R01DC019090

Dendritic Mechanisms Underlying Behaviorally-Relevant Activity in a Descending Auditory Pathway - Project Summary/Abstract

Active listening is central to auditory cognition, supporting critical functions such as stream segregation, linguistic analysis, and perceptual learning. To this end, the brain must accurately represent the physical properties of acoustic signals and subsequently parse sounds based on their behavioral relevance.

Whereas the encoding of primary features such as amplitude and spectral content typically begins in specialized brainstem and midbrain circuits, the mechanisms by which sounds attain behavioral relevance are poorly understood. A long-standing assumption is that descending projections from auditory cortex, which contact most early ascending auditory circuits, play a critical role in ascribing behavioral relevance to sounds. Indeed, descending auditory cortical projections could provide an anatomical substrate for "top-down" signals to control the "bottom-up" encoding of acoustic features.

Despite this presumed importance, little is known about the function of descending auditory cortical neurons in attentive listening, nor do we understand the biophysical mechanisms that dictate their contribution to central auditory processing. Our goal is to address these knowledge gaps in behaving mice by studying the descending pathway from auditory cortex to inferior colliculus, an auditory midbrain region critical for perceiving complex sounds.

Our unpublished results support a working hypothesis whereby auditory cortico-collicular neurons encode learned information, thereby transmitting signals that amplify the representation of behaviorally relevant sound features in early auditory circuits. Our data further suggest that a key mechanism underlying the activity of auditory cortico-collicular neurons during active listening is the non-linear generation of dendritic spikes, powerful electrical events that initiate in the apical dendrites of cortical neurons and drive high-frequency burst firing at the soma.

We propose testing these hypotheses using a unique combination of sub-cellular 2-photon Ca2+ imaging, optogenetics, and behavioral assays in awake, head-fixed mice. The positive outcome will be to establish functional and mechanistic answers for the operation of a descending auditory cortical pathway during attentive listening, thereby shedding light on a critical yet poorly understood facet of the central auditory system.

Regents Of The University Of Michigan

TO INVESTIGATE SOLUTIONS TO PROBLEMS DIRECTLY RELEVANT TO INDIVIDUALS WITH DEAFNESS OR DISORDERS OF HUMAN COMMUNICATION IN THE AREAS OF HEARING, BALANCE, SMELL, TASTE, VOICE, SPEECH, AND LANGUAGE. THE NATIONAL INSTITUTE ON DEAFNESS AND OTHER COMMUNICATION DISORDERS (NIDCD) SUPPORTS RESEARCH AND RESEARCH TRAINING, INCLUDING INVESTIGATION INTO THE ETIOLOGY, PATHOLOGY, DETECTION, TREATMENT, AND PREVENTION OF DISORDERS OF HEARING AND OTHER COMMUNICATION PROCESSES, PRIMARILY THROUGH THE SUPPORT OF BASIC AND APPLIED RESEARCH IN ANATOMY, AUDIOLOGY, BIOCHEMISTRY, BIOENGINEERING, EPIDEMIOLOGY, GENETICS, IMMUNOLOGY, MICROBIOLOGY, MOLECULAR BIOLOGY, THE NEUROSCIENCES, OTOLARYNGOLOGY, PSYCHOLOGY, PHARMACOLOGY, PHYSIOLOGY, PSYCHOPHYSICS, SPEECH-LANGUAGE PATHOLOGY, AND OTHER SCIENTIFIC DISCIPLINES. THE NIDCD SUPPORTS: (1) RESEARCH INTO THE EVALUATION OF TECHNIQUES AND DEVICES USED IN DIAGNOSIS, TREATMENT, REHABILITATION, AND PREVENTION OF DISORDERS OF HEARING AND OTHER COMMUNICATION PROCESSES, (2) RESEARCH INTO PREVENTION AND EARLY DETECTION AND DIAGNOSIS OF HEARING LOSS AND SPEECH, VOICE, AND LANGUAGE DISORDERS AND RESEARCH INTO PREVENTING THE EFFECTS OF SUCH DISORDERS BY MEANS OF APPROPRIATE REFERRAL AND REHABILITATION, (3) RESEARCH INTO THE DETECTION, TREATMENT, AND PREVENTION OF DISORDERS OF HEARING AND OTHER COMMUNICATION PROCESSES IN THE ELDERLY POPULATION AND ITS REHABILITATION TO ENSURE CONTINUED EFFECTIVE COMMUNICATION SKILLS, AND (4) RESEARCH TO EXPAND KNOWLEDGE OF THE EFFECTS OF ENVIRONMENTAL AGENTS THAT INFLUENCE HEARING OR OTHER COMMUNICATION PROCESSES. SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM: TO INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, TO ENCOURAGE SMALL BUSINESS PARTICIPATION IN FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION. SMALL BUSINESS TECHNOLOGY TRANSFER (STTR) PROGRAM: TO STIMULATE AND FOSTER SCIENTIFIC AND TECHNOLOGICAL INNOVATION THROUGH COOPERATIVE RESEARCH AND DEVELOPMENT CARRIED OUT BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO FOSTER TECHNOLOGY TRANSFER BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION.

93.173 - Research Related to Deafness and Communication Disorders

National Institute on Deafness and Other Communication Disorders (NIDCD) [HHS - NIH]

Michigan United States

State-Wide

NIH Research Project Grant (Parent R01 Clinical Trial Not Allowed) (PA-20-185)

Amendment Since initial award the End Date has been extended from 12/31/25 to 02/28/31 and the total obligations have increased 487% from $552,374 to $3,239,769.