumed changes in autism based on results from studies in rodent models. Excitatory (red) and inhibitory (blue) connections between structures along the pathway are illustrated along with the changes to these connections and the activity within areas in rodent models of autism. Connections are primarily ipsilateral unless otherwise stated. There is increased activity in structures such as the lateral superior olive (LSO), the medial geniculate nucleus of the thalamus (MGN), thalamic reticular nucleus (TRN), the auditory cortex (specifically in layers 2/3), and the prefrontal cortex. Activity is consistently decreased in the dorsal and ventral lateral lemniscus (DNLL and VNLL) and the anterior auditory field (AAF) of the rat auditory cortex. Activity in other areas is either unchanged or results are conflicted. The connection from the ventral cochlear nucleus (VCN) to the LSO is increased in strength, while the strength of the connection from the anterior VCN (AVCN) to the medial nucleus of the trapezoid body (MNTB) is decreased. Signals from the VCN take longer to reach the SPON and from the MGN take longer to reach the auditory cortex in rodent models of autism. The speed of other connections is either unchanged or disputed between studies. The strength of connections between contralateral auditory cortices and between the auditory and prefrontal cortex is decreased, as is the feedback connection from the prefrontal cortex to the TRN