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[0] Buonomano DV, Merzenich MM, Cortical plasticity: from synapses to maps.Annu Rev Neurosci 21no Issue 149-86 (1998)

[0] Kilgard MP, Merzenich MM, Cortical map reorganization enabled by nucleus basalis activity.Science 279:5357, 1714-8 (1998 Mar 13)

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ref: -0 tags: recurrent cortical model adaptation gain V1 LTD date: 02-11-2018 19:06 gmt revision:0 [head]

PMID-18336081 Adaptive integration in the visual cortex by depressing recurrent cortical circuits.

  • Mainly focused on the experimental observation that decreasing contrast increases latency to both behavioral and neural response (latter in the later visual areas..)
  • Idea is that synaptic depression in recurrent cortical connections mediates this 'adaptive integration' time-constant to maintain reliability.
  • Model also explains persistent activity after a flashed stimulus.
  • No plasticity or learning, though.
  • Rather elegant and well explained.

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ref: -0 tags: David Kleinfeld cortical vasculature laser surgery network occlusion flow date: 09-23-2016 06:35 gmt revision:1 [0] [head]

Heller Lecture - Prof. David Kleinfeld

  • Also mentions the use of LIBS + q-switched laser for precisely drilling holes in the scull. Seems to work!
    • Use 20ns delay .. seems like there is still spectral broadening.
    • "Turn neuroscience into an industrial process, not an art form" After doing many surgeries, agreed!
  • Vasodiliation & vasoconstriction is very highly regulated; there is not enough blood to go around.
    • Vessels distant from a energetic / stimulated site will (net) constrict.
  • Vascular network is most entirely closed-loop, and not tree-like at all -- you can occlude one artery, or one capillary, and the network will route around the occlusion.
    • The density of the angio-architecture in the brain is unique in this.
  • Tested micro-occlusions by injecting rose bengal, which releases free radicals on light exposure (532nm, 0.5mw), causing coagulation.
  • "Blood flow on the surface arteriole network is insensitive to single occlusions"
  • Penetrating arterioles and venules are largely stubs -- single unbranching vessels, which again renders some immunity to blockage.
  • However! Occlusion of a penetrating arteriole retards flow within a 400 - 600um cylinder (larger than a cortical column!)
  • Occulsion of many penetrating vessels, unsurprisingly, leads to large swaths of dead cortex, "UBOS" in MRI parlance (unidentified bright objects).
  • Death and depolarizing depression can be effectively prevented by excitotoxicity inhibitors -- MK801 in the slides (NMDA blocker, systemically)

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ref: -0 tags: intracortical utah array fabrication MEMS Normann date: 08-14-2014 01:35 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-1937509 A silicon-based, three-dimensional neural interface: manufacturing processes for an intracortical electrode array.

  • Campbell PK1, Jones KE, Huber RJ, Horch KW, Normann RA. (1991)
  • One of (but not the) first papers describing their methods / idea (I think).
  • First conf paper: {1294} (1988)
  • later adopted glass frit insulator --

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ref: Ganguly-2011.05 tags: Carmena 2011 reversible cortical networks learning indirect BMI date: 01-23-2013 18:54 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

PMID-21499255[0] Reversible large-scale modification of cortical networks during neuroprosthetic control.

  • Split the group of recorded motor neurons into direct (decoded and controls the BMI) and indirect (passive) neurons.
  • Both groups showed changes in neuronal tuning / PD.
    • More PD. Is there no better metric?
  • Monkeys performed manual control before (MC1) and after (MC2) BMI training.
    • The majority of neurons reverted back to original tuning after BC; c.f. [1]
  • Monkeys were trained to rapidly switch between manual and brain control; still showed substantial changes in PD.
  • 'Near' (on same electrode as direct neurons) and 'far' neurons (different electrode) showed similar changes in PD.
    • Modulation Depth in indirect neurons was less in BC than manual control.
  • Prove (pretty well) that motor cortex neuronal spiking can be dissociated from movement.
  • Indirect neurons showed decreased modulation depth (MD) -> perhaps this is to decrease interference with direct neurons.
  • Quote "Studies of operant conditioning of single neurons found that conconditioned adjacent neurons were largely correlated with the conditioned neurons".
    • Well, also: Fetz and Baker showed that you can condition neurons recorded on the same electrode to covary or inversely vary.
  • Contrast with studies of motor learning in different force fields, where there is a dramatic memory trace.
    • Possibly this is from proprioception activating the cerebellum?

Other notes:

  • Scale bars on the waveforms are incorrect for figure 1.
  • Same monkeys as [2]

____References____

[0] Ganguly K, Dimitrov DF, Wallis JD, Carmena JM, Reversible large-scale modification of cortical networks during neuroprosthetic control.Nat Neurosci 14:5, 662-7 (2011 May)
[1] Gandolfo F, Li C, Benda BJ, Schioppa CP, Bizzi E, Cortical correlates of learning in monkeys adapting to a new dynamical environment.Proc Natl Acad Sci U S A 97:5, 2259-63 (2000 Feb 29)
[2] Ganguly K, Carmena JM, Emergence of a stable cortical map for neuroprosthetic control.PLoS Biol 7:7, e1000153 (2009 Jul)

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ref: Zacksenhouse-2007.07 tags: Zacksenhouse 2007 Odoherty Nicolelis cortical adaptation BMI date: 01-06-2012 03:10 gmt revision:3 [2] [1] [0] [head]

PMID-17637835[0] Cortical modulations increase in early sessions with brain-machine interface.

  • "we demonstrate that the modulations of the firing-rates of cortical neurons increased abruptly after the monkeys started operating the BMI"
    • My hypothesis: is this like LMAN? Injection of noise for the purpose of exploration?
    • Their hypothesis: we are listening to the noise or effect of increased processing / congnitive load.
    • Alternative: decreased feedback / scrabled feedback makes the individual control signals themselves less controlled.
  • Describes spikes as inhomogeneous poisson processes, and breaks things down thusly.
  • Also develop a parametric model of neuronal firing based on tuning to movement, including velocity and acceleration.
  • Fano factor of recorded neurons increased during BCWH & BCWOH.
  • Percent overall modulation (POM) higher in brain control. That is, the variance explained not by the inhomogeneous poisson process, but rather by firing rate variations.
    • "[T]he ensemble-POM increased mainly due to an increase in the variance of the spike-count, which was not matched by the change in the mean spike-count."
  • Figure 6 is pretty convincing, actually.
  • PVM (percent velocity modulation) correlates strongly with POM, but with a fractional slope, indicating that veolocity tuning accounts for only a fraction of the variance.
    • "Since the increase in POM was not matched by increasing PVM or PKM, the higher neuronal rate modulations observed during brain control cannot be explained only by increased modulations due to the kinematics of the movement."

____References____

[0] Zacksenhouse M, Lebedev MA, Carmena JM, O'Doherty JE, Henriquez C, Nicolelis MA, Cortical modulations increase in early sessions with brain-machine interface.PLoS One 2:7, e619 (2007 Jul 18)

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ref: MolinaLuna-2007.03 tags: ICMS microstimulation cortical thin-film electrodes histology MEA date: 01-03-2012 22:54 gmt revision:2 [1] [0] [head]

PMID-17178423[0] Cortical stimulation mapping using epidurally implanted thin-film microelectrode arrays.

  • they claim that thin-film electrodes are better than microelectrode arrays, as they show less evidence of cortical damage.
    • thin-film electrodes show higher reproducability
    • more accurate spatial arrangement.
  • epidural stimulation (they were implanted between the dura and skull)

____References____

[0] Molina-Luna K, Buitrago MM, Hertler B, Schubring M, Haiss F, Nisch W, Schulz JB, Luft AR, Cortical stimulation mapping using epidurally implanted thin-film microelectrode arrays.J Neurosci Methods 161:1, 118-25 (2007 Mar 30)

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ref: Tehovnik-2006.08 tags: ICMS cortical microstimulation pyramidal neurons date: 12-20-2011 06:08 gmt revision:1 [0] [head]

PMID-16835359[0] Direct and indirect activation of cortical neurons by electrical microstimulation.

  • looked at ICMS via single-cell recording, behavior, and fMRI.
  • These properties suggested that microstimulation activates the most excitable elements in cortex, that is, by and large the fibers of the pyramidal cells.
    • this is a useful result to perhaps reference..

____References____

[0] Tehovnik EJ, Tolias AS, Sultan F, Slocum WM, Logothetis NK, Direct and indirect activation of cortical neurons by electrical microstimulation.J Neurophysiol 96:2, 512-21 (2006 Aug)

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ref: Buonomano-1998.01 tags: cortical plasticity learning review LTD LTP date: 10-07-2008 03:27 gmt revision:1 [0] [head]

PMID-9530495[0] Cortical plasticity: from synapses to maps

  • focuses on synaptic plasticity as the underlying mechanism of behavior-dependent cortical maps/representations.
  • "within limits, the cortex can allocate cortical area in a use-dependent manner"
  • synaptic plasticity -> STDP via NMDA, etc.
    • demonstrated with intracellular recordings of cat M1 & simultaneous stimulation of the ventrolateral thalamus & intracellular depolarization. Facilitation was short lasting and not present in all neurons.
    • demonstrated in rat auditory cortex / recording in layer 2/3 , stimulate layer 2/3 & White matter/6.
    • review of Ca+ hypothesis of LTP/LTD balance: if the Ca+ influc is below a threshold, LTD occurs; if it is above a certain threshold, LTP.
      • not sure how long LTD has been demonstrated -- 15 min?
  • cellular conditioning = direct induction of plastic changes in the selective responses of individual neurons in vivo as a result of short-term conditioning protocols. this is what we are interested in, for now.
    • this review does not explicitly deal with BG-DA / ACh reinforcement, only timing dependent plasticity, in visual and auditory cortex.
  • cortical plasticity:
    • talk about the revealing/unmasking of hidden responses when sections of cortex are deafferented or digits were amputated.
    • talk about training-based approaches: training increases cortical representation of a sensory modality / skill/ etc. The cortex can differentially 'allocate' area in a use-dependent manner throughout life.
    • cortical map changes are not reflected by changes in thalamic somatotopy.

____References____

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ref: Walton-2005.02 tags: dopamine anterior cingulate mesocortical date: 02-05-2007 19:19 gmt revision:2 [1] [0] [head]

PMID-15727537 The mesocortical dopamine projection to anterior cingulate cortex plays no role in guiding effort-related decisions.

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ref: Kilgard-1998.03 tags: dopamine basal_forebrain nucleus_basalis cortical_plasticity date: 0-0-2007 0:0 revision:0 [head]

PMID-9497289[0] Cortical map reorganization enabled by nucleus basalis activity

  • idea, very cool: that stimulation in the nucleus basalis (partially acetylcholine-releasing center in the brain) of the rat, when paired with audio tone presentation, causes the auditory cortex to to reorganize so as to better represent the presented stimulus(stimuli). Note the rats were not tasked with anything, and were placed in a soundproofed box.
  • stimulation protocol: 200ms of 70-150ua current delivered to the NB through bipolar platinum stimulation electrodes. current was set at the threshold needed to desynchronize cortical EEG during slow-wave sleep.
    • how ever did they come up with this metric? EEG desynchronizaton?
____References____