Science Daily | May 2018 | Brain activity helps explain diabetics’ negative feelings, risk for depression
A US study suggests that negative feelings in people with a diagnosis of diabetes, or prediabetes, might be due to problems regulating blood sugar levels that influence emotional response in the brain (via Science Daily).
Researchers gauged the startle response of participants, to provide a measure of their central nervous system activity, using tiny electrodes placed below their eye. The participants were shown a series of negative, positive and neutral images designed to elicit an emotional response. The electrodes captured the rate of flinch or startle, a contraction we cannot control, associated with each image.
Their findings show that participants with higher levels of insulin resistance were more startled by negative pictures. They argue the evidence is even more compelling when combined with the results of EEG tests recording activity when the brain is at rest. Study participants with prediabetes and Type 2 diabetes had more activity on the right side of the brain, which is associated with depression and negative emotions. By extension, if someone is predisposed to focusing on negative things, it may become a barrier for losing weight and reversing health issue
Tovah Wolf, an author of the study said: “For people with blood sugar problems, being more stressed and reactive can cause blood sugar to spike. If people with prediabetes and diabetes are trying to reverse or treat the disease, stressful events may hinder their goals,” Wolf said. “Frequent negative reactions to stressful events can lead to a lower quality of life and create a vicious cycle that makes it difficult to be healthy.
The full news item is available from Science Daily
This paper has now been published in Psychosomatic Medicine
Pre-diabetes and type 2 diabetes (i.e., hyperglycemia) are characterized by insulin resistance (IR). These problems with energy metabolism may exacerbate emotional reactivity to negatively valenced stimuli and related phenomena like predisposition toward negative affect, as well as cognitive deficits. Higher emotional reactivity is seen with hyperglycemia and IR. Yet, it is largely unknown how metabolic dysfunction correlates with related neural, hormonal, and cognitive outcomes.
Among 331 adults from the Midlife in the United States (MIDUS), we cross-sectionally examined eye- blink response (EBR) to gauge reactivity to negative, positive, or neutrally-valenced pictures from international affect picture system (IAPS) stimuli proximal to an acoustic startle probe. Increased EBR to negative stimuli was considered an index of stress reactivity. Frontal alpha asymmetry, a biomarker of negative affect predisposition, was determined using resting electroencephalography (EEG).
Baseline urinary cortisol output was collected. Cognitive performance was gauged using the Brief Test of Adult Cognition by telephone (BTACT). Fasting glucose and insulin characterized hyperglycemia or the homeostatic model assessment of IR (HOMA-IR).
Higher HOMA-IR corresponded to an increased startle response, measured by EBR magnitude, for negative versus positive stimuli [R2=0.218, F(1,457)=5.48, p=.020, euglycemia: Mean±SD=.092±.776, hyperglycemia: Mean±SD=.120±.881]. Participants with hyperglycemia vs. euglycemia showed greater right frontal alpha asymmetry [F(1,307)=6.62, p=.011, euglycemia: Mean±SD=.018±.167, hyperglycemia: Mean±SD=-.029±.160] and worse BTACT arithmetic performance [F(1,284)=4.25, p=.040, euglycemia: Mean±SD=2.390±1.526), hyperglycemia: Mean±SD=1.920±1.462]. Baseline urinary cortisol (log10 μg/12 hr) was also dysregulated in individuals with hyperglycemia [[F(1,324)=5.09, p=.025, euglycemia: Mean±SD=1.052±.332, hyperglycemia: Mean±SD=.961±.362].
These results suggest that dysmetabolism is associated with increased emotional reactivity, predisposition toward negative affect, and specific cognitive deficits.
Wolf, T, Tsenkova, V, Ryff, C., Richard, D. , J. Davidson, Auriel A. Willette. Neural, Hormonal, and Cognitive Correlates of Metabolic Dysfunction and Emotional Reactivity. Psychosomatic Medicine, 2018; 1 DOI: 10.1097/PSY.0000000000000582
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