Properties of the diffuse thalamocortical system, human intelligence and differentiated vs integrated modes of learning

In complementary reports Robinson (1982a, b) describes how the transmission characteristics or time constants of thalamic and cortical neuron populations of the diffuse thalamocortical system (DTS) can be evaluated in human subjects. Equating these constants with the Pavlovian property of ‘strength’ it was predicted that they should relate to Extraversion and Neuroticism scores on the Eysenck Personality Questionnaire (EPQ). This prediction was confirmed and the results provide direct support for the theories of Pavlov and Eysenck. The present report describes additional results which confirm predictions relating the DTS constants to performance on the Wechsler Adult Intelligence Scale (WAIS) and on the Embedded Figures Test (EFT). An important finding was that a measure of deviation from intermediate and ‘balanced’ values of the DTS constants loads to the extent of -0.80 on the WAIS ‘memory’ or ‘attention/ concentration’ factor. More generally, the results provide further support for Pavlov's conception of brain-behaviour relationships and suggest that the DTS plays a fundamental role in determining a broad spectrum of human psychological differences including some associated with the concepts of intelligence and cognitive style. These IQ and cognitive style differences are explained as the immediate and longer-term consequences, respectively, of differences in the distribution of background cortical activity mediated by the DTS.