Introductory notes before zebra finch song have unique timing properties while sharing acoustic properties with song.

Preparatory neural activity precedes the initiation of simple movements and a key feature of this preparatory activity is its trial-by-trial correlation with features of the upcoming movement. Recent studies in the zebra finch, a songbird with a complex, naturally learned, movement sequence (song), have suggested that the repeats of short introductory notes (INs) at the start of each song bout, reflect motor preparation. However, whether IN properties correlate with upcoming song features remains poorly understood.

A high-throughput screen in mESCs to identify the cross-talk between signaling, endocytosis, and pluripotency.

Embryonic stem cell fate is regulated by various cellular processes. Recently, the process of endocytosis has been implicated in playing a role in the maintenance of self-renewal and pluripotency of mouse embryonic stem cells. A previous siRNA-based screen interrogated the function of core components of the endocytic machinery in maintaining the pluripotency of embryonic stem cells, revealing a crucial role for clathrin mediated endocytosis.

Cell-cell adhesions in embryonic stem cells regulate the stability and transcriptional activity of β-catenin.

E-cadherin (CDH1) is involved in maintaining cell-cell adhesions in embryonic stem cells (ESCs). However, its function in the context of cell fate decisions is largely unknown. Using mouse ESCs (mESCs), we demonstrate that E-cadherin and β-catenin interact at the membrane and continue to do so upon internalization within the cell.

Intrinsic motivation for singing in songbirds is enhanced by temporary singing suppression and regulated by dopamine.

Behaviors driven by intrinsic motivation are critical for development and optimization of physical and brain functions, but their underlying mechanisms are not well studied due to the complexity and autonomy of the behavior. Songbirds, such as zebra finches, offer a unique opportunity to study neural substrates of intrinsic motivation because they spontaneously produce many renditions of songs with highly-quantifiable structure for vocal practice, even in the absence of apparent recipients ("undirected singing"). Neural substrates underlying intrinsic motivation for undirected singing are still poorly understood partly because singing motivation cannot be easily manipulated due to its autonomy.

Introductory gestures before songbird vocal displays are shaped by learning and biological predispositions.

Numerous animal displays begin with introductory gestures. For example, lizards start their head-bobbing displays with introductory push-ups, and many songbirds begin their vocal displays by repeating introductory notes (INs) before producing their learned song. Among songbirds, the acoustic structure and the number of INs produced before song vary considerably between individuals in a species.

Altering Opioid Neuromodulation in the Songbird Basal Ganglia Modulates Vocalizations.

Although the interplay between endogenous opioids and dopamine (DA) in the basal ganglia (BG) is known to underlie diverse motor functions, few studies exist on their role in modulating speech and vocalization. Vocal impairment is a common symptom of Parkinson's disease (PD), wherein DA depletion affects striosomes rich in μ-opioid receptors (μ-ORs). Symptoms of opioid addiction also include deficiencies in verbal functions and speech.

Sensory feedback independent pre-song vocalizations correlate with time to song initiation.

The song of the adult male zebra finch is a well-studied example of a learned motor sequence. Song bouts begin with a variable number of introductory notes (INs) before actual song production. Previous studies have shown that INs progress from a variable initial state to a stereotyped final state before each song.

Clathrin-Mediated Endocytosis Regulates a Balance between Opposing Signals to Maintain the Pluripotent State of Embryonic Stem Cells.

Endocytosis is implicated in the maintenance of embryonic stem cell (ESC) pluripotency, although its exact role and the identity of molecular players remain poorly understood. Here, we show that the clathrin heavy chain (CLTC), involved in clathrin-mediated endocytosis (CME), is vital for maintaining mouse ESC (mESC) pluripotency. Knockdown of Cltc resulted in a loss of pluripotency accompanied by reduced E-cadherin (E-CAD) levels and increased levels of transforming growth factor β (TGF-β) and extracellular signal-regulated kinase (ERK) signaling.

Pre-Bout Neural Activity Changes in Premotor Nucleus HVC Correlate with Successful Initiation of Learned Song Sequence.

Preparatory activity, characterized by gradual, longer timescale changes in neural activity, is present in a number of different brain areas before the onset of simple movements and is believed to be important for movement initiation. However, relatively little is known about such activity before initiation of naturally learned movement sequences. The song of an adult male zebra finch is a well studied example of a naturally learned movement sequence and previous studies have shown robust premotor activity immediately before song.

Emergence of context-dependent variability across a basal ganglia network.

Context dependence is a key feature of cortical-basal ganglia circuit activity, and in songbirds the cortical outflow of a basal ganglia circuit specialized for song, LMAN, shows striking increases in trial-by-trial variability and bursting when birds sing alone rather than to females. To reveal where this variability and its social regulation emerge, we recorded stepwise from corticostriatal (HVC) neurons and their target spiny and pallidal neurons in Area X. We find that corticostriatal and spiny neurons both show precise singing-related firing across both social settings.

Behavioral and neural signatures of readiness to initiate a learned motor sequence.

All movements are thought to be "prepared" in the brain before initiation, and preparation can be impaired in motor diseases. However, little is known about what sort of preparation precedes self-initiated, naturally learned sequences of movements. Here we took advantage of a canonical example of a precisely timed learned motor sequence, adult zebra finch song, to examine motor preparation.

Rats smell in stereo.

It has been hypothesized that rats and other mammals can use stereo cues to localize odor sources, but there is limited behavioral evidence to support this hypothesis. We found that rats trained on an odor-localization task can localize odors accurately in one or two sniffs. Bilateral sampling was essential for accurate odor localization, with internasal intensity and timing differences as directional cues.