1 2 3 4 5 Dynamic sound localization in cats 6 7 8

2 3 4 5 Dynamic sound localization in cats 6 7 8 Janet L. Ruhland, Amy E. Jones, and Tom C.T. Yin 9 Department of Neuroscience and the Neuroscience Training Program 10 University of Wisconsin 11 Madison, Wisconsin 53706 12 13 14 15 Abbreviated title: Dynamic sound localization 16 17 18 Electronic mail:[email protected] 19 Current address: 20 Dept. of Neuroscience and Neuroscience Training Program 21 290 Medical Science Bldg. 22 University of Wisconsin-Madison 23 Madison, WI 53706 24 608 262 0368 (voice) 25 608 265 5512 (FAX) 26 27 ABSTRACT 28 Sound localization in cats and humans relies on head-centered acoustic cues. Studies have shown that 29 humans are able to localize sounds during rapid head movements that are directed toward the target or other objects 30 of interest. We studied whether cats are able to utilize similar dynamic acoustic cues to localize acoustic targets 31 delivered during rapid eye-head gaze shifts. We trained cats with visual-auditory two-step tasks in which we 32 presented a brief sound burst during saccadic eye-head gaze shifts toward a prior visual target. No consistent or 33 significant differences in accuracy or precision were found between this dynamic task (two-step saccade) and the 34 comparable static task (single saccade when the head is stable) in either horizontal or vertical directions. Cats 35 appear to be able to process dynamic auditory cues and execute complex motor adjustments to accurately localize 36 auditory targets during rapid eye-head gaze shifts. 37 38 39 INTRODUCTION 40 41 Sound localization along the horizontal, or azimuthal, 42 plane requires binaural processing of interaural time and 43 level differences (ITDs and ILDs, respectively) of the 44 incoming acoustic signals. ITDs can be computed from 45 pure tone frequencies up to about 1200-1500 Hz via 46 phase locking. Temporal features can also be extracted 47 from complex sounds of higher carrier frequency such as 48 bursts of narrow band noise and sinusoidally amplitude49 modulated (SAM) tones if the modulating frequency is 50 not too high. Localizing sounds in elevation relies on the 51 broadband spectral shapes of head-related transfer 52 functions (HRTFs) that result from the direction53 dependent filtering properties of the head and pinnae 54 (Tollin and Yin, 2009). Both sets of cues are based upon 55 the position of the head relative to the sound source. 56 Human psychophysical studies show that accurate 57 sound localization can occur in situations where the body, 58 head, and ears are moving during sound presentation. 59 Normal hearing listeners typically orient both their head 60 and their gaze toward an auditory target (Fuller, 1992; 61 Thurlow et al., 1967). Studies have shown how head 62 movement could be used as a strategy to facilitate sound 63 localization ability, especially in compromised situations 64 where the sound source contains limited frequencies, the 65 Articles in PresS. J Neurophysiol (June 10, 2015). doi:10.1152/jn.00105.2015