@inproceedings {Behrens1542_2016,
	year = {2016},
	author = {Behrens, Derik and Klump, Georg Martin},
	title = {Comparison of Sensitivity in Prepulse Inhibition and Operant Conditioning Procedures measuring Sound Localization Acuity in the Mouse},
	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
In an intensity difference limen paradigm in C57BL/6 mice,
the sensitivity observed in an operant conditioning procedure
was much larger than the sensitivity observed with a prepulse
inhibition (PPI) procedure (Behrens & Klump 2015). Here,
we compare the sensitivity of both procedures in a sound
localization paradigm investigating, whether the sensitivity
difference observed in an intensity difference limen paradigm
may also be found in other paradigms.
Methods
The mice were presented with an acoustic background of
repeated 100 ms noise stimuli broadcast from a reference
speaker. At random times, one of the stimuli in the sequence
was replaced by a stimulus that was broadcast from a test
speaker located 12.5° to 180° apart from the reference
speaker. Broadband (20 kHz bandwidth, 20 kHz center
frequency) and narrowband (500 Hz bandwidth, 25 kHz
center frequency) noise stimuli were presented in separate
sessions. In the operant procedure, a Go/No-Go paradigm
with food rewards was used and hit- and false-alarm rates
served to calculate the sensitivity measure d’. In the PPI
procedure, the movement of the mouse elicited by a 110 dB
SPL startle stimulus (35 ms, 2-50 kHz) was measured using
a piezo-electric pressure transducer. We applied an ROC
analysis by comparing the distribution of startle amplitudes
with a change in speaker location to that without such a
change and calculated d(a) values, a sensitivity measure that
corresponds to d’.
Results
For both procedures, the mean sensitivity measure increased
with an increase of the angle between test and reference
speaker. In the operant conditioning procedure, the sensitivity
for large speaker separations reached d’-values of around
3.0 (broadband noise) and 2.0 (narrowband noise). The
results obtained by the PPI procedure showed a much lower
sensitivity, reaching da-values of 1.0 (broadband noise) and
only 0.3 (narrowband noise).
Conclusions
The higher sensitivity observed in the operant procedure
results in lower thresholds for localizing broadband noise
than in the PPI procedure in which the subjects showed a
lower sensitivity. The operant procedure also revealed a large
sensitivity of C57BL/6 mice to localize narrowband noise
stimuli, whereas in the PPI procedure the sensitivity was so
low that no threshold could be determined. Thus, the operant
procedure will allow obtaining measures of localization acuity
when the PPI procedure fails. The observation of a higher
sensitivity in operant conditioning procedures compared to
PPI procedures appears to be a more general effect.
Funding
This study was funded by the DFG (TRR 31 and Cluster of
Excellence “Hearing4all”)}
}