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Liu Y, Li Y, Peng Y, Yu H, Xiao Z. Bilateral Interactions in the Mouse Dorsal Inferior Colliculus Enhance the Ipsilateral Neuronal Responses and Binaural Hearing. Front Physiol 2022; 13:854077. [PMID: 35514328 PMCID: PMC9061965 DOI: 10.3389/fphys.2022.854077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 04/01/2022] [Indexed: 11/13/2022] Open
Abstract
The inferior colliculus (IC) is a critical centre for the binaural processing of auditory information. However, previous studies have mainly focused on the central nucleus of the inferior colliculus (ICC), and less is known about the dorsal nucleus of the inferior colliculus (ICD). Here, we first examined the characteristics of the neuronal responses in the mouse ICD and compared them with those in the inferior colliculus under binaural and monaural conditions using in vivo loose-patch recordings. ICD neurons exhibited stronger responses to ipsilateral sound stimulation and better binaural summation than those of ICC neurons, which indicated a role for the ICD in binaural hearing integration. According to the abundant interactions between bilateral ICDs detected using retrograde virus tracing, we further studied the effect of unilateral ICD silencing on the contralateral ICD. After lidocaine was applied, the responses of some ICD neurons (13/26), especially those to ipsilateral auditory stimuli, decreased. Using whole-cell recording and optogenetic methods, we investigated the underlying neuronal circuits and synaptic mechanisms of binaural auditory information processing in the ICD. The unilateral ICD provides both excitatory and inhibitory projections to the opposite ICD, and the advantaged excitatory inputs may be responsible for the enhanced ipsilateral responses and binaural summation of ICD neurons. Based on these results, the contralateral ICD might modulate the ipsilateral responses of the neurons and binaural hearing.
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Affiliation(s)
| | | | | | | | - Zhongju Xiao
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
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Tomasi SO, Umana GE, Scalia G, Rubio-Rodriguez RL, Raudino G, Rechberger J, Geiger P, Chaurasia B, Yaǧmurlu K, Lawton MT, Winkler PA. Perforating Arteries of the Lemniscal Trigone: A Microsurgical Neuroanatomic Description. Front Neuroanat 2021; 15:675313. [PMID: 34512277 PMCID: PMC8427497 DOI: 10.3389/fnana.2021.675313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 07/16/2021] [Indexed: 11/24/2022] Open
Abstract
Background: The perforating arteries in the dorsolateral zone of the midbrain play a crucial role in the functions of the brain stem. Their damage due to herniation, pathological lesions, or surgery, favored by the narrow tentorial incisura, can lead to hemorrhages or ischemia and subsequently to severe consequences for the patient. Objective: In literature, not much attention has been directed to the perforating arteries in the lemniscus; in fact, no reports on the perforators of this anatomical region are available. The present study aims to a detailed analysis of the microanatomy and the clinical implications of these perforators, in relation to the parent vessels. We focused on the small vessels that penetrate the midbrain's dorsolateral surface, known as lemniscal trigone, to understand better their microanatomy and their functional importance in the clinical practice during the microsurgical approach to this area. Methods: Eighty-seven alcohol-fixed cadaveric hemispheres (44 brains) without any pathological lesions provided the material for studying the perforating vessels and their origin around the dorsolateral midbrain using an operating microscope (OPMI 1 FC, Zeiss). Measurements of the perforators' distances, in relation to the parent vessels, were taken using a digital caliper. Results: An origin from the SCA could be found in 70.11% (61) and from the PCA in 27.58% (24) of the hemispheres. In one hemisphere, an origin from the posterior choroidal artery was found (4.54%). No perforating branches were discovered in 8.04% of specimens (7). Conclusion: The perforating arteries of the lemniscal trigone stem not only from the superior cerebellar artery (SCA), as described in the few studies available in literature, but also from the posterior cerebral artery (PCA). Therefore, special attention should be paid during surgery to spare those vessels and associated perforators. A comprehensive understanding of the lemniscal trigone's perforating arteries is vital to avoid infarction of the brainstem when treating midbrain tumors or vascular malformations.
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Affiliation(s)
- Santino Ottavio Tomasi
- Department of Neurological Surgery - Christian Doppler Klinik, Salzburg, Austria
- Department of Neurosurgery, Paracelsus Medical University Salzburg, Salzburg, Austria
- Laboratory for Microsurgical Neuroanatomy - Christian Doppler Klinik, Salzburg, Austria
| | - Giuseppe Emmanuele Umana
- Department of Neurosurgery, Cannizzaro Hospital, Trauma Center, Gamma Knife Center, Catania, Italy
| | - Gianluca Scalia
- Neurosurgery Unit, Highly Specialized Hospital and of National Importance “Garibaldi”, Catania, Italy
| | - Roberto Luis Rubio-Rodriguez
- Skull Base and Cerebrovascular Laboratory, University of California, San Francisco, San Francisco, CA, United States
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, United States
- Department of Otolaryngology - Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Giuseppe Raudino
- Department of Neurosurgery - Humanitas, Istituto Clinico Catanese, Catania, Italy
| | - Julian Rechberger
- Department of Neurosurgery, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Philipp Geiger
- Department of Neurosurgery, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Bipin Chaurasia
- Department of Neurosurgery, Neurosurgery Clinic, Birgunj, Nepal
| | - Kaan Yaǧmurlu
- Department of Neurosurgery, University of Virginia, Charlottesville, VA, United States
| | - Michael T. Lawton
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, United States
| | - Peter A. Winkler
- Department of Neurological Surgery - Christian Doppler Klinik, Salzburg, Austria
- Department of Neurosurgery, Paracelsus Medical University Salzburg, Salzburg, Austria
- Laboratory for Microsurgical Neuroanatomy - Christian Doppler Klinik, Salzburg, Austria
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Cheng L, Mei HX, Huang Y. Inter-collicular suppression compresses all types of rate-amplitude functions of inferior collicular neurons in mice. Physiol Res 2016; 65:527-36. [PMID: 27070749 DOI: 10.33549/physiolres.933182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The two inferior colliculi (IC) are paired structures in the midbrain that are connected to each other by a bundle of commissural fibers. The fibers play an important role in coordinating sound signal processing between the two inferior colliculi. This study examined inter-collicular suppression on sound signal processing in amplitude domain of mice by measuring the rate-amplitude functions (RAFs) of neurons in one IC during the electrical stimulation of the opposite IC. Three types (monotonic, saturated and non-monotonic) RAFs of collicular neurons were measured before and during inter-collicular suppression. Inter-collicular suppression significantly increased the slope, decreased the dynamic range and narrowed down the responsive amplitude of all RAFs to high amplitude level but did not change the type of most (36/43, 84 %) RAFs. As a result, all types of RAFs were compressed at a greater degree at low than at high sound amplitude during inter-collicular suppression. These data indicate that inter-collicular suppression improve sound processing in the high amplitude domain.
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Affiliation(s)
- L Cheng
- School of Psychology, Central China Normal University, Wuhan, China.
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Plastic Change in the Auditory Minimum Threshold Induced by Intercollicular Effects in Mice. Neural Plast 2016; 2016:4195391. [PMID: 27057363 PMCID: PMC4739261 DOI: 10.1155/2016/4195391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 11/09/2015] [Accepted: 11/19/2015] [Indexed: 11/17/2022] Open
Abstract
In the auditory pathway, the commissure of the inferior colliculus (IC) interconnects the two ICs on both sides of the dorsal midbrain. This interconnection could mediate an interaction between the two ICs during sound signal processing. The intercollicular effects evoked by focal electric stimulation for 30 min could inhibit or facilitate auditory responses and induce plastic changes in the response minimum threshold (MT) of IC neurons. Changes in MT are dependent on the best frequency (BF) and MT difference. The MT shift is larger in IC neurons with BF differences ≤2 kHz than in those with BF differences >2 kHz. Moreover, MTs that shift toward electrically stimulated IC neurons increase with the increasing MT difference between the two ICs. The shift in MT lasts for a certain period of time and then returns to previous levels within ~150 min. The collicular interactions are either reciprocal or unilateral under alternate stimulating and recording conditions in both ICs. Our results suggest that intercollicular effects may be involved in the acoustic experience-dependent plasticity of the MT of IC neurons.
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