Cortical Column: If you don’t understand the function, do the anatomy – Bert Sakmann – 5/07/12

Cortical Column: If you don’t understand the function, do the anatomy – Bert Sakmann – 5/07/12

Bert Sakmann, MD, PhD.
Winner of the Nobel Prize in Physiology or Medicine 1991 for discoveries concerning the function of single ion channels in cells.
Inaugural Scientific Director, Max Planck Florida Institute.

Decision-making based on sensory input can be dependent on representation of a sensory stimulus in only one or a few cortical columns. Thus, soma location, dendrite morphology and presynaptic innervation in a column represent key determinants of functional responses of individual neurons, such as sensory-evoked spiking. We reconstructed the three-dimensional networks formed by thalamocortical afferents from the lemniscal pathway and excitatory neurons of an anatomically defined cortical column in rat vibrissal cortex. We objectively classify nine cortical cell types and quantify the number and distribution of their somata, dendrites and thalamocortical synapses. Somata and dendrites of most cell types intermingle, while thalamocortical connectivity depends strongly upon the cell type and the three-dimensional soma location of the postsynaptic neuron. Correlating dendrite morphology and thalamocortical connectivity to functional responses revealed that the lemniscal afferents can account for cell type- and location-specific subthreshold and spiking responses after passive whisker touch comparable to touch during decision-making. The results provide the first quantitative three-dimensional anatomical description of the cell type-specific lemniscal synaptic wiring diagram and elucidate structure-function relationships of this physiologically relevant pathway at single-cell resolution.

Krasnow Institute Lecture Room – Rm 229 – 4:00pm