Cochlear implants (CIs) restore activity in the deafened auditory system via electrical stimulation of the auditory nerve. As the spread of electric current in biological tissues is rather broad, the spectral information provided by electrical CIs is limited. Optogenetic stimulation of the auditory nerve has been suggested for artificial sound coding with improved spectral selectivity, as light can be conveniently confined in space. Yet, the foundations for optogenetic sound coding strategies remain to be established. Here, we parametrized stimulus-response-relationships of the auditory pathway in gerbils for optogenetic stimulation. Upon activation of the auditory pathway by waveguide-based optogenetic stimulation of the spiral ganglion, we recorded neuronal activity of the auditory midbrain, in which neural representations of spectral, temporal, and intensity information can be found. Screening a wide range of optical stimuli and taking the properties of optical CI emitters into account, we aimed to optimize stimulus paradigms for potent and energy-efficient activation of the auditory pathway. We report that efficient optogenetic coding builds on neural integration of millisecond stimuli built from microsecond light pulses, which optimally accommodate power-efficient laser diode operation. Moreover, we performed an activity-level-dependent comparison of optogenetic and acoustic stimulation in order to estimate the dynamic range and the maximal stimulation intensity amenable to single channel optogenetic sound encoding, and indicate that it complies well with speech comprehension in a typical conversation (65 dB). Our results provide a first framework for the development of coding strategies for future optogenetic hearing restoration.
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http://dx.doi.org/10.1016/j.brs.2023.09.018 | DOI Listing |
Neurosurg Focus Video
January 2025
Department of Neurosurgery.
Surgically remediable epilepsy of the eloquent brain poses the added challenge of preserving function while curing disease. Long-standing epileptogenic lesions have tenacious seizure networks and significant functional reorganizations. Large multilobar lesions may involve multiple functional areas, thereby challenging the limits of functional brain mapping.
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January 2025
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
While animals readily adjust their behavior to adapt to relevant changes in the environment, the neural pathways enabling these changes remain largely unknown. Here, using multiphoton imaging, we investigate whether feedback from the piriform cortex to the olfactory bulb supports such behavioral flexibility. To this end, we engage head-fixed male mice in a multimodal rule-reversal task guided by olfactory and auditory cues.
View Article and Find Full Text PDFElife
January 2025
Department of Psychology, University of York, North Yorkshire, United Kingdom.
Processing pathways between sensory and default mode network (DMN) regions support recognition, navigation, and memory but their organisation is not well understood. We show that functional subdivisions of visual cortex and DMN sit at opposing ends of parallel streams of information processing that support visually mediated semantic and spatial cognition, providing convergent evidence from univariate and multivariate task responses, intrinsic functional and structural connectivity. Participants learned virtual environments consisting of buildings populated with objects, drawn from either a single semantic category or multiple categories.
View Article and Find Full Text PDFeNeuro
January 2025
Neuronal Circuits and Behavior Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD 21224-6823, U.S.A.
The anterior hypothalamic area (AHA) is a key brain region for orchestrating defensive behaviors. Using in vivo calcium imaging in mice, we observed that AHA neuronal activity increases during foot shock delivery and foot-shock associated auditory cues. We found that following shock-induced increases in AHA activity, a decrease in activity coincides with the onset of grooming behavior.
View Article and Find Full Text PDFThis case report explores the interplay between childhood trauma, social phobia, psychotic symptoms, and minority stress in a 27-year-old transgender male. L presented with psychotic symptoms, including auditory verbal hallucinations and self-referential phenomena, which were accompanied by a history of childhood sexual and emotional abuse, as well as social phobia. These challenges were further compounded by experiences of stigma, rejection, and stress related to his gender identity.
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