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. Author manuscript; available in PMC: 2010 Jul 2.
Published in final edited form as: Neurobiol Learn Mem. 2009 Jan 23;91(3):298–309. doi: 10.1016/j.nlm.2008.12.010

Fig. 4.

Fig. 4

Differential spectro-temporal response profiles for the pre-training baseline (A and D), 24 h post-initial-training (B and E) and 24 h post-reversed-contingencies-training (C and F). The plots represent original 3-D response surfaces (A–C) and 2-D response maps (D–F) as areas delineating quintiles; each color represents the area containing 20% of responses measured according to their amplitudes ranked top to bottom. (A and D) Pre-training response differences (IP minus IU) were small: they were slightly smaller around the CS frequency (horizontal dashed line) and modestly larger at sidebands in the IP animals compared to the IU group. The color of the peaks corresponds to high positive differential values (responses in IP animals greater than responses in IU animals); the color of the valleys corresponds to negative differential values (responses in IU animals greater than responses in IP animals). (B and E) Initial training, as measured 24 h later (IP minus IU), resulted in a CS-specific associative effect in the IP compared to the IU groups. The peak on the response surface (B) occupies the space only at and around the CS frequency while the valleys occupy the sideband frequencies’ territory. (E) The quantified response profile (IP minus IU) provides further detail of the spectro-temporal domain of the conditioning effect. It shows that the maximum behavioral associative effect took place at and around the CS, with maximum occurring ~1–3 s after tone onset. These changes indicate the formation of specific associative behavioral memory following tone–NBstm pairing. (C and F) After reversal of the contingencies (IU minus IP on this plot), the IU group acquired specific associative memory compared with the IP group. This time, however, the maximum response occurred with a longer latency of ~5–10 s. Such an evolution indicates that associative training after unpaired CS and NBstm presentation is still effective, although delayed. This process is accompanied by a concomitant decrement in responses to tones surrounding the CS-band frequencies. Such a center/periphery response combination, being more precise in frequency and time dimensions, enhances the signal-to-noise resolution of the system in detecting and responding to the CS frequency.