Abstract
In order to explore the possible mechanism of corticofugal modulation of excitatory frequency tuning curves (EFTCs) of midbrain neurons, we examined the change of sharpness, frequency-intensity response area, minimum threshold of both EFTCs and inhibitory frequency tuning curves (IFTCs) of inferior collicular neurons during corticofugal modulation using two-tone inhibition paradigm and micro-electrical stimulation technique. Our data showed that corticofugal inhibition increased sharpness, minimum threshold, and decreased the frequency-intensity response area of EFTCs, at the same time it decreased the sharpness, minimum threshold but increased the frequency-intensity response area of IFTCs. The opposite results were observed for EFTCs and IFTCs of corticofugally facilitated inferior collicular neurons. During corticofugal inhibition, the percent change of frequency-intensity response area of EFTCs had significant correlation with the percent change of that of IFTCs. These data suggest that cortical neurons are likely to improve frequency information processing of inferior collicular neurons by modulation of IFTCs.
Similar content being viewed by others
References
Druga, R., Syka, J., Rajkowska, G., Projections of auditory cortex onto the inferior colliculus in the rat, Physiol. Res., 1997, 46: 215.
Feliciano, M., Potashner, S. J., Evidence for a glutamatergic pathway from the guinea pig auditory cortex to the inferior colliculus, J. Neurochem., 1995, 65: 1348.
Herbert, H., Aschoff, A., Ostwald, J., Topography of projections from the auditory cortex to the inferior colliculus in the rat, J. Comp. Neurol., 1991, 304: 103.
Saldana, E., Feliciano, M., Mugnaini, E., Distribution of descending projections from primary auditory neocortex to inferior colliculus mimics the topography of intracollicular projections, J. Comp. Neurol., 1996, 371: 15.
Torterolo, P., Zurita, P., Pedemonte, M. et al., Auditory cortical efferent actions upon inferior colliculus unitary activity in the guinea pig, Neurosci. Lett., 1998, 249: 172.
Winer, J. A., Larue, D. T., Diehl, J. J. et al., Auditory cortical projections to the cat inferior colliculus, J. Comp. Neurol., 1998, 400: 147.
Jen, P. H. S., Chen, Q. C., Sun, X. D., Corticofugal regulation of auditory sensitivity in the bat inferior colliculus, J. Comp. Physiol., 1998, 183: 683.
Jen, P. H. S., Zhang, J. P., Corticofugal regulation of excitatory and inhibitory frequency tuning curves of bat inferior collicular neurons, Brain Res., 1999, 841: 184.
Sun, X. D., Chen, Q. C., Jen, P. H. S., Corticofugal control of central auditory sensitivity in the big brown bat,Eptesicus fuscus, Neurosci. Lett., 1996, 212: 131.
Zhang, Y., Suga, N., Yan, J., Corticofugal modulation of frequency processing in bat auditory system, Nature, 1997, 387: 900.
Jen, P. H. S., Sun, X. D., Shen, J. X. et al., Cytoarchitecture and sound activated responses in the auditory cortex of the big brown bat,Eptesicus fuscus, Acta Otolaryngol., 1997, 532: 61.
Fuzessery, Z. M., Hall, J. C., Role of GABA in shaping frequency tuning and creating FM sweep selectivity in the inferior colliculus, J. Neurophysiol., 1996, 76: 1059.
Author information
Authors and Affiliations
Corresponding author
About this article
Cite this article
Zhang, J., Sun, X. & Jen, P.H.S. Corticofugal modulation of frequency tuning of inferior collicular neurons in big brown bat,Eptesicus fuscus . Chin.Sci.Bull. 46, 836–839 (2001). https://doi.org/10.1007/BF02900434
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02900434