What are the consequences of a parietal lobe lesion in humans? To what extent do they illuminate our understanding of parietal lobe function?.
As part of the central nervous system the parietal lobe is important for integrating different forms of information, especially those concerning the outside sensory world and various sensory modalities. Consequently lesions to this area have a profound and wide array of effects on behavior. As with much of the central nervous system the studies of the symptoms of people with gross lesions in the parietal lobe are especially important because they provide insight into lobe functioning. Since most animals do not rely as heavily on the parietal lobes and monkeys who have the most similarities in lobe structure and function are difficult to derive data from relating to spatial or language cognition, much of what we know about the parietal lobe is from or influenced by research concerning lesional affects. As the consequences of lobe lesions are influenced by the location of the lesion within the lobe, symptoms of parietal lobe lesions will be described in reference to these primary areas of anterior and posterior lobules with reference to hemispheres when significant.
Damage to the anterior parietal regions is marked by deficits in the somatosensory process which is primarily concerned with tactile control. With this knowledge it can be deduced that the anterior parietal region integrates sensory information with motor movements and are associated with many other regions of the brain. Symptoms include abnormally high sensory thresholds, impaired sense of position, and a number of other deficits. One symptom is the deficit in the recognition of objects through touch, known as astereognosis. The symptom of simultaneous extinction is marked by failure to attend to more than one stimulus at a time. This disorder gives light to the importance of the parietal lobe in allowing us to distinguish and perceive stimuli in an environment where we are bombarded with multiple tactile stimulus at any given time.