Ventral striatal gamma oscillations are highly variable from trial to trial, and are dominated by behavioural state, and only weakly influenced by outcome value.

The human and rodent ventral striatal local field potentials show striking oscillations in the gamma band (~ 40-100 Hz), which have been linked to aspects of behaviour such as reward anticipation and delivery, movement initiation, learning from feedback, and decision-making. These oscillations show a rich temporal organization, whose relationship with behavioural variables is not well understood. Here, we show that, in rats performing a conditioned approach task, low-gamma and high-gamma oscillations during an immobile reward anticipation epoch were largely insensitive to outcome value, even though rats distinguished behaviourally between different outcomes, and single units encoded outcome value.