Figure 7.
A strong correlation between presynaptic and postsynaptic efficacy exists for both L2/3 to L2/3 connections and inputs to L5. a, Quantal size is correlated with release probability for L2/3 to L2/3 connections (r2 = 0.37, p < 0.001). The three colored points refer to the three example connections d–f. The correlation between presynaptic and postsynaptic efficacy also holds for L5 inputs (b; r2 = 0.51, p < 0.01). c, For L 2/3 to L 2/3 connections, Pr is also negatively correlated with N (r2 = 0.36, p < 0.001). The error bars in a–c are SEs. Red dotted lines in a–c represent linear fits. d–f, Representative examples of L2/3 to L2/3 connections for which we were able to fit a binomial model (illustrated in a as colored points; connection d refers to the blue circle, connection e to the pink circle, and connection f to the green circle). The strength of connection is represented by the color, with blue representing a weak connection and green representing a strong connection. Binomial model fit parameters are also listed for each connection.