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[Relation between frequency modulation direction selectivity and forward masking of inferior collicular neurons: a study on in vivo intracellular recording in mice.] [Article in Chinese]

FU Zi-Ying, ZENG Hong, Tang Jia^*, LI Jie, LI Juan, CHEN Qi-Cai

School of Life Sciences and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, China

Abstract

It has been reported that the frequency modulation (FM) or FM direction sensitivity and forward masking of central auditory neurons are related with the neural inhibition, but there are some arguments, because no direct evidence of inhibitory synaptic input was obtained in previous studies using extracellular recording. In the present study, we studied the relation between FM direction sensitivity and forward masking of the inferior collicular (IC) neurons using in vivo intracellular recordings in 20 Mus musculus Km mice. Thirty seven with complete data among 93 neurons were analyzed and discussed. There was an inhibitory area which consisted of inhibitory postsynaptic potentials (IPSP) at high frequency side of frequency tuning of up-sweep FM (FM_U) sensitive neurons (n = 12) and at low frequency side of frequency tuning of down-sweep FM (FM_D) selective neurons (n = 8), while there was no any inhibitory area at both sides of frequency tuning of non-FM sweep direction (FM_N) sensitive neurons (n = 17). Therefore, these results show that the inhibitory area at low or high frequency side of frequency tuning is one of the mechanisms for forming FM sweep direction sensitivity of IC neurons. By comparison of forward masking produced by FM_U and FM_D sound stimuli in FM_U, FM_D and FM_N neurons, the selective FM sounds could produce stronger forward masking than the non-selective in FM_U and FM_D neurons, while there was no forward masking difference between FM_U and FM_D stimuli in the FM_N neurons. We suggest that the post-action potential IPSP is a potential mechanism for producing stronger forward masking in FM_U and FM_D neurons.

Key words: Inferior collicular neuron; FM direction sensitivity; forward masking; in vivo intracellular recording

Received: 2012-09-07　　Accepted: 2012-11-18

Corresponding author: 唐佳　　E-mail: bobaytang@yahoo.com.cn

Citing This Article：

FU Zi-Ying, ZENG Hong, Tang Jia, LI Jie, LI Juan, CHEN Qi-Cai. [Relation between frequency modulation direction selectivity and forward masking of inferior collicular neurons: a study on in vivo intracellular recording in mice.] [Article in Chinese]. Acta Physiol Sin 2013; 65 (3): 329-337 (in Chinese with English abstract).