Michael J. Krashes, Ph.D.

Research Goal

The ultimate goal of my research is to decipher the wiring diagram that underlies hunger. To achieve this, we employ novel genetic tools and techniques to dissect conserved feeding circuits with the hopes of furthering our understanding of the behaviors that drive humans to obtain food and ultimately how these behaviors can be manipulated to battle human eating afflictions.

Research In Plain Language

Hunger is an intensely strong motivational state that every human being battles on a daily basis. Importantly, its abnormal regulation lies at the heart of obesity and feeding disorders. It is remarkable how little we know about its cause. Our research group tries to understand how the brain works to control feeding behavior using the rodent brain as a model. We are interested in studying how the brain brings together information sensed from its external environment and its own internal states, including memory, to guide eating behavior.

Feeding, and the subsequent nutrition gained from this particular act, is a fundamental behavior shared by all living organisms. In short, humans, like all species, must eat to survive. Animals must satiate hunger and meet energy needs. They must detect and remember stimuli linked with getting food. In addition, these external cues have different meanings depending on the internal state of the organism. For example, although we are aware of the location of our refrigerator at all times, we only retrieve food from it when we feel hungry.

Feeding can be simplistically divided into three phases. In phase one, a brain region called the hypothalamus integrates with internal hormones and signals to regulate energy balance. In phase two, the pleasurable and rewarding aspects influence the drive to obtain food. In phase three, memory processes direct the learning and memory of food locations. Prior studies have investigated these phases of eating separately. However, these phases are equally important and it makes sense to study their interaction.

Our research aims to understand the connection between these phases. We try to tease apart the functions of the brain circuits involved in appetite. Our studies examine the relationship between satiety signals from the hypothalamus and neural networks that control food seeking. We study the neural circuits that guide the behavior of obtaining food. We focus on brain systems that underlie motivational drives and learning and memory processes. To achieve this, we use a combination of genetic and molecular tools.