Slide 10

The intracellular injection of low, high, and low amplitude sine waves at 2 Hz results in a decrease in responsitivity that is similar to that occuring during contrast adaptation to visual stimuli (left traces). Replacement of the low amplitude sine wave with hyperpolarizing current pulses reveal that the hyperpolarization following adaptation is associated with an increase in apparent input conductance (right traces). This result indicates that adaptation is an intrinsic properties of cortical pyramidal neurons and is mediated by a hyperpolarization of the membrane potential.