Rational choice theorys propositions, that economic actors strictly follow an optimization calculus, denying any kind of influence from social action, has been challenged for years within economic discourse and economic sociology. Re-conceptualizations of the Homo Economicus acknowledge the emotional influence on individual decision making within social contexts. The interdisciplinary research field of neuroeconomics has become a strong reference point in scientific and more so within socio-economic-political discourse as part of the emerging neurocultural framing of todays neoliberal society. We analyse the recent formation of the Homo Neuroeconomicus with respect to the current dispute around concepts of separation and competition versus interaction of emotional and rational processing that should predict economic decision making. We outline the permanent gendered connotations of this knowledge production and their impact on the persistence of biologically grounded and separated processes of emotional or rational processing. With an in-depth analysis of a case study, i.e., the (neuro-) biological explanation for the financial crisis by the Frankfurter Zukunftsrat in 2009, we exemplify how biological explanations and references to separate processes of emotional or rational decision making are utilized to legitimize individual responsibility and failure. This neglects socio-structural contexts and symbolic inscriptions in the concept of the Homo Neuroeconomicus.