关键词: 高级发声中枢, 侧别优势, 声学特征, 成年雄性斑胸草雀

Abstract:

Songbird is an ideal animal model for the study of human language. There are functional similarities between telencephalon nucleus HVC (high vocal center) in songbird and Broca’s area in the human brain. The songs of songbird arise by an integration of activity from two neural pathways that emanate from nucleus HVC which plays an important role in song production and sensorimotor learning. Human brain known to be important for speech and language is usually much larger on the dominant side. Lesion of HVC is likely to uncover any asymmetries of function in the central song system. To determine the lateral asymmetry in HVC control of song production, electrolytic lesions of HVC and acoustic analysis technology were used. In our experiments, all birds received unilateral HVC lesion prior to bilateral HVC lesion, and then sound were compared and analyzed before and after electrolytic lesion of HVC. Fifteen adult males (left lesion, n = 8; right lesion, n = 7) received lesion targeting HVC. Structure of syllables has the characteristics of fast frequency modulations in adult male zebra finches, motifs of songs consist of several sequentially arranged syllables. Songs and long calls were analyzed spectrographically using Sound Analysis Pro (SAP), we extracted the acoustic parameters including durations, amplitude, fundamental frequency, mean frequency, peak frequency, frequency modulation, amplitude modulation and similarity score. Nissl-counterstained sections of all brains were carefully examined to assess lesion damage. The results showed that the lesion of left HVC had no significant influence to frequency and intensity features in song and long call. Lesion of right HVC result in amplitude, frequency modulation, amplitude modulation decreased significantly (p < 0.05) in long call, and amplitude, mean frequency, peak frequency reduced significantly (p < 0.05) in song. The change of temporal feature after bilateral HVC lesions suggested that the coding of the temporal feature requires the both hemispheres integration of the song system. HVC has right dominance in the control frequency and intensity features, but in the control temporal feature requires both sides of HVC.

Key words: high vocal center, side dominance, acoustic characteristicsadult male zebra finch