This is the readme for the matlab script associated with the paper: Weiler N, Wood L, Yu J, Solla SA, Shepherd GM (2008) Top-down laminar organization of the excitatory network in motor cortex. Nat Neurosci 11:360-6 Abstract: --------- Cortical layering is a hallmark of the mammalian neocortex and a major determinant of local synaptic circuit organization in sensory systems. In motor cortex, the laminar organization of cortical circuits has not been resolved, although their input-output operations are crucial for motor control. Here, we developed a general approach for estimating layer-specific connectivity in cortical circuits and applied it to mouse motor cortex. From these data we computed a laminar presynaptic --> postsynaptic connectivity matrix, W(post,pre), revealing a complement of stereotypic pathways dominated by layer 2 outflow to deeper layers. Network modeling predicted, and experiments with disinhibited slices confirmed, that stimuli targeting upper, but not lower, cortical layers effectively evoked network-wide events. Thus, in motor cortex, descending excitation from a preamplifier-like network of upper-layer neurons drives output neurons in lower layers. Our analysis provides a quantitative wiring-diagram framework for further investigation of the excitatory networks mediating cortical mechanisms of motor control. Documentation for laminarWsimulation.m script: ---------------------------------------------- Simulates the flow of activity within and across laminar levels in the local pyramidal neuron network, based on a connectivity matrix (W) measured by laser scanning photostimulation. The simulation is a simple neural network simulation: p(n) ----> c * W ----> p(n+1) where p(n=0) is an input vector ('inputvector') representing a laminar profile of activity, c is a global scaling constant ('gain'), W is a measured connectivity matrix, and p(n+1) is an output vector, which is fed back into the network as the input vector for the next iteration. For further details, see Weiler et al., 2008, Nature Neuroscience. 2008 Gordon Shepherd, Northwestern University Usage: ------ Type the name of the script, laminarWsimulation, at the matlab command prompt. You should see an image that looks like: A related model for vibrissal M1, vibrissal S1, and S2, mapped in comparable fashion in Hooks et al (2011), is available at: https://senselab.med.yale.edu/ModelDB/ShowModel.asp?model=137743