Lateral intraparietal cortex
Lateral Parietal Cortex (area LIP) found in the intraparietal sulcus This area is most likely involved in eye movements, as electrical stimulation evokes saccades (quick movements) of the eyes. It is also thought to contribute to working memory associated with guiding eye movements.
The last statement has been examined using a socalled Delayed-saccade task:
1. An animal focuses on a point in the middle of a computer screen.
2. A target (for instance a shape) is presented at a peripheral location on the screen.
3. The target is removed - following is a variable-length delay period.
4. The initial focus point in the middle of the screen is removed.
5. Saccadic movements of the animal's eyes makes it focus on the location of the target (2).
Neurons in area LIP have been proven to start responding in 2 (synonomous with a normal stimulus-evoked response).
The neurons keep responding during the delay period - until the middle focus point is removed.
As the focus point is removed and the neural response stops, the saccadic eye movements start, and the animal soon focuses on the excact location of the previously shown target.
The conclusion of this task experiment is that neurons in area LIP seem to store information (the location of the target) useful for guiding the saccadic movements; that is, this area of the cortex shows modality specifc working memory.
Areas showing specificity for other modalities have been located.
References
Bear, Connors et Paradiso:"Neuroscience, Exploring the Brain", 3rd. edition, 2007, Lippincott Williams & Wilkins (pp. 757–758)
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