Siyi Bai1,4 · Xinyuan Cao1  · Min Xie1  · Guanglong Sun1  · Xiaohui Wang1,4 · Leilei Zheng1  · Xinjian Li1,3 · Zheng Lin1  · Lixia Gao1,2,3,4

1 Department of Psychiatry, The Second Affiliated Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou 310058, China 

2 Nanhu Brain-computer Interface Institute, Hangzhou 311100, China 

3 NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Science and Brain‑machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China 

4 Key Laboratory of Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, China

Abstract

The acoustic flutter is processed through complementary monotonic rate coding and cannot be modulated by other acoustic parameters in the auditory cortex (AC). However, it remains unclear how the inferior colliculus (IC) encodes acoustic flutter, especially when changing other acoustic parameters. Here, we recorded IC neural activity in response to acoustic flutter and determined the existence of conjunctive processing between repetition rate and other acoustic parameters. We found that most IC neurons also encode the repetition rate at the flutter range through complementary monotonic rate coding. In addition, although the acoustic parameters did not change their monotonicity, most IC neurons encode both repetition rate and other acoustic parameters, different from the flutter processing in AC. Thus, complementary monotonic rate coding for acoustic flutter was widespread in the auditory system; however, coding specificity for repetition rate increased from IC to AC, and the capacity for conjunctive coding with other acoustic parameters decreased.

Keywords

Acoustic flutter; Repetition rate; Inferior colliculus; Synchronized neurons; Non-synchronized neurons; Monotonic rate coding; Nonhuman primate; Marmoset

[SpringerLink]