Studying the functions of neuronal circuits in the central auditory system

Ten percent of the human population suffers from central auditory system disorders, yet we understand very little about its role in making sense of sounds.

In my lab, we take a systems neuroscience approach to study the functions of the central auditory system using electrophysiology, imaging, optogenetics, behavioral testing, cochlear implants and neural network modeling.

The goal of our research is to give a new insight into the functions of the auditory system, with a particular focus on its high adaptability. We hope that our results will lead to new ways of reinstating normal connectivity in cases of abnormal signal processing.

For more information feel free to contact me or read about our research on this page, or under publications.

Tania Rinaldi Barkat

Sounds and hearing play a pivotal role in human communication. People who suffer from central auditory processing abnormalities are affected in their daily lives and might not be able to appreciate even the most basic verbal communication. Tinnitus, in which phantom sounds are experienced in the absence of acoustic stimulation, is an example of pathology of the central auditory system. More than 10% of the population suffers from it.

Despite the importance of hearing in human communication, we still understand very little of how sounds are perceived and how they are processed in the central auditory system, and particularly in the auditory cortex, to allow us to make sense out of them. The periphery of the auditory system is better understood; the powerful cochlear implants or hearing aids used nowadays are model results of the translational research stemming from basic findings in the peripheral auditory system. However, the central auditory system, and the auditory cortex in particular, is still only poorly understood.

The aim of our lab is to understand the role of neuronal circuits in making sense of sounds. We use a systems neuroscience approach and combine optogenetics, in vivo electrophysiology (extracellular and patch-clamp), functional imaging (voltage-sensitive dye and 2P calcium imaging), behavioral assays, cochlear implants and computer modeling to explore the functions of neuronal circuits in the mouse central auditory system.


Ongoing work in our group is directed towards three main questions:

  • How do auditory cortical responses develop during adolescence and how can they be modified?
  • What neuronal circuits are involved in specific sound features, and how do they influence behavior?
  • What influences does context have on regulating these auditory neuronal circuits?

The lab’s results will provide a new understanding of how sounds are processed and perceived. Learning how distinct neural circuits code for auditory inputs of increasing complexity will shed light on the function of the auditory cortex, on the role of different circuits in characterizing the behavioral response to a sensory input, and eventually on the cause of abnormal signal processing in brain disorders. The results will contribute towards a richer comprehension of normal function and will hold the key for remediating abnormal auditory signal processing following a history of compromised hearing or deafness

Ongoing projects in the lab are aimed at:

  • Characterizing the juvenile development of auditory responses to sounds of increasing complexity. We are also determining critical periods for these complex sounds, as well as factors controlling this developmental plasticity. Finally, we are assessing the behavioral consequences of modifying a specific cortical circuit in auditory relevant tasks and describing the relationship of auditory cortical activity to perception and behavior.
    The results shed a new light on how the brain processes different sound features during development, and identify what cortical circuits are engaged by specific sound features. By characterizing the plasticity of the auditory cortex, our research will eventually be crucial for remediating abnormal signal processing following compromised hearing in adults.
  • Defining the neuronal subpopulations involved in specific sound features and describing the corresponding behavioral phenotypes. Responses to a wide range of sounds in the inferior colliculus, medial geniculate body and auditory cortex are characterized following light-driven control of the excitability of subsets of neurons. Using specific manipulations like the ones allowed thanks to optogenetics, we then assess the behavioral consequences of controlling targeted neuronal subpopulations in auditory relevant tasks.
    The results elucidate the role of neuronal subpopulations in the central auditory system. Our aim is to set the ground for a theory of auditory forebrain function.
  • Probing the influence of attention on the functions of auditory circuits. We all intuitively grasp the clear distinction in how we perceive sounds while we actively listen compared to when we passively hear, but the brain processes underpinning this difference between an attentive a passive state remain elusive. We are combining electrophysiology, optogenetics and functional imaging in behaving animals to compare neuronal responses in both states.
    The results emerging from this project will deepen the current knowledge of the neural mechanisms of attention and engagement, and will help future research investigating pathologies in which such mechanisms are disrupted, such as attention deficit-hyperactivity disorder and autism.
  • Using cochlear implants to suppress aberrant activity in models of hearing abnormalities. Several hearing abnormalities, such as tinnitus, hyperacusis or some form of hearing impairments, are caused by central auditory dysfunctions. Recent observations in humans have shown that cochlear implants might, in some cases, help these conditions. The mechanisms of actions are however not understood. We are using the cochlear implant mouse model in combination with electrophysiology to study the plasticity of the auditory system in disease. We are describing how cochlear implant stimulation is represented in the brain and characterizing what kind of plastic changes take place following long-term cochlear stimulation.
    Being able to explore the high adaptability of the auditory system to try to reinstate normal neural activity in compromised hearing might hold the key for powerful tools for translational research.