Inactivating Anterior Insular Cortex Reduces Risk Taking

Abstract

We often have to make risky decisions between alternatives with outcomes that can be better or worse than the outcomes of safer alternatives. Although previous studies have implicated various brain regions in risky decision making, it remains unknown which regions are crucial for balancing whether to take a risk or play it safe. Here, we focused on the anterior insular cortex (AIC), the causal involvement of which in risky decision making is still unclear, although human imaging studies have reported AIC activation in various gambling tasks. We investigated the effects of temporarily inactivating the AIC on rats' risk preference in two types of gambling tasks, one in which risk arose in reward amount and one in which it arose in reward delay. As a control within the same subjects, we inactivated the adjacent orbitofrontal cortex (OFC), which is well known to affect risk preference. In both gambling tasks, AIC inactivation decreased risk preference whereas OFC inactivation increased it. In risk-free control situations, AIC and OFC inactivations did not affect decision making. These results suggest that the AIC is causally involved in risky decision making and promotes risk taking. The AIC and OFC may be crucial for the opposing motives of whether to take a risk or avoid it.

Involvement of the rostral agranular insular cortex in nicotine self-administration in rats

“…Within animal studies involving insular cortex manipulations, studies have demonstrated both a role for the CGIC [14,15,17,41,42] or RAIC [16,[43][44][45][46][47] or both [13,48] in addiction relevant behaviors. To our knowledge, only two studies thus far have compared manipulations of the CGIC vs. RAIC and found differential involvement in addiction-relevant behaviors.…”

A neural network that links brain function, white-matter structure and risky behavior

“…Activity in the insula is associated with tracking risk (Ishii et al, 2012; Naqvi et al, 2014; Paulus et al, 2003; Kuhnen and Knutson, 2005), and patients with insula lesions make choices that reflect insensitivity to the odds of winning on gambling tasks (Clark et al, 2008). In addition, projections from the midbrain to the striatum signal the presence of motivationally salient events, and anticipatory dopaminergic responses modulate risk preferences (St Onge and Floresco, 2009; Sugam et al, 2012).…”

Orbitofrontal or accumbens dopamine depletion does not affect risk-based decision making in rats

“…Considerable evidence implicated the OFC in risk-taking; however, its exact role is still a matter of debate. For instance, transient or permanent OFC inactivation increased, decreased, or left unaffected risktaking and these mixed effects might be accounted for in part by the type of task, time point of inactivation during task acquisition, or targeted OFC subregion (Floresco, St Onge, Ghods-Sharifi, & Winstanley, 2008;Ishii, Ohara, Tobler, Tsutsui, & Iijima, 2012;Jentsch, Woods, Groman, & Seu, 2010;Mobini et al, 2002;Pais-Vieira, Lima, & Galhardo, 2007;Zeeb & Winstanley, 2011). Of note, a recent study using a probabilistic discounting task similar to the one used here showed that OFC lesions promoted risk aversion (Abela & Chudasama, 2013).…”