Cortex; a journal devoted to the study of the nervous system and behavior
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Remembering the past and imagining the future are complex endeavours proposed to rely on a core neurobiological brain system. In the behavioural variant of frontotemporal dementia (bvFTD), regional patterns of brain atrophy affect medial prefrontal and temporal cortices of this core network. While autobiographical memory impairments have been documented in bvFTD, it remains unknown whether the ability to imagine future events is also compromised. ⋯ In contrast, in bvFTD, disruption of past retrieval correlated with atrophy in medial prefrontal regions, whereas future thinking deficits were associated with atrophy of frontopolar, medial temporal regions including the right hippocampus, and lateral temporal and occipital cortices. Our results point to the involvement of multiple brain regions in facilitating retrieval of past, and simulation of future, events. Damage to any of these key regions thus adversely affects the ability to engage in personally relevant mental time travel.
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An attentional bias to threat has been causally related to anxiety. Recent research has linked nonconscious attentional bias to threat with variability in the integrity of the amygdala - anterior cingulate pathway, which sheds light on the neuroanatomical basis for a behavioral precursor to anxiety. However, the extent to which structural variability in amygdala - anterior cingulate integrity relates to the functional connectivity within this pathway and how such functional connectivity may relate to attention bias behavior, remain critical missing pieces of the puzzle. ⋯ We found that greater biases in attention to threat predicted greater levels of uncinate fasciculus integrity, greater positive amygdala - anterior cingulate functional connectivity, and greater amygdala coupling with a broader social perception network including the superior temporal sulcus, tempoparietal junction (TPJ), and somatosensory cortex. Additionally, greater levels of uncinate fasciculus integrity correlated with greater levels of amygdala - anterior cingulate intrinsic functional connectivity. Thus, high bias individuals displayed a heightened degree of amygdala - anterior cingulate connectivity during basal conditions, which we believe predisposes these individuals to focus their attention on signals of threat within their environment.