McGinley, J.J., Magruder , K., Morrill, A.R., Worthen , J., Flamini , M., & Friedman, B.H.

1. CARDIOVASCULAR RESPONSES TO LATERALIZED FACIAL COOLING AND FOOT COLD PRESSOR TASKS: IMPLICATIONS FOR ANS REGULATION MODELS McGinley, J.J., Magruder, K., Morrill, A.R., Worthen, J., Flamini, M., & Friedman, B.H. RESEARCH OBJECTIVES Left-side cold pressor elicits larger BP response Left-side cold pressor elicits larger SC response • Much research has addressed the issue of lateralized autonomic nervous system activity, but no consensus has emerged. • Right hemisphere dominance in sympathetic nervous system (SNS) regulation is well-established, but both the right (e.g., Thayer & Lane, 2009) and left (e.g., Craig, 2005) hemispheres have been implicated in regulating parasympathetic nervous system (PNS) activity. • Few studies have adequately used manipulations that have lateralized PNS and SNS responses within the same design. • The current study was designed to address this oversight by using lateralized facial cooling and foot cold pressor tasks to explore this issue. mmHG Left-side cold pressor elicits IBI decrease. Vagal measures suggest no significant laterality differences. CURRENT STUDY • Subjects: • 73 right-handed undergraduates (female=37) • Tasks • Subjects submerged each foot (separately) in ice water (~9°C) up to the ankle. • The foot submersion periods were three minutes in duration. • The facial cooling tasks were modified to cover the lower portion of the face. They covered only the mandibular branch of the trigeminal nerve. They were 2 minutes in duration, but the cardiovascular responses attenuated by the end of the 1st minute and therefore only the 1st minute was used in the analyses. Each task was preceded by a three minute baseline period, and followed by a three minute recovery period. • Physiological Measurements: • Electrocardiogram (ECG) and blood pressure (BP) • Inter-beat intervals (IBI) and heart rate variability (HRV) were derived from the ECG signal. Root means square of successive differences (RMSSD) from the temporal domain and high frequency (HF) power from the spectral domain were used. • Systolic (SBP), diastolic (DBP), and (MAP) were derived from the BP signal. • Skin conductance responses (SCR) were used for a non-cardiovascular autonomic measure. DISCUSSION • Further support for the right hemisphere regulation of SNS activity was supported by increases in SBP, DBP, MAP, SCR, and a decrease in IBI for left foot cold pressor compared to right foot cold pressor. • Lateralized support for PNS regulation was not directly clarified. There was no significant lateralized difference for change in RMSSD or HF power between the left and right facial cooling tasks. The manipulation was possibly not robust enough to elicit statistically significant lateralized differences, but it must be suggested that lateralization of PNS activity may not be a standardized phenotype across individuals. RESULTS • Averaged across three minute submersion periods, there was a significant decrease in IBI from left foot compared to right foot submersion (F(1,68)=3.989,p=.05) . There were also increases in SBP (F(1,66)=5.414, p<.05), DBP (F(1,67)=4.561, p<.05), and MAP (F(1.66)=5.488, p<.05) in the same direction. These findings further support right hemisphere regulation of SNS responses. • To address PNS lateralization, RMSSD and HF power were averaged over the first minute of the facial cooling tasks. Neither RMSSD (F(1,68)=1.798, p>.1) nor HF power (F(1,68)=1.921, p>.1) reached significance levels. • SC responses for the left foot cold pressor showed larger increases than for the right foot cold pressor(F(1,62)=5.273, p<.05). IMPLICATIONS • Right hemisphere regulation of SNS activity logically fits with existing laterality models of negative affect and avoidance mentality. • Views of PNS regulation may benefit from a less limited model. It is likely that both hemispheres serve a substantial role in PNS regulation since important cognitive and affective qualities such as attentional and emotional regulation are key to adaptive responding to the environment. Presented at the 23rd annual conference for the Association of Psychological Science (APS) May 27th, 2011, Washington, D.C. Presented at the 52nd annual meeting for the Society for Psychophysiological Research (SPR) September 20th, 2012, New Orleans, LA Correspondence to: jaredmc@vt.edu Correspondence to: jaredmc@vt.edu