Frontal lobe regulatory control mechanisms: Evidence for diminished frontal eye field capacity in hostile violence-prone men.
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.