Configurational encoding of complex visual forms by single neurons of monkey temporal cortex.

Single neurons in the anterior inferior temporal (IT) cortex respond to complex visual stimuli. Here we examined whether the stimulus-selectivity of the anterior IT neurons was determined solely on the basis of the geometric similarity of object forms, or was modifiable through visual experiences in adulthood. We trained Japanese monkeys (Macaca fuscata) in the visual delayed matching-to-sample task or visual stimulus-stimulus association task. Computer-generated visual forms, fractal patterns or Fourier descriptors, were used as stimuli. Single-unit recording from these trained monkeys showed that the stimulus-selectivity of neurons in the anterior IT cortex could be acquired according to the requirements of memory tasks. The results indicate that the neural representation of complex visual objects is dynamically altered through both tuning and association processes. We discuss these neurophysiological findings in relation to neuropsychological investigations of ablation effects in the primate.