All animals including humans have to solve problems relating to foraging and predation. We have evolved particular capacities shaped by successful solutions to these problems. Some of these capacities are fundamental including innate reflexes and conditioned reflexes involved in flight and fight responses, orienting, chasing, eating, drinking, copulating and other forms of consummatory behaviour. These kinds of behaviour are stereotyped, reflexive, and controlled by specific eliciting cues. Beyond these bodily adaptations, mammals and some birds (as far as we know) have evolved the capacity for instrumental conditioning using which they are able to learn new actions and how, when and where best to perform those actions given sometimes very specific task demands and constraints. These actions are instrumental to satisfying sometimes very specific needs and desires based on the consequences they bring about. Some such actions are essentially acquired reflexes, what we typically call habits or skills, that involve the formation of new sensory-motor associations built through a process of reinforcement. These actions are, therefore, often highly stereotyped motor movements. Other instrumental actions are driven not by eliciting stimuli but by cognitive processes encoding their relationship to the consequences that they bring about. This latter class of action is the most flexible and highly elaborated form of behaviour in the animal kingdom. Using these flexible actions, we can learn to do almost anything that we want and gain access to almost anything we need. These actions are typically called ‘goal-directed’ because their acquisition encodes, and their performance achieves, the specific consequences or goals that we have in mind.
Our aim is to understand these forms of instrumental action; how they are acquired, selected, evaluated and executed; how they are elaborated or extended into sequences of actions; and how actions of different types – be they goal-directed, habitual or simple reflexes – impinge on and are integrated with one another to ensure our behaviour remains adaptive. We seek to understand these kinds of action at the behavioural, psychological and neural levels of analysis; the motor learning processes engaged; and the forms of learning, memory, motivational and the emotional process that emerge to support them.
To achieve these goals, we have assembled a highly experienced, multidisciplinary research team to implement an innovative translational research program using cutting edge research tools in rodents and humans to study the mechanisms of instrumental conditioning and of cognitive-emotional integration in decision-making and how these processes break down in specific psychopathology.
Decision-making as a category of activity is just the implementation of instrumental conditioning in simple performance, when one action or sequence of actions is either performed or not performed, or in choice, when a decision is made to implement one or other course of goal-directed action. With regard to the latter, the operation of decision processes is often complex and involves the evaluation of competing courses of action on the basis of their degree of relationship to, and the reward value of, their specific consequences. It is, therefore, dependent on evaluative processes that compare the value of competing actions or, when actions and outcomes are otherwise similarly valued, predictive stimuli that provide information about the relative likelihood of one or other outcome [the influence of advertising being a commonly experienced example of this effect outside the lab]. This latter form of stimulus-based choice is derived from the predicted values of actions and is studied using the Pavlovian-instrumental transfer paradigm.
Given this general program, our specific research projects can be collected under four broad aims as follows:
To establish the role of the prefrontal cortex in the acquisition of goal-directed action, and its relationship to afferent and efferent structures, particularly the striatum, amygdala, thalamus and hippocampus, in this process.
To discern how cortical inputs to the striatum affect the acquisition of goal-directed and habitual actions and contribute to learning-related plasticity in the striatum; i.e., changes in intracellular signalling, dopamine release and the activity of specific cell types.
To understand the operation and function of the specific neuromodulatory systems that determine the operation of the basal ganglia and their involvement in the cortical - basal ganglia circuits that mediate instrumental conditioning, the thalamo-striatal circuits that mediate the updating of instrumental learning, and the role of these circuits in the selection of actions during decision-making.
To study the basic motivational and emotional processes that affect instrumental performance including those through which the outcomes of actions are evaluated and those allowing predictive learning to affect choice performance.