Figure 4.

Operant sensory discrimination task. A, B, Cats were presented vertical (CS⁻, A) or horizontal gratings (CS⁺, B). The CS⁺ had a variable duration (10–18 s) and was followed by a second grating (4 s) of shifted orientation (5–45°), during which the cat had to lick to obtain a liquid food reward at CS⁺ offset. Each session, ∼25 CS⁺ and 25 CS⁻ were presented in random order (40 s between onset of each CS). C, D, Lick frequency (y-axis) as a function of time (x-axis) during trials where the CS⁺ (C) or CS⁻ (D) were presented.