RT Journal Article
SR Electronic
T1 Spectral Integration in the Inferior Colliculus of the Mustached Bat
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 8533
OP 8541
DO 10.1523/JNEUROSCI.20-22-08533.2000
VO 20
IS 22
A1 Scott A. Leroy
A1 Jeffrey J. Wenstrup
YR 2000
UL http://www.jneurosci.org/content/20/22/8533.abstract
AB Acoustic behaviors including orientation and social communication depend on neural integration of information across the sound spectrum. In many species, spectral integration is performed by combination-sensitive neurons, responding best when distinct spectral elements in sounds are combined. These are generally considered a feature of information processing in the auditory forebrain. In the mustached bat's inferior colliculus (IC), they are common in frequency representations associated with sonar signals but have not been reported elsewhere in this bat's IC or the IC of other species. We examined the presence of combination-sensitive neurons in frequency representations of the mustached bat's IC not associated with biosonar. Seventy-five single-unit responses were recorded with the best frequencies in 10–23 or 32–47 kHz bands. Twenty-six displayed single excitatory tuning curves in one band with no additional responsiveness to a second signal in another band. The remaining 49 responded to sounds in both 10–23 and 32–47 kHz bands, but response types varied. Sounds in the higher band were usually excitatory, whereas sounds in the lower band either facilitated or inhibited responses to the higher frequency signal. Interactions were usually strongest when the higher and lower frequency stimuli were presented simultaneously, but the strength of interactions varied. Over one-third of the neurons formed a distinct subset; they responded most sensitively to bandpass noise, and all were combination sensitive. We suggest that these combination-sensitive interactions are activated by elements of mustached bat social vocalizations. If so, neuronal integration characterizing analysis of social vocalizations in many species occurs in the IC.