Mark Laubach PhD
Associate Professor of Neurobiology; Associate Fellow, Pierce Laboratory
Basal ganglia; Frontal cortex; Associative learning; Decision making; Working memory; Multi-electrode recording; Reversible inactivation methods, including optogenetic techniques; Intra-cranial drug administration; Advanced statistical analysis; Computational models
We are currently engaged in the following research projects:
1) Determining the role of medial frontal cortex in mediating sequential changes in behavioral performance, e.g., boosting attention to external stimuli after mistakes are made, and enabling self-control over action.
2) Determining how aging impairs frontal function with regard to working memory and reward processing.
3) Understanding the neural control of food intake.
We study how the frontal cortex and basal ganglia work together to control behavior. A topic of special interest is the role of persistent firing by frontal cortical neurons in executive control (anticipation, working memory, inhibitory control). Reaction time and decision-making tasks have been used prominently in our work over the past several years. Most recently, we have used simple tasks for studying the role of fronto-striatal systems in the control of food intake.
Our principal methodology is neuronal ensemble recording. In addition, we use reversible inactivation methods (e.g., fluorescent muscimol), local injections of drugs, optogenetic methods, and anatomical tract-tracing methods to study brain function from a systems perspective. We also use statistical classifiers and other multivariate statistical methods to study neural coding at the single neuron and neuronal populations levels.
Extensive Research Description
The goal of the Laubach Laboratory is to understand the role of the frontal cortex and basal ganglia in value-based decision making, food-seeking behavior, and the cognitive control of action. We wish to understand how frontal regions of the brain learn predictive relationships between stimuli and outcomes (such as food) and control action selection. We are carrying out three lines of research related to these topics. First, we are studying how errors influence neuronal activity to improve future task performance. Second, we are studying how the values of external stimuli, including rewards, are learned and flexibly tracked under changing environmental circumstances and how these aspects of stimuli and actions are mapped onto neuronal activity. Third, we are studying how working memory, based on persistent firing by neurons in the frontal cortex, is used to link together sequences of goal-directed actions. To study these issues, we use multi-electrode recording methods in awake, behaving rodents, methods for reversible inactivating brain regions (e.g., fluorescent muscimol), tract-tracing methods, and, most recently, optogenetic methods. We are also active in developing methods for quantifying how neuronal spike trains and population activity represent information about behavior, how spike trains relate to fluctuations in local field potentials, and how to relate the diffusion of fluorescent drugs and AAVs in the brain to behavioral effects of the drugs and AAVs on behavior (enabling functional volumetric imaging and tract-tracing studies in the brains of behaviorally characterized animals).