I performed a few sensory stimulation experiments in thalamus and recorded responses of pyramidal neurons in cortex using whole cell patch clamp in vivo. Interestingly, I found that just after the response, neurons show no activity for at least 100 ms. Does anyone know a reason for it or the mechanism behind it? It would be really helpful at this stage. I am attaching the figure.
Thank you in advance,
Arjun
Hi Arjun:
I don't know quite well with your experimental configuration or physiology of the brain regions you are interested in.
However, generally speaking there're already many reasons for this temporary silence. The first one could be network. Usually the excitatory input occurs prior to inhibitory input, because the inhibitory input comes from inhibitory neurons in the network and so the number of synapses involved in inhibitory pathway are usually more. So the delay of inhibitory input makes the silent period later than active period you observed.
The second reason could be cell's intrinsic properties. After the cell is excited usually it will enter a self-limiting status. In electrophysiological sense, some delayed rectifier like M-type potassium channels will be opened after excitation and also the synapse may go into refractory period.
Since your object involves thalamic-cortical pathway, I personally think that the above reason may not only occur in the neuron you are recording but in many neurons that involved in this pathway. So maybe you can check the physiology of the network and cell intrinsic properties to give yourself an answer.
Hope this helps.
Best
Yao
What Yao said, but i'll simplify: It's feedforward inhibition. Both on the cell in question, and the network in the round.
Thank you Yao and William. Do you have any specific reference to point out.?
Gabernet et al., 2005 springs to mind. Kruglikov and Rudy, 2008 is also vaguely relevant. Not super relevant, but it's a cool paper.- Probably Isaacson and Scanziani, 2011 is a review worth a read as well.
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