Resolution in azimuth sound localization in the Mongolian gerbil (Meriones unguiculatus)

Abstract

Minimum resolvable angles (MRAs) for sound localization in azimuth in the gerbil were determined in a behavioral study using tones, 300-Hz bands of noise centered at frequencies between 500 Hz and 8 kHz and broad-band noise of on average 60 dB SPL overall level. Using the method of constant stimuli, seven gerbils were trained in a two-alternative-forced-choice procedure to indicate if sounds were presented to them from the left or from the right by choosing the left or right arm of a Y-shaped cage. The MRA is the minimum angle between two loudspeaker locations that the gerbils discriminated. Animals were either stimulated from the front (N=4) or from the back (N=3). The MRA for broad-band noise randomly varying in level by +/- 6 dB was 23 degrees and 45 degrees for gerbils stimulated from the front or back, respectively. Generally a gerbil's MRA for tones declined up to 2 kHz reaching 20 degrees and 31 degrees for gerbils stimulated from the front or back, respectively, and the MRA was generally increased above this frequency. Results for narrow-band noise stimuli were similar. Results are discussed with respect to the available interaural cues and physiological mechanisms of sound localization in the gerbil.

Population Coding of Interaural Time Differences in Gerbils and Barn Owls

“…Because there have been relatively few studies on the ability of gerbils to localize sounds using ITDs (Heffner and Heffner, 1988;Maier and Klump, 2006;Maier et al, 2008), we tested their ability to localize sounds in the horizontal plane using a 2AFC task, the design of which is illustrated in Figure 1a. We trained gerbils to place their nose in a ring to disrupt a light beam and elicit a sound from one of two speakers, which were spaced symmetrically about the midline at various angles.…”

Anatomical connections suitable for the direct processing of neuronal information of different modalities via the rodent primary auditory cortex

“…Consequently, the gerbil has become a highly valuable animal model for auditory (for some overview see Budinger and Klump, 2008), visual (Ellard, 1998;Fite et al, 2003), other sensory (Vallejo et al, 2000;Hwang et al, 2008) and multisensory studies (Cahill et al, 1996;Budinger et al, 2006). It is also successfully used for investigations on brain development, aging and disease (Cheal, 1986;Stuermer and Scheich, 2000;Gleich et al, 2007;Kotak et al, 2007), behaviour (e.g., sound localization: Maier and Klump, 2006;Siveke et al, 2008), learning and memory mechanisms Schicknick et al, 2008).…”

Exploring binaural hearing in gerbils (Meriones unguiculatus) using virtual headphones

“…Four earlier studies investigated gerbils’ sound localization of tones or narrow-band signals between 500 Hz and 20 kHz [9–11,48]. To compare data across studies, we calculated or extracted minimal resolvable angles (MRAs, for details, see [11]) from the present data and data from three of the four previous studies (S5 Fig). In general, the MRAs across studies and frequencies fell within the same range.…”

“…Because of its good low frequency hearing that parallels that of humans [6], studying sound localization and the processing of interaural time differences (ITDs) in this species has received particular attention [1,5,7–12]. Though the gerbil's sound localization ability has been investigated extensively by a number of laboratories [7,9–11], its behavioral sensitivity to ITDs and interaural level differences (ILDs), the major cues for sound localization in the azimuthal plane, remains unknown. So far, the gerbil's ITD and ILD sensitivity has only been inferred from acoustic measurements [13] and derived from its sound localization performance using free-field stimuli that favor the use of either interaural cue [9–11].…”

“…Though the gerbil's sound localization ability has been investigated extensively by a number of laboratories [7,9–11], its behavioral sensitivity to ITDs and interaural level differences (ILDs), the major cues for sound localization in the azimuthal plane, remains unknown. So far, the gerbil's ITD and ILD sensitivity has only been inferred from acoustic measurements [13] and derived from its sound localization performance using free-field stimuli that favor the use of either interaural cue [9–11]. Knowledge of the behavioral sensitivities of gerbils to ITDs and ILDs will pose an important step towards interpreting findings from physiological studies.…”