Repeated microinjections into the medial prefrontal cortex (mPFC) impair extinction of conditioned place preference in mice

Repeated microinjections into the medial prefrontal cortex (mPFC) impair extinction of conditioned place preference in mice Groblewski Cunningham

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Repeated microinjections into the medial prefrontal cortex (mPFC) impair extinction of conditioned place preference in mice 2012 Behavioural Brain Research 10.1016/j.bbr.2012.01.059 Groblewski2012-repeated-microinjections-into-the-medial-pre Groblewski2012-repeated-microinjections-into-the-medial-pre.txt, the project's staged copy 3fbf1f856952e545a69a3d2f677f529e6e512e78 not-redistributable neuroscience

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them The intra-mPFC microinjection procedure itself, and whether repeating it is compatible with studying extinction learning. Quotation withheld because this record is not cleared for redistribution. null-result Quotation withheld because this record is not cleared for redistribution. extinction of ethanol-induced conditioned place preference Quotation withheld because this record is not cleared for redistribution. behavioural-experiment behavioural-experiment Quotation withheld because this record is not cleared for redistribution. mechanisms repeated cannula and injector insertion destroys tissue in Layers I-III of the mPFC on both sides of the midline, removing projection neurons that normally regulate the nucleus accumbens and basolateral amygdala, and the loss of that top-down regulation is what blocks extinction learning Quotation withheld because this record is not cleared for redistribution. mechanisms cumulative mechanical damage from implantation plus repeated infusions amounts to a partial lesion of a region already shown to be necessary for extinction, so the injection itself reproduces the lesion effect regardless of what is infused Quotation withheld because this record is not cleared for redistribution. The vehicle group could not serve as the control, because whatever impaired extinction affected vehicle and drug alike Quotation withheld because this record is not cleared for redistribution. Only a group that never had the procedure could reveal it, which is why the no-surgery control was added in the second experiment Quotation withheld because this record is not cleared for redistribution. The proposed cause: the repeated procedure damages the very region it is delivering into, amounting to a partial lesion Quotation withheld because this record is not cleared for redistribution. Because the cannula sat on the midline, the damage was bilateral rather than confined to one hemisphere Quotation withheld because this record is not cleared for redistribution. The damaged layers contain projection neurons to accumbens and amygdala whose activity changes with drug cues, which is a route from local damage to the behavioural failure Quotation withheld because this record is not cleared for redistribution. Surgery and anaesthesia were ruled out by comparison with their own earlier study matched on strain, frame, coordinates, anaesthesia and surgeon Quotation withheld because this record is not cleared for redistribution. The planned within-subject comparisons were run regardless of the interaction and are acknowledged as not statistically justified. what this limits: every within-subject comparison reported: THIS METHOD OF ANALYSIS, ALTHOUGH NOT STATISTICALLY JUSTIFIED, WAS IMPLEMENTED BECAUSE OF THE NARROW DETECTION WINDOW AND INCREASED VARIABILITY inherent to the paradigm Quotation withheld because this record is not cleared for redistribution. The proposed explanation via damage to mPFC projection neurons is untested and needs confirmation. what this limits: the projection-damage explanation: FURTHER EXAMINATION OF THE EFFECTS OF THE MICROINJECTION PROCEDURE ON THESE SPECIFIC PROJECTIONS ... IS REQUIRED - proposed, not tested Quotation withheld because this record is not cleared for redistribution. As performed, the microinjection procedure cannot be used to test intra-mPFC pharmacological manipulations of EtOH-CPP extinction. what this limits: any pharmacological use of this procedure: IRRESPECTIVE OF HOW EACH COMPONENT ... CONTRIBUTES TO THE OBSERVED EFFECT, AS CURRENTLY PERFORMED, THIS PROCEDURE IS NOT ADEQUATELY SUITED TO EXAMINE THE EFFECTS OF INTRA-mPFC PHARMACOLOGICAL MANIPULATIONS ON EXTINCTION Quotation withheld because this record is not cleared for redistribution. The authors state that their own analysis is not statistically justified, and say why they used it anyway duplicate of: limitations[0] · what this limits: the same scope as limitations[0] - the within-subject comparisons are acknowledged as not statistically justified, with the reason given Quotation withheld because this record is not cleared for redistribution. Animals were removed for failing to acquire a preference and for histology, about a third of each experiment what this limits: the sample behind Experiment 1: A TOTAL OF 18 ANIMALS WERE REMOVED FROM ANALYSIS (9 SHOWED LESS THAN 50% PREFERENCE ON TEST 1 AND AN ADDITIONAL 9 WERE REMOVED FOR NOT MEETING HISTOLOGICAL CRITERIA) Quotation withheld because this record is not cleared for redistribution. Non-learners were excluded by an a priori rule, which is disclosed and defended by reference to prior practice what this limits: the same scope as limitations[4], with the rule and its justification: WE DECIDED, A PRIORI, TO REMOVE ANIMALS THAT FAILED TO EXPRESS A PLACE PREFERENCE OF GREATER THAN 50% ON TEST 1 Quotation withheld because this record is not cleared for redistribution. The strongest extra evidence - doubling extinction to six days - is reported as data not shown what this limits: the strongest supporting evidence for the extinction claim, which is not shown: DESPITE DOUBLING THE NUMBER OF EXTINCTION TRIALS, WE FOUND THAT BOTH mPFC-INJECTED GROUPS CONTINUED TO EXHIBIT IMPAIRED EXTINCTION Quotation withheld because this record is not cleared for redistribution. The damage-to-projection account is offered as conceivable and explicitly not established what this limits: the same scope as limitations[1] - the damage-to-projection account is offered as conceivable and explicitly not established Quotation withheld because this record is not cleared for redistribution. No group-by-test interaction reached significance in either experiment, so the key contrast rests on the planned within-group comparisons what this limits: the central group contrast: THE INITIAL 2-WAY ANOVA REVEALED A MAIN EFFECT OF TEST [F(1,40) = 9.3, p < .005] BUT NOT GROUP, AND NO SIGNIFICANT GROUP x TEST INTERACTION (p's > .05), so the effect rests on the planned comparisons Quotation withheld because this record is not cleared for redistribution. an additional group given NO SURGERY AT ALL (the No Sx group), alongside the vehicle-infused and drug-infused groups eliminates: the handling involved in the microinjection procedure - being restrained and manipulated - as the cause of the change in extinction learning, which a vehicle control alone cannot separate because it is handled too · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. control - VEHICLE: everything but the drug, which is the standard control and here shares the confound Quotation withheld because this record is not cleared for redistribution. control - NO PROCEDURE AT ALL: no surgery, no cannula, no injection, and the only group in which extinction occurred Quotation withheld because this record is not cleared for redistribution. the manipulation - as intended: reversible pharmacological inactivation of a region during extinction trials Quotation withheld because this record is not cleared for redistribution. the manipulation - as delivered: cumulative mechanical damage from repeating the delivery, which is a lesion and not an inactivation Quotation withheld because this record is not cleared for redistribution. extinction procedure - single-session, as in conditioned fear, where one injection suffices and this problem never arises Quotation withheld because this record is not cleared for redistribution. extinction procedure - multi-day, as required for ethanol place preference, where the injections must be repeated and the damage accumulates Quotation withheld because this record is not cleared for redistribution. extends → Groblewski et al. mPFC lesion findings [1] and the rat bupivacaine microinjection procedure [2] Quotation withheld because this record is not cleared for redistribution. builds-on → Groblewski et al. (2011) [1] electrode-insertion control result Quotation withheld because this record is not cleared for redistribution. extends → Groblewski et al. on mPFC lesions impairing extinction of ethanol place preference Quotation withheld because this record is not cleared for redistribution. critiques → the repeated intra-mPFC microinjection procedure as a tool for multi-day extinction studies differs in: THE AXIS IS THE NUMBER OF INJECTIONS, AND MINIMISING IT DOES NOT HELP. 'the damage caused by intra-mPFC injections even when the number of injections was minimized, was sufficient enough to impair extinction - an effect that persisted despite extended extinction training.' The critique of the procedure is dosed: it survives the obvious remedy. Quotation withheld because this record is not cleared for redistribution. microinjection —causes→ lesion microinjection lesion strength of the relation: 0.9 Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the tissue damage 'MAY HAVE BEEN sufficient' to amount to a lesion; causes is hedged. Quotation withheld because this record is not cleared for redistribution. microinjection —causes→ extinction microinjection extinction strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. medial prefrontal cortex —causes→ extinction medial prefrontal cortex extinction strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. EVIDENCE CORRECTED (RE-GROUNDED) · vehicle —contrasted-with→ No Sx vehicle No Sx EVIDENCE CORRECTED: RE-GROUNDED. The old span named only the No Sx group. This sentence names both and carries the contrast with its direction - 'the No Sx, BUT NOT Vehicle or Bupivacaine, group…'. — strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. prelimbic —part-of→ medial prefrontal cortex prelimbic medial prefrontal cortex strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. infralimbic —part-of→ medial prefrontal cortex infralimbic medial prefrontal cortex strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. guide cannula —part-of→ microinjection guide cannula microinjection strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but a guide cannula was IMPLANTED for the microinjections; part-of is loose. Quotation withheld because this record is not cleared for redistribution. conditioned place preference —operationalised-as→ conditioned stimuli conditioned place preference conditioned stimuli strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the conditioned stimuli were the tactile cues of the place-preference task; operationalised-as is loose. Quotation withheld because this record is not cleared for redistribution. conditioned fear —contrasted-with→ conditioned place preference conditioned fear conditioned place preference differs in: THE AXIS IS HOW MUCH TRAINING EXTINCTION TAKES. 'Quotation withheld' Both are extinction; they differ on the schedule needed, which is why a procedure validated on one can fail on the other for reasons that have nothing to do with the mechanism. · strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. ANOVA ANOVA Quotation withheld because this record is not cleared for redistribution. two-way ANOVA with interaction term two-way ANOVA with interaction term Quotation withheld because this record is not cleared for redistribution. paired t-test paired t-test Quotation withheld because this record is not cleared for redistribution. Bonferroni correction for multiple comparisons Bonferroni correction for multiple comparisons Quotation withheld because this record is not cleared for redistribution. alpha level / significance threshold alpha level / significance threshold Quotation withheld because this record is not cleared for redistribution. standard error of the mean standard error of the mean Quotation withheld because this record is not cleared for redistribution. Neither the vehicle nor the bupivacaine group showed significant extinction of ethanol place preference. Quotation withheld because this record is not cleared for redistribution. In the second experiment only the no-surgery group showed a significant drop in place preference. Quotation withheld because this record is not cleared for redistribution. The experiments suggest some component of the microinjection procedure, not merely the handling, interfered with extinction. Quotation withheld because this record is not cleared for redistribution. Doubling the extinction trials did not rescue extinction: both injected groups kept showing place preference. Quotation withheld because this record is not cleared for redistribution. The authors conclude the repeated intra-mPFC microinjection technique, as performed, is unsuitable for studying extinction of ethanol place preference in mice. Quotation withheld because this record is not cleared for redistribution. Surgery and anaesthesia alone are ruled out as the cause, since a single electrode insertion at the same coordinates in earlier work left extinction intact. Quotation withheld because this record is not cleared for redistribution. vehicle and bupivacaine groups both failed to extinguish Quotation withheld because this record is not cleared for redistribution. in the second experiment only the unoperated group extinguished Quotation withheld because this record is not cleared for redistribution. handling alone does not explain it, since the no-surgery group was handled and still extinguished Quotation withheld because this record is not cleared for redistribution. the tissue damage was substantial and limited mainly to layers I-III of the mPFC Quotation withheld because this record is not cleared for redistribution. doubling the extinction training did not rescue it Quotation withheld because this record is not cleared for redistribution. surgery and anaesthesia were ruled out by a matched earlier study in which a single electrode insertion did not impair extinction Quotation withheld because this record is not cleared for redistribution. bupivacaine bupivacaine Quotation withheld because this record is not cleared for redistribution. bupivacaine bupivacaine Quotation withheld because this record is not cleared for redistribution. extinction extinction Quotation withheld because this record is not cleared for redistribution. No Sx group No Sx group Quotation withheld because this record is not cleared for redistribution. injector-tip location injector-tip location Quotation withheld because this record is not cleared for redistribution. n=108 — total number of adult male DBA/2J mice used across the experiments Quotation withheld because this record is not cleared for redistribution. F (1,33) = 4.3, p < .05 — main effect of Test on percent time on the ethanol-paired floor in Experiment 1 Quotation withheld because this record is not cleared for redistribution. F (1,40) = 9.3, p < .005 — main effect of Test on place preference in Experiment 2 Quotation withheld because this record is not cleared for redistribution. t (11) = 2.5 p < .05 — the only significant within-group preference reduction, found in the No-Surgery group Quotation withheld because this record is not cleared for redistribution. 18 — animals excluded from Experiment 1, split between failure to show preference and failed histology Quotation withheld because this record is not cleared for redistribution. less than 25% — share of subjects that failed to acquire a place preference after two conditioning trials Quotation withheld because this record is not cleared for redistribution. .05 — the alpha level adopted for all statistical tests Quotation withheld because this record is not cleared for redistribution. 0.2 μL over 2 min (0.1 μL/min) — volume and rate of each intra-mPFC infusion of vehicle or bupivacaine Quotation withheld because this record is not cleared for redistribution. n=108 — total mice across both experiments before exclusions Quotation withheld because this record is not cleared for redistribution. 18 animals removed — exclusions in Experiment 1 - nine non-learners and nine on histology Quotation withheld because this record is not cleared for redistribution. 16 animals removed — the equivalent in Experiment 2 Quotation withheld because this record is not cleared for redistribution. 0.2 μL over 2 min — the injection volume and rate, chosen to inactivate most of the target subregions Quotation withheld because this record is not cleared for redistribution. >90% of neuronal activation — the intended coverage of the inactivation, from prior diffusion studies Quotation withheld because this record is not cleared for redistribution. 2 g/kg — the ethanol dose paired with the floor cue Quotation withheld because this record is not cleared for redistribution.

The full text of this article is not redistributable, so it is not included here. The evidence sentences are withheld with it; the tag layer and its grounding status remain. The article itself is at https://doi.org/10.1016/j.bbr.2012.01.059.