The inferior colliculus of the rat: Quantitative immunocytochemical study of GABA and glycine

Merchán, Miguel Á.; Aguilar, Luís Fuentes; Lopez‐Poveda, Enrique A.; Malmierca, Manuel S.

doi:10.1016/j.neuroscience.2004.12.030

Cited by 120 publications

(112 citation statements)

References 90 publications

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…We found a definite difference in the sensitivity of GABAergic and glycinergic transmission to exogenous and endogenous serotonin. Although the underlying mechanisms for differential sensitivity to serotonergic modulation remain unknown, we speculate that the number of serotonin receptors expressed on GABAergic neurons is much more than on glycinergic neurons (6). The difference in the density of serotonergic innervation may have also contributed to our findings.…”

mentioning

confidence: 76%

Serotonergic modulation of inhibitory synaptic transmission in mouse inferiorcolliculus

2014

View full text Add to dashboard Cite

The inferior colliculus (IC) transmits the ascending auditory signal to the thalamic medial geniculate nucleus. Previous studies have reported that serotonergic input originating from the raphe nuclei has a strong influence on signal processing within the central nucleus of the IC. To identify the cellular target for the serotonergic modulation in the IC, we examined the effect of serotonin as well as selective serotonin reuptake inhibitor (SSRI) fluvoxamine on spontaneous GABAergic and glycinergic inhibitory postsynaptic currents (sIPSCs) recorded with whole-cell recordings. Consistent with earlier studies, we confirmed that serotonin robustly enhanced the frequency, but not amplitude, of GABAergic sIPSCs. It should be noted that the application of fluvoxamine alone marginally increased the frequency of GABAergic sIPSCs. These findings suggest that serotonin is endogenously released even in slice preparations, and it negatively modulates the tone of activity of inhibitory neurons within IC. We also examined the effect of serotonin and fluvoxamine on glycinergic sIPSCs and found that serotonin has a significantly weaker effect on glycinergic sIPSCs than on GABAergic sIPSCs. The differential sensitivity of the GABAergic and glycinergic sIPSCs to serotonin implies that serotonergic input plays a specific role in auditory information processing. Moreover, it suggests that the serotonergic input may contribute to pathological conditions such as tinnitus.Auditory pathways ascending through the brainstem play important roles in processing complex auditory information. Recent studies have suggested that the inferior colliculus (IC), a key relay nucleus in the midbrain, receives large number of serotonergic innervations originating in the raphe nuclei (4). This suggests that serotonin is crucial for the modulation of auditory information processing in the ascending auditory pathway through the brainstem. Current research suggests that the application of serotonin in slice preparations robustly enhances the frequency of GABAergic spontaneous IPSCs (sIPSC) recorded in the central nucleus of IC neurons (8). This implies that serotonin causes excitation of the inhibitory interneurons by increasing firing of GABAergic neurons. It is well known that both glycinergic inhibitory interneurons and GABAergic neurons are found in the IC (1). In this study, we aimed to compare the effect of serotonin on GABAergic and glycinergic inhibitory transmission in the IC. In addition, we elucidated the effect of endogenously released serotonin on inhibitory transmission by examining the effect of serotonin-selective reuptake inhibitor (SSRI), fluvoxamine, on spontaneous GABAergic and glycinergic inhibitory postsynaptic currents (sIPSCs) measured using whole-cell recordings. All experiments were performed according to the guidelines for the care and use of laboratory animals of Hokkaido University. C57BL/6J mice (8-35 days

show abstract

mentioning

confidence: 76%

Serotonergic modulation of inhibitory synaptic transmission in mouse inferiorcolliculus

2014

View full text Add to dashboard Cite

show abstract

“…However, one general trend we observed was that stimulation of most surface regions required high current levels for activation (unpublished observation). This is consistent with the high current levels (i.e., ∼20-80 nC vs. stimulation within the ICC of 6-25 nC for AMI-3 shown in Figure 13) required to reach threshold and comfortable levels in the one patient who was stimulated on the surface of the IC (Colletti et al, 2007) and the ability to shut off ICC neurons, thus the ascending sound pathway, through electrical stimulation of the outer IC regions (Jen, Sun, & Chen, 2001;Jen, Zhou, Zhang, Chen, & Sun, 2002) because of complex inhibitory interactions (Kelly & Caspary, 2005;Merchan, Aguilar, Lopez-Poveda, & Malmierca, 2005). This may also explain why a previous attempt at stimulating the surface of the IC resulted in no auditory sensations (Simmons et al, 1964).…”

Section: Placement Of the Arraymentioning

confidence: 99%

Auditory Midbrain Implant: A Review

Lim

Lenarz

2009

Trends in Amplification

View full text Add to dashboard Cite

The auditory midbrain implant (AMI) is a new hearing prosthesis designed for stimulation of the inferior colliculus in deaf patients who cannot sufficiently benefit from cochlear implants. The authors have begun clinical trials in which five patients have been implanted with a single shank AMI array (20 electrodes). The goal of this review is to summarize the development and research that has led to the translation of the AMI from a concept into the first patients. This study presents the rationale and design concept for the AMI as well a summary of the animal safety and feasibility studies that were required for clinical approval. The authors also present the initial surgical, psychophysical, and speech results from the first three implanted patients. Overall, the results have been encouraging in terms of the safety and functionality of the implant. All patients obtain improvements in hearing capabilities on a daily basis. However, performance varies dramatically across patients depending on the implant location within the midbrain with the best performer still not able to achieve open set speech perception without lip-reading cues. Stimulation of the auditory midbrain provides a wide range of level, spectral, and temporal cues, all of which are important for speech understanding, but they do not appear to sufficiently fuse together to enable open set speech perception with the currently used stimulation strategies. Finally, several issues and hypotheses for why current patients obtain limited speech perception along with several feasible solutions for improving AMI implementation are presented.

show abstract

“…Prominent sources of GABAergic input to the IC include the dorsal nucleus of the lateral lemniscus (DNLL), commissural and intrinsic input, whereas both GABAergic and glycinergic inputs are derived from lower levels of the auditory system, including the superior olivary complex (Saldana et al 2009) and intermediate (INLL) and ventral (VNLL) nuclei of the lateral lemniscus (Fubara et al 1996;Merchan et al 2005;Pollak and Park 1995;Winer et al 1995). This divergent array of inhibitory input provides the framework for a complex network of sound processing within the IC.…”

mentioning

confidence: 99%

Differential roles of GABAergic and glycinergic input on FM selectivity in the inferior colliculus of the pallid bat

Williams

Fuzessery

2011

Journal of Neurophysiology

View full text Add to dashboard Cite

Williams AJ, Fuzessery ZM. Differential roles of GABAergic and glycinergic input on FM selectivity in the inferior colliculus of the pallid bat. J Neurophysiol 106: 2523-2535. First published July 20, 2011 doi:10.1152/jn.00569.2011.-Multiple mechanisms have been shown to shape frequency-modulated (FM) selectivity within the central nucleus of the inferior colliculus (IC) in the pallid bat. In this study we focus on the mechanisms associated with sideband inhibition. The relative arrival time of inhibition compared with excitation can be used to predict FM responses as measured with a two-tone inhibition paradigm. An early-arriving low-frequency inhibition (LFI) prevents responses to upward sweeps and thus shapes direction selectivity. A late-arriving high-frequency inhibition (HFI) suppresses slow FM sweeps and thus shapes rate selectivity for downward sweeps. Iontophoretic application of gabazine (GBZ) to block GABA A receptors or strychnine (Strych) to block glycine receptors was used to assess the effects of removal of inhibition on each form of FM selectivity. GBZ and Strych had a similar effect on FM direction selectivity, reducing selectivity in up to 86% of neurons when both drugs were coapplied. FM rate selectivity was more resistant to drug application with less than 38% of neurons affected. In addition, only Strych could eliminate FM rate selectivity, whereas GBZ alone was ineffective. The loss of FM selectivity was directly correlated to a loss of the respective inhibitory sideband that shapes that form of selectivity. The elimination of LFI correlated to a loss of FM direction selectivity, whereas elimination of HFI correlated to a loss of FM rate selectivity. Results indicate that 1) although the majority of FM direction selectivity is created within the IC, the majority of rate selectivity is inherited from lower levels of the auditory system, 2) a loss of LFI corresponds to a loss of FM direction selectivity and is created through either GABAergic or glycinergic input, and 3) a loss of HFI corresponds to a loss of FM rate selectivity and is created mainly through glycinergic input.

show abstract

The inferior colliculus of the rat: Quantitative immunocytochemical study of GABA and glycine

Cited by 120 publications

References 90 publications

Serotonergic modulation of inhibitory synaptic transmission in mouse inferiorcolliculus

Serotonergic modulation of inhibitory synaptic transmission in mouse inferiorcolliculus

Auditory Midbrain Implant: A Review

Differential roles of GABAergic and glycinergic input on FM selectivity in the inferior colliculus of the pallid bat

Contact Info

Product

Resources

About