The Inferior Colliculus: A Center for Convergence of Ascending and Descending Auditory Information

2004 ◽  
Vol 3 (4) ◽  
pp. 215-229 ◽  
Author(s):  
Manuel S. Malmierca
Keyword(s):  
Inferior Colliculus ◽  
Auditory Information

Neuromodulatory Feedback to the Inferior Colliculus

2018 ◽  
pp. 576-610 ◽  
Author(s):  
Laura Hurley
Keyword(s):  
Inferior Colliculus ◽  
Auditory System ◽  
Auditory Processing ◽  
Internal State ◽  
Brain Regions ◽  
Auditory Information ◽  
Situational Variables ◽  
Acoustic Stimuli ◽  
Functionally Diverse ◽  
Behavioral Information

The inferior colliculus (IC) receives prominent projections from centralized neuromodulatory systems. These systems include extra-auditory clusters of cholinergic, dopaminergic, noradrenergic, and serotonergic neurons. Although these modulatory sites are not explicitly part of the auditory system, they receive projections from primary auditory regions and are responsive to acoustic stimuli. This bidirectional influence suggests the existence of auditory-modulatory feedback loops. A characteristic of neuromodulatory centers is that they integrate inputs from anatomically widespread and functionally diverse sets of brain regions. This connectivity gives neuromodulatory systems the potential to import information into the auditory system on situational variables that accompany acoustic stimuli, such as context, internal state, or experience. Once released, neuromodulators functionally reconfigure auditory circuitry through a variety of receptors expressed by auditory neurons. In addition to shaping ascending auditory information, neuromodulation within the IC influences behaviors that arise subcortically, such as prepulse inhibition of the startle response. Neuromodulatory systems therefore provide a route for integrative behavioral information to access auditory processing from its earliest levels.

scholarly journals Integration of locomotion and auditory signals in the mouse inferior colliculus

2019 ◽  
Author(s):  
Yoonsun Yang ◽  
Joonyeol Lee ◽  
Gunsoo Kim
Keyword(s):  
Inferior Colliculus ◽  
Neural Activity ◽  
Stimulus Presentation ◽  
Sound Stimulus ◽  
Frequency Selectivity ◽  
Auditory Information ◽  
Neural Signals ◽  
Sound Processing ◽  
Auditory Integration ◽  
Evoked Activity

AbstractThe inferior colliculus (IC) is the major midbrain auditory integration center, where virtually all ascending auditory inputs converge. Although the IC has been extensively studied for sound processing, little is known about the neural activity of the IC in moving subjects, as frequently happens in natural hearing conditions. Here we show, by recording the IC neural activity in walking mice, the activity of IC neurons is strongly modulated by locomotion in the absence of sound stimulus presentation. Similar modulation was also found in deafened mice, demonstrating that IC neurons receive non-auditory, locomotion-related neural signals. Sound-evoked activity was attenuated during locomotion, and the attenuation increased frequency selectivity across the population, while maintaining preferred frequencies. Our results suggest that during behavior, integrating movement-related and auditory information is an essential aspect of sound processing in the IC.

Immediate Changes in Tuning of Inferior Colliculus Neurons Following Acute Lesions of Cat Spiral Ganglion

2002 ◽  
Vol 87 (1) ◽  
pp. 434-452 ◽  
Author(s):  
Russell L. Snyder ◽  
Donal G. Sinex
Keyword(s):  
Inferior Colliculus ◽  
Spiral Ganglion ◽  
Primary Auditory Cortex ◽  
Compound Action Potential ◽  
Central Nucleus ◽  
Auditory Information ◽  
Cells Of Origin ◽  
Wide Range ◽  
Before And After ◽  
Evoked Compound Action Potential

In previous studies, we demonstrated that acute lesions the spiral ganglion (SG), the cells of origin of the auditory nerve (AN), change the frequency organization of the inferior colliculus central nucleus (ICC) and primary auditory cortex (AI). In those studies, we used a map/re-map approach and recorded the tonotopic organization of neurons before and after restricted SG lesions. In the present study, response areas (RAs) of ICC multi-neuronal clusters were recorded to contralateral and ipsilateral tones after inserting and fixing-in-place tungsten microelectrodes. RAs were recorded from most electrodes before, immediately (within 33–78 min) after, and long(several hours) after restricted mechanical lesions of the ganglion. Each SG lesion produced a “notch” in the tone-evoked compound action potential (CAP) audiogram corresponding to a narrow range of lesion frequencies with elevated thresholds. Responses of contralateral IC neurons, which responded to these lesion frequencies, underwent an elevation in threshold to the lesion frequencies with either no change in sensitivity to other frequencies or with dramatic decreases in threshold to lesion-edge frequencies. These changes in sensitivity produced shifts in characteristic frequency (CF) that could be more than an octave. Thresholds at these new CFs matched the prelesion thresholds of neurons tuned to the lesion-edge frequencies. Responses evoked by ipsilateral tones delivered to the intact ear often underwent complementary changes, i.e., decreased thresholds to lesion frequency tones with little or no change in sensitivity to other frequencies. These results indicate that responses of IC neurons are produced by convergence of auditory information across a wide range of AN fibers and that the acute “plastic” changes reported in our previous studies occur within 1 h of an SG lesion.

scholarly journals Integration of locomotion and auditory signals in the mouse inferior colliculus

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Yoonsun Yang ◽  
Joonyeol Lee ◽  
Gunsoo Kim
Keyword(s):  
Inferior Colliculus ◽  
Neural Activity ◽  
Neuronal Population ◽  
Frequency Selectivity ◽  
Hearing Impaired ◽  
Auditory Information ◽  
Neural Signals ◽  
Sound Processing ◽  
Auditory Integration ◽  
Evoked Activity

The inferior colliculus (IC) is the major midbrain auditory integration center, where virtually all ascending auditory inputs converge. Although the IC has been extensively studied for sound processing, little is known about the neural activity of the IC in moving subjects, as frequently happens in natural hearing conditions. Here, by recording neural activity in walking mice, we show that the activity of IC neurons is strongly modulated by locomotion, even in the absence of sound stimuli. Similar modulation was also found in hearing-impaired mice, demonstrating that IC neurons receive non-auditory, locomotion-related neural signals. Sound-evoked activity was attenuated during locomotion, and this attenuation increased frequency selectivity across the neuronal population, while maintaining preferred frequencies. Our results suggest that during behavior, integrating movement-related and auditory information is an essential aspect of sound processing in the IC.

Single-Unit Responses in the Inferior Colliculus of Decerebrate Cats I. Classification Based on Frequency Response Maps

1999 ◽  
Vol 82 (1) ◽  
pp. 152-163 ◽  
Author(s):  
Ramnarayan Ramachandran ◽  
Kevin A. Davis ◽  
Bradford J. May
Keyword(s):  
Frequency Response ◽  
Spontaneous Activity ◽  
Inferior Colliculus ◽  
Single Unit ◽  
Broadband Noise ◽  
Auditory Information ◽  
Type I ◽  
Rate Level ◽  
Type V ◽  
Decerebrate Cats

This study proposes a classification system for neurons in the central nucleus of the inferior colliculus (ICC) that is based on excitation and inhibition patterns of single-unit responses in decerebrate cats. The decerebrate preparation allowed extensive characterization of physiological response types without the confounding effects of anesthesia. The tone-driven discharge rates of individual units were measured across a range of frequencies and levels to map excitatory and inhibitory response areas for contralateral monaural stimulation. The resulting frequency response maps can be grouped into the following three populations: type V maps exhibit a wide V-shaped excitatory area and no inhibition; type I maps show a more restricted I-shaped region of excitation that is flanked by inhibition at lower and higher frequencies; and type O maps display an O-shaped island of excitation at low stimulus levels that is bounded by inhibition at higher levels. Units that produce a type V map typically have a low best frequency (BF: the most sensitive frequency), a low rate of spontaneous activity, and monotonic rate-level functions for both BF tones and broadband noise. Type I and type O units have BFs that span the cat’s range of audible frequencies and high rates of spontaneous activity. Like type V units, type I units are excited by BF tones and noise at all levels, but their rate-level functions may become nonmonotonic at high levels. Type O units are inhibited by BF tones and noise at high levels. The existence of distinct response types is consistent with a conceptual model in which the unit types receive dominant inputs from different sources and shows that these functionally segregated pathways are specialized to play complementary roles in the processing of auditory information.

The Nuclei of the Lateral Lemniscus

2019 ◽  
pp. 444-472
Author(s):  
Felix Felmy
Keyword(s):  
Inferior Colliculus ◽  
Auditory Processing ◽  
Fiber Bundle ◽  
Auditory Brainstem ◽  
Superior Olivary Complex ◽  
Auditory Information ◽  
Lateral Lemniscus ◽  
Sound Sources ◽  
Dorsal Nucleus ◽  
The Individual

Parallel processing streams guide ascending auditory information through the processing hierarchy of the auditory brainstem. Many of these processing streams converge in the lateral lemnisucus, the fiber bundle that connects the cochlear nuclei and superior olivary complex with the inferior colliculus. The neuronal populations within the lateral lemniscus can be segregated according to their gross structure-function relationships into three distinct nuclei. These nuclei are termed ventral, intermedial, and dorsal nucleus, according to their position within the lemniscal fiber bundle. The complexity of their input pattern increases in an ascending fashion. The three nuclei employ different neurotransmitters and exhibit distinct synaptic and biophysical features. Yet they all share a large heterogeneity. Functionally, the ventral nucleus of the lateral lemniscus has been hypothesized to reduce spectral splatter by generating a rapid, temporally precise feedforward onset inhibition in the inferior colliculus. In the intermedial nucleus of the lateral lemniscus a cross-frequency integration has been observed. The hallmark of the dorsal nucleus of the lateral lemniscus is the generation of a long-lasting inhibition in its contralateral counterpart and the inferior colliculus. This inhibition is proposed to generate a suppression of sound sources during reverberations and could act as a temporal filter capable of removing spurious interaural time differences. While great advances have been made in understanding the role that these nuclei play in auditory processing, the functional diversity of the individual neuronal responsiveness within each nucleus remains largely unsolved.

Neuron Types, Intrinsic Circuits, and Plasticity in the Inferior Colliculus

2018 ◽  
pp. 502-526
Author(s):  
Tetsufumi Ito ◽  
Munenori Ono ◽  
Douglas L. Oliver
Keyword(s):  
Inferior Colliculus ◽  
De Novo ◽  
Future Research ◽  
Auditory Information ◽  
Wide Range ◽  
Neuronal Types ◽  
Key Issues ◽  
Complex Features ◽  
Local Circuits ◽  
Local Connection

The inferior colliculus is a critical auditory center in the midbrain which virtually acts as a hub of all ascending and descending auditory information flows. Wide variety of neuronal responses to sound is found in the IC, and this variety emerges not only from the wide range of extrinsic afferent inputs, but also from the complex features of the local circuits in the IC, for example, the mosaic pattern of extrinsic fiber termination, the various neuronal types each of which compose different patterns of local connection, and the unique forms of synaptic plasticity de novo. This chapter reviews the recent progress in understanding these features, and identifies the key issues for future research.

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