Figure 3.

Cholinergic influences on the auditory cortical organization without fear conditioning. The representative best frequency map, derived from cortical mapping of respones to pure tones of 45 different frequencies at 15 different intensities, show tonotopy of naïve primary auditory cortex (A) and the corresponding map following the pairing of 9 kHz sounds with stimulation of the cholinergic nucleus basalis of the basal forebrain (B). A comparable auditory cortical reorganization did not occur with pairing of sounds with such stimulation after a lesioning of cholinergic rather than GABAergic nucleus basalis neurons. Credit: From Kilgard and Merzenich (1998). Reprinted with permission from AAAS.