Fan Langchen, Henry Kenneth S, Carney Laurel H
Department of Biomedical Engineering, University of Rochester, Rochester, NY, United States.
Department of Neuroscience, University of Rochester, Rochester, NY, United States.
Front Neurosci. 2022 Dec 1;16:997656. doi: 10.3389/fnins.2022.997656. eCollection 2022.
Human listeners are more sensitive to tones embedded in diotic noise when the tones are out-of-phase at the two ears (NS) than when they are in-phase (NS). The difference between the tone-detection thresholds for these two conditions is referred to as the binaural masking level difference (BMLD) and reflects a benefit of binaural processing. Detection in the NS condition has been explained in modeling studies by changes in interaural correlation (IAC), but this model has only been directly tested physiologically for low frequencies. Here, the IAC-based hypothesis for binaural detection was examined across a wide range of frequencies and masker levels using recordings in the awake rabbit inferior colliculus (IC). IAC-based cues were strongly correlated with neural responses to NS stimuli. Additionally, average rate-based thresholds were calculated for both NS and NS conditions. The rate-based neural BMLD at 500 Hz matched rabbit behavioral data, but the trend of neural BMLDs across frequency differed from that of humans.
当双耳的音调不同相（NS）时，与同相（NS）相比，人类听众对嵌入双耳噪声中的音调更敏感。这两种情况下音调检测阈值的差异被称为双耳掩蔽级差（BMLD），它反映了双耳处理的优势。在建模研究中，通过双耳相关性（IAC）的变化来解释NS条件下的检测，但该模型仅在生理上针对低频进行了直接测试。在此，使用清醒家兔下丘（IC）的记录，在广泛的频率和掩蔽水平范围内检验了基于IAC的双耳检测假设。基于IAC的线索与对NS刺激的神经反应密切相关。此外，还计算了NS和NS条件下基于平均发放率的阈值。500Hz时基于发放率的神经BMLD与家兔行为数据相符，但神经BMLD随频率的变化趋势与人类不同。
