Understanding the neuropsychological symptoms associated with cortical dysfunction

Damage to association cortices can result in a variety of cognitive and behavioral symptoms. Superficially, the relationship between lesion sites and the corresponding symptoms seems constant. However, some degree of dissociation of symptoms among patients with different etiologies appears to be the rule rather than the exception, even when the lesion locations appear similar in neuroimaging studies. Examinations of patients with primary progressive aphasia (PPA) have challenged the classic language model that is based on observations mainly made in patients with cerebrovascular diseases. The neuropsychological findings of patients with semantic variant PPA and neuroimaging evidence in healthy subjects converge to indicate that the anterior temporal lobe is an important component of language and semantic networks. Recent findings, however, have demonstrated that atrophy and dysfunction in patients with semantic variant PPA involve a number of regions in addition to the anterior temporal lobe. This indicated that specifically linking language deficits to the anterior temporal lobe is difficult. An understanding the pathophysiological processes is require to comprehend the symptoms of cortical dysfunction, especially in the association cortices.