Spatial updating and the maintenance of visual constancy
Surprisingly, we found that in split-brain monkeys, LIP neurons can remap stimulus traces across hemifields, though this signal is weaker than that associated with within-hemifield remapping.
During the task, participants could either clearly view their surroundings (full vision) or visuo-spatial information was reduced by means of translucent goggles (reduced vision).Across the population of LIP neurons, remapping is effectively independent of saccade direction.These findings indicate that the activity of LIP neurons can contribute to the maintenance of spatial constancy throughout the visual field. Flexible working memory representation of the relationship between an object and its location as revealed by interactions with attention. Street (2009) “Working Memory Impairment in People with Williams Syndrome: Effects of Delay, Task and Stimuli” Brain and Cognition, 69: 495-503. We tested this by monitoring the activity of neurons in LIP while varying the direction over which a stimulus trace must be updated.
We found that individual neurons remap stimulus traces in multiple directions, though the strength of the remapped response is variable.
This indicates that a distributed network of brain regions supports spatial updating.
Neural Basis of Cognitive Control over Movement Inhibition: Human f MRI and Primate Electrophysiology Evidence.
We tested this by comparing the signal related to within- and across-hemifield remapping.
We predicted that in split-brain monkeys, across-hemifield remapping would be abolished while within-hemifield remapping would remain robust.
Courtney (2008) “Differential neural activation for updating rule versus stimulus information in working memory.” Neuron, 59: 173-182.