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[0] Isoda M, Hikosaka O, Switching from automatic to controlled action by monkey medial frontal cortex.Nat Neurosci 10:2, 240-8 (2007 Feb)

[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: Lin-2006.12 tags: nucleus_basalis GABA ACh attention basal_forebrain sleep date: 12-07-2011 03:51 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-16928796[0] Fast modulation of prefrontal cortex activity by basal forebrain noncholinergic neuronal ensembles

in the author's own words:

  • in the intro sections, you can find the summary background info you need, both anatomical and functional. Despite the fact that most people think of this as solely the cholinergic projection system, my data is pointing to a very important role for the non-ACh projection system (most likely GABAergic!) in fast cortical modulation and ATTENTION. The relevant thing for you here is that, when people stimulated nucleus basalis and claimed the effect to be cholinergic, I believe most stimulation protocols (short bursts) are in fact mimicking the natural activity pattern of non-ACh projection system, and therefore should be re-interpreted with caution.
  • the intro, as promised, is concise, relevant, and has a lot of references.
  • key hypothesis is that the BF has GABA projections onto GABAergic interneurons in the PFC
    • typically, people focus on ACh projections.. perhaps as a matter of tradition?
    • PFC is reciprocally connected to the BF
  • secondary thing to test was the difference in behavior of the basal-forebrain tonic neurons (BFTN) between sleep and wake states.

____References____

[0] Lin SC, Gervasoni D, Nicolelis MA, Fast modulation of prefrontal cortex activity by basal forebrain noncholinergic neuronal ensembles.J Neurophysiol 96:6, 3209-19 (2006 Dec)

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ref: Isoda-2007.02 tags: SMA saccade basal_forebrain executive function 2007 microstimulation SUA cortex sclin date: 10-03-2008 17:12 gmt revision:2 [1] [0] [head]

PMID-17237780[0] Switching from automatic to controlled action by monkey medial frontal cortex.

  • SCLIN's blog entry
  • task: two monkeys were trained to saccade to one of two targets, left/right pink/yellow. the choice was cued by the color of the central fixation target; when it changed, they should saccade to the same-colored target.
    • usually, the saccade direction remained the same; sometimes, it switched.
    • the switch could either occur to the same side as the SUA recording (ipsilateral) or to the opposite (contralateral).
  • found cells in the pre-SMA that would fire when the monkey had to change his adapted behavior
    • both cells that increased firing upon an ipsi-switch and contra-switch
  • microstimulated in SMA, and increased the number of correct trials!
    • 60ua, 0.2ms, cathodal only,
    • design: stimulation simulated adaptive-response related activity in a slightly advanced manner
    • don't actually have that many trials of this. humm?
  • they also did some go-nogo (no saccade) work, in which there were neurons responsive to inhibiting as well as facilitating saccades on both sides.
    • not a hell of a lot of neurons here nor trials, either - but i guess proper statistical design obviates the need for this.
  • I think if you recast this in tems of reward expectation it will make more sense and be less magical.
  • would like to do shadlen-similar type stuff in the STN
questions
  1. how long did it take to train the monkeys to do this?
  2. what part of the nervous system looked at the planned action with visual context, and realized that the normal habitual basal-ganglia output would be wrong?
    1. probably the whole brain is involved in this.
    2. hypothetical path of error trials: visual system -> cortico-cortico projections + context activation -> preparatory motor activity -> basal ganglia + visual context (is there anatomical basis for this?) -> activation of some region that detects the motor plan is unlikely to result in reward -> SMA?

____References____

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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____