Large GABAergic neurons form a distinct subclass within the mouse dorsal cortex of the inferior colliculus with respect to intrinsic properties, synaptic inputs, sound responses, and projections

Geis, Hans-Rüdiger; Borst, Jannie

doi:10.1002/cne.23170

Cited by 37 publications

(44 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this regard, the rodent MGB differs from the MGB of other species, such as the cat, but also from the neighboring lateral geniculate nucleus, both of which have GABAergic interneurons (Arcelli et al, 1996; Winer and Larue, 1996). Synaptic inhibition in the MGB arrives via feedforward GABA projections from the IC (Winer et al, 1996; Peruzzi et al, 1997; Ito et al, 2011; Rudiger et al, 2013; Mellott et al, 2014) or from the reticular nucleus of the thalamus (Rouiller et al, 1985; Bartlett and Smith, 1999; Zhang et al, 2008), which makes precise topographic connections with sensory thalamic nuclei (Lam and Sherman, 2007; Cotillon-Williams et al, 2008). …”

Section: Discussionmentioning

confidence: 99%

Persistent Thalamic Sound Processing Despite Profound Cochlear Denervation

Chambers

Salazar

Polley

2016

Front. Neural Circuits

View full text Add to dashboard Cite

Neurons at higher stages of sensory processing can partially compensate for a sudden drop in peripheral input through a homeostatic plasticity process that increases the gain on weak afferent inputs. Even after a profound unilateral auditory neuropathy where >95% of afferent synapses between auditory nerve fibers and inner hair cells have been eliminated with ouabain, central gain can restore cortical processing and perceptual detection of basic sounds delivered to the denervated ear. In this model of profound auditory neuropathy, auditory cortex (ACtx) processing and perception recover despite the absence of an auditory brainstem response (ABR) or brainstem acoustic reflexes, and only a partial recovery of sound processing at the level of the inferior colliculus (IC), an auditory midbrain nucleus. In this study, we induced a profound cochlear neuropathy with ouabain and asked whether central gain enabled a compensatory plasticity in the auditory thalamus comparable to the full recovery of function previously observed in the ACtx, the partial recovery observed in the IC, or something different entirely. Unilateral ouabain treatment in adult mice effectively eliminated the ABR, yet robust sound-evoked activity persisted in a minority of units recorded from the contralateral medial geniculate body (MGB) of awake mice. Sound driven MGB units could decode moderate and high-intensity sounds with accuracies comparable to sham-treated control mice, but low-intensity classification was near chance. Pure tone receptive fields and synchronization to broadband pulse trains also persisted, albeit with significantly reduced quality and precision, respectively. MGB decoding of temporally modulated pulse trains and speech tokens were both greatly impaired in ouabain-treated mice. Taken together, the absence of an ABR belied a persistent auditory processing at the level of the MGB that was likely enabled through increased central gain. Compensatory plasticity at the level of the auditory thalamus was less robust overall than previous observations in cortex or midbrain. Hierarchical differences in compensatory plasticity following sensorineural hearing loss may reflect differences in GABA circuit organization within the MGB, as compared to the ACtx or IC.

show abstract

Section: Discussionmentioning

confidence: 99%

Persistent Thalamic Sound Processing Despite Profound Cochlear Denervation

Chambers

Salazar

Polley

2016

Front. Neural Circuits

View full text Add to dashboard Cite

show abstract

“…The LG neuron may be a similar detector of coincident activation. Since LG cells have the lowest input resistance among IC cell types and appear to have the best temporal precision of neurons in the IC (Geis and Borst, 2013), the activity of many excitatory axosomatic terminals on LG neurons may be ideal for the generation of a short-latency, well-time response.…”

Section: Discussionmentioning

confidence: 99%

“…In the IC, large GABAergic (LG) neurons are tectothalamic neurons with dense axosomatic excitatory inputs from presynaptic terminals that contain the vesicular glutamate transporter 2 (VGLUT2) (Geis and Borst, 2013; Ito et al, 2009; Ito and Oliver, 2012a). Previously, we used retrograde labeling and VGLUT gene expression to identify possible sources of the dense VGLUT2 axosomatic terminals.…”

Section: Introductionmentioning

confidence: 99%

Local and commissural IC neurons make axosomatic inputs on large GABAergic tectothalamic neurons

Ito

Oliver

2014

J of Comparative Neurology

View full text Add to dashboard Cite

Large GABAergic (LG) neurons are a distinct type of neuron in the inferior colliculus (IC) identified by their dense VGLUT2-containing axosomatic synaptic terminals. Yet, the sources of these terminals are unknown. Since IC glutamatergic neurons express VGLUT2, and IC neurons are known to have local collaterals, we tested the hypothesis that these excitatory, glutamatergic axosomatic inputs on LG neurons come from local axonal collaterals and commissural IC neurons. We injected a recombinant viral tracer into the IC which enabled Golgi-like GFP labeling in both dendrites and axons. In all cases, we found terminals positive for both GFP and VGLUT2 (GFP+/VGLUT2+) that made axosomatic contacts on LG neurons. One to six axosomatic contacts were made on a single LG cell body by a single axonal branch. The GFP-labeled neurons giving rise to the VGLUT2+ terminals on LG neurons were close by. The density of GFP+/VGLUT2+ terminals on the LG neurons was related to the number of nearby GFP-labeled cells. On the contralateral side, a smaller number of LG neurons received axosomatic contacts from GFP+/VGLUT2+ terminals. In cases with a single GFP-labeled glutamatergic neuron, the labeled axonal plexus was flat, oriented in parallel to the fibrodendritic laminae, and contacted 9–30 LG cell bodies within the plexus. Our data demonstrated that within the IC microcircuitry, there is a convergence of inputs from local IC excitatory neurons on LG cell bodies. This suggests that LG neurons are heavily influenced by the activity of the nearby laminar glutamatergic neurons in the IC.

show abstract

“…In the IC, large GABAergic (LG) neurons are tectothalamic neurons (Bartlett and Smith, 1999; Peruzzi et al, 1997; Winer et al, 1996), and are encircled by dense axosomatic excitatory inputs from presynaptic terminals that contain the vesicular glutamate transporter 2 (VGLUT2) (Geis and Borst, 2013; Ito et al, 2009; Ito and Oliver, 2012). To elucidate the function of LG neurons, it is important to establish the origin of the axosomatic terminals.…”

Section: Introductionmentioning

confidence: 99%

Convergence of lemniscal and local excitatory inputs on large GABAergic tectothalamic neurons

Ito

Hioki

Sohn

et al. 2015

J of Comparative Neurology

View full text Add to dashboard Cite

Large GABAergic (LG) neurons form a distinct cell type in the inferior colliculus (IC), identified by the presence of dense VGLUT2-containing axosomatic terminals. Although some of the axosomatic terminals originate from local and commissural IC neurons, it has been unclear whether LG neurons also receive axosomatic inputs from the lower auditory brainstem nuclei, i.e. cochlear nuclei (CN), superior olivary complex (SOC), and nuclei of the lateral lemniscus (NLL). In this study, we injected recombinant viral tracers that force infected cells to express GFP in a Golgi-like manner into the lower auditory brainstem nuclei to determine whether these nuclei directly innervate LG cell somata. Labeled axons from CN, SOC and NLL terminated as excitatory axosomatic endings, identified by co-labeling of GFP and VGLUT2, on single LG neurons in the IC. Each excitatory axon made only a few axosomatic contacts on each LG neuron. Inputs to a single LG cell are unlikely to be from a single brainstem nucleus, since lesions of individual nuclei failed to eliminate most VGLUT2-positive terminals on the LG neurons. The estimated number of inputs on a single LG cell body was almost proportional to the surface area of the cell body. Double injections of different viruses in IC and in a brainstem nucleus showed that LG neurons received inputs from both. These results demonstrated that both ascending and intrinsic sources converge on the LG somata to control inhibitory tectothalamic projections.

show abstract

Large GABAergic neurons form a distinct subclass within the mouse dorsal cortex of the inferior colliculus with respect to intrinsic properties, synaptic inputs, sound responses, and projections

Cited by 37 publications

References 56 publications

Persistent Thalamic Sound Processing Despite Profound Cochlear Denervation

Persistent Thalamic Sound Processing Despite Profound Cochlear Denervation

Local and commissural IC neurons make axosomatic inputs on large GABAergic tectothalamic neurons

Convergence of lemniscal and local excitatory inputs on large GABAergic tectothalamic neurons

Contact Info

Product

Resources

About