Binaural Response Properties and Sensitivity to Interaural Difference of Neurons in the Auditory Cortex of the Big Brown Bat, Eptesicus fuscus. (1st January 2020)

• Record Type: Journal Article
• Authors: Yang, Ying; Chen, Qi Cai; Shen, Jun Xian; Jen, Philip H.-S.
• Is Part Of: Neuroscience. Volume 424(2020)
• Page Start: 72
• Page End: 85
• Publication Date: 2020-01-01
• Subjects: AC auditory cortex -- BF best frequency -- EE excitation–excitation -- EI excitation–inhibition -- EO contralateral excitation -- FTCs frequency tuning curves -- ILD inter-aural level differences -- LLF latency-level function -- MT minimum threshold -- PST peri-stimulus-time -- RLFs rate-level functions; bat -- binaurality and frequency representation -- interaural level difference (ILD) -- tonotopic organization -- primary auditory cortex; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2019.11.024
• Languages: English
• ISSNs: 0306-4522

Abstract

Highlights: Frequency and binaurality representation in the AC of the big brown bat, Eptesicus fuscus, is studied. The number of impulses and latency of AC neurons varied with sound level and inter-aural level differences (ILD). AC neurons are columnarly organized in best frequency, minimum threshold, binaurality and ILD curves. Different frequency and binaurality representation in the AC of three bat species is compared and discussed. Abstract: This study examines binaural response properties and sensitivity to interaural level difference of single neurons in the primary auditory cortex (AC) of the big brown bat, Eptesicus fuscus under earphone stimulation conditions. Contralateral sound stimulation always evoked response from all 306 AC neurons recorded but ipsilateral sound stimulation either excited, inhibited or did not affect their responses. High best frequency (BF) neurons typically had high minimum threshold (MT) and low BF neurons had low MT. However, both BF and MT did not correlate with their recording depth. The BF of these AC neurons progressively changed from high to low along the anteromedial-posterolateral axis of the AC. Their number of impulses and response latency varied with sound level and inter-aural level differences (ILD). Their number of impulses typically increased either monotonically or non-monotonically to a maximum and the latency shortened to a minimum at a specific sound level. Among 205 AC neurons studied at varied ILD, 178 (87%) and 127 (62%) neurons discharged maximally and responded with the shortest response latency at a specific ILD, respectively. Neurons sequentially isolated within an orthogonal electrode puncture shared similar BF, MT, binaurality and ILD curves. However, the response latency of these AC neurons progressively shortened with recording depth. Species-specific difference among this bat, the mustached bat and the pallid bat is discussed in terms of frequency and binaurality representation in the AC.