Mindfulness training and exercise differentially impact fear extinction neurocircuitry.

BACKGROUND: The ability to extinguish a maladaptive conditioned fear response is crucial for healthy emotional processing and resiliency to aversive experiences. Therefore, enhancing fear extinction learning has immense potential emotional and health benefits. Mindfulness training enhances both fear conditioning and recall of extinguished fear; however, its effects on fear extinction learning are unknown. Here we investigated the impact of mindfulness training on brain mechanisms associated with fear-extinction learning, compared to an exercise-based program. METHODS: We investigated BOLD activations in response to a previously learned fear-inducing cue during an extinction paradigm, before and after an 8-week mindfulness-based stress reduction program (MBSR, n = 49) or exercise-based stress management education program (n = 27). RESULTS: The groups exhibited similar reductions in stress, but the MBSR group was uniquely associated with enhanced activation of salience network nodes and increased hippocampal engagement. CONCLUSIONS: Our results suggest that mindfulness training increases attention to anticipatory aversive stimuli, which in turn facilitates decreased aversive subjective responses and enhanced reappraisal of the memory.

Hippocampal circuits underlie improvements in self-reported anxiety following mindfulness training.

INTRODUCTION: Mindfulness meditation has successfully been applied to cultivate skills in self-regulation of emotion, as it employs the unbiased present moment awareness of experience. This heightened attention to and awareness of sensory experience has been postulated to create an optimal therapeutic exposure condition and thereby improve extinction learning. We recently demonstrated increased connectivity in hippocampal circuits during the contextual retrieval of extinction memory following mindfulness training. METHODS: Here, we examine the role of structural changes in hippocampal subfields following mindfulness training in a randomized controlled longitudinal study using a two-day fear-conditioning and extinction protocol. RESULTS: We demonstrate an association between mindfulness training-related increases in subiculum and decreased hippocampal connectivity to lateral occipital regions during contextual retrieval of extinguished fear. Further, we demonstrate an association between decreased connectivity and decreases in self-reported anxiety following mindfulness training. CONCLUSIONS: The results highlight the role of the subiculum in gating interactions with contextual stimuli during memory retrieval and, also, the mechanisms through which mindfulness training may foster resilience.

How Does Preexisting Hypertension Affect Patients with Intracerebral Hemorrhage?

BACKGROUND AND PURPOSE: Patients with intracerebral hemorrhage (ICH) frequently present with hypertension, but it is unclear if this is due to pre-existing hypertension (prHTN) or to the bleed itself or associated pain. We sought to assess the relationship between prHTN and admission systolic blood pressure (aBP) and bleed severity. METHODS: We retrospectively assessed the relationship between prHTN and aBP and NIHSS in patients with ICH at 3 institutions. RESULTS: Of 251 patients, 170 (68%) had prHTN based on history of hypertension/antihypertensive use. Median aBP was significantly higher in those with prHTN (155 mm Hg (IQR 135-181) versus 139 mm Hg (IQR 124-158), P < .001). Patients with left ventricular hypertrophy (LVH) on electrocardiogram (ECG) or transthoracic echocardiogram (TTE) had significantly higher aBP than those without LVH (median aBP 195 mm Hg (IQR 155-216) for patients with LVH on ECG versus 147 mm Hg (IQR 129-163) for patients with no LVH on ECG, P < .001; median aBP 181 mm Hg (IQR 153-214) for patients with LVH on TTE versus 152 mm Hg (IQR 137-169) for patients with no LVH on TTE, P = .01). prHTN was associated with a higher median NIHSS (11 (IQR 3-20) for patients with history of hypertension/antihypertensive use versus 6 (IQR 1-14) for patients without this history (P = .02); 9 (IQR 3-19) versus 5 (IQR 2-13) for patients with/without LVH on ECG (P = .085); and 10 (IQR 5-18) versus 5 (IQR 1-13) for patients with/without LVH on TTE (P = .046). CONCLUSIONS: Patients with ICH who have prHTN have higher aBP and NIHSS, suggesting that prHTN may worsen reactive hypertension in the setting of ICH.