Figure 7. Spatial generalization of the effect of conditioning in a simple cell recorded in a 12-week-old kitten.

Conventions are as in Fig. 6. The RF was characterized before and after pairing in 8 positions and showed a simple structure with non-overlapping ‘on’ and ‘off’ fields. The fourth position (arrow) was submitted to 40 differential pairing trials (data not shown) during which the ‘on’ response was associated with a negative pulse of current (S⁻, -7 nA) and the ‘off’ response paired with a positive current (S⁺, +11 nA). After conditioning, the balance of ‘on’ and ‘off’ responses was modified across the whole extent of the RF: ‘on’ responses in the ‘on’ field were significantly decreased, while ‘off’ responses evoked in the ‘off’ field were potentiated. The GCR changed accordingly from 0.27 to 0.57 (P < 0.0011). Calibration bars: A, 1 s, 10 AP s⁻¹, 0.5 deg; B, 5 AP trial⁻¹.