Auditory frequency and intensity discrimination in pigmented rats

Neural Mechanisms of Selective Auditory Attention in Rats (Dissertation)

“…The Weber ratio in this task is 0.1 octave or 7.2% in frequency near 7.9 kHz at 60dB SPL. This Weber ratio is higher than previous studies using a frequency change detection task (Syka et al, 1996;Talwar and Gerstein, 1998). This is probably due to the fact that the animals do not have perfect memory of the perceptual boundary.…”

“…The ability of rats to discriminate fine frequencies has been demonstrated in earlier studies (Syka et al, 1996;Talwar and Gerstein, 1998). In these studies, they asked the rats to detect a frequency change in two sequential tones or a series of tones.…”

“…The strain of rats I used (Long-Evans) is the same as in the study by Syka et al (Syka et al, 1996) while Talwar et al (Talwar and Gerstein, 1998) used Wistar rats in their study. It is unlikely that the difference in frequency discriminability between my result and previous studies is due to rat strain differences.…”

“…Evan though the sound intensity (60 dB SPL) in the frequency discrimination task I used is well above the threshold around 8 kHz (<10 dB SPL), considering the fact that auditory intensity discrimination threshold of the rats is only 1~3 dB SPL at 8 kHz 40~50dB SPL above threshold (Hack, 1971;Syka et al, 1996), it is possible that by changing only stimulus frequency, the perceived intensity will also change with it. Especially in paradigms that present multiple stimuli of the same frequency, a small deviant in frequency (oddball) can escape the effect of stimulus specific adaptation and unleash stronger responses (Ulanovsky et al, 2003).…”

“…The rats have different auditory sensitivity at different tone frequencies measured by detection threshold (Hack, 1960;Kelly and Masterton, 1977;Syka et al, 1996). Evan though the sound intensity (60 dB SPL) in the frequency discrimination task I used is well above the threshold around 8 kHz (<10 dB SPL), considering the fact that auditory intensity discrimination threshold of the rats is only 1~3 dB SPL at 8 kHz 40~50dB SPL above threshold (Hack, 1971;Syka et al, 1996), it is possible that by changing only stimulus frequency, the perceived intensity will also change with it.…”