Regularly firing neurons in the inferior colliculus have a weak interaural intensity difference sensitivity.
The spike discharge regularity may be important in the processing of information in the auditory pathway. It has already been shown that many cells in the central nucleus of the inferior colliculus fire regularly in response to monaural stimulation by the best frequency tones. The aim of this study was to find how the regularity of units was affected by adding ipsilateral tone, and how interaural intensity difference sensitivity is related to regularity. Single unit recordings were performed from 66 units in the inferior colliculus of the anaesthetized guinea pig in response to the best frequency tone. Regularity of firing was measured by calculating the coefficient of variation as a function of time of a unit's response. There was a positive correlation between coefficient of variation and interaural intensity difference sensitivity, indicating that highly regular units had very weak and irregular units had strong interaural intensity difference sensitivity responses. Three effects of binaural interaction on the sustained regularity were observed: constant coefficient of variation despite change in rate (66% of the units), negative (20%) and positive (13%) rate-CV relationships. A negative rate-coefficient of variation relationship was the dominant pattern of binaural interaction on the onset regularity.
Nasimi
Ali
A
Department of Physiology, Isfahan University of Medical Sciences, Isfahan, Iran. nasimi@med.mui.ac.ir
Rees
Adrian
A
D000161:Acoustic Stimulation / Q000379:methods; D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004594:Electrophysiology / Q000379:methods; D005260:Female; D006168:Guinea Pigs; D007245:Inferior Colliculi / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000502:physiology*; D012680:Sensitivity and Specificity; D013017:Sound Localization / Q000502:physiology*
J Neurophysiol. 1997 Jun;77(6):2945-65
9212248
J Neurophysiol. 1988 Jul;60(1):1-29
3404211
J Neurophysiol. 1988 Jan;59(1):184-211
3343600
J Neurosci. 2001 Apr 15;21(8):2861-77
11306638
Exp Brain Res. 1987;68(2):379-92
3691710
J Neurosci. 2008 Dec 24;28(52):14230-44
19109505
J Neurophysiol. 1994 May;71(5):1797-825
8064349
Brain Res. 1989 Oct 23;500(1-2):302-12
2605499
J Neurophysiol. 1987 Apr;57(4):1130-47
3585457
Hear Res. 1992 Aug;61(1-2):73-85
1526896
J Comp Physiol A. 1992 Nov;171(4):541-53
1469669
Brain Res. 1992 Feb 14;572(1-2):5-18
1611537
J Neurophysiol. 1998 May;79(5):2416-31
9582217
J Neurosci. 1993 May;13(5):2050-67
8478690
J Acoust Soc Am. 1989 Dec;86(6):2172-84
2600308
Med Biol Eng. 1972 Sep;10(5):662-72
5076431
J Neurophysiol. 1990 May;63(5):1191-212
2358869
J Neurophysiol. 1995 Oct;74(4):1701-13
8989406