Learning and maintenance of skilled movements require exploration motor space selection appropriate actions. Vocal learning social context-dependent plasticity in songbirds depend on a basal ganglia circuit, which actively generates vocal variability. Dopamine the reduces trial-to-trial neural variability when bird engages courtship song. Here, we present evidence for unique, tonically active, excitatory interneuron songbird that makes strong synaptic connections onto output pallidal...

Significance Neural activity in the adult brain plays a key role mediating experience-dependent neural plasticity. We show that inhibiting electrical song nucleus, robust nucleus of arcopallium, bird decreases number new projection neurons added to afferent HVC. Our results are consistent with general principle activity-based target selection newborn during nervous system development and support idea developmental plasticity exploit similar mechanisms. Understanding mechanisms influencing...

Ecomorphology studies focus on understanding how anatomical and behavioral diversity result in differences performance, ecology, fitness. In mammals, the determinate growth of skeleton entails that bite performance should change throughout ontogeny until feeding apparatus attains its adult size morphology. Then, interspecific phenotypes are expected to drive food resource partitioning patterns lineage diversification. However, Formal tests these predictions lacking for majority mammal...

Subtle quantitative abnormalities in neuronal populations derived from the rhombic lip (i.e. arcuate nucleus at ventral medullary surface, external granular layer of cerebellum) have been reported victims sudden infant death syndrome (SIDS). In this study, we examined inferior olive, a major derivative, to determine if subtle also involve SIDS. We analyzed number and density neurons reactive astrocytes olive 29 SIDS cases controls. Computer-assisted cell counting procedures were used...

Seasonally breeding songbirds exhibit pronounced annual changes in song behavior, and the morphology physiology of telencephalic neural circuit underlying production learned song. Each season, new adult-born neurons are added to pallial nucleus HVC response seasonal steroid hormone levels, send long axonal projections their target nucleus, robust arcopallium (RA). We investigated role that adult neurogenesis plays reconstruction this circuit. labeled newborn with BrdU, RA-projecting...

Songbirds learn vocalizations by hearing and practicing songs. As song develops, the tempo becomes faster more precise. In songbird brain, discrete nuclei form interconnected myelinated circuits that control acquisition production. The myelin sheath increases speed of action potential propagation insulating axons neurons reducing membrane capacitance. brain in density, but time course development across has not been systematically studied a quantitative fashion. We tested hypothesis...

Mice fed on a vitamin A acetate (VAA)-supplemented diet respond to concentrations of oxazolone which are too low elicit contact sensitivity standard diet. This study has investigated whether enhanced responsiveness could be due VAA-induced changes in antigen-presenting cell function. The draining lymph nodes were used as the source for accessory populations, and cells from control sensitized mice either or VAA compared syngeneic allogeneic responses. Their ability induce delayed-type...

While hormone-driven plasticity in the adult brain is well studied, underlying cellular and molecular mechanisms are less understood. One example of this seasonal avian brain, where song nuclei exhibit hormonally driven changes response to changing photoperiod circulating sex steroid hormones. Hormone receptor activation nucleus HVC (proper name) elicits a robust change activity target RA (robust arcopallium), but signal responsible for unknown. This study addressed whether brain-derived...

Animals need to accurately sense changes in their body position perform complex movements. It is increasingly clear that the vertebrate central nervous system contains a variety of cells capable detecting motion, addition comparatively well-understood mechanosensory vestibular and peripheral proprioceptors. One such intriguing lower spinal cord column birds, also known as avian lumbosacral organ (LSO), which thought act set balance sensors allow birds detect movements separately from head...

Birds are exceptionally adept at controlling their body position. For example, they can coordinate rapid movements of while stabilizing head. Intriguingly, this ability may rely in part on a mechanosensory organ the avian lower spinal cord called lumbosacral (LSO). However, molecular mechanotransduction mechanisms have not been identified cord. Here, we report presence glycinergic neurons LSO that exhibit immunoreactivity for myosin7a and espin, molecules essential function maintenance hair...

In adult songbirds, new neurons are born in large numbers the proliferative ventricular zone telencephalon and migrate to adjacent song control region HVC (acronym used as proper name) [A. Reiner et al. , J. Comp. Neurol. 473 377–414 (2004)]. Many of these send long axonal projections robust nucleus arcopallium (RA). The HVC–RA circuit is essential for producing stereotyped learned song. function neurogenesis this has not been clear. A previous study suggested that it important production...

Abstract In adult songbirds, the telencephalic song nucleus HVC and its efferent target RA undergo pronounced seasonal changes in morphology. breeding birds, there are increases volume total neuron number, neuronal soma area compared to nonbreeding birds. At end of breeding, neurons die through caspase‐dependent apoptosis thus, size decreases. Changes driven by circulating testosterone (T) levels. Infusing T, or metabolites 5α‐dihydrotestosterone (DHT) 17 β‐estradiol (E2), intracerebrally...

Adrenergic receptors are mediators of adrenergic and noradrenergic modulation throughout the brain. Previous studies have provided evidence for expression in midbrain auditory nucleus, inferior colliculus (IC), but not examined cellular patterns detail. Here, we utilize multichannel fluorescent situ hybridization to detect receptor-encoding mRNA male female mice. We found α1 , α2A β2 all areas IC. While observed similar levels across subregions IC, was expressed differentially. To account...

Abstract Birds are exceptionally adept at controlling their body position. For example, they can coordinate rapid movements of while stabilizing head. Intriguingly, this ability may rely in part on a mechanosensory organ the avian lower spinal cord called lumbosacral (LSO). However, molecular mechanotransduction mechanisms have not been identified cord. Here, we report presence glycinergic neurons LSO that exhibit immunoreactivity for myosin7a and epsin, molecules essential function...

Songbirds learn to produce vocalizations early in life by listening to, then copying the songs of conspecific males. The anterior forebrain pathway, homologous a basal ganglia-forebrain circuit, is essential for song learning. projection between striato-pallidal structure, Area X, and medial portion dorsolateral thalamic nucleus (DLM) strongly hyperpolarizing adults, due very negative chloride reversal potential (Person & Perkel, Neuron 46:129-140, 2005). determined, part, expression level...