Neuropsychological "systems efficiency" and positron emission tomography

Abstract

Positron emission tomography (PET) has dramatically improved our ability to examine the functioning of the living brain. PET studies of neural pathways of the major sensory modalities--auditory, visual, somatosensory--have confirmed many traditional neuropsychological concepts, such as cross-lateral representation and regional functioning to particular primary sensory cortical areas. Other PET studies have used radioisotopes to examine relationships between radiopharmaceutical agents and neurobehavioral functioning in both normal and neuropathological states. In some areas, PET methodology requires further refinement. For example, effort should be made to develop the technology to do multiple scans within a short time frame; statistical procedures to examine relationships between neuropsychological tasks and the activity or presence of radiopharmaceutical agents in multiple sites; adequate controls for experimental error; and activation paradigms controlling the nonspecific effects of simple arousal. PET activation models of cognition suggest that a "systems efficiency" approach to assessing neuropsychological test performance involving both serial and parallel processing would be useful. These developments will improve empirical methodology and our understanding of brain-behavior relationships.

IQ-Related fMRI Differences during Cognitive Set Shifting

“…According to the capacity-constrained view of cognition, decision-making processes rely on underlying neural systems whose efficiency is affected by several factors including the neurochemistry, interconnectivity and strategies they employ (Parks et al 1989; Just and Carpenter 1992). Thus “neural efficiency” results from individual differences in the amount of neural resources available for cognitive processing (Haier et al 1992; Rypma and D'Esposito 1999; Reichle et al 2000; Rypma et al 2002).…”