Fig. 7.

Diagram depicting each of the system states that was impacted by 15-day chronic social stress and a hypothesized causal pathway, from stress activation of the immune system to altered mesolimbic DA function and resultant impaired reward processing. The solid arrows linking chronic social stress with each separate system depict the causal relationships identified in this study. The dashed arrow linking each pair of systems depicts the causal relationship hypothesized to exist between them which can be investigated in the present model. For each system state the factors that were studied and demonstrated to be affected by CSS are indicated, with either a quantitative increase (↑) or decrease (↓) in the factor in CSS compared with CON mice. BBB = blood-brain barrier and denotes that peripheral-to-brain immune activation would require BBB passage in the case of some mediating pathways. CSS effects on factors marked with an asterisk were not analysed in this study and the effects were demonstrated in previous studies.