Bock paper (lecture 7)

[mblohr]

This paper discusses mapping cortical networks using two sensor modalities/frequencies - two-photon calcium imaging to characterize functional properties of neurons and EM to trace the neurons' local network. What are inhibitory neurons, interneurons, and targets, as well as preferred orientations? These topics are mentioned frequently in the paper, and it would be interesting to learn more about their functions/importance. Also, are there any potential benefits in using hyperspectral imaging/CCD technology, polarization, or submillimeter (280GHz+) sensors for this type of work?

[dlee138]

Interneurons, as the term "inter" would imply, are neurons that connect other neurons together. They are generally (but not always) inhibitoray such as the GABAergic interneuron mentioned in the paper. They reside in different areas of the body such as the cortex, cerebellum, and spinal cord. For instance, spinal interneurons connect sensory neurons to motor neurons. In the Bock paper, they investigated signals from multiple excitatory pyramidal neurons relay to an inhibitory interneuron. One of the inhibitory neuron did not have a preferred orientation and was speculated to be a GABAergic interneuron. Other interneurons were targeted by pyrimidal cells with varying orientions. Although I am not completely sure about the preferred orientation of these neurons, I believe they tuned the preferred orientation of the pyrimidal cells by assigning weights to each of the preferred orientations.

[yaxigeigei]

Or we can see interneurons as the counterpart of some inverters in electronics - receiving 5 volt, sending out -5 volt; receiving excitation, sending out inhibition. Preffered orientation is very well explained by Erika in another thread of our chat room. Methodologically, in this paper, neurons absorbed an fluorescent indicator for measuring their activity/spiking. If the stimulus being presented is their prefered one, they would literally blink under the microscope. In practice, we decide which stimulus is their prefered one by looking at when they blink, i.e. find blinking => see what is the concurrent (prefered) stimulus.