Functional connectivity in reward‐related networks is associated with individual differences in gambling strategies in male Lister hooded rats

Abstract

Individuals with gambling disorder display deficits in decision-making in the Iowa Gambling Task. The rat Gambling Task (rGT) is a rodent analogue that can be used to investigate the neurobiological mechanisms underlying gambling behaviour. The aim of this explorative study was to examine individual strategies in the rGT and investigate possible behavioural and neural correlates associated with gambling strategies. Thirtytwo adult male Lister hooded rats underwent behavioural testing in the multivariate concentric square field™ (MCSF) and the novel cage tests, were trained on and performed the rGT and subsequently underwent resting-state functional magnetic resonance imaging (R-fMRI). In the rGT, stable gambling strategies were found with subgroups of rats that preferred the suboptimal safest choice as well as the disadvantageous choice, that is, the riskiest gambling strategy. R-fMRI results revealed associations between gambling strategies and brain regions central for reward networks.Moreover, rats with risky gambling strategies differed from those with strategic and intermediate strategies in brain functional connectivity. No differences in behavioural profiles, as assessed with the MCSF and novel cage tests, were observed between the gambling strategy groups. In conclusion, stable individual differences in gambling strategies were found. Intrinsic functional connectivity using R-fMRI provides novel evidence to support the notion that individual differences in gambling strategies are associated with functional connectivity in brain regions important for reward networks.

Exploring decision-making strategies in the Iowa gambling task and rat gambling task

“…Studies investigating inter-individual variability in decision-making using various versions of rodent gambling tasks found subpopulations of decision-makers ( Rivalan et al, 2009 ; Pittaras et al, 2016 ; Cabeza et al, 2020 ; Tjernström et al, 2022 ), suggesting similar variability as observed in healthy humans ( Steingroever et al, 2013 ). Similar to the standard scoring approaches commonly used in the IGT ( Bechara et al, 2000b ), many rGT studies tend to group the options into advantageous and disadvantageous choices, and the main focus has been on factors and treatments that attenuate the disadvantageous options in favor of the more advantageous choices ( Rivalan et al, 2011 ; Zeeb and Winstanley, 2011 ; Adams et al, 2017a , b ).…”

“…One choice is clearly the most advantageous, and the remaining three options are increasingly disadvantageous. We and others have shown that the majority of rats learn and maintain a stable choice on the most advantageous option associated with smaller immediate gains but greater overall net gain, in favor of the disadvantageous options associated with larger immediate gains but greater overall net losses ( Zeeb et al, 2009 ; Zeeb and Winstanley, 2011 ; Barrus et al, 2015 ; Barrus and Winstanley, 2016 ; Tjernström et al, 2022 ). Decisions are based on reinforcer/punishment feedback gained during the task and studies have established that similar brain regions, as observed in humans performing the IGT (such as DLPFC and VMPFC/orbitofrontal cortex), are activated during the course of the rGT ( Zeeb et al, 2015 ).…”

“…The rat data used herein are combined based on two previous studies ( Tjernström et al, 2022 ; Tjernström and Roman, 2022 ; manuscript resubmitted for review). Outbred male Lister Hooded (HsdOla:LH, Envigo, Horst, Netherlands; N = 72) rats were delivered at 5–6 weeks of age.…”

“…The rGT procedure has been described in detail elsewhere ( Tjernström et al, 2022 ). The rGT took place in five-hole operant chambers (34 × 33 × 33 cm) placed inside ventilated sound-attenuating cabinets (56 × 56 × 70 cm; Med Associates, St. Albans, VT, United States).…”

“…Decisions are based on reinforcer/punishment feedback gained during the task and studies have established that similar brain regions, as observed in humans performing the IGT (such as DLPFC and VMPFC/orbitofrontal cortex), are activated during the course of the rGT ( Zeeb et al, 2015 ). In addition, individuals with different gambling strategies in the rGT were found to differ in connectivity in regions associated with brain reward networks ( Tjernström et al, 2022 ).…”