Abstract:

Objective To explore the effects of stimulus intensity on gap detection responses of onset neurons in inferior colliculus(IC) of guinea pigs.  Methods Gap stimuli were noise bursts, with levels from 10 to 80?dB SPL. A series of silent gaps including 0, 1, 2, 4, 8, 16, 48 and 96ms gap duration were embedded between the initial 100?ms white noise burst (NB1) and the final 50ms burst (NB2) in the stimuli. The minimal gap threshold (MGT), first spike latency (FSL) andNB2 recovery rate were also analyzed according to four intensity groups: minimum threshold (MT), MT+10dB SPL (MT+10), MT+20dB SPL(MT+20), and MT+30dB SPL(MT+30). ResultsThirtyfive onset units were collected from 96 recorded neurons. The average MGT was (22.91±4.36)ms, (9.00±2.69)ms, (4.00±0.49)ms and (11.33±3.11)ms in the groups of MT, MT+10, MT+20 and MT+30, respectively (P<0.01). However, this effect was not significant among the group of suprathreshold. The NB2recovery rate in 48ms gap duration was 0.44±0.15, 0.83±0.12, 0.88±0.07 and 0.61±0.10, respectively. The FSL in 0ms gap duration was (12.86±0.72)ms, (11.65±0.64)ms, (11.03±0.65)ms and (10.68±0.55)ms respectively in the four groups. ConclusionThe level of white noise gap stimuli has some effects on thegap response in the onset unit of inferior colliculus in guinea pigs.

Key words: Guinea pig; Inferior colliculus; Gap detection; Stimulus intensity