Article
Neurosciences
Luke A. Shaheen, Sean J. Slee, Stephen V. David
Summary: The study found that task engagement can modulate sound coding in the auditory midbrain, with little effect on the central IC but significant modulation in noncentral areas. This led to enhanced responses for target tones compared to distractor noise, increasing neural discriminability between the two.
JOURNAL OF NEUROSCIENCE
(2021)
Article
Audiology & Speech-Language Pathology
William A. Noftz, Nichole L. Beebe, Jeffrey G. Mellott, Brett R. Schofield
Summary: The study revealed dense cholinergic innervation in the NBIC, ICt, and ICrp regions, with cholinergic projections likely contacting both GABAergic and non-GABAergic cells. These cholinergic axons may affect multisensory processing by modulating excitatory and inhibitory circuits in these areas. The similarity of axons and their targets suggests a common function for cholinergic innervation across the three areas.
Article
Biology
Hannah M. Oberle, Alexander N. Ford, Deepak Dileepkumar, Jordyn Czarny, Pierre F. Apostolides
Summary: Corticofugal projections from the neocortex to evolutionarily ancient subcortical structures are common in mammalian sensory systems, allowing the cortex to control ascending sensory representations predictively or in a feedback manner. This study focused on the projection from the mouse auditory cortex to the inferior colliculus (IC), revealing that although individual synapses were weak, IC neurons integrated inputs from multiple corticofugal axons to generate reliable depolarizations. Descending signals reached the IC within 30 ms of sound onset and were found to nonlinearly amplify IC neurons' acoustic responses.
Article
Multidisciplinary Sciences
Lauren J. Kreeger, Catherine J. Connelly, Preeti Mehta, Boris Zemelman, Nace L. Golding
Summary: A new study identified a distinct population of excitatory neurons in the inferior colliculus that exhibit diverse temporal responses to sound. These neurons show uniform morphology and provide spatially restricted excitation exclusively to the ventral auditory thalamus.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Clinical Neurology
Maria Michael, Bettina Julia Wolf, Astrid Klinge-Strahl, Marcus Jeschke, Tobias Moser, Alexander Dieter
Summary: This study establishes the foundation for optogenetic sound coding by parametrizing the stimulus-response relationships of the auditory pathway. The results show that efficient optogenetic coding can be achieved through neural integration of millisecond stimuli built from microsecond light pulses, and it is consistent with speech comprehension.
Article
Biology
Daniela Saderi, Zachary P. Schwartz, Charles R. Heller, Jacob R. Pennington, Stephen David
Summary: Generalized arousal and task engagement have separate effects on auditory neural processing, with pupil size showing a more prominent effect in the inferior colliculus. Task engagement is positively correlated with pupil size, indicating that some effects attributed to task engagement may actually be due to pupil size fluctuations.
Article
Geriatrics & Gerontology
Amir M. Mafi, Nick Tokar, Matthew G. Russ, Oren Barat, Jeffrey G. Mellott
Summary: This study aimed to investigate the disrupted excitatory-inhibitory balance during aging, and found significant synaptic loss in the lateral cortex of the IC during old age, while minimal loss in middle age. Moreover, synaptic changes during middle age may lead to an increase in excitation.
NEUROBIOLOGY OF AGING
(2022)
Article
Anatomy & Morphology
Eugenia Gonzalez-Palomares, Luciana Lopez-Jury, Francisco Garcia-Rosales, Julio C. Hechavarria
Summary: The study found that mutual information between neuronal responses and acoustic stimuli, as well as response redundancy in pairs of neurons recorded simultaneously, increase exponentially with IC depth in the auditory midbrain. This occurs regardless of the type of sound presented to bats (echolocation or communication), indicating the existence of mutual information and redundancy maps at the midbrain level that cannot be predicted based on the frequency composition of natural sounds and classic neuronal tuning curves.
BRAIN STRUCTURE & FUNCTION
(2021)
Article
Neurosciences
Kenneth E. Hancock, Bertrand Delgutte
Summary: Dichotic pitches, such as the Huggins pitch and the binaural edge pitch, are perceptual illusions created by binaural interactions. In this study, scientists investigated the neural responses of binaural neurons in the auditory midbrain and found that these neurons encode the frequency of dichotic pitches through specific features in their firing rates. These findings provide physiological evidence for the neural mechanisms underlying dichotic pitches.
JOURNAL OF NEUROPHYSIOLOGY
(2023)
Article
Neurosciences
Charles A. Williams, Kimberly E. Miller, Nisa P. Williams, Christine V. Portfors, David J. Perkel
Summary: Adrenergic receptors play important roles in the modulation of adrenergic and noradrenergic signaling in the brain, with different subtypes showing differential expression patterns in the inferior colliculus (IC) of male and female mice. This study found a coordinated pattern of adrenergic receptor expression in the IC, with little developmental change in expression levels. Additionally, co-expression of multiple adrenergic receptor subtypes was observed in IC cells, indicating a potential for combined modulatory effects of these receptors.
JOURNAL OF COMPARATIVE NEUROLOGY
(2021)
Article
Cell Biology
Kathryn Lynn Carzoli, Georgios Kogias, Jessica Fawcett-Patel, Siqiong June Liu
Summary: Carzoli et al. demonstrate that fear memory formation is driven by activity in cerebellar interneurons, which involves an increase in intrinsic excitability specific to learning and the loss of endocannabinoid-HCN signaling. This highlights the significance of moving beyond traditional investigations of memory formation focused on synaptic plasticity.
Article
Neurosciences
Kathryne M. Allen, Angeles Salles, Sangwook Park, Mounya Elhilali, Cynthia F. Moss
Summary: This study explored the neural underpinnings of sonar object discrimination in the presence of acoustic clutter caused by physical objects. It was found that some inferior colliculus neurons in bats encode acoustic features that can be used to discriminate between sonar objects, but the effect of background clutter on this discrimination is highly variable. In some cases, clutter impaired discrimination, while in other instances clutter enhanced acoustic features, suggesting that environmental clutter may augment cues for sonar target discrimination.
JOURNAL OF NEUROPHYSIOLOGY
(2021)
Article
Neurosciences
Jeremie Sibille, Jens Kremkow, Ursula Koch
Summary: This study investigates the physiological mechanisms underlying acoustic hypersensitivity in Fragile X syndrome by studying the response patterns of neurons in the inferior colliculus (IC) of Fmr1 -/- mice. The results show that Fmr1 -/- mice exhibit broadening frequency tuning, increased firing, altered excitation-inhibition balance, and reduced response latencies, all expected features of acoustic hypersensitivity. Additionally, enhanced offset-rebound activity outside the excitatory frequency response area was observed in all neuronal response types of Fmr1 -/- mice.
FRONTIERS IN NEUROSCIENCE
(2022)
Article
Biochemistry & Molecular Biology
Hong-Nhung Tran, Quy-Hoai Nguyen, Ji-eun Jeong, Duc-Linh Loi, Youn Hee Nam, Tong Ho Kang, Jaeseung Yoon, Kwanghee Baek, Yongsu Jeong
Summary: Our study identifies the embryonic patterning gene Dbx1 as a key player in the development and survival of the inferior colliculus (IC) in the midbrain. We find that Dbx1 prevents apoptotic cell death in postnatal IC by repressing genes involved in cell death. Furthermore, we uncover that Tcf7l2 functions downstream of Dbx1 and loss of Tcf7l2 leads to IC phenotypes similar to Dbx1 mutant mice. We also demonstrate that the Dbx1-Tcf7l2 cascade functions upstream of Ap-2 delta, essential for IC development and survival.
CELL DEATH AND DIFFERENTIATION
(2023)
Review
Behavioral Sciences
Silvio Macias, Daniel A. Llano
Summary: This study takes a comparative approach to understand the top-down modulation mechanisms in the mammalian and amphibian inferior colliculus (IC). The key question addressed is whether the thalamotectal projections in mammals and amphibians are homologous and how they interact with projections from the cerebral cortex. The behavioral significance of these descending pathways is also considered, particularly in anurans' ability to navigate complex acoustic landscapes without a corticocollicular projection.
JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY
(2023)
Article
Behavioral Sciences
Florian Rau, Jan Clemens, Victor Naumov, R. Matthias Hennig, Susanne Schreiber
JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY
(2015)