Anterior Posterior Factors in the Generation of Emotionality

The effect of precise lesion location was not taken into account by the early studies on lateralization of emotional behavior reviewed above. With improved anatomical specification of lesions (X-ray computed tomography and more recently MRI), it has become apparent that the anterior-posterior dimension is an important factor in predicting the occurrence of emotional changes following unilateral lesions. Robinson and colleagues (1984) found that poststroke depression was more frequent in the case of anterior lesions of the left hemisphere, and its severity correlated with the distance from the frontal pole (Robinson, 1996). In contrast, for the right hemisphere, poststroke mania was significantly associated with damage to right anterior regions (Starkstein and Robinson, 1988), while damage to right posterior lesions was more associated with depression (Robinson et al., 1984). Importantly, the relationship between poststroke depression and left anterior locus of lesion held when patients with aphasic symptoms were excluded or the effect of aphasia was partialled out (Starkstein and Robinson, 1988).

Another important variable not considered in early studies is the extent of damage to subcortical structures. The head of the caudate, particularly on the left, has been associated with poststroke depression (Robinson et al., 1984), while the right thalamus and right basal ganglia has been associated with mania (Starkstein et al., 1990).

0 0

Post a comment