Browsing by Author "Walters, Robert P."

Now showing 1 - 5 of 5
  • Thumbnail Image
    Capacity theory: A neuropsychological perspective on shared neural systems regulating hostile violence prone behavior and the metabolic syndrome
    Harrison, Patti Kelly; Walters, Robert P.; DeVore, Benjamin B.; Harrison, David W. (2016-01-13)
  • Thumbnail Image
    Frontal lobe regulation of blood glucose levels: support for the limited capacity model in hostile violence-prone men.
    Walters, Robert P.; Harrison, Patti Kelly; Campbell, Ransom W.; Harrison, David W. (2016-12)
    Hostile men have reliably displayed an exaggerated sympathetic stress response across multiple experimental settings, with cardiovascular reactivity for blood pressure and heart rate concurrent with lateralized right frontal lobe stress (Trajanoski et al., in Diabetes Care 19(12):1412-1415, 1996; see Heilman et al., in J Neurol Neurosurg Psychiatry 38(1):69-72, 1975). The current experiment examined frontal lobe regulatory control of glucose in high and low hostile men with concurrent left frontal lobe (Control Oral Word Association Test [verbal]) or right frontal lobe (Ruff Figural Fluency Test [nonverbal]) stress. A significant interaction was found for Group × Condition, F (1,22) = 4.16, p ≤ .05 with glucose levels (mg/dl) of high hostile men significantly elevated as a function of the right frontal stressor (M = 101.37, SD = 13.75) when compared to the verbal stressor (M = 95.79, SD = 11.20). Glucose levels in the low hostile group remained stable for both types of stress. High hostile men made significantly more errors on the right frontal but not the left frontal stressor (M = 17.18, SD = 19.88) when compared to the low hostile men (M = 5.81, SD = 4.33). These findings support our existing frontal capacity model of hostility (Iribarren et al., in J Am Med Assoc 17(19):2546-2551, 2000; McCrimmon et al., in Physiol Behav 67(1):35-39, 1999; Brunner et al., in Diabetes Care 21(4):585-590, 1998), extending the role of the right frontal lobe to regulatory control over glucose mobilization.
  • Thumbnail Image
    Frontal lobe regulatory control mechanisms: Evidence for diminished frontal eye field capacity in hostile violence-prone men.
    Harrison, Patti Kelly; Campbell, Ransom W.; Smith, Andrew J.; Mitchell, Gina A.; Walters, Robert P.; Harrison, David W. (2016-02-03)
    Background: 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). Material/Methods: 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 onthe 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. Results: 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. Conclusions: 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.
  • Thumbnail Image
    Frontal Regulation of Blood Glucose Levels as a Function of Hostility
    Walters, Robert P. (Virginia Tech, 2005-05-02)
    From a neuropsychological perspective, hostile men have displayed dysregulation of right cerebral systems as evidenced through an exaggerated sympathetic stress response, with cardiovascular reactivity for blood pressure and heart rate. Altered right cerebral functioning, with hostility and anger, has been demonstrated within functional cerebral systems to include auditory (Demaree & Harrison, 1997), visual (Harrison & Gorelczenko, 1990; Herridge, Harrison, Mollet, & Shenal, 2003), somatosensory (Herridge, Harrison, & Demaree, 1997; Rhodes, Harrison, & Demaree, 2002), motor (Demaree, Higgins, Williamson, & Harrison, 2002) and premotor systems (Williamson & Harrison, 2003). Each of these studies has demonstrated cardiovascular reactivity (blood pressure and heart rates measures) concurrently with altered sensory or motor functional correlates of the right hemisphere. However, the neuropsychological mechanisms and functional regulation for the mobilization of glucose have not been examined.
  • Thumbnail Image
    Hostile-Diabetic Men: An Examination of Peripheral Glucose and QEEG Magnitudes Subsequent to Lateralized Fluency-Stressors
    Walters, Robert P. (Virginia Tech, 2009-05-28)
    Using the Limited Capacity Model of hostility (Walters & Harrison, 2006; Williamson & Harrison, 2005; Williamson, Harrison, & Walters, 2007) as a guide, the stress response of individuals with a variable and dysregulated fuel supply to their brain (diabetes) was examined subsequent to lateralized fluency-stress. This theoretical "capacity" model of hostility was applied to a relatively unknown population of high hostile-diabetics. Given the associations between hostility and diabetes, it was argued that a very robust stress response would be evident, as measured as by peripheral glucose and QEEG magnitudes, as a result of modest regulatory capacity subsequent to right frontal lobe stress. Moreover, it was expected that high hostile-diabetics would show diminished performance on neuropsychological indicants of right frontal functions.