COGNITIVE BIAS, FUNCTIONAL CORTICAL GEOMETRY, AND THE FRONTAL LOBES -LATERALITY, SEX, AND HANDEDNESS

Performance of patients with quadrant lesions on the inherently ambigu ous Cognitive Bias Task (CBT) suggests sexual dimorphism in the fundam ental aspects of functional cortical geometry, by emphasizing differen t cerebral axes. In right-handed males, extreme context-dependent and context-independent response selection biases are reciprocally linked to left vs. right frontal systems. In right-handed females, these comp lementary biases appear to be reciprocally linked to posterior vs. fro ntal cortices, Frontal lobe functions are more lateralized in males th an females due to sexual dimorphism of the left frontal systems. Both in males and females, patterns of CBT scores in non-right-handers with quadrant lesions are opposite to those found in right-handers. This s uggests the existence of two functionally and neurally distinct cognit ive selection mechanisms. Both mechanisms involve the frontal lobes, b ut their exact neuroanatomy depends on sex and handedness.