Rules defining adult synaptic connectivity, the
Basic Rules for Cortical Synaptic Organization have been set
out in a book called, Cortical
Circuits. We are now testing the application of the Rules at
successive stages in the development of cortical circuits in the barrel region of mouse
somatosensory cortex.
Approaches: We use the transmission electron
microscope to examine single and serial thin sections through barrel
cortex containing neurochemically identified nerve cells.
Intracellular recording and injection of label is also used. These
approaches, combined with the making of extensive 3-dimensional
reconstructions, permit us to define neuronal types and to identify
their synaptic patterns. Of particular interest is to elucidate the
spatial distribution of synapses over neuronal surfaces, such as is
depicted for the pyramidal neuron shown above.
We have developed a unique, computerized, electron
microscopic 3-D reconstruction system to facilitate the collection
and analysis of fine structural data. This system is being used to
plot changes in the numbers and types of synapses over time, and to
determine the effects of sensory deprivation on synaptic
connectivity.
Current projects include:
