Publications by authors named "Allison Ponzio"

9 Publications

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Cortical thickness and resting-state cardiac function across the lifespan: A cross-sectional pooled mega-analysis.

Psychophysiology 2020 Oct 10. Epub 2020 Oct 10.

Norwegian Centre for Mental Disorders Research (NORMENT), Institute of Clinical Medicine, University of Oslo, Oslo, Norway.

Understanding the association between autonomic nervous system [ANS] function and brain morphology across the lifespan provides important insights into neurovisceral mechanisms underlying health and disease. Resting-state ANS activity, indexed by measures of heart rate [HR] and its variability [HRV] has been associated with brain morphology, particularly cortical thickness [CT]. While findings have been mixed regarding the anatomical distribution and direction of the associations, these inconsistencies may be due to sex and age differences in HR/HRV and CT. Previous studies have been limited by small sample sizes, which impede the assessment of sex differences and aging effects on the association between ANS function and CT. To overcome these limitations, 20 groups worldwide contributed data collected under similar protocols of CT assessment and HR/HRV recording to be pooled in a mega-analysis (N = 1,218 (50.5% female), mean age 36.7 years (range: 12-87)). Findings suggest a decline in HRV as well as CT with increasing age. CT, particularly in the orbitofrontal cortex, explained additional variance in HRV, beyond the effects of aging. This pattern of results may suggest that the decline in HRV with increasing age is related to a decline in orbitofrontal CT. These effects were independent of sex and specific to HRV; with no significant association between CT and HR. Greater CT across the adult lifespan may be vital for the maintenance of healthy cardiac regulation via the ANS-or greater cardiac vagal activity as indirectly reflected in HRV may slow brain atrophy. Findings reveal an important association between CT and cardiac parasympathetic activity with implications for healthy aging and longevity that should be studied further in longitudinal research.
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http://dx.doi.org/10.1111/psyp.13688DOI Listing
October 2020

Emotional arousal amplifies competitions across goal-relevant representation: A neurocomputational framework.

Cognition 2019 06 8;187:108-125. Epub 2019 Mar 8.

Davis School of Gerontology, University of Southern California, USA.

Emotional arousal often facilitates memory for some aspects of an event while impairing memory for other aspects of the same event. Across three experiments, we found that emotional arousal amplifies competition among goal-relevant representations, such that arousal impairs memory for multiple goal-relevant representations while enhancing memory for solo goal-relevant information. We also present a computational model to explain the mechanisms by which emotional arousal can modulate memory in opposite ways via the local/synaptic-level noradrenergic system. The model is based on neurophysiological observations that norepinephrine (NE) released under emotional arousal is locally controlled by glutamate levels, resulting in different NE effects across regions, gating either long-term potentiation or long-term depression by activating different adrenergic receptors depending on NE concentration levels. This model successfully replicated behavioral findings from the three experiments. These findings suggest that the NE's local effects are key in determining the effects of emotion on memory.
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http://dx.doi.org/10.1016/j.cognition.2019.02.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7102494PMC
June 2019

Arousal increases neural gain via the locus coeruleus-norepinephrine system in younger adults but not in older adults.

Nat Hum Behav 2018 7;2:356-366. Epub 2018 May 7.

Department of Psychology, University of Southern California, Los Angeles, CA, USA.

In younger adults, arousal amplifies attentional focus to the most salient or goal-relevant information while suppressing other information. A computational model of how the locus coeruleus-norepinephrine (LC-NE) system can implement this increased selectivity under arousal and an fMRI study comparing how arousal affects younger and older adults' processing indicate that the amplification of salient stimuli and the suppression of non-salient stimuli are separate processes, with aging affecting suppression without impacting amplification under arousal. In the fMRI study, arousal increased processing of salient stimuli and decreased processing of non-salient stimuli for younger adults. In contrast, for older adults, arousal increased processing of both low and high salience stimuli, generally increasing excitatory responses to visual stimuli. Older adults also showed decline in LC functional connectivity with frontoparietal networks that coordinate attentional selectivity. Thus, among older adults, arousal increases the potential for distraction from non-salient stimuli.
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http://dx.doi.org/10.1038/s41562-018-0344-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6176734PMC
May 2018

Brain structural concomitants of resting state heart rate variability in the young and old: evidence from two independent samples.

Brain Struct Funct 2018 Mar 18;223(2):727-737. Epub 2017 Sep 18.

Department of Psychology, The Ohio State University, Columbus, OH, USA.

Previous research has shown associations between brain structure and resting state high-frequency heart rate variability (HF HRV). Age affects both brain structure and HF HRV. Therefore, we sought to examine the relationship between brain structure and HF HRV as a function of age. Data from two independent studies were used for the present analysis. Study 1 included 19 older adults (10 males, age range 62-78 years) and 19 younger adults (12 males, age range 19-37). Study 2 included 23 older adults (12 males; age range 55-75) and 27 younger adults (17 males; age range 18-34). The root-mean-square of successive R-R-interval differences (RMSSD) from ECG recordings was used as time-domain measure of HF HRV. MRI scans were performed on a 3.0-T Siemens Magnetom Trio scanner. Cortical reconstruction and volumetric segmentation were performed with the Freesurfer image analysis suite, including 12 regions as regions of interests (ROI). Zero-order and partial correlations were used to assess the correlation of RMSSD with cortical thickness in selected ROIs. Lateral orbitofrontal cortex (OFC) cortical thickness was significantly associated with RMSSD. Further, both studies, in line with previous research, showed correlations between RMSSD and anterior cingulate cortex (ACC) cortical thickness. Meta-analysis on adjusted correlation coefficients from individual studies confirmed an association of RMSSD with the left rostral ACC and the left lateral OFC. Future longitudinal studies are necessary to trace individual trajectories in the association of HRV and brain structure across aging.
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http://dx.doi.org/10.1007/s00429-017-1519-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828882PMC
March 2018

Higher locus coeruleus MRI contrast is associated with lower parasympathetic influence over heart rate variability.

Neuroimage 2017 04 17;150:329-335. Epub 2017 Feb 17.

Department of Psychology, The Ohio State University, Columbus, OH, USA.

The locus coeruleus (LC) is a key node of the sympathetic nervous system and suppresses parasympathetic activity that would otherwise increase heart rate variability. In the current study, we examined whether LC-MRI contrast reflecting neuromelanin accumulation in the LC was associated with high-frequency heart rate variability (HF-HRV), a measure reflecting parasympathetic influences on the heart. Recent evidence indicates that neuromelanin, a byproduct of catecholamine metabolism, accumulates in the LC through young and mid adulthood, suggesting that LC-MRI contrast may be a useful biomarker of individual differences in habitual LC activation. We found that, across younger and older adults, greater LC-MRI contrast was negatively associated with HF-HRV during fear conditioning and spatial detection tasks. This correlation was not accounted for by individual differences in age or anxiety. These findings indicate that individual differences in LC structure relate to key cardiovascular parameters.
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http://dx.doi.org/10.1016/j.neuroimage.2017.02.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5391255PMC
April 2017

Neuromelanin marks the spot: identifying a locus coeruleus biomarker of cognitive reserve in healthy aging.

Neurobiol Aging 2016 Jan 29;37:117-126. Epub 2015 Oct 29.

Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA; Department of Psychology, University of Southern California, Los Angeles, CA, USA; Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA.

Leading a mentally stimulating life may build up a reserve of neural and mental resources that preserve cognitive abilities in late life. Recent autopsy evidence links neuronal density in the locus coeruleus (LC), the brain's main source of norepinephrine, to slower cognitive decline before death, inspiring the idea that the noradrenergic system is a key component of reserve (Robertson, I. H. 2013. A noradrenergic theory of cognitive reserve: implications for Alzheimer's disease. Neurobiol. Aging. 34, 298-308). Here, we tested this hypothesis using neuromelanin-sensitive magnetic resonance imaging to visualize and measure LC signal intensity in healthy younger and older adults. Established proxies of reserve, including education, occupational attainment, and verbal intelligence, were linearly correlated with LC signal intensity in both age groups. Results indicated that LC signal intensity was significantly higher in older than younger adults and significantly lower in women than in men. Consistent with the LC-reserve hypothesis, both verbal intelligence and a composite reserve score were positively associated with LC signal intensity in older adults. LC signal intensity was also more strongly associated with attentional shifting ability in older adults with lower cognitive reserve. Together these findings link in vivo estimates of LC neuromelanin signal intensity to cognitive reserve in normal aging.
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http://dx.doi.org/10.1016/j.neurobiolaging.2015.09.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5134892PMC
January 2016

Dedifferentiation of emotion regulation strategies in the aging brain.

Soc Cogn Affect Neurosci 2015 Jun 6;10(6):840-7. Epub 2014 Nov 6.

Department of Psychology and Department of Gerontology, University of Southern California, Los Angeles, CA 90089-0191, USA Department of Psychology and Department of Gerontology, University of Southern California, Los Angeles, CA 90089-0191, USA.

Different emotion regulation strategies are distinctly represented in the brains of younger adults. Decreasing a reaction to a negative situation by reinterpreting it (reappraisal) relies on cognitive control regions in the prefrontal cortex, while distracting away from a stressor involves more posterior medial structures. In this study, we used Multi-Voxel pattern analyses (MVPA) to examine whether reappraisal and distraction strategies have distinct representations in the older adult brain, or whether emotion regulation strategies become more dedifferentiated in later life. MVPA better differentiated the two emotion regulation strategies for younger adults than for older adults, and revealed the greatest age-related differences in differentiation in the posterior medial cortex (PMC). Univariate analyses revealed equal PMC recruitment across strategies for older adults, but greater activity during distraction than reappraisal for younger adults. The PMC is central to self-focused processing, and thus our findings are consistent with the possibility that focusing on the self may be a default mechanism across emotion regulation strategies for older people.
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http://dx.doi.org/10.1093/scan/nsu129DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4448030PMC
June 2015

Hearing something emotional influences memory for what was just seen: How arousal amplifies effects of competition in memory consolidation.

Emotion 2014 Dec 13;14(6):1137-42. Epub 2014 Oct 13.

Davis School of Gerontology.

Enhanced memory for emotional items often comes at the cost of memory for the background scenes. Because emotional foreground items both induce arousal and attract attention, it is not clear whether the emotion effects are simply the result of shifts in visual attention during encoding or whether arousal has effects beyond simple attention capture. In the current study, participants viewed a series of scenes that each either had a foreground object or did not have one, and then, after each image, heard either an emotionally arousing negative sound or a neutral sound. After a 24-hr delay, they returned for a memory test for the objects and scenes. Postencoding arousal decreased recognition memory of scenes shown behind superimposed objects but not memory of scenes shown alone. These findings support the hypothesis that arousal amplifies the effects of competition between mental representations, influencing memory consolidation of currently active representations.
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http://dx.doi.org/10.1037/a0037983DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4242586PMC
December 2014

The effects of emotion regulation on explicit memory depend on strategy and testing method.

Emotion 2013 Dec 5;13(6):1041-54. Epub 2013 Aug 5.

Psychology Department, University of San Francisco.

Although previous work has shown that emotion regulation strategies can influence memory, the mechanisms through which different strategies produce different memory outcomes are not well understood. We examined how two cognitive reappraisal strategies with similar elaboration demands but diverging effects on visual attention and emotional arousal influenced explicit memory for emotional stimuli and for the strategies used to evaluate the stimuli. At encoding, participants used reappraisal to increase and decrease the personal relevance of neutral and emotional pictures. In two experiments, recall accuracy was highest for emotional pictures featured on increase trials, intermediate for emotional pictures featured on look (respond naturally) trials, and lowest for emotional pictures featured on decrease trials. This recall pattern emerged after a short delay (15 min) and persisted over a longer delay (48 hr). Memory accuracy for the strategies used to evaluate the pictures showed a different pattern: Strategy memory was better for emotional pictures featured on decrease and increase trials than for pictures featured on look trials. Our findings show that the effects of emotion regulation on memory depend both on the particular strategy engaged and the particular aspect of memory being tested.
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http://dx.doi.org/10.1037/a0033533DOI Listing
December 2013