کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6271977 1614776 2015 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Descending and tonotopic projection patterns from the auditory cortex to the inferior colliculus
ترجمه فارسی عنوان
الگوهای پیش بینی نزولی و تنتاپیک از قشر شنوایی تا کمر به پایین
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب (عمومی)
چکیده انگلیسی


- Corticofugal projections were identified from both A1 and VRB to the ICC.
- Fibers from VRB were fewer and less tonotopically organized than those from A1.
- A1 corticofugal fibers were distributed across the isofrequency laminae of ICC.
- VRB corticofugal fibers were more prevalent in caudal-medial ICC regions.

The inferior colliculus (IC) receives many corticofugal projections, which can mediate plastic changes such as shifts in frequency tuning or excitability of IC neurons. While the densest projections are found in the IC's external cortices, fibers originating from the primary auditory cortex (AI) have been observed throughout the IC's central nucleus (ICC), and these projections have shown to be organized tonotopically. Some studies have also found projections from other core and non-core cortical regions, though the organization and function of these projections are less known. In guinea pig, there exists a non-core ventrorostral belt (VRB) region that has primary-like properties and has often been mistaken for AI, with the clearest differentiating characteristic being VRB's longer response latencies. To better understand the auditory corticofugal descending system beyond AI, we investigated if there are projections from VRB to the ICC and if they exhibit a different projection pattern than those from AI. In this study, we performed experiments in ketamine-anesthetized guinea pigs, in which we positioned 32-site electrode arrays within AI, VRB, and ICC. We identified the monosynaptic connections between AI-to-ICC and VRB-to-ICC using an antidromic stimulation method, and we analyzed their locations across the midbrain using three-dimensional histological techniques. Compared to the corticocollicular projections to the ICC from AI, there were fewer projections to the ICC from VRB, and these projections had a weaker tonotopic organization. The majority of VRB projections were observed in the caudal-medial versus the rostral-lateral region along an isofrequency lamina of the ICC, which is in contrast to the AI projections that were scattered throughout an ICC lamina. These findings suggest that the VRB directly modulates sound information within the ascending lemniscal pathway with a different or complementary role compared to the modulatory effects of AI, which may have implications for treating hearing disorders.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Neuroscience - Volume 300, 6 August 2015, Pages 325-337
نویسندگان
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