Today we’ll look at the other model referenced by the paper reviewed in my blog post from four days ago “Brain Modeling Using NEURON, Interneurons, and Resonant Circuits.” The model is “MEG of Somatosensory Neocortex (Jones et al. 2007)” and the paper that described it is titled “Neural Correlates of Tactile Detection: A Combined Magnetoencephalography and Biophysically Based Computational Modeling Study” (published October 3, 2007 in the Journal of Neuroscience).

Figure 1. Example view of the “MEG of Somatosensory Neocortex (Jones et al. 2007)” model downloaded from ModelDB and running in NEURON. Somatic membrane potential traces from model layer 2/3 (black) and layer 5 (red) pyramidal neurons running in NEURON.

The paper examined human touch perception. The authors looked at what happens in the sensory cerebral cortex devoted to the skin when a human detects being touched. The team recorded magnetic fields produced by electrical currents in the brain (magnetoencephalography or MEG) and carried out computational neural modeling.

A brief touch to a subject’s fingertip evoked a consistent MEG signal in their primary somatosensory cortex. The MEG signal predicted that the subject would detect being touched beginning about 70 milliseconds after the stimulus was initiated.

A simulation of the evoked response was created that reproduced all the major peaks recorded from the human subjects. The partial model of primary somatosensory cortex included 10 pyramidal cells and 3 inhibitory interneurons in layers 2 and 3 and another 10 pyramidal cells and 3 inhibitory interneurons in layer 5. Please see the paper for details about connectivity. The model provided a reasonable interpretation of the electrophysiological origin of the evoked primary somatosensory cortex response and the response characteristics correlated with human perception.

You can reproduce some of the paper’s figure 5 by running the “MEG of Somatosensory Neocortex (Jones et al. 2007)” model downloaded from ModelDB in NEURON.

• FIrst download NEURON (if you don’t already have it) from the NEURON Download and install web page.

Note: Those with more than a passing interested in using NEURON may find the book or e-book by its creators useful “The NEURON Book.”

• Next download the “MEG of Somatosensory Neocortex (Jones et al. 2007)” model from ModelDB.

Note: Don’t forget to compile the files in the project folder. On the Macintosh computer you drag the project folder to NEURON’s mknrndll program icon.

Figure 2. A magnetoencephalography trace from model primary somatosensory cortex running in NEURON.

• Load the model’s init-cortex.hoc file
• Next load wiring-config_suprathresh.hoc
• Finally load demo.ses

NEURON should be displaying about eleven windows. Go to the window titled “RunControl” and click on the “Init & Run” button. You should see the model’s electrical activity being traced out as it’s generated in about five of those windows. For instance, one window should display the membrane potentials of a layer 2/3 pyramidal cell and a layer 5 pyramidal cell like in Figure 1 above. Another window should display a magnetoencephalography trace like in Figure 2 above.


Other related blog posts:

Brain Modeling Using NEURON, Interneurons, and Resonant Circuits

Mandatory Publication of Computational Brain Models Simultaneously with Paper!

Brain Modeling Using NEURON: Superficial Pyramidal, Deep Pyramidal, Aspiny, and Stellate Neurons