This 2016 New York rodent study found:
“By using unbiased and whole-brain imaging techniques, we uncover a number of cortical and subcortical brain structures that have lower activity in the animals showing helplessness than in those showing resilience following the LH [learned helplessness] procedure. We also identified the LC [locus coeruleus] as the sole subcortical area that had enhanced activity in helpless animals compared with resilient ones.
Some of the brain areas identified in this study – such as areas in the mPFC [medial prefrontal cortex], hippocampus, and amygdala – have been previously implicated in clinical depression or depression-like behavior in animal models. We also identified novel brain regions previously not associated with helplessness. For example, the OT [olfactory tubercle], an area involved in odor processing as well as high cognitive functions including reward processing, and the Edinger–Westphal nucleus containing centrally projecting neurons implicated in stress adaptation.
The brains of helpless animals are locked in a highly stereotypic pathological state.”
Concerning the study’s young adult male subjects:
“To achieve a subsequent detection of neuronal activity related to distinct behavioral responses, we used the c-fosGFP transgenic mice expressing c-FosGFP under the control of a c-fos promoter. The expression of the c-fosGFP transgene has been previously validated to faithfully represent endogenous c-fos expression.
Similar to wild-type mice, approximately 22% (32 of 144) of the c-fosGFP mice showed helplessness.”
The final sentence of the Introduction section:
“Our study..supports the view that defining neuronal circuits underlying stress-induced depression-like behavior in animal models can help identify new targets for the treatment of depression.”
Helplessness is both a learned behavior and a cumulative set of experiences during every human’s early life. Therapeutic approaches to detrimental effects of helplessness can be different with humans than with rodents in that we can address causes.
The researchers categorized activity in brain circuits as causal in the Discussion section:
“Future studies aimed at manipulating these identified neural changes are required for determining whether they are causally related to the expression of helplessness or resilience.”
Studying whether or not activity in brain circuits induces helplessness in rodents may not inform us about causes of helplessness in humans. Our experiences are often the ultimate causes of helplessness effects. Many of our experiential “neural changes” are only effects, as demonstrated by this and other studies’ induced phenotypes such as “Learned Helplessness” and “Prenatally Restraint Stressed.”
Weren’t the researchers satisfied that the study confirmed what was known and made new findings? Why attempt to extend animal models that only treat effects to humans, as implied in the Introduction above and in the final sentence of the Discussion section:
“Future studies aimed at elucidating the specific roles of these regions in the pathophysiology of depression as well as serve as neural circuit-based targets for the development of novel therapeutics.”
http://journal.frontiersin.org/article/10.3389/fncir.2016.00003/full “Whole-Brain Mapping of Neuronal Activity in the Learned Helplessness Model of Depression” (Thanks to A Paper a Day Keeps the Scientist Okay)