Attentional modulation strength in cortical area MT depends on stimulus contrast

Neuron. 2002 Jul 18;35(2):365-70. doi: 10.1016/s0896-6273(02)00778-x.


The attentional modulation of sensory information processing in the visual system is the result of top-down influences, which can cause a multiplicative modulation of the firing rate of sensory neurons in extrastriate visual cortex, an effect reminiscent of the bottom-up effect of changes in stimulus contrast. This similarity could simply reflect the multiplicity of both effects. But, here we show that in direction-selective neurons in monkey visual cortical area MT, stimulus and attentional effects share a nonlinearity. These neurons show higher response gain for both contrast and attentional changes for intermediate contrast stimuli and smaller gain for low- and high-contrast stimuli. This finding suggests a close relationship between the neural encoding of stimulus contrast and the modulating effect of the behavioral relevance of stimuli.

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Attention / physiology
  • Contrast Sensitivity / physiology*
  • Lighting
  • Macaca mulatta / anatomy & histology
  • Macaca mulatta / physiology*
  • Motion Perception / physiology*
  • Neurons / cytology*
  • Photic Stimulation
  • Temporal Lobe / cytology
  • Temporal Lobe / physiology*
  • Visual Cortex / cytology
  • Visual Cortex / physiology*
  • Visual Fields / physiology
  • Visual Pathways / cytology
  • Visual Pathways / physiology*