Three patients with non-REM parasomnias experienced episodes of Cotard delusion—believing they were dead or dying and unable to perceive their bodies as their own. These nihilistic mentations occurred during confusional arousals from sleep and were accompanied by panic. EEG source analysis indicated right-hemispheric hypoactivity during the episodes. The authors argue that aberrant activation of the salience network and default mode network—two major intrinsic networks of wakefulness—underlies these states. Such dreamlike mentations are rarely remembered and likely underreported, but can cause significant distress and worsen clinical outcomes if unaddressed.
Cannabis use is a strong environmental risk factor for schizophrenia, but the mechanism is unknown. This theoretical paper argues that exogenous cannabinoids may directly affect T-type calcium channels in the thalamus. These channels are critical for amplifying corticothalamic inputs and generating neuronal burst firing, which is important for trans-thalamic cortico-cortical interactions. Interference with burst firing could impair these interactions, leading to a relative disconnection between cortical areas, reduced ability to recognize re-afferent sensory inputs, and psychosis. Δ(9)THC may be more detrimental than cannabidiol because it increases thalamic neuron excitability through its direct effect on T-type calcium channels.