Psychedelics, Emotional Processing and the Importance of the Amygdala | Dasha Anderson, M.Sc.

Описание: Recent research indicates that serotonergic psychedelics such as psilocybin could show promise as a rapidly acting treatment for depression (Cahart-Harris et al, 2016; 2021), among other psychiatric conditions such as end-of-life anxiety (Griffiths et al, 2016; Ross et al, 2016). However, the neurobiological mechanisms underlying such effects remain unclear. Given the effects of psilocybin on alleviating negative emotions, one avenue of research has been to examine whether psilocybin has a regenerative effect on brain structures involved in emotional processing, such as the amygdala. The amygdala is a subcortical structure that we have long thought plays a pinnacle role in affective processing, particularly of fearful and threatening stimuli. Indeed, this brain structure is thought to have been moulded by evolution to detect threatening and other negative stimuli and generate psychological and physiological states of fear. Importantly, this structure may be crucially involved in the development and maintenance of depression. Negative emotional biases are a core feature of depression, with depressed patients attending more strongly to negative stimuli, showing better memory for negative stimuli and commonly misclassifying ambiguous stimuli (e.g. faces) as negative (Ma, 2015). Consistent with this, neuroimaging studies have revealed that, in untreated patients with depression, the amygdala responds more strongly to negative stimuli such as unhappy and angry faces (Ma et al, 2015), and conventional antidepressant medications weaken this so-called ‘hyperreactivity’ (Patin & Hurlemann, 2011). In this presentation I will discuss recent neuroimaging evidence exploring the effects of psilocybin and other psychedelics on amygdala reactivity and the possible role of this complex structure in explaining the rapid antidepressant effects of such drugs (Barrett et al, 2020; Kraehenmann et al, 2015; Mertens et al, 2020; Mueller et al, 2017; Roseman et al, 2018). During this exploration, I will touch upon some of the possible neurobiological mechanisms by which psychedelics may exert their effects on the amygdala from the level of brain network dynamics to the level of individual 5-HT receptor properties and, with psychedelics offering a regenerative experience to users not just neurobiologically but also psychologically, I will further attempt to relate these findings to important higher-level concepts such as emotional blunting, emotional reconnection and acceptance. However, with research in this area not only in its nascent stages but also sometimes contradictive, I will highlight a few of the common methodological challenges associated with the empirical study of these drugs, particularly in neuroimaging and clinical settings.