A study was done on prairie voles (Bosch et al. 2009, Bosch et al. 2016) that discovered a decrease in oxytocin levels in the nucleus accumbens "mediated by corticotropin-releasing factor (CRF)" which created a depressive response in male voles when they are separated from their partners. From this study, a possible conclusion to be drawn is that prolonged grief disorder could be associated with continued disruptions in the reward center of the brain. Based on studies by Le Roy et al. 2019, the dysregulation can potentially be due to a continued reliance by an individual on a deceased attachment figure. This continued reliance is what may cause the increase of activation in the reward center which leads to a feeling of yearning for the deceased, a key symptom of prolonged grief disorder.