title: Connectional Modularity of Top-Down and Bottom-Up Multimodal Inputs to the Lateral Cortex of the Mouse Inferior Colliculus.
abstract: The lateral cortex of the inferior colliculus receives information from both auditory and somatosensory structures and is thought to play a role in multisensory integration. Previous studies in the rat have shown that this nucleus contains a series of distinct anatomical modules that stain for GAD-67 as well as other neurochemical markers. In the present study, we sought to better characterize these modules in the mouse inferior colliculus and determine whether the connectivity of other neural structures with the lateral cortex is spatially related to the distribution of these neurochemical modules. Staining for GAD-67 and other markers revealed a single modular network throughout the rostrocaudal extent of the mouse lateral cortex. Somatosensory inputs from the somatosensory cortex and dorsal column nuclei were found to terminate almost exclusively within these modular zones. However, projections from the auditory cortex and central nucleus of the inferior colliculus formed patches that interdigitate with the GAD-67-positive modules. These results suggest that the lateral cortex of the mouse inferior colliculus exhibits connectional as well as neurochemical modularity and may contain multiple segregated processing streams. This finding is discussed in the context of other brain structures in which neuroanatomical and connectional modularity have functional consequences.
  
  
  
  Many brain regions contain subnuclear microarchitectures, such as the matrix-striosome organization of the basal ganglia or the patch-interpatch organization of the visual cortex, that shed light on circuit complexities. In the present study, we demonstrate the presence of one such micro-organization in the rodent inferior colliculus. While this structure is typically viewed as an auditory integration center, its lateral cortex appears to be involved in multisensory operations and receives input from somatosensory brain regions. We show here that the lateral cortex can be further subdivided into multiple processing streams: modular regions, which are targeted by somatosensory inputs, and extramodular zones that receive auditory information.
authors: Neuroscience Program.|Beckman Institute.
authors: Alexandria M H
authors: 0000-0003-4766-2258
authors: AM
authors: Lesicko
authors: Beckman Institute.|College of Veterinary Medicine, and.
authors: Teodora S
authors: 0000-0002-6070-7783
authors: TS
authors: Hristova
authors: Beckman Institute.
authors: Kathleen C
authors: 0000-0001-8972-1178
authors: KC
authors: Maigler
authors: Neuroscience Program, d-llano@illinois.edu.|Beckman Institute.|Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801.
authors: Daniel A
authors: 0000-0003-0933-1837
authors: DA
authors: Llano
mesh_terms: D000818:Animals; D001303:Auditory Cortex / Q000166:cytology*; D063132:Connectome / Q000379:methods*; D005260:Female; D007245:Inferior Colliculi / Q000166:cytology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009415:Nerve Net / Q000737:chemistry*; D009434:Neural Pathways / Q000166:cytology*; D013003:Somatosensory Cortex / Q000166:cytology*
keywords: GAD; auditory; midbrain; module; multisensory; tract tracing