Figure 6.

Saccade coding schemes in the cortical eye fields (A), model of gain-field neuron (B), and suggested organization of gain-field neurons in the parietal cortex (C). A, Dorsal view of a partially inflated brain. Insets represent the coding patterns suggested by our fMRI correlation analysis. All cortical eye fields have information about the saccade vector in their spatial patterns of activation (retinotopic scheme). Area mIPS also has multiplexed information about the saccadic target destination, regardless of the initial position (spatiotopic representation). B, A typical behavior of a gain-field neuron. The receptive field (colored circle) moves with the fixation point (white cross), and the level of response is modulated by gaze position (most responsive receptive field represented in red circle). The inset on the right captures the receptive field properties in a single icon: it shows the neural response for the most responsive gaze location (colored in an orange fixation cross) and its matching receptive field, colored in red. C, Example of a voxel, consisting of gain-field neurons (I–IV) that share the same head-centered location of their most responsive receptive field (red circle) but differ in their optimal angle of gaze (orange cross). Such an organization may underlie the spatiotopic sensitivity found in the mIPS.