Biology subjects

Felmingham, K. L.

Publications and source records attributed to Felmingham, K. L..

3 recordsLinked to original sources

bioRxiv2026

Sleep and emotional memory: translating neural response at encoding to memory accuracy in men and women with and without PTSD

BackgroundGrowing evidence suggests that sleep plays an important role in PTSD outcomes, potentially due to its influence on emotional memory consolidation, though these mechanisms remain unknown. This study sought to test the hypotheses that sleep neurophysiology, PTSD status, and sex moderates the degree to which the late positive potential (LPP) mediates memory accuracy for affective visual stimuli. MethodsN = 39 participants (18 female) viewed 75 negative and 75 neutral IAPS images while EEG was recorded. After viewing the images, participants took a two-hour long nap which was followed by a memory assessment. Memory accuracy was measured using d = Z(hit rate) - Z(false alarm rate), where hit rate refers to the proportion of images seen during the memory assessment that are correctly identified as being previously seen, false alarm rate refers to the proportion of images seen during the memory assessment that are incorrectly identified as being previously seen, and Z() is the inverse cumulative distribution function of the standard normal distribution function. ResultsThe early (300 - 1000 ms) and late (1000 - 1500 ms) LPP mediated enhanced discrimination accuracy for emotional compared to neural stimuli (d) (ps < 0.001). The association between the late LPP and d was moderated by sleep such that the association was stronger when participants spent proportionately more time in N3 and REM (p = 0.02). The differences in reactivity between emotional and neutral images for both the early and late LPP were attenuated in PTSD+ individuals vs. controls (ps < 0.001). Despite mediation results showing greater d for emotional compared to neutral stimuli, women showed overall worse memory accuracy for negative compared to neutral stimuli (p < 0.001) whereas men showed no difference (p = 0.64). ConclusionsN3 and REM sleep play a critical role for memory of stimuli that produce large and sustained neural responses. PTSD is marked by a diminished ability to distinguish between negative and neutral information. More research is critical to understand sex effects on emotional memory.

neuroscience↗

bioRxiv2024

Altered basal forebrain regulation of intrinsic brain networks in depressive and anxiety disorders

Depressive and anxiety disorders are characterized by altered connectivity within and between the default mode (DMN) and salience networks. Basal forebrain subdivisions, critical for regulating network activity, remain understudied across these conditions. To address this gap, we analyzed 7-Tesla resting-state functional magnetic resonance imaging data from a transdiagnostic sample (n = 70), primarily with depressive and anxiety disorders, and healthy controls (n = 77). We used spectral dynamic causal modelling to assess effective connectivity between the medial septum/diagonal band (Ch1-3), nucleus basalis of Meynert (Ch4), ventral pallidum, and DMN and salience networks. Healthy participants showed excitatory connectivity from Ch1-3 to the DMN and from Ch4 to the anterior insula. In contrast, clinical participants exhibited greater inhibitory Ch4 to DMN connectivity and increased excitatory connectivity from Ch4 to the anterior insula. Wide-spread Ch4 connectivity dysfunction may implicate the cholinergic system as a mechanistic and therapeutic target for depressive and anxiety disorders.

neuroscience↗

bioRxiv2021

A thalamo-centric neural signature for restructuring negative self-beliefs

Negative self-beliefs are a core feature of psychopathology. Despite this, we have a limited understanding of the brain mechanisms by which negative self-beliefs are cognitively restructured. Using a novel paradigm, we had participants use Socratic questioning techniques to restructure self-beliefs during ultra-high resolution 7-Tesla functional magnetic resonance imaging (UHF fMRI) scanning. Cognitive restructuring elicited prominent activation in a fronto-striato-thalamic circuit, including the mediodorsal thalamus (MD), a group of deep subcortical nuclei believed to synchronize and integrate prefrontal cortex activity, but which has seldom been directly examined with fMRI due to its small size. Increased activity was also identified in the medial prefrontal cortex (MPFC), a region consistently activated by internally focused mental processing, as well as in lateral prefrontal regions associated with regulating emotional reactivity. Using Dynamic Causal Modelling (DCM), evidence was found to support the MD as having a strong excitatory effect on the activity of regions within the broader network mediating cognitive restructuring. Moreover, the degree to which participants modulated MPFC-to-MD effective connectivity during cognitive restructuring predicted their individual tendency to engage in repetitive negative thinking. Our findings represent a major shift from a cortico-centric framework of cognition and provide important mechanistic insights into how the MD facilitates key processes in cognitive interventions for common psychiatric disorders. In addition to relaying integrative information across basal ganglia and the cortex, we propose a multifaceted role for the MD whose broad excitatory pathways act to increase synchrony between cortical regions to sustain complex mental representations, including the self.

neuroscience↗