Frontiers in auditory processing, learning, and plasticity
Sunday, September 22, 2024
Basic and Translational Research
•
S172
•
12:00 PM
>
1:00 PM
•
Frontiers in auditory processing, learning, and plasticity
•
Dragonnier 5 – 236
Basic and Translational Research
The mammalian auditory system is remarkably adaptable allowing it to form sensory representations related to perception, learning, and communication of acoustic signals. Deficits to the neural processes underlying this adaptability have been implicated in language, developmental and learning disorders. This panel will bring together auditory neuroscientists studying the neural basis of auditory processing and behavior along the entire auditory pathway from the periphery to the auditory cortex. The goal is to understand how acoustic signals are encoded along the auditory pathway, how brain state alters sound processing, and the neural circuits that underlie auditory perception and behavior. Jeremie Barral will discuss how sounds are transmitted along the mouse auditory pathway using optogenetic manipulations with large-scale multi-area recordings. Yves Boubenec will address how primary and non-primary regions of the ferret auditory cortex processes complex natural sounds that have multiscale temporal structure (e.g. vocalizations, speech). Brice Bathellier will discuss how sleep alters sensory responses in the auditory cortex. Michele Insanally will discuss the neural mechanisms that support auditory perceptual learning using optogenetics and silicon probe recordings in mouse auditory cortex. The talk titles from each panelist are listed below.
•
INT307
•
Time-limited integration windows constrain and organize hierarchical computation in ferret auditory cortex
>
Y.
Yves
BOUBENEC
Content : Much remains unknown about the cellular computations that allow animals to integrate across the complex multiscale structure that defines natural sounds (e.g., vocalizations, speech). One central question is whether single neurons in the auditory cortex effectively integrate across many different timescales in a context-dependent fashion, or whether multiscale integration is instantiated by populations of neurons with diverse but fixed integration timescales. Using a recently developed experimental/computational paradigm, we show that single neurons throughout ferret auditory cortex integrate information within a time-limited “integration window”, beyond which sounds have little effect on the neural response. These windows vary widely (~15 to 250 ms) across the auditory cortex, increasing substantially from primary- to non-primary regions across all cortical layers, and are largely unaffected by the category, duration, and information rate of natural sounds. These findings reveal that multiscale computation is accomplished by a diverse set of hierarchically organized integration windows, each specialized for a particular timescale
•
INT314
•
Dynamic gating of auditory perceptual flexibility by diverse cortical responses
>
M.
Michele
INSANALLY (Pittsburgh)
Content : The ability to flexibly respond to sensory cues in dynamic environments is essential to adaptive auditory-guided behaviors such as navigation and communication. How does the auditory system flexibly gate sensory information to select appropriate behavioral strategies based on sensory input and context? Auditory neural responses during behavior are diverse, ranging from highly-reliable ‘classical’ responses (i.e. robust, frequency-tuned cells) to irregular or seemingly random ‘non-classically responsive’ firing patterns (i.e., nominally non-responsive cells) that fail to demonstrate any significant trial-averaged responses to sensory inputs or other behavioral factors. While classically responsive cells have been extensively studied for decades, the contribution of non-classically responsive cells to behavior has remained underexplored despite their prevalence. Recent work has shown that non-classically responsive cells in auditory cortex contain significant stimulus and choice information and encode flexible task rules. While it has been shown that both classically and non-classically responsive units are essential for asymptotic task performance their role during learning is unknown. In this talk, I will describe how diverse cortical responses emerge and evolve during flexible behavior, and how top-down inputs shape these responses during auditory learning. We combine high-density single-unit recordings, chemogenetics, projection-specific optogenetic manipulations, and population decoding during an auditory reversal learning task to explore the network dynamics underlying flexible auditory behavior.
•
INT313
•
Conservation of sensory processing in the auditory cortex in sleep
>
B.
Brice
BATHELLIER (France)
Content : Sleep is a physiological state often associated with the loss of conscious perception of sensory stimuli. Even though brain signatures of sleep have been studied for years, the mechanisms that prevent sensory information from reaching consciousness remains to be elucidated. Recent findings suggest that the loss of perception experienced in anesthesia may be due to neurons population activity coding of stimuli in the cortex collapsing into the spontaneous activity subspace, therefore reflecting internally generated dynamics rather than evoked sensory responses. In this study, we examined whether this property is also at play during sleep. We used two-photon calcium imaging to record the responses to sounds of hundreds of neurons simultaneously in the primary auditory cortex of awake and naturally asleep mice. The analysis of the population activity revealed that, contrary to anesthesia, sounds were encoded with highly similar population activity patterns between the awake and NREM states. This conservation of sounds representations between wakefulness and sleep suggests that sensory processing is impacted by qualitatively different mechanisms in anesthesia and in sleep. Moreover, while under anesthesia, sound representations in cortex are highly deteriorated, our result indicate that high-level cortical processing of sounds is intact during NREM sleep, a property that is at odd with the classical view that in sleep thalamus gates sensory information to cortex, but which may however be critical for survival.
•
INT312
•
Feedforward propagation along the mouse auditory pathway
>
J.
Jeremie
BARRAL
Content : How spikes propagate along multiple layer networks has been extensively studied with computational models. Feedforward networks are a prominent model able to transmit information rapidly, but these networks have been difficult to isolate in the intact mammalian brain. Here, we focus on the auditory network which is characterized by multiple connected relays. We used sound and optogenetic stimulations to drive the auditory periphery and monitored neuronal activity at two locations along the auditory pathway simultaneously, using large-scale electrophysiological recordings. We observed fast and efficient propagation of pulse packets, in agreement with a feedforward description of the auditory network. We further determined the state-phase diagram of spike propagation and demonstrated the presence of an attractor fixpoint that enables robust and quick transfer of information. However, propagation was not limited to only synchronized events. Prolonged firing was also evoked and necessary to promote an efficient transfer of graded inputs and subsequent readout in downstream structures. Taken together, the auditory network combines both temporal and firing rate modes of propagation to reliably encode the different dimensions of sound features.
|