Figure 1.
Graphs showing average cumulative 1/3 octave band frequency spectrum (Hertz) with relative sound pressure level (dB) of sitar music (A) and noise (B).
In the X axis the contributions of different 1/3 octave frequency bands are seen and the Y axis of the graph represents the unique sound pressure level for each 1/3 octave frequency band which yield the output sound pressure level of 110 dB. Note that the variations of sound pressure levels of the different frequency bands are more in the music stimulus (A) as compared to the noise stimulus (B).
Figure 2.
Time expanded wave form of music (A) and noise (B) stimulus.
(A) Note the complex wave form of the music stimulus with variations in wavelength with time. (B) The simple wave form of noise stimulus shows no variations in wave length with time.
Figure 3.
Spectrograms showing sound energy content of music (A) and noise (B) stimulus expressed as function of frequency and time.
(A) Note that in the music stimulus, the high sound energy (bright yellow colour) is distributed over the entire frequency range and a particular pattern is repeated over time (note the double arrows ↔). (B) In the noise stimulus the high sound energy (bright yellow colour) is centered around 2.7 kHz. (C) Colour panel encodes the range of sound energy: colour toward white denotes high energy and toward black denotes less energy.
Figure 4.
Changes in plasma corticosterone and noradrenaline level.
(A) Histogram shows plasma corticosterone level (nmol/l) at PH1 in male and female of control and experimental groups. No significant alteration of plasma corticosterone level is observed in either of the sexes following music or noise stimulation, although females show significantly higher level as compared to males in all three groups. * indicates comparison of corticosterone level between male and female. (B) Histogram shows plasma noradrenaline level (ng/ml) at PH1 in male and female of control and experimental groups. Moderate increase of plasma noradrenaline level in music and excessive increase in noise stimulated group is observed compared to control. * indicates comparison of control with music and noise and # indicates comparison between music and noise. *** p≤0.001; ###p≤0.001.
Figure 5.
Immunolocalization of synaptophysin.
(A) Photomicrograph of PH1 chick hippocampus shows synaptophysin immunoreactivity (arrows) in the control group. (B) Cytosolic expression of synaptophysin (arrows) is seen at higher magnification. (C) Cerebellum used as positive control, shows synaptophysin immunopositive Purkinje cells (arrows) at PH1. (D) Photomicrograph of hippocampus, showing lack of immunopositivity (negative control). H = Hippocampus; Ce = Cerebellum. Scale bars = 50 µm (A, C, D); 20 µm (B).
Figure 6.
(A) Photomicrograph showing PSD-95 immunoreactivity (arrows) in the hippocampus of control chicks at PH1. (B) PSD-95 immunolocalization in the cytosol (arrows) and in the terminal boutons (arrowheads) in the neuropil of the hippocampus region. (C) Positive control shows immunostaining of the Purkinje cells (arrows) in the chick cerebellum. (D) Photomicrograph of hippocampus, showing lack of immunopositivity (negative control). H = Hippocampus; Ce = Cerebellum. Scale bars = 50 µm (A, C, D); 20 µm (B).
Figure 7.
Western blot and densitometric analysis for synaptophysin.
(A) Immunoblot shows levels of synaptophysin (37 kDa) in the chick hippocampus at PH1. The lane next to the molecular weight markers shows synaptophysin protein in chick cerebellum at PH1 as positive control. (B) α-tubulin used as loading control, is seen as bands of equal intensities at 55 kDa. (C) Histogram shows significant increase of synaptophysin in PH1 chick hippocampus of the music stimulated group and significant decrease in the noise stimulated group as compared to the control. (D) Both rat and chick hippocampus extracts show bands for synaptophysin at the same molecular weight level, confirming the specificity of the antibody to the same epitope *** p≤0.001; * p≤0.038. MW = Molecular weight marker, Ce = Cerebellum; C = Control; M = Music; N = Noise; CH = Chick Hippocampus; RH = Rat Hippocampus.
Figure 8.
Western blot and densitometric analysis for PSD-95.
(A) Immunoblot shows levels of PSD-95 (95 kDa) in the chick hippocampus at PH1. The lane next to the molecular weight markers shows PSD-95 protein in chick cerebellum at PH1 as positive control. (B) α-tubulin used as loading control, is seen as bands of equal intensities at 55 kDa. (C) Histogram shows significant increase of PSD-95 in PH1 chick hippocampus of the music stimulated group and significant decrease in the noise stimulated group compared to the control. (D) Both rat and chick hippocampus show bands for PSD-95 at the same molecular weight level, confirming the specificity of the antibody to the same epitope. *** p≤0.001. MW = Molecular weight marker, Ce = Cerebellum; C = Control; M = Music; N = Noise; CH = Chick Hippocampus; RH = Rat Hippocampus.
Figure 9.
Effects of loud music and noise exposure on spatial orientation and learning.
Line graphs, show the time (Mean ± SD) taken to exit the isolation box (A), total time (Mean ± SD) to reach the target (B) and exploration time (Mean ± SD) in the T-arm (C) in all the 3 trials in all the groups. Note the significantly less time taken by the chicks of music stimulated group and more time by the noise stimulated group in A–C in all the 3 trials as compared to the control. Inter-trial comparison shows significant reduction in time by the third trial in A and B in the control group and in A–C in the music stimulated group. Noise group does not show any alteration in time in successive trials (A–C). * indicates inter-group comparison and # indicates inter-trial comparison. *** p≤0.001; ## p≤0.014; ### p≤0.001. IBL = Isolation box latency; TT = Total time; ET = Exploration time; 1, 2, 3 denote trial number 1, 2 and 3.
Figure 10.
Effects of loud music and noise exposure on spatial memory.
Histograms showing the time (Mean ± SD) taken to exit the isolation box (A), total time (Mean ± SD) to reach the target (B) and the exploration time (Mean ± SD) in the T-arm (C) during the third and fourth trial (24 h after the third trial). No significant alteration is observed between the trials in control and music stimulated group (A–C). Note that the time taken by the noise stimulated chicks is significantly increased in the fourth trial compared to the third for all the three parameters (A–C). *** p≤0.001; ** p≤0.004; * p≤0.03. IBL = Isolation box latency; TT = Total time; ET = Exploration time; 3, 4 denote third and fourth trial.
Table 1.
Data (mean±SD) of open field test conducted in control, music and noise exposed chicks.