An opportunity for high school and college students to chat with brain science researchers at Harvard University.

Dustin Tillman
Graduate Student, Lab of Jeff Macklis, Harvard University

Dustin is a third-year Ph.D. student in Jeff Macklis’ lab at Harvard studying how neurons form complex circuits. Neurons are specialized cells in the nervous system that use electricity to transmit information with other neurons, similar to wires in a computer. However, neurons are born as spherical cells without any connections to other neurons. As neurons mature, they extend long projections (called axons) to form precise connections with other neurons, giving rise to incredibly intricate circuits. Growth cones are miniature compartments at the tips of these extending projections that guide neurons to their appropriate targets. If growth cones don’t navigate correctly, circuits can be miswired, leading to a variety of neurological disorders. His investigations center on two types of neurons that are born in the same brain region, but extend projections to vastly different target areas. In particular, he is focusing on how growth cones are different between these two types of neurons, and how improper formation of these circuits might play a role in the onset of Lou Gherig’s disease.

Yasmin Escobedo Lozoya
Postdoctoral Researcher, Lab of Susan Dymecki, Harvard Medical School

The electrical activity of brain circuits is complex and dynamic. Understanding how these dynamics relate to mental processes and how they arise from the properties of their components is a fundamental task of modern neuroscience. Yasmin’s focus is understanding how the properties of individual neurons and their interconnections contribute to circuit dynamics. In living animals, single units of a network, brain cells called ‘neurons’, differ in how much their activity stands out from the overall activity of the network, ie. to what extent they are “soloists” vs. part of a “chorus”. Her Ph.D. work addressed how these seemingly distinct dynamics arise and how they relate to the underlying network connectivity. She now explores how neuromodulatory systems within brains exploit this intrinsic flexibility of circuit dynamics to nudge circuits into states useful to the animal. She studies this in the context of the neuromodulation of reward memory formation by neurons that make the transmitter serotonin. Her work will answer if a class of serotonin neurons functions akin to the switches of an old-fashioned telephone switchboard: they control which circuits should be connected and when by tuning circuit dynamics to allow or prevent communication, thereby turning inter-area communication on or off.