Article Figures & Data
Figures
- Figure 1.
Acoustic stimuli. Oscillogram of the pulse-echo (echo highlighted in blue) pairs and spectrogram and power spectra of the echoes used as stimulus. Insets indicate the frequencies of the amplitude notches in the echoes of surface. The emitted signal was a 3-ms downward frequency-modulated sweep starting at 70 kHz and ending at 20 kHz.
- Figure 2.
Topographical organization of the CF and the mean FSL in the A1 of the Mexican free-tailed bat. A, CF as a function of the anterior-posterior location. B, Mean FSL as a function of the cortical location. C, Relation between CF and mean FSL. Details about the topographical and functional organization of the A1 in the Mexican free-tailed bat can be found in Macias et al. (2019).
- Figure 3.
Example response to repetitive stimuli. A, Frequency response area of an example neuron tuned with a CF of 35 kHz. The CF coincides with the frequency of one of the amplitude notches in the echo recorded from the 150-grit sandpaper. B, Dot-raster display of the response of the neuron shown in A to three sequences of different repetition rate. In each response, blue dots represent the response to the flat surface and red dots represent the response to the 150-grit sandpaper. C, Number of spikes as a function of time for the responses shown in B. D, Mean FSL as a function of time for the responses shown in B. E, Latency stability across trials calculated as the SD of the mean FSL as a function of time for the responses shown in B. F, Response precision calculated as the HWHH of the autocorrelation function of the PSTH as a function of time.
- Figure 4.
Responses to repetitive stimuli in the cortical neuronal population. A, In response to the 10-Hz sequence, the number of spikes per trial did not change across time for any of the three surfaces (flat, 60- and 150-grit). B, C, There is a reduction of the number of spikes across time in response to the 12- and 15-Hz sequences for the three surfaces. Red line indicates the mean normalized number of spikes for all 165 neurons. D, In response to the 10-Hz sequence, there are no changes in the latency stability across time for any of the three surfaces (flat, 60- and 150-grit). E, F, There is an increase of the latency stability (reduction of the SD of the FSL) across time in response to the 12- and 15-Hz sequences for the three surfaces. G, There were no changes in the response precision (calculated as the HWHH on the autocorrelation function of the PSTH) across time in response to the 10-Hz sequence. H, I, Decrease of the HWHH in response to the 12- and 15-Hz sequences.
- Figure 5.
Sequences of pulses-echoes at high repetition rate increase SNRs of neuronal synchronization patterns. A, Synchronization patterns calculated for the responses to the first and the tenth pulse-echo pairs from the flat surface of each repetition rate. B, Synchronization patterns calculated for the responses to the first and the tenth pulse-echo pairs from the 60-grit surface of each repetition rate. C, Synchronization patterns calculated for the responses to the first and the tenth pulse-echo pairs from the 150-grit surface of each repetition rate. All synchronization matrices were calculated for 155 neurons from four bats. D, SNR calculated for each synchronization pattern in response to the three sequences. In each plot, black lines represent the response to the flat surface, red line represents the response to the 60-grit surface, and blue line represents the response to the 150-grit surface. SNR was calculated using the response to the first pulse-echo pair in each sequence as a reference.
- Figure 6.
MI and the effect of sample size (# trials). Performance for bias-correction method used to calculate information values. Figure shows the data from the responses of neurons tuned to 30 kHz. Data were generated with statistics derived from the real experimental data to assess whether the number of trials included was sufficient for accurate calculation of MI). Calculation of MI was accurate at >15 trials, which was less than the number (30) used in our study.
- Figure 7.
MI increases across time. A, Non-notched neuron (CF does not coincide with the frequency of any notch). B, Example neuron with CF = 30 kHz. C, Example neuron with CF = 35 kHz. D, Example neuron with CF = 45 kHz. MI across time for each example neuron is represented in blue. Gray lines represent MI across time for all the recorded neurons. Red line indicates mean MI for all neurons in each group.
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