Transitive inference reasoning is impaired by focal lesions in parietal cortex rather than rostrolateral prefrontal cortex

• Published in: Neuropsychologia 2013-02, Vol.51 (3), p.464-471
• Main Authors: Waechter, Randall L., Goel, Vinod, Raymont, Vanessa, Kruger, Frank, Grafman, Jordan
• Format: Article
• Language: English
• Subjects: Adult and adolescent clinical studies; Antibodies; BA 10; BA 7; Biological and medical sciences; Brain Injuries - complications; Brain Injuries - diagnostic imaging; Brain Injuries - pathology; Cognition Disorders - etiology; Cortex (parietal); Cortex (prefrontal); Humans; Intelligence; Male; Medical sciences; Memory; Middle Aged; Neuroimaging; Neuropsychological Tests; Organic mental disorders. Neuropsychology; Parietal cortex; Parietal Lobe - diagnostic imaging; Parietal Lobe - pathology; Parietal Lobe - physiopathology; Prefrontal Cortex - diagnostic imaging; Prefrontal Cortex - pathology; Prefrontal Cortex - physiopathology; Problem Solving - physiology; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Reaction Time; Rostrolateral prefrontal cortex; Short term memory; Tomography, X-Ray Computed; Transitive inference
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2012.11.026

Transitive inference reasoning involves the examination and comparison of a given number of relational pairs in order to understand overall group hierarchy (e.g., A>B, B>C, C>D; therefore is A>D?). A number of imaging studies have demonstrated the role of the parietal cortex for resolving transitive inferences. Some studies also identify the rostrolateral prefrontal cortex as being critical for “relational integration” processes supporting transitive reasoning. To clarify this issue, we carried out a transitive inference study involving neurological patients with focal lesions to the rostrolateral prefrontal (n=5) or parietal cortices (n=7), as well as normal controls (n=6). The patients and controls were statistically matched on age, education, pre-injury IQ, general memory, working memory, and performance/full IQ, though the rostrolateral patients did score significantly higher than the normal controls on verbal IQ. Results indicate that patients with focal lesions to the parietal cortex were impaired in the task relative to both the patients with focal lesions to rostrolateral prefrontal cortex and the control group, and there was no difference in task performance between the rostrolateral prefrontal and the control groups. This result continued to hold after controlling for verbal IQ as a covariate. These findings point to a critical role for the parietal cortex, rather than the rostrolateral prefrontal, in transitive inference. Since the groups performed similarly on a working memory task, working memory cannot fully account for the result, suggesting a specific role of parietal cortex in transitive inference. ► Transitive inference reasoning involves the examination of relational pairs (e.g. A>B; B>C; C>D). ► The parietal cortex (PLC) is important for resolving transitive inferences. ► Other studies implicate frontal cortex (BA 10) for resolving transitive inferences. ► This patient study implicates the PLC rather than BA 10 for this task. ► This result is not fully explained by working memory deficits in PLC patients.