DOI: 10.5061/dryad.n1h4n
title: Data from: How spatial release from masking may fail to function in a highly directional auditory system

description: Spatial release from masking (SRM) occurs when spatial separation between
 a signal and masker decreases masked thresholds. The mechanically-coupled
 ears of Ormia ochracea are specialized for hyperacute directional hearing,
 but the possible role of SRM, or whether such specializations exhibit
 limitations for sound source segregation, is unknown. We recorded
 phonotaxis to a cricket song masked by band-limited noise. With a masker,
 response thresholds increased and localization was diverted away from the
 signal and masker. Increased separation from 6° to 90° did not decrease
 response thresholds or improve localization accuracy, thus SRM does not
 operate in this range of spatial separations. Tympanal vibrations and
 auditory nerve responses reveal that localization errors were consistent
 with changes in peripheral coding of signal location and flies localized
 towards the ear with better signal detection. Our results demonstrate
 that, in a mechanically coupled auditory system, specialization for
 directional hearing does not contribute to source segregation.
description: Translational velocity
 in response to the target signal and masker presented
 aloneMasker presentation
 started and ended 0.5 and 4.5 seconds after the onset of data acquisition
 respectively. Signal presentation started and ended 1.0 and 4.0 seconds
 after the onset of data acquisition, respectively. Data plotted in figure
 2A.Figure_2
 - source data 1.xlsxSteering velocity in
 response to the target signal and noise aloneMasker presentation
 started and ended 0.5 and 4.5 seconds after the onset of data acquisition
 respectively. Signal presentation started and ended 1.0 and 4.0 seconds
 after the onset of data acquisition, respectively. Data plotted in figure
 2B.Figure_2
 - source data 2.xlsxVirtual walking path in
 response to the target signal and masker presented alone‘X’ and ‘Y’ coordinates
 of virtual walking paths measured from the trackball system. Data plotted
 in figure 2C.Figure_2 - source data
 3.xlsxBehavioral response
 thresholds in response to a target signal in quiet, spatially grouped, and
 separated signal and maskerData plotted in figure
 3.Figure_3
 - source data 1.xlsxTranslational velocity
 in response to spatially grouped target signal and masker presented at
 different signal-to-noise ratios (SNRs)The target signal was
 presented at 76 dB SPL while the masker intensity was varied to achieve
 three SNRs (-6, 0, +6 dB). Masker presentation started and ended 0.5 and
 4.5 seconds after the onset of data acquisition respectively. Signal
 presentation started and ended 1.0 and 4.0 seconds after the onset of data
 acquisition, respectively. Data plotted in figure 4A
 (left).Figure 4 - source data
 1.xlsxSteering velocity in
 response to spatially grouped target signal and masker presented at
 different signal-to-noise ratios (SNRs)The target signal was
 presented at 76 dB SPL while the masker intensity was varied to achieve
 three SNRs (-6, 0, +6 dB). Masker presentation started and ended 0.5 and
 4.5 seconds after the onset of data acquisition respectively. Signal
 presentation started and ended 1.0 and 4.0 seconds after the onset of data
 acquisition, respectively. Data plotted in figure 4B
 (left).Figure 4 - source data
 2.xlsxVirtual walking path in
 response spatially grouped target signal and masker presented at different
 signal-to-noise ratios (SNRs).The target signal was
 presented at 76 dB SPL while the masker intensity was varied to achieve
 three SNRs (-6, 0, +6 dB). ‘X’ and ‘Y’ coordinates of virtual walking
 paths measured from the trackball system. Data plotted in figure 4C
 (left).Figure 4 - source data
 3.xlsxTranslational velocity
 in response to spatially separated target signal and masker presented at
 different signal-to-noise ratios (SNRs).The target signal was
 presented at 76 dB SPL while the masker intensity was varied to achieve
 three SNRs (-6, 0, +6 dB). Masker presentation started and ended 0.5 and
 4.5 seconds after the onset of data acquisition respectively. Signal
 presentation started and ended 1.0 and 4.0 seconds after the onset of data
 acquisition, respectively. Data plotted in figure 4A
 (right).Figure 4 - source data
 4.xlsxSteering velocity in
 response to spatially separated target signal and masker presented at
 different signal-to-noise ratios (SNRs)The target signal was
 presented at 76 dB SPL while the masker intensity was varied to achieve
 three SNRs (-6, 0, +6 dB). Masker presentation started and ended 0.5 and
 4.5 seconds after the onset of data acquisition respectively. Signal
 presentation started and ended 1.0 and 4.0 seconds after the onset of data
 acquisition, respectively. Data plotted in figure 4B
 (right).Figure 4 - source data
 5.xlsxVirtual walking path in
 response to spatially separated target signal and masker presented at
 different signal-to-noise ratios (SNRs).The target signal was
 presented at 76 dB SPL while the masker intensity was varied to achieve
 three SNRs (-6, 0, +6 dB). ‘X’ and ‘Y’ coordinates of virtual walking
 paths measured from the trackball system. Data plotted in figure 4C
 (right).Figure 4 - source data
 6.xlsxVirtual walking path in
 response to the target signal presented in isolation.The target signal was
 presented at 76 dB SPL from a forward speaker. ‘X’ and ‘Y’ coordinates of
 virtual walking paths measured from the trackball system. Data plotted in
 figure 5A.Figure_5- source data
 1.xlsxVirtual walking path in
 response to spatially grouped target signal and masker presented at equal
 intensity.The target signal was
 presented at 76 dB SPL from a forward speaker while the masker was
 presented at the same intensity from an adjacent speaker to the right. ‘X’
 and ‘Y’ coordinates of virtual walking paths measured from the trackball
 system. Data plotted in figure 5B.Figure_5- source data
 2.xlsxVirtual walking path in
 response to spatially grouped target signal and masker presented at equal
 intensity.The target signal was
 presented at 76 dB SPL from a forward speaker while the masker was
 presented at the same intensity from an adjacent speaker to the left. ‘X’
 and ‘Y’ coordinates of virtual walking paths measured from the trackball
 system. Data plotted in figure 5C.Figure_5- source data
 3.xlsxVirtual walking path in
 response to spatially grouped target signal and maskers presented at equal
 intensity.The target signal was
 presented at 76 dB SPL from a forward speaker while two coherent maskers
 were presented at the same combined intensity from adjacent speakers to
 the left and right of the signal speaker. ‘X’ and ‘Y’ coordinates of
 virtual walking paths measured from the trackball system. Data plotted in
 figure 5D.Figure_5- source data
 4.xlsxVirtual walking path in
 response to spatially separated target signal and masker presented at
 equal intensityThe target signal was
 presented at 76 dB SPL from a forward speaker while the masker was
 presented at the same intensity from a lateral speaker to the right. ‘X’
 and ‘Y’ coordinates of virtual walking paths measured from the trackball
 system. Data plotted in figure 5E.Figure_5- source data
 5.xlsxVirtual walking path in
 response to spatially separated target signal and masker presented at
 equal intensityThe target signal was
 presented at 76 dB SPL from a forward speaker while the masker was
 presented at the same intensity from a lateral speaker to the left. ‘X’
 and ‘Y’ coordinates of virtual walking paths measured from the trackball
 system. Data plotted in figure 5F.Figure_5- source data
 6.xlsxVirtual walking path in
 response to spatially grouped target signal and maskers presented at equal
 intensityThe target signal was
 presented at 76 dB SPL from a forward speaker while two coherent maskers
 werepresented at the same combined intensity from lateral speakers to the
 left and right of the signal speaker. ‘X’ and ‘Y’ coordinates of virtual
 walking paths measured from the trackball system. Data plotted in figure
 5G.Figure_5- source data
 7.xlsxRaw traces of tympanal
 vibration in response to combined signal and masker under conditions of
 masker source located near (grouped) or far (separated) from signal
 source.Ipsi- and contralateral
 refer to the masker. Signal pulses were repeated at 400 ms intervals
 during continuous masker broadcast.Figure 6 - source data
 1.xlsxNormalized-amplitude
 tympanal vibration responsesVibration measurements
 are normalized to the peak response in response to the target signal. Data
 plotted in figure 6B, C.Figure 6 - source data
 2.xlsxSmoothed tympanal
 vibration responses.Measurements smoothed
 with a 2000-point sliding rms window.Figure 6 - source data
 3.xlsxEffective amplitude
 measurementsEffective amplitude
 measurements (i.e. within-trace signal-to-noise ratio) from smoothed
 tympanal responses for 23 iterations of signal within the masker. Signal
 amplitudes were measured from 30 ms time segments corresponding with
 signal pulses; masker amplitudes were measured from 30 ms segments in the
 middle of the interpulse interval (i.e. 200 ms after signal-pulse onset).
 Data plotted in figure 6D.Figure 6 - source data
 4.xlsxRaw laser vibrometry
 measurements from the masker ipsi- and contralateral ears in response to
 spatially separated target signal and masker at varied signal-to-noise
 ratios (SNRs)The target signal was
 broadcast from the forward location at 76 dB SPL while the masker was
 broadcast from a lateral position at varied intensities to achieve three
 SNRs (-6, 0, +6 dB). Data from different flies are found as separate Excel
 sheets within the data file. Effected amplitude measurements derived from
 the raw data are plotted in figure 7A. Figure 7 – Source data 2.
 Mid-angular headings from behavioural experiments. Excel file include
 responses to a 76 dB SPL target signal broadcast alone from the forward
 speaker, a masker broadcast alone from the forward speaker, and the 76 dB
 SPL target signal and masker broadcast at varied signal-to-noise ratios
 (-6, 0, +6 dB) from spatially grouped or separated speakers. Data plotted
 in figure 7C.figure_7 - source data
 1.xlsxMid-angular headings
 from behavioural experiments.Excel file include
 responses to a 76 dB SPL target signal broadcast alone from the forward
 speaker, a masker broadcast alone from the forward speaker, and the 76 dB
 SPL target signal and masker broadcast at varied signal-to-noise ratios
 (-6, 0, +6 dB) from spatially grouped or separated speakers. Data plotted
 in figure 7C.figure_7 - source data
 2.xlsxRoot Mean Square (RMS)
 values calculated from multiunit recordings of left and right auditory
 nerve.RMS calculated over 40
 ms time segments during an interval with a target signal and a spatially
 separated masker broadcast at varied signal-to-noise ratios (-18, -12, -6,
 0, +6 dB), and an equivalent time window during masker broadcast alone.
 Signal detection theory was applied to RMS measurements to masked
 thresholds for the masker ipsi- and contralateral ears. These data are
 plotted in figure 8C.figure_8 - source data
 1.xlsx