Figure 1. Response homeostasis is maintained on a cell-by-cell basis in vivo in β2^−/− and BMPr-mutant mice but not AC1^−/− mice.

All graphs depict scatter plots of receptive field (RF) peak response versus RF area in the log domain on a cell-by-cell basis. A, response homeostasis in β2^−/− SC neurons (from Chandrasekaran et al. 2007, reproduced with persmission from the Society for Neuroscience). Both control and β2^−/− neuron responses are fitted well by a line of slope −1, demonstrating that, in each cell, RF area and response are precisely coordinated (control as grey circles; r²= 0.59; β2^−/− as black circles; r²= 0.58). B, response homeostasis in BMPr mutants (from Chandrasekaran et al. submitted). Plot of RF peak response versus RF area from littermate control (r²= 0.67) and BMPr mutant cells (r²= 0.7) are well fitted by a line of slope −1, demonstrating that the changes in RF shape do not prevent neurons in the SC from maintaining response homeostasis. C, response homeostasis is disrupted in AC1^−/− SC neurons (from Shah et al. submitted). Control neuron responses are fitted well by a line of slope −1, demonstrating that, in each cell, RF area and response are precisely coordinated (control as grey squares; r²= 0.53). In AC1^−/− neurons, however, such a relationship does not hold, and responses are poorly fitted by a line of slope −1 (AC1^−/− as black triangles, r²= 0.21).