After earning his PhD, he was a
postdoctoral researcher at
Purdue University, and became an assistant professor at the
University of California, Irvine in 1976. He developed a new method to manipulate proteins in
cell membranes called "
in situ electrophoresis". In 1985, he moved to the
Yale School of Medicine to conduct research in proteins and
synapses. Later he became a professor at
Columbia University and then at the
University of California, San Diego in 1996. During this period he made significant discoveries in molecular neurobiology that developed into a new study area on
neurotrophins. Poo and his colleagues also invented a new method called the "growth cone turning assay", now widely used in neuroscience for measuring
axon growth and guidance in reaction to extracellular guidance molecules and mechanical stimuli. He moved to the
University of California, Berkeley in 2000, where he later became Paul Licht Distinguished Professor in Biology. At Berkeley, he made many new discoveries in understanding the factors that determine the development of axons and
dendrites in
neurons. He also made important discoveries in
synaptic plasticity, demonstrating that
spike-timing-dependent plasticity plays a crucial role in neuron connections. ==Career in China==