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[0] Wood F, Fellows M, Donoghue J, Black M, Automatic spike sorting for neural decoding.Conf Proc IEEE Eng Med Biol Soc 6no Issue 4009-12 (2004)

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ref: -2013 tags: larkum calcium spikes dendrites association cortex binding date: 02-23-2021 19:52 gmt revision:3 [2] [1] [0] [head]

PMID-23273272 A cellular mechanism for cortical associations: and organizing principle for the cerebral cortex

  • Distal tuft dendrites have a second spike-initiation zone, where depolarization can induce a calcium plateau of up to 50ms long.  This depolarization can cause multiple spikes in the soma, and can be more effective at inducing spikes than depolarization through the basal dendrites.  Such spikes are frequently bursts of 2-4 at 200hz. 
  • Bursts of spikes can also be triggered by backpropagation activated calcium (BAC), which can half the current threshold for a dendritic spike. That is, there is enough signal propagation for information to propagate both down the dendritic arbor and up, and the two interact non-linearly.  
  • This nonlinear calcium-dependent association pairing can be blocked by inhibition to the dendrites (presumably apical?). 
    • Larkum argues that the different timelines of GABA inhibition offer 'exquisite control' of the dendrites; but these sorts of arguments as to computational power always seem lame compared to stating what their actual role might be. 
  • Quote: "Dendritic calcium spikes have been recorded in vivo [57, 84, 85] that correlate to behavior [78, 86].  The recordings are population-level, though, and do not seem to measure individual dendrites (?). 

See also:

PMID-25174710 Sensory-evoked LTP driven by dendritic plateau potentials in vivo

  • We demonstrate that rhythmic sensory whisker stimulation efficiently induces synaptic LTP in layer 2/3 (L2/3) pyramidal cells in the absence of somatic spikes.
  • It instead depends on NMDA-dependent dendritic spikes.
  • And this is dependent on afferents from the POm thalamus.

And: The binding solution?, a blog post covering Bittner 2015 that looks at rapid dendritic plasticity in the hippocampus as a means of binding stimuli to place fields.

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ref: Wood-2004.01 tags: spikes sorting BMI Black Donoghue prediction kalman date: 04-06-2007 21:57 gmt revision:2 [1] [0] [head]

PMID-17271178[0] automatic spike sorting for neural decoding

  • idea: select the number of units (and, indeed, clustering) based on the ability to predict a given variable. makes sense!
  • results:
    • human sorting: 13,5 cm^2 MSE
    • automatic spike sorting: 11.4 cm^2 MSE
      • yes, I know, the increase is totally dramatic.
  • they do not say if this could be implemented in realtime or not. hence, probably not.

____References____

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ref: notes, bookmark-0 tags: spikes action_potentials neurons subthreshold depolarization c.elegans date: 0-0-2006 0:0 revision:0 [head]

"Millisecond-timescale, genetically targeted optical control of neural activity" http://www.nature.com/neuro/journal/v8/n9/full/nn1525.html

what they did:

  • expressed ChR2 receptor in cultured hippocampal neurons.
  • ChR2 is a rapidly-gated light-sensitive cation channel recently isolated from unicellular green alga
  • cells were transfected via lentivirus
  • caused spiking in cells by exposing them to 5-15ms flashes of blue light.
  • stimulation was reliable to 30hz
  • stimulated spikes had low jitter - 2ms or so.
  • light stimulation protocol was robust across different neurons.
  • expression of the light-gated channel did not alter the properties of the neurons or their health etc.
  • they think it might be applicable to in-vivo mamalian studies!
  • Subthreshold!
    • for many cellular and systems neuroscience processes subthreshold depolarizations convey physiologically significant information.
    • the neurons in c.elegans do not spike!
    • subthreshold depolarizations are potent for activating synapes-to-nucleus signaling
    • the relative timing of subthreshold and suprathreshold depolarizations can determine the direction of synaptic plasticity.
    • subthreshold depolarizations operate in the more linear regime of membrane voltage