David Harrison

... Verbal Learning and Cardiovascular Regulation. Gina Alice Mollet Abstract ... individuals demonstrate heightened cardiovascular liability (Davis, Matthews, & McGrath, 2000) and are more likely to engage in behaviors that put them at risk for CVD (Calhoun et al., 2001). ...

Theories of spreading activation primarily involve semantic memory networks. However, the existence of separate verbal and visuospatial memory networks suggests that spreading activation may also occur in visu-ospatial memory networks. The purpose of the present investigation was to explore this possibility. Specifically, this study sought to create and describe the design frequency corpus and to determine whether this measure of visuospatial spreading activation was related to right hemisphere functioning and spreading activation in verbal memory networks. We used word frequencies taken from the Controlled Oral Word Association Test and design frequencies taken from the Ruff Figural Fluency Test as measures of verbal and visuospatial spreading activation, respectively. Average word and design frequencies were then correlated with measures of left and right cerebral functioning. The results indicated that a significant relationship exists between performance on a test of right posterior functioning (Block Design) and design frequency. A significant negative relationship also exists between spreading activation in semantic memory networks and design frequency. Based on our findings, the hypotheses were supported. Further research will need to be conducted to examine whether spreading activation exists in visu-ospatial memory networks as well as the parameters that might modulate this spreading activation, such as the influence of neurotransmitters.

Arousal theory as discussed within the present paper refers to those mechanisms and neural systems involved in central nervous system activation and more specifically the systems involved in cortical activation. Historical progress in the evolution of arousal theory has led to a better understanding of the functional neural systems involved in arousal or activation processes and ultimately contributed much to our current theories of emotion. Despite evidence for the dynamic interplay between the left and right cerebral hemispheres, the concepts of cerebral balance and dynamic activation have been emphasized in the neuropsychological literature. A conceptual model is proposed herein that incorporates the unique contributions from multiple neuropsychological theories of arousal and emotion. It is argued that the cerebral hemispheres may play oppositional roles in emotion partially due to the differences in their functional specializations and in their persistence upon activation. In the presence of a threat or provocation, the right hemisphere may activate survival relevant responses partially derived from hemispheric specializations in arousal and emotional processing, including the mobilization of sympathetic drive to promote heightened blood pressure, heart rate, glucose mobilization and respiratory support necessary for the challenge. Oppositional processes and mechanisms are discussed, which may be relevant to the regulatory control over the survival response; however, the capacity of these systems is necessarily limited. A limited capacity mechanism is proposed, which is familiar within other physiological systems, including that providing for the prevention of muscular damage under exceptional demand. This capacity theory is proposed, wherein a link may be expected between exceptional stress within a neural system and damage to the neural system. These mechanisms are proposed to be relevant to emotion and emotional disorders. Discussion is provided on the possible role of currently applied therapeutic interventions for emotional disorders.

The experiment was designed to test the relationship between self-reported hostility and the capacity of frontal eye field regulatory control over visual smooth pursuit eye movements. Previous research has demonstrated a relationship between hostility, violence-prone aggression, and poorly regulated sympathetic control including traditional measures of cardiovascular risk. Capacity Theory (see Harrison, 2015) specifically predicts diminished reflex regulation , dystonia, or spasticity with conditions which exceed the capacity of the frontal systems involved in the response. For visual smooth pursuit eye movements, the frontal eye fields regulate/inhibit ipsilateral visuomotor reflexes under directional control of the superior colliculi and pontine region. Moreover, directional eye movements reflecting intentional direction of visual smooth pursuit derive from premotor regions at each dorsolateral frontal eye field and with directional intent toward the contralateral hemispace (e.g., right frontal eye field directs intentional eye movements toward the left hemispace and inhibits saccadic movements toward the right hemispace). We tested a total number of 48 college-age men evenly divided between two groups, twenty-four low-hostiles and twenty-four high-hostiles. All subjects were acquired from the undergraduate Psychology pool and the project was approved by the Human Subjects Committee and the Institutional Review Board. In order to continue in the experiment, subjects had to have scored within either the low (0-19) or high (29-50) range of self-reported hostility on the Cook-Medley Hostility Scale (CMHS). Due to their relatively heightened cerebral lateralization, only men were used to ensure as much homogeneity as possible within the experiment, so as to draw conclusions based solely on independent variable differences. Hostile men were compared with low hostile men using the electrooculogram (EOG). Smooth pursuit errors were identified in the EOG record as phasic errors in the analogue record. Hostile men produced significantly more smooth pursuit irregularities in comparison with low hostiles, consistent with the predictions of Capacity Theory, supporting the contention of diminished frontal eye field integrity in hostile, violence-prone men. These findings sit collectively among a systematic line of research with accumulating evidence implicating capacity limitations for frontal lobe regulatory control in hostile, violence-prone individuals. The broader research implication is suggestive for remediation and preventative techniques for the amelioration of confrontative and/or coercive stress using these brain systems. Moreover, the theory specifically is predictive of heightened sensitivity for the sensory and emotional analyzers residing at the other end of the longitudinal tracts and within posterior brain regions. Emotional sensitivity reflecting coercive threat analysis, feelings of external control by others, and sensitivity to the emotional array presented by others' facial expressions, tone of voice, and by innuendo may ultimately be a social disability. This effect may be propagated further in any social interaction where others may evaluate the hostile, violence-prone individual as insensitive and callous, perhaps.

Citation DeVore BB, Harrison DW. Brain mechanisms in blood glucose mobilization and absorption: The role of the left and the right frontal regions in the regulatory control of blood glucose levels. With the ravaging effects of glucose related diseases (such as diabetes) on the rise, an increased understanding of the central mechanisms involved in glucose mobilization and absorption, and the potential development of the metabolic syndrome, is becoming increasingly important. Although, substantive efforts have been expended to better understand the peripheral mechanisms involved with the systemic processing of glucose, there remains a pau-city of research dedicated to the central neural aspects largely involved in the mobilization and absorption of blood glucose. Despite this lack of research, the relationship between emotional states of anger or fear and those oppositional processes associated with quiescent states or digestive uptake have been clearly related to blood glucose levels. 1-3 Moreover, and perhaps most relevant here, is that the differential emotional states just described have been established with origins in cerebral laterality and with regulatory control mechanisms largely relegated to the frontal lobes and executive brain systems. 4-6 We have provided evidence with the potential to bridge this gap between brain theory and research on peripheral mechanisms with specializations of the right brain for intense emotional states and sympathetic drive 7-10 and with somewhat oppositional specializations of the left brain for quiescent states and perhaps parasympathetic drive. Functional cerebral systems theory 11-14 demonstrates the regulatory control over sympathetic drive by the frontal lobe executive regions, where incremental blood pressure, heart rate, sweating, cholesterol levels, and blood glucose levels may provide the biological resources and reserves for the fight with relevance to insure success in meeting the potentially coercive threat or challenge. Furthermore , cerebral balance theory 7 supports oppositional mechanisms with quiescent states and the establishment of resource reserves largely by left cerebral systems. This brief review of current neuropsychological research will present a theoretical foundation, based upon Alexander Lu-ria's functional cerebral systems theory, for the preferential activation of glucose metabolism by the right cerebral hemisphere (Figure 1). Fundamental to the presented argument is the theoretical construct, that the majority of emotional processing, particularly intense emotions such as anger or fear, are lateralized to the right hemisphere. 15 Research in our lab looking at violent-prone individuals has consistently supported this theory by showing decreased frontal lobe regulation of right posterior anger and negative emotionally responsive brain regions. 4,16 Of further import to the theory of right hemi-spheric glucose mobilization is evidence showing sympathetic response is substantially under right hemispheric control and that overall cardiovascular recruitment is driven by right hemi-spheric activation. Current research efforts, 17 comparison studies of the left-versus-right sided cerebrovascular accidents, 18 and unilateral intracarotid sodium amobarbital injections (UISAI) [Wada technique] 18 all support the relative role of the right hemisphere in sympathetic response. Given the integral role of blood glucose as the major fuel source for the brain, it follows