@inproceedings {Palanca-Castan1799_2016,
	year = {2016},
	author = {Palanca-Castan, Nicolas and Laumen, Geneviève and Reed, Darrin and Köppl, Christine},
	title = {Characterization of the Binaural Interaction Component in Barn Owl (Tyto alba)},
	booktitle = {Assoc. Res. Otolaryng. MidWinter Meeting (ARO)},
	URL = {http://c.ymcdn.com/sites/www.aro.org/resource/resmgr/Abstract_Archives/UPDATED_2016_ARO_Abstract_Bo.pdf},
	abstract = {Background
The auditory brainstem response (ABR) is an evoked potential
that reflects the responses to sound by the brainstem neural
centers. The binaural interaction component (BIC) is obtained
by subtracting the sum of the monaural ABR responses from
the binaural response. It is assumed to represent the activity
of binaural nuclei (Jewett, 1970, Electroencephalogr. Clin.
Neurophysiol. 28: 609–618). The amplitude and latency
of the BIC are dependent on the binaural cues presented
(Furst et al., 1990, Hear. Res. 187: 63–72). The BIC can be
used to non-invasively test binaural processing. However,
any conclusions are limited by the lack of knowledge of the
relevant processes at the level of individual neurons. The aim
of this study is to characterize the ABR and BIC in the barn
owl, an animal where the ITD-processing neural circuits have
been extensively studied.
Methods
ABRs were measured in 9 adult barn owls. Responses to
chirps at different levels and ITDs were recorded, and the BIC
was derived as a function of ITD. To determine the extent of
the crosstalk caused by the presence of the interaural canal,
compound action potential (CAP) recordings were collected
for two other adult barn owls. All BIC measurements were
taken below the level of crosstalk.
Results
The ABR in barn owl showed 2-3 waves in the first 10 ms of
recording. Wave I only appeared consistently at high levels.
Wave II and III increased in amplitude and decreased in latency
with increasing stimulus level. The most salient component of
the BIC was a negative deflection (DN1) that corresponded
to wave III. The latency of DN1 closely corresponded to the
latency of local neurophonic potentials recorded in nucleus
laminaris (Carr et al. 2015, J. Neurophysiol., in press). Both
the amplitude and latency of DN1 varied with changing ITD.
Conclusion
The most visible component of the BIC (DN1) was
associated with nucleus laminaris and is thus likely to reflect
the known processes of ITD computation in this nucleus.
DN1 was a negative deflection, which indicates a smaller
response to binaural stimulation than predicted by the
sum of monaural responses. This negative polarity is not
consistent with previous predictions (Wada and Starr, 1989,
Electroencephalogr. Clin. Neurophysiol. 56, 340–351) for an
excitatory-excitatory system such as the one present in barn
owl, and alternative models like the one by Gaumond and
Psaltikidou (1991, J. Acoust. Soc. Am. 89: 454:456) need to
be considered.
Funding
NPC, GL, CK funded by the DFG (TRR31) and the cluster of
excellent “Hearing4all”. DK supported by the program “Function
and pathophysiology of the auditory system” funded by
the state of Lower Saxony, Germany.}
}