In broad terms, the study of functional network disruption in the degenerative dementias is in its infancy. Some conditions, such as AD, have been widely investigated with the described approaches. Other illnesses, such as PDD and DLB, as well as FTD language variants, largely remain to be explored. In PD and DLB, a disease-specific ICA networks has not yet been identified with task-free fMRI, but recent work suggests a link to a basal ganglia network, anti-correlated with the DMN, which might be affected in these disorders.123 Similarly, graph theoretical approaches may be used to assess functional changes in the PD spectrum. In addition, novel and more sophisticated approaches such as Bayesian network modelling may provide additional markers of connectivity by assessing causal relationships between nodes. Preliminary findings from the analysis of DMN with this method in AD look promising.138
