Figure 10.
Population averaged phase locking responses to AM. Yellow lines indicate attend AM condition, blue lines indicate attend BW condition. A and B: VSpp-based discriminability (ROCa) of AM from unmodulated sounds. In cells that were significant VS encoders both A1 (A, n = 30) and ML (B, n = 37), VSpp-based discriminability of AM was not significantly different between attention conditions at any AM level (P > 0.05, signed-rank test). At low modulation depths (AM level = 1), A1 had significantly better AM discriminability than ML (P = 0.02, Wilcoxon rank sum test); however, they were not significantly different at the higher modulation depths (AM levels 2 and 3, P > 0.05, Wilcoxon rank sum test). C and D: population averaged phase locking responses (VSpp) in all cells for A1 (C, n = 92) and ML (D, n = 122). VSpp is greater in A1 (C) than ML (D) at low AM depths (AM level 1, P = 0.01; AM level 2, P = 0.002, Wilcoxon ranked sum test), though phase locking is more similar (not significantly different) at the highest AM depth (P = 0.73, Wilcoxon ranked sum). There was no significant difference in either VSpp between attentional conditions in either area (P > 0.05 for all AM levels, Wilcoxon signed rank test). AM, amplitude modulation; A1, primary auditory cortex; BW, bandwidth; ML, middle lateral belt; ROCa, area under the receiver operating characteristic; VSpp, phase-projected vector strength.