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Sanes, D. H.

Publications and source records attributed to Sanes, D. H..

10 recordsLinked to original sources

Auditory perceptual expertise: Amplitude modulation rate discrimination near the threshold for detection

Many perceptual skills improve with a few days of training. However, weeks or months of practice may be required to reach a level of expertise on complex tasks (Watson, 1980). Here, we explored how gerbils attain expertise on a difficult task: amplitude modulation (AM) rate discrimination at very shallow AM depths, similar to the depths used during vocal communication. Using an appetitive Go-Nogo procedure, we first trained 6 gerbils to perform an AM discrimination task (Nogo: 4 Hz; Go: 4.25-10 Hz) at a depth of 0 dB (re: 100% depth). Animals were then trained to perform AM discrimination at successively shallower depths, from -3 to -18 dB, requiring an average of 5-10 days of practice to reach a performance metric of d[≥]1 for each depth. Finally, we determined that AM discrimination thresholds were nearly identical between 0 to -12 dB, and only slightly elevated at -15 dB. Improvements in performance were accompanied by a large reduction in response time during procedural learning, and a gradual reduction of response time during perceptual learning, even as AM depth became shallower (i.e., more difficult). The shallowest depth at which gerbils displayed peak performance on the AM discrimination task is similar to their lowest AM depth detection thresholds. These results suggest performance on challenging auditory perceptual tasks require prolonged practice, and is accompanied by increased automaticity (i.e., lower response time) that stabilizes once expertise is achieved.

animal behavior and cognition↗

Family identity is represented within vocal categories by the gerbil auditory cortex

Vocalizations are integral to social communication, with acoustic features that may convey both meaning and information about an animals identity or emotional state. The neural representation of vocalizations must therefore permit animals to generalize across one set of acoustic features to recognize meaning, and a different set of features to recognize vocalizer identity. To test this idea, we recorded the responses of gerbil core auditory cortex (AC) neurons to a large array (n>1500) of variants drawn from four vocalization categories and produced by 5 different families. Each vocalization category could be decoded from AC population activity with high accuracy, despite the acoustic variance across vocalization renditions or different families-of-origin, and displayed a boundary effect (i.e., better classification across, than within, a category). Moreover, the family identity of each vocalization category could be decoded from a larger AC population. Thus, AC activity can be used to simultaneously predict vocalization category and family identity, and is robust to the natural range of acoustic variance.

neuroscience↗

Vocal Call Locator Benchmark (VCL) for localizing rodent vocalizations from multi-channel audio

Understanding the behavioral and neural dynamics of social interactions is a goal of contemporary neuroscience. Many machine learning methods have emerged in recent years to make sense of complex video and neurophysiological data that result from these experiments. Less focus has been placed on understanding how animals process acoustic information, including social vocalizations. A critical step to bridge this gap is determining the senders and receivers of acoustic information in social interactions. While sound source localization (SSL) is a classic problem in signal processing, existing approaches are limited in their ability to localize animal-generated sounds in standard laboratory environments. Advances in deep learning methods for SSL are likely to help address these limitations, however there are currently no publicly available models, datasets, or benchmarks to systematically evaluate SSL algorithms in the domain of bioacoustics. Here, we present the VCL Benchmark: the first large-scale dataset for benchmarking SSL algorithms in rodents. We acquired synchronized video and multi-channel audio recordings of 767,295 sounds with annotated ground truth sources across 9 conditions. The dataset provides benchmarks which evaluate SSL performance on real data, simulated acoustic data, and a mixture of real and simulated data. We intend for this benchmark to facilitate knowledge transfer between the neuroscience and acoustic machine learning communities, which have had limited overlap.

neuroscience↗

Cingulate cortex facilitates auditory perception under challenging listening conditions

We often exert greater cognitive resources (i.e., listening effort) to understand speech under challenging acoustic conditions. This mechanism can be overwhelmed in those with hearing loss, resulting in cognitive fatigue in adults, and potentially impeding language acquisition in children. However, the neural mechanisms that support listening effort are uncertain. Evidence from human studies suggest that the cingulate cortex is engaged under difficult listening conditions, and may exert top-down modulation of the auditory cortex (AC). Here, we asked whether the gerbil cingulate cortex (Cg) sends anatomical projections to the AC that facilitate perceptual performance. To model challenging listening conditions, we used a sound discrimination task in which stimulus parameters were presented in either Easy or Hard blocks (i.e., long or short stimulus duration, respectively). Gerbils achieved statistically identical psychometric performance in Easy and Hard blocks. Anatomical tracing experiments revealed a strong, descending projection from layer 2/3 of the Cg1 subregion of the cingulate cortex to superficial and deep layers of primary and dorsal AC. To determine whether Cg improves task performance under challenging conditions, we bilaterally infused muscimol to inactivate Cg1, and found that psychometric thresholds were degraded for only Hard blocks. To test whether the Cg-to-AC projection facilitates task performance, we chemogenetically inactivated these inputs and found that performance was only degraded during Hard blocks. Taken together, the results reveal a descending cortical pathway that facilitates perceptual performance during challenging listening conditions. Significance StatementSensory perception often occurs under challenging conditions, such a noisy background or dim environment, yet stimulus sensitivity can remain unaffected. One hypothesis is that cognitive resources are recruited to the task, thereby facilitating perceptual performance. Here, we identify a top-down cortical circuit, from cingulate to auditory cortex in the gerbils, that supports auditory perceptual performance under challenging listening conditions. This pathway is a plausible circuit that supports effortful listening, and may be degraded by hearing loss.

neuroscience↗

Distinct developmental trajectories of autonomous behaviors and agency in rodents

Behavioral interactions within the nuclear family play a pivotal role in the emergence of agency: the capacity to regulate physiological, psychological and social needs. While behaviors may develop over days or weeks in line with nervous system maturation, individual behaviors can occur on sub-second time scales making it challenging to track development in lab studies with brief observation periods, or in field studies with limited temporal precision and animal identification. Here we study development in families of gerbils, a highly social rodent, collecting tens of millions of behavior time points and implementing machine learning methods to track individual subjects. We provided maturing gerbils with a large, undisturbed environment between postnatal day 15 and the age at which they would typically disperse from the family unit (day 30). We identified complex and distinct developmental trajectories for food and water acquisition, solitary exploration, and social behaviors, some of which displayed sex differences and diurnal patterns. Our work supports the emergence of well-delineated autonomous and social behavior phenotypes that correlate with specific periods and loci of neural maturation.

animal behavior and cognition↗

Unsupervised discovery of family specific vocal usage in the Mongolian gerbil

In nature, animal vocalizations can provide crucial information about identity, including kinship and hierarchy. However, lab-based vocal behavior is typically studied during brief interactions between animals with no prior social relationship, and under environmental conditions with limited ethological relevance. Here, we address this gap by establishing long-term acoustic recordings from Mongolian gerbil families, a core social group that uses an array of sonic and ultrasonic vocalizations. Three separate gerbil families were transferred to an enlarged environment and continuous 20-day audio recordings were obtained. Using a variational autoencoder (VAE) to quantify 583,237 vocalizations, we show that gerbils exhibit a more elaborate vocal repertoire than has been previously reported and that vocal repertoire usage differs significantly by family. By performing gaussian mixture model clustering on the VAE latent space, we show that families preferentially use characteristic sets of vocal clusters and that these usage preferences remain stable over weeks. Furthermore, gerbils displayed family-specific transitions between vocal clusters. Since gerbils live naturally as extended families in complex underground burrows that are adjacent to other families, these results suggest the presence of a vocal dialect which could be exploited by animals to represent kinship. These findings position the Mongolian gerbil as a compelling animal model to study the neural basis of vocal communication and demonstrates the potential for using unsupervised machine learning with uninterrupted acoustic recordings to gain insights into naturalistic animal behavior.

animal behavior and cognition↗

Developmental hearing loss-induced perceptual deficits are rescued by cortical expression of GABAB receptors

Even transient periods of developmental hearing loss during the developmental critical period have been linked to long-lasting deficits in auditory perception, including temporal and spectral processing, which correlate with speech perception and educational attainment. In gerbils, hearing loss-induced perceptual deficits are correlated with a reduction of both ionotropic GABAA and metabotropic GABAB receptor-mediated synaptic inhibition in auditory cortex, but most research on critical period plasticity has focused on GABAA receptors. We developed viral vectors to express both endogenous GABAA or GABAB receptor subunits in auditory cortex and tested their capacity to restore perception of temporal and spectral auditory cues following critical period hearing loss in the Mongolian gerbil. HL significantly impaired perception of both temporal and spectral auditory cues. While both vectors similarly increased IPSCs in auditory cortex, only overexpression of GABAB receptors improved perceptual thresholds after HL to be similar to those of animals without developmental hearing loss. These findings identify the GABAB receptor as an important regulator of sensory perception in cortex and point to potential therapeutic targets for developmental sensory disorders. Significance StatementHearing loss in children can induce deficits in aural communication that persevere even after audibility has returned to normal, suggesting permanent changes to the auditory central nervous system. In fact, a reduction in cortical synaptic inhibition has been implicated in a broad range of developmental disorders, including hearing loss. Here, we tested the hypothesis that developmental hearing loss-induced perceptual impairments in gerbils are caused by a permanent reduction of auditory cortical inhibitory synapse strength. We found that virally-mediated expression of a GABAB receptor subunit in gerbil auditory cortex was able to restore two auditory perceptual skills in juvenile animals reared with hearing loss, suggesting that cortical synaptic inhibition is a plausible therapeutic target for sensory processing disorders.

neuroscience↗

Transformation of acoustic information to sensory decision variables in the parietal cortex

The process by which sensory evidence contributes to perceptual choices requires an understanding of its transformation into decision variables. Here, we address this issue by evaluating the neural representation of acoustic information in auditory cortex-recipient parietal cortex while gerbils either performed an auditory discrimination task or while they passively listened to identical acoustic stimuli. During task performance, decoding performance of simultaneously recorded parietal neurons reflected psychometric sensitivity. In contrast, decoding performance during passive listening was significantly reduced. Principal component and geometric analyses each revealed the emergence of decision-relevant, linearly separable manifolds, but only during task engagement. Finally, using a clustering analysis, we found subpopulations of neurons that may reflect the encoding of separate segments during task performance: stimulus integration and motor preparation or execution. Taken together, our findings demonstrate how parietal cortex neurons integrate and transform encoded auditory information to guide sound-driven perceptual decisions.

neuroscience↗

Auditory processing remains sensitive to environmental experience during adolescence

Development is a time of great opportunity. A heightened period of neural plasticity contributes to dramatic improvements in perceptual, motor, and cognitive skills. However, developmental plasticity poses a risk: greater malleability of neural circuits exposes them to environmental factors that may impede behavioral maturation. While these risks are well-established prior to sexual maturity (i.e., critical periods), the degree of neural vulnerability during adolescence remains uncertain. To address this question, we induced a transient period of hearing loss (HL) spanning adolescence in the gerbil, confirmed by assessment of circulating sex hormones, and asked whether behavioral and neural deficits are diminished. Wireless recordings were obtained from auditory cortex neurons during perceptual task performance, and within-session behavioral and neural sensitivity were compared. We found that a transient period of adolescent HL caused a significant perceptual deficit (i.e., amplitude modulation detection thresholds) that could be attributed to degraded auditory cortex processing, as confirmed with both single neuron and population-level analyses. In contrast, perceptual deficits did not occur when HL of the same duration was induced in adulthood. To determine whether degraded auditory cortex encoding was attributable to an intrinsic change, we obtained auditory cortex brain slices from adolescent HL animals, and recorded synaptic and discharge properties from auditory cortex pyramidal neurons. There was a clear and novel phenotype, distinct from critical period HL: excitatory postsynaptic potential amplitudes were elevated in adolescent HL animals, whereas inhibitory postsynaptic potentials were unchanged. This is in contrast to critical period deprivation, where there are large changes to synaptic inhibition. Taken together, these results show that diminished adolescent sensory experience can cause long-lasting behavioral deficits that originate, in part, from a dysfunctional cortical circuit. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/439537v2_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@50b787org.highwire.dtl.DTLVardef@1410662org.highwire.dtl.DTLVardef@a0fa6org.highwire.dtl.DTLVardef@897b1c_HPS_FORMAT_FIGEXP M_FIG Summary of experimental design and main findings. C_FIG

neuroscience↗

Dopaminergic signaling supports auditory social learning

Explicit rewards are commonly used to reinforce a behavior, a form of learning that engages the dopaminergic neuromodulatory system. In contrast, skill acquisition can display dramatic improvements from a social learning experience, even though the observer receives no explicit reward. Here, we test whether a dopaminergic signal contributes to social learning in naive gerbils that are exposed to, and learn from, a skilled demonstrator performing an auditory discrimination task. Following five exposure sessions, naive observer gerbils were allowed to practice the auditory task, and their performance was assessed across days. We first tested the effect of an explicit food reward in the observers compartment that was yoked to the demonstrators performance during exposure sessions. Naive observer gerbils with the yoked reward learned the discrimination task significantly faster, as compared to unrewarded observers. The effect of this explicit reward was abolished by administration of a D1/D5 dopamine receptor antagonist during the exposure sessions. Similarly, the D1/D5 antagonist reduced the rate of learning in unrewarded observers. To test whether a dopaminergic signal was sufficient to enhance social learning, we administered a D1/D5 receptor agonist during the exposure sessions in which no reward was present, and found that the rate of learning occurred significantly faster. Finally, a quantitative analysis of observer vocalizations and movements during the exposure sessions suggest behavioral strategies that contribute to social learning. Together, these results are consistent with a dopamine-dependent reward signal during social learning.

neuroscience↗