PROJECT SUMMARY
Skill acquisition can be facilitated by social experience, usually through exposure to a conspecific performing a
well-defined behavior. In fact, social learning (SL) is pivotal to the acquisition of many core behaviors, including
aural communication. Although the neural bases for auditory SL remain uncertain, one plausible hypothesis is
that social experience may induce experience-dependent plasticity in auditory cortex (AC), as found for many
forms of learning, thereby facilitating auditory task acquisition. Social learning may also have implications for
developmental hearing loss (HL), a prevalent sensory impairment that is associated with persistent deficits in
speech and language acquisition, especially since social factors are thought to facilitate language acquisition in
children with HL. Three Aims test predictions that emerge from this hypothesis: Aim 1 first demonstrates the
positive impact of SL on task learning: Naïve Observer gerbils receive five days of exposure to a trained
Demonstrator performing an amplitude modulation rate discrimination task. An opaque divider separates
Observer and Demonstrator, such that visual cues are absent. Observer gerbils are then permitted to practice
the auditory task, and the rate of learning assessed. To test the prediction that AC activity is required, AC will
be inactivated during social experience. Aim 1 will go on to test the prediction that dopaminergic
neuromodulation within AC is be necessary for social learning. We will first determine whether dopamine is
released in AC during social experience, using fiber photometry and a genetically expressed dopamine sensor.
We will then block dopamine receptors in AC during social exposure to determine whether the benefits of
social experience are diminished. Aim 2 tests the prediction that AC neuron sensitivity to auditory cues will be
enhanced during SL. Gerbils will be instrumented with electrode arrays in AC, and recorded during five days of
social exposure. Single neuron and population responses to auditory task stimuli will be assessed to determine
if improved neural sensitivity during observation can explain the rate of task acquisition rate during practice. To
test the contribution of an auditory social cue (i.e., Demonstrator vocalizations), recordings will be obtained
from Observers exposed to auditory task cues plus playback of demonstrator vocalizations. Aim 3 tests the
prediction that SL will improve task acquisition in hearing loss-reared animals. Juvenile gerbils will receive
either permanent (malleus removal) or transient (earplugs) conductive HL. Animals will then be instrumented
with electrode arrays in AC, and assessed as in Aim 2. Innovations in this proposal are to: (i) extend current
auditory learning paradigms to include social cues, (ii) use wireless recordings during learning to make within-
animal comparisons of neural and behavioral sensitivity, and (iii) shift the current emphasis in HL research
from a focus on degraded sensory processing to one that considers how social factors may facilitate auditory
skills. If successful, the project will identify a CNS mechanism that mediates socially-enhanced auditory
learning, and provide a novel approach to remediate sensory and cognitive barriers in children with HL.