| Description |
Song learning in Zebra Finches (Taeniopygia guttata) occurs during a critical period between 30-90 post hatch days, and involves acquisition of an acoustic model and a sensorimotor period of increasingly improving imitation of this model. Young birds sing highly variable songs early during this period and then song becomes more stereotyped and "crystallizes" at around 90 days of age. After this adult zebra finches sing a highly stereotyped song that consists of 3-8 different syllables that are repeated several times into a song bout (Zann 1993; Williams 2008). Production of song involves a well -characterized neural circuitry of dedicated brain nuclei. The main forebrain areas for production are the robust nucleus of the arcopallium (RA) and HVC (used as a proper name), located in motor and sensorimotor cortical areas, respectively (Zann 1993; Williams 2008). The establishment of the neural circuitry for stereotyped song production is paralleled by expression of proteoglycan structures. Specifically, the formation of perineuronal nets (PNNs) in HVC and RA has been linked to the crystallization event (Balmer et al. 2009). Whereas the role of chondroitin sulfate in these PNNs is well established, heparan sulfate proteoglycans are also expressed in HVC and RA, but their specific role in establishment and maintenance of a stereotyped motor program for song is not known. In this study, we investigated the role of heparan sulfate proteoglycans in song stereotypy by enzymatically digesting these structures in RA and HVC of adult male zebra finches. Although some small syllable frequency differences were observed in the heparitinase-in fused subjects, this treatment did not result in a striking difference in overall acoustic structure of syllables. |
