Reward-related neuronal activities in basal ganglia of domestic chicks

Abstract

We aimed to reveal what is coded in the basal ganglia of domestic chicks. In the water-reinforced 'go' task, chicks learned to peck selectively at a colored bead in order to obtain a drop of water. Out of 38 units obtained, seven showed excitatory activities specifically during the reward period. In the food-reinforced go/no-go task, chicks learned to discriminate two colors to obtain mash food after a delay period. They also learned to ignore another color, which was not associated with a reward. Out of 27 units obtained, four showed excitatory activities during the cue period, specifically when a food reward was anticipated. LPO neurons may code qualities of the obtained rewards, and also chick's anticipation of the forthcoming rewards.

Competitor suppresses neuronal representation of food reward in the nucleus accumbens/medial striatum of domestic chicks

“…However, this idea is not plausible given that our previous lesion experiments failed to cause any detectable changes in the latencies or performance of pecks at the response bar or food [21,24]. Furthermore, we have not found a correlation between activity of MSt/NAc neurons and pecking actions [22,23].…”

“…Representation of gained reward has been repeatedly documented in chicks [23] and rats [44][45][46] in terms of changes in activity (either excitatory or inhibitory) that 21 appear when reward is delivered. In probe extinction trials, for most neurons, these activity changes immediately vanished [45], supporting the idea that the reward-period activity represents actual reward.…”

“…Further, electrophysiological experiments in freely behaving chicks revealed that MSt/NAc neurons encoded the amount or proximity of reward during the initial cue period in which the color cue signaled the associated food reward [22]. MSt/NAc neurons with cue-period activity were also activated during delay and reward periods in which food reward was predicted and delivered [23]. However, a functional role for these multiple codes related to food reward remains elusive, except for an indirect suggestion that they might be involved in the computation of prediction error, as in cases of extinction [24].…”

Neuro-economics in chicks: Foraging choices based on amount, delay and cost

“…Detailed tract-tracing studies combined with neurochemical and ultrastructural characterizations suggest that the ventral striatum plays a pivotal role in controlling memory-based decision paradigms [12]. Actually, in appetitive color discrimination tasks, a population of neurons responded to visual cues associated with rewards, irrespective of whether operant peck was required or not [25,52]; so far, however, reliable data are not available as to whether the same ensemble of neurons are responsible for both appetitive and aversive memories. Similar reward-related anticipatory activities have been found in a variety of regions including arcopallium [4] and nidopallium caudolaterale [27,42].…”

Sustained activation and executive control in the avian prefrontal cortex

“…For example, there is considerable evidence that the neural activity of PFC neurons is modulated by the magnitude, preference, or certainty of a reward [22,27,37]. Likewise, neural correlates of magnitude and preference of rewards have also been noted in the avian brain [17,38]. With respect to the issue of certainty, the certainty of reward following forget-reward trials (100%) is surely greater than following a remember trial, where performance averaged around 85-90% correct.…”