Effect of prenatal sound stimulation on medio-rostral neostriatum/hyperstriatum ventrale region of chick forebrain: a morphometric and immunohistochemical study.
The higher auditory association area in chick forebrain, i.e. medio-rostral neostriatum/hyperstriatum ventrale region (MNH), is involved in juvenile auditory filial imprinting. Studies show that neuronal size as well as expression of calcium-binding proteins, parvalbumin (PV) and calbindin D28K (CaBP) are regulated by neuronal activation. In the present study, we have determined the effect of extra auditory stimulation, given as a prenatal sound enrichment protocol, on MNH neurons of posthatch day 1 chicks. Patterned species-specific or musical (sitar) sounds were provided in a graded manner from embryonic day 10 through hatching. Thionin and immunohistochemically stained (PV and CaBP) neurons were evaluated by morphometric methods. The thionin-stained MNH neurons of both the auditory stimulated groups showed a significant increase in nuclear area compared to controls. The change in nuclear dimension was greater in the music-stimulated than in the species-specific sounds-stimulated group. These observations indicate a positive influence of prenatal sound stimulation on MNH neurons. The auditory stimulated groups also demonstrated an increase in the proportion of PV- and CaBP-neurons compared to controls, with the species-specific sounds-stimulated group showing a significantly higher percentage of immunostained cells than the music-stimulated group. However, immunostained cells of both the auditory stimulated groups did not show a significant change in size. These cytoplasmic proteins, by acting as intracellular buffers, enable neurons to display high electrical activity without calcium overload. The influx of Ca(2+) ions is essential for long-term potentiation, a phenomenon important for learning and memory. The increase in percentage of the neurons containing calcium-binding proteins may provide a morphological basis for enhancement of auditory imprinting and learning.
Panicker
Harsha
H
Department of Anatomy, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
Wadhwa
Shashi
S
Roy
Tara S
TS
D000161:Acoustic Stimulation / Q000379:methods / Q000706:statistics & numerical data; D000818:Animals; D000831:Animals, Newborn; D002642:Chick Embryo; D002645:Chickens; D005260:Female; D007150:Immunohistochemistry; D017072:Neostriatum / Q000737:chemistry / Q000166:cytology* / Q000502:physiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D016548:Prosencephalon / Q000737:chemistry / Q000166:cytology* / Q000502:physiology