The MDTHA had lower CM and lower BOLD signals for cocaine abusers than for control subjects. These results are consistent with previous studies that documented reduced DA release [5] and reduced activation [17], [18], [42] in the MDTHA for cocaine abusers compared to control subjects. The MDTHA is innervated by norepinephrinergic and dopaminergic neurons [43]. Our current findings may therefore reflect a dysfunctional norepinephrinergic and dopaminergic regulation of the MDTHA in cocaine addicts. This interpretation is further supported by the negative correlation between the thalamic CM signals and the years of cocaine use, which suggests that functional connectivity could be a better marker than BOLD responses for the precise characterization of drug-related neuroadaptations. The positive correlation of thalamic BOLD and CM signals in control subjects and the lack of similar correlations in cocaine subjects further supports this conclusion.
