Transcranial magnetic stimulation is used to make inferences about relationships between brain areas and their functions because, in contrast to neuroimaging tools, it modulates neuronal activity. The central aim of this article is to critically evaluate to what extent it is possible to draw causal inferences from repetitive TMS data. To that end, we describe the logical limitations of inferences based on rTMS experiments. The presented analysis suggests that rTMS alone does not provide the sort of premises that are sufficient (...) to warrant strong inferences about the direct causal properties of targeted brain structures. Overcoming these limitations demands a close look at the designs of rTMS studies, especially the methodological and theoretical conditions which are necessary for the functional decomposition of the relations between brain areas and cognitive functions. The main points of this article are that TMS-based inferences are limited in that stimulation-related causal effects are not equivalent to structure-related causal effects due to TMS side effects, the electric field distribution, and the sensitivity of neuroimaging and behavioral methods in detecting structure-related effects and disentangling them from confounds. Moreover, the postulated causal effects can be based on indirect effects. A few suggestions on how to manage some of these limitations are presented. We discuss the benefits of combining rTMS with neuroimaging in experimental reasoning and we address the restrictions and requirements of rTMS control conditions. The use of neuroimaging and control conditions allows stronger inferences to be gained, but the strength of the inferences that can be drawn depends on the individual experiment’s designs. Moreover, in some cases, TMS might not be an appropriate method of answering causality-related questions or the hypotheses have to account for the limitations of this technique. We hope this summary and formalization of the reasoning behind rTMS research can be of use not only for scientists and clinicians who intend to interpret rTMS results causally but also for philosophers interested in causal inferences based on brain stimulation research. (shrink)

Basic affects reflect the diversity of satisfactions and discomforts that are inherited tools for living from our ancestral past. Affects are neurobiologically-ingrained potentials of the nervous system, which are triggered, moulded and refined by life experiences. Cognitive, information- processing approaches and computational metaphors cannot penetrate foundational affective processes. Animal models allow us to empirically analyse the large-scale neural ensembles that generate emotional-action dynamics that are critically important for creating emotional feelings. Such approaches offer robust neuro-epistemological strategies to decode the fundamental (...) nature of affects in all mammals, including humans, but they remain to be widely implemented. Here I summarize how we can develop a cross-species affective neuroscience that probes the neural nature of emotional affective states by studying the instinctual emotional apparatus of the mammalian body and brain. Affective feelings and emotional actions may reflect the dynamics of the primal viscero-somatic homunculus of SELF-representation. (shrink)