Caitlin Mace

Novel tools have allowed researchers to intervene into circuits at the mesoscale. The results of these interventions are often explained by appeal to functions. How are functions ascribed to circuit parts experimentally? I identify two kinds of function ascription practices in circuit interventions. Analysis of these practices shows us that what makes function ascriptions challenging is a lack of interventive control and insufficient constraints on the class of candidate functions to discriminate in practice. One kind of function ascription practice—subtractive analysis—fares better at addressing these challenges.

Whether neurons represent or play a mere causal role is a foundational issue in philosophy of neuroscience. Evidence that neurons perform a representational role is weakened by the possibility of explaining experimental results by appeal to brute causal processes alone. Despite this, neuroscientists ascribe representational content to patterns of neural activity to explain experimental results. An important problem with this practice is determining which content to ascribe to the neural representation. One view is that researchers are only warranted in ascribing the content determined by particular experimental results. An alternative view is that researchers are warranted in appealing to the broader research domain to determine the content of a putative neural representation. In this paper, I argue that both are warranted; either alone is insufficient. Using optogenetics research on memory engrams as a case study, I show how researchers ascribe content to neural representations and justify their approach. Whether a particular content ascription is warranted depends on particular experimental results, the broader research domain that is appealed to, and how results from various animal models, probes, and experimental paradigms are generalized.