Neural sensitivity to frequency changes in song structure in a high-order auditory area reflects tutor song memory in adult songbirds.

Vocal learners, including humans and songbirds, acquire their complex vocalizations by accurately memorizing and imitating the vocal patterns of other individuals. In songbirds, the caudomedial nidopallium (NCM), considered the secondary auditory region, has been suggested to play a critical role in memorizing and recognizing the songs of tutors. However, the mechanisms by which NCM neurons encode the acoustic information of tutor song are not yet fully understood.

Sparse representation of neurons for encoding complex sounds in the auditory cortex.

Listening in complex sound environments requires rapid segregation of different sound sources, e.g., having a conversation with multiple speakers or other environmental sounds.

Rapid rebalancing of co-tuned ensemble activity in the auditory cortex.

Sensory information is represented by small varying neuronal ensembles in sensory cortices. In the auditory cortex (AC) repeated presentations of the same sound activate differing ensembles indicating high trial-by trial variability in activity even though the sounds activate the same percept. Efficient processing of complex acoustic signals requires that these sparsely distributed neuronal ensembles actively interact in order to provide a constant percept.

Daily singing of adult songbirds functions to maintain song performance independently of auditory feedback and age.

Many songbirds learn to produce songs through vocal practice in early life and continue to sing daily throughout their lifetime. While it is well-known that adult songbirds sing as part of their mating rituals, the functions of singing behavior outside of reproductive contexts remain unclear. Here, we investigated this issue in adult male zebra finches by suppressing their daily singing for two weeks and examining the effects on song performance.

Cross-modal implicit learning of random time patterns.

Perception is sensitive to statistical regularities in the environment, including temporal characteristics of sensory inputs. Interestingly, implicit learning of temporal patterns in one modality can also improve their processing in another modality. However, it is unclear how cross-modal learning transfer affects neural responses to sensory stimuli.

Auditory memory of complex sounds in sparsely distributed, highly correlated neurons in the auditory cortex.

Listening in complex sound environments requires rapid segregation of different sound sources e.g., speakers from each other, speakers from other sounds, or different instruments in an orchestra, and also adjust auditory processing on the prevailing sound conditions.

Simultaneous mnemonic and predictive representations in the auditory cortex.

Recent studies have shown that stimulus history can be decoded via the use of broadband sensory impulses to reactivate mnemonic representations.. However, memories of previous stimuli can also be used to form sensory predictions about upcoming stimuli.

Auditory memory for random time patterns in cochlear implant listeners.

Learning about new sounds is essential for cochlear-implant and normal-hearing listeners alike, with the additional challenge for implant listeners that spectral resolution is severely degraded. Here, a task measuring the rapid learning of slow or fast stochastic temporal sequences [Kang, Agus, and Pressnitzer (2017). J.

Decoding the Content of Auditory Sensory Memory Across Species.

In contrast to classical views of working memory (WM) maintenance, recent research investigating activity-silent neural states has demonstrated that persistent neural activity in sensory cortices is not necessary for active maintenance of information in WM. Previous studies in humans have measured putative memory representations indirectly, by decoding memory contents from neural activity evoked by a neutral impulse stimulus. However, it is unclear whether memory contents can also be decoded in different species and attentional conditions.

Cortical mapping of mismatch responses to independent acoustic features.

Predictive coding is an influential theory of neural processing underlying perceptual inference. However, it is unknown to what extent prediction violations of different sensory features are mediated in different regions in auditory cortex, with different dynamics, and by different mechanisms. This study investigates the neural responses to synthesized acoustic syllables, which could be expected or unexpected, along several features.

Memory for Random Time Patterns in Audition, Touch, and Vision.

Perception deals with temporal sequences of events, like series of phonemes for audition, dynamic changes in pressure for touch textures, or moving objects for vision. Memory processes are thus needed to make sense of the temporal patterning of sensory information. Recently, we have shown that auditory temporal patterns could be learned rapidly and incidentally with repeated exposure [Kang et al.

Auditory memory for random time patterns.

The acquisition of auditory memory for temporal patterns was investigated. The temporal patterns were random sequences of irregularly spaced clicks. Participants performed a task previously used to study auditory memory for noise [Agus, Thorpe, and Pressnitzer (2010).

Acquisition versus consolidation of auditory perceptual learning using mixed-training regimens.

Learning is considered to consist of two distinct phases-acquisition and consolidation. Acquisition can be disrupted when short periods of training on more than one task are interleaved, whereas consolidation can be disrupted when a second task is trained after the first has been initiated. Here we investigated the conditions governing the disruption to acquisition and consolidation during mixed-training regimens in which primary and secondary amplitude modulation tasks were either interleaved or presented consecutively.

Audiovisual integration in children listening to spectrally degraded speech.

Purpose: The study explored whether visual information improves speech identification in typically developing children with normal hearing when the auditory signal is spectrally degraded.

Method: Children (n=69) and adults (n=15) were presented with noise-vocoded sentences from the Children's Co-ordinate Response Measure (Rosen, 2011) in auditory-only or audiovisual conditions. The number of bands was adaptively varied to modulate the degradation of the auditory signal, with the number of bands required for approximately 79% correct identification calculated as the threshold.