TABLE 5.
Summary of the brain areas involved in the expression of separation across species.
| Species (Sex) | How to elicit it (Imaging method) | Neural changes (↗ increase/↘ decrease) | References |
| Social pain and separation anxiety | |||
| Humans–Homo sapiens | Participants playing Cyberball being excluded from a game (fMRI) |
↗ anterior cingulate cortex, right ventral prefrontal cortex | Eisenberger et al., 2003 |
| Humans–Homo sapiens (Men and Women) |
Subjects receiving the feedback of another participant whether they like them or not along with their picture (fMRI) |
Romantic rejection ↗ ventrolateral prefrontal cortex and anterior insula |
Hsu et al., 2020 For a review: van der Watt et al., 2021 |
| Humans–Homo sapiens (Mothers) |
Mother listening to their own infant cry compared to white noise (fMRI) |
↗ anterior cingulate cortex, medial preoptic area, medial preoptic area, bed nucleus of the stria terminalis | Lorberbaum et al., 1999, 2002 |
| Humans–Homo sapiens (Mothers) |
Mother (healthy group) viewing a separation from their children compared to another child (fMRI) |
Separation anxiety ↘ medial prefrontal cortex |
Schechter et al., 2012 |
| Loneliness | |||
| Humans–Homo sapiens | Social vs. non-social image presentation (functional imaging methods) |
↗ prefrontal cortex, anterior insula, amygdala, hippocampus and posterior superior cortex | Review paper: Lam et al., 2021 |
| Short-term loss | |||
| Macaques–Macaca mulatta (Males only) | Separation of juveniles from their mother (PET scan) |
↗ right dorsolateral prefrontal cortex, right ventral temporal/occipital lobe ↘ left dorsolateral prefrontal cortex |
Rilling et al., 2001 |
| Voles *–Microtus ochrogaster (Males only) *not a brain imaging study |
Separation from the pair bond (3 days) | ↘ of striatal oxytocin signaling in the nucleus accumbens shell | Bosch et al., 2016 |
| Titi monkey–Plecturocebus cupeus (Males only) |
Short-term separation from the pair bond (48 h) (PET scan) |
↘ lateral septum, ventral pallidum, paraventricular nucleus of the hypothalamus, periaqueductal gray, and cerebellum | Hinde et al., 2016 |
| Long-term loss and grief | |||
| Titi monkey–Plecturocebus cupeus (Males only) |
Long-term separation from the pair bond (2–3 weeks) (PET scan) |
↘ reduced FDG uptake in the central amygdala, reduced whole brain FDG uptake | Hinde et al., 2016 |
| Humans–Homo sapiens (Women) |
Presentation of photographs or verbal evocation of a deceased (fMRI) |
By picture or verbal stimulation: ↗ posterior cingulate cortex, medial/superior frontal gyrus, and cerebellum Picture: ↗ cuneus, superior lingual gyrus, insula, dorsal anterior cingulate cortex, inferior temporal gyrus, and fusiform gyrus Verbal: ↗ pre-cuneus, precentral gyrus, midbrain, and vermis |
Gündel et al., 2003 |
| Humans–Homo sapiens (Women) |
Presentation of photographs or verbal evocation of a deceased (fMRI) |
Only for complicated grief: ↗ nucleus accumbens Normal and complicated grief: ↗ dorsal anterior cingulate cortex, insula, periaqueductal central gray |
O’Connor et al., 2008 |
| Humans–Homo sapiens (Women) |
Evocation of a pet loss within the last 3 months (fMRI) |
↗ amygdala, the rostral and dorsal anterior cingulate cortex, as well as the dorsolateral PFC | Freed et al., 2009 |
Names in bold are brain part regularly found in neural changes related to emotion.