Amygdala and prefrontal cortex functioning during night time

The amygdala and prefrontal cortex have distinct roles in emotional regulation, and their functioning is significantly influenced by sleep.

When you lack sleep, the amygdala becomes more reactive to emotional stimuli. Normally, the medial prefrontal cortex, which is connected to the amygdala, acts as a regulatory mechanism, moderating emotional responses. However, with insufficient sleep, this connection weakens, and the amygdala becomes overly responsive, leading to heightened emotional reactions even to neutral stimuli. This means that even slight sleep deprivation, such as getting less than six hours for several consecutive nights, can make you more emotionally unstable and reactive 1.

During Rapid Eye Movement (REM) sleep, specific brain activities illustrate how emotional regulation continues at night. REM sleep is marked by the activation of various brain regions involved in visual, memory, and emotional processing, including the amygdala. Meanwhile, the dorsolateral prefrontal cortex, crucial for logical thinking, shows decreased activity, suggesting a reduced influence on controlling emotions during dreams 2. This might explain why dreams often lack rational control and can be highly emotional.

In essence, sufficient sleep helps maintain a healthy balance between the amygdala's emotional responses and the prefrontal cortex's regulatory control, supporting emotional stability both day and night. 3 4.