The Entorhinal Cortical Alvear Pathway Differentially Excites Pyramidal Cells and Interneuron Subtypes in Hippocampal CA1

The Entorhinal Cortical Alvear Pathway Differentially Excites Pyramidal Cells and Interneuron Subtypes in Hippocampal CA1 Bell Delong Goswamee McQuiston

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The Entorhinal Cortical Alvear Pathway Differentially Excites Pyramidal Cells and Interneuron Subtypes in Hippocampal CA1 2021 Cerebral Cortex (New York, N.Y.: 1991) 10.1093/cercor/bhaa359 Bell2021-the-entorhinal-cortical-alvear-pathway-diffe Bell2021-the-entorhinal-cortical-alvear-pathway-diffe.txt, the project's staged copy ead3686400d7dbde1cb2ea54f86b6ccb3409c325 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 alvear pathway from entorhinal cortex to hippocampal CA1 - a major excitatory input whose physiological impact was unknown Quotation withheld because this record is not cleared for redistribution. what the synapses this pathway makes in the deep layers actually do, since their existence was known from anatomy and never tested Quotation withheld because this record is not cleared for redistribution. the pathway cannot drive pyramidal cells to fire but does drive interneurons, unequally by subtype, so its effect on the region is feedforward inhibition Quotation withheld because this record is not cleared for redistribution. mechanism Quotation withheld because this record is not cleared for redistribution. entorhinal alvear pathway input to hippocampal CA1 Quotation withheld because this record is not cleared for redistribution. electrophysiology electrophysiology Quotation withheld because this record is not cleared for redistribution. mechanisms Glutamatergic alvear terminals in stratum oriens excite local interneurons, which in turn hyperpolarize CA1 pyramidal cells through GABA-A receptors, so the net effect of the pathway on pyramidal cells is inhibition rather than excitation Quotation withheld because this record is not cleared for redistribution. mechanisms Rhythmic burst firing of alvear-driven PV perisomatic interneurons imposes rhythmic perisomatic inhibition on pyramidal cells, which the authors propose as a contribution to theta rhythm generation Quotation withheld because this record is not cleared for redistribution. the excitatory input onto pyramidal cells is monosynaptic but too weak to reach threshold even under theta burst stimulation Quotation withheld because this record is not cleared for redistribution. while the same input drives interneurons to fire, and the inhibition arriving at PC is therefore disynaptic Quotation withheld because this record is not cleared for redistribution. with parvalbumin cells doing more than half of it, shown by silencing them during the stimulation Quotation withheld because this record is not cleared for redistribution. and both sets of synapses facilitating, which marks them as low release probability Quotation withheld because this record is not cleared for redistribution. Most recorded stratum oriens interneurons could not be anatomically classified because biocytin fills were insufficient. what this limits: every result reported by interneuron type: NONE OF THESE 13 NEURONS HAD SUFFICIENT AXONAL FILL TO PERMIT ANATOMICAL IDENTIFICATION Quotation withheld because this record is not cleared for redistribution. Whether the theta-coherent MEC layer 2 pyramidal cells actually contribute to the alvear pathway is unknown, weakening the proposed link to theta rhythm generation. what this limits: the link between the theta-coherent MEC L2 pyramidal cells and this pathway: IT IS UNKNOWN WHETHER THESE MEC L2 PCs CONTRIBUTE TO THE ALVEAR PATHWAY Quotation withheld because this record is not cleared for redistribution. The relative strength of the temporo-ammonic and alvear pathways cannot be settled from earlier work. what this limits: any ranking of the two pathways by strength: A DIRECT COMPARISON BETWEEN THE STRENGTHS OF TA AND ALVEAR INPUTS WAS NOT POSSIBLE WITH PREVIOUS STUDIES Quotation withheld because this record is not cleared for redistribution. whether the recently identified projection neurons that fire with theta actually contribute to this pathway is unknown what this limits: the same scope as limitations[1] - the calbindin-expressing projection neurons whose firing correlates with theta are not shown to contribute here Quotation withheld because this record is not cleared for redistribution. the region studied was chosen by which transgenic mice existed rather than by the question what this limits: why this region and not another: THE MEC WAS CHOSEN AS THE VIRAL EXPRESSION TARGET BY VIRTUE OF THE available transgenic line, so the anatomy studied follows the reagent Quotation withheld because this record is not cleared for redistribution. and the comparison with the other pathway cannot be made against the earlier literature, because the standard stimulation site activates both plus a third input what this limits: the same scope as limitations[2], with the reason: SLM STIMULATION POTENTIALLY ACTIVATES ALVEAR INPUTS, so the earlier comparison does not isolate the pathway it names Quotation withheld because this record is not cleared for redistribution. a channel expressed in one projection population, which is what makes a single pathway separable from the three that share its target layer Quotation withheld because this record is not cleared for redistribution. the driver lines that decide which region can be targeted - and here, which region was studied Quotation withheld because this record is not cleared for redistribution. the reported distribution of tau across the two pathways, used to argue the studied one matters clinically Quotation withheld because this record is not cleared for redistribution. theta burst stimulation as the physiological input pattern, rather than single shocks Quotation withheld because this record is not cleared for redistribution. the light stimulus confined to the two deep layers rather than delivered to the whole slice eliminates: the responses arising from the same axons' terminals in the distal layer, which the pathway also reaches · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. sodium channel blockade followed by potassium channel blockade, applied to both response types eliminates: a monosynaptic origin for the inhibitory response - 4-AP could not rescue the IPSCs inhibited by TTX, so inhibitory synaptic transmission driven by alvear input stimulation was NOT monosynaptic · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. synaptic delay measured separately for the two postsynaptic populations eliminates: the reading that the interneuron responses are relayed rather than direct, since their delay is shorter than the pyramidal one · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. post hoc anatomical reconstruction of the recorded interneurons eliminates: the possibility that the recorded cells were not the horizontally oriented population the pathway is claimed to engage · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. optogenetic silencing of parvalbumin interneurons during the same stimulation eliminates: attributing the whole inhibitory response to the subtype merely because it fires most - the silencing measures its share at more than half · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. A MAJOR INPUT PATHWAY WITH NO PHYSIOLOGY ATTACHED TO IT: the alvear pathway is a MAJOR EXCITATORY INPUT to hippocampal CA1, YET NOTHING IS KNOWN ABOUT ITS PHYSIOLOGICAL IMPACT Quotation withheld because this record is not cleared for redistribution. and it is not a minor route - in rodent it CARRIES MOST of the entorhinal input to dorsal CA1, and its effect on the postsynaptic neurons HAS NOT, TO OUR KNOWLEDGE, BEEN REPORTED Quotation withheld because this record is not cleared for redistribution. with the gap dated - the synaptic boutons were described in 1996 and THE PHYSIOLOGICAL IMPACT OF THE SYNAPSES HAS NOT BEEN INVESTIGATED since Quotation withheld because this record is not cleared for redistribution. THE REGION STUDIED WAS CHOSEN BY THE TOOLS THAT EXISTED: the medial entorhinal cortex was chosen as the viral expression target BY VIRTUE OF THE TRANSGENIC MICE AVAILABLE Quotation withheld because this record is not cleared for redistribution. A DISAGREEMENT DIVIDED BY PREPARATION: SOME GROUPS observed monosynaptic suprathreshold activation after stimulation in vivo, WHEREAS OTHER GROUPS observed only subthreshold events Quotation withheld because this record is not cleared for redistribution. and the in vitro literature does not disagree with itself at all - ex vivo stimulation has CONSISTENTLY been found to give subthreshold responses, so the preparation is what the disagreement turns on Quotation withheld because this record is not cleared for redistribution. THE COMPARISON EVERYONE WOULD WANT COULD NOT BE MADE BEFORE, AND THE PAPER SAYS WHY: stimulating the distal layer activates the other pathway, this pathway's own distal terminals, AND a thalamic input, so A DIRECT COMPARISON BETWEEN THE STRENGTHS OF THE TWO WAS NOT POSSIBLE WITH PREVIOUS STUDIES Quotation withheld because this record is not cleared for redistribution. THE SAME TARGET REGION, TWO INPUTS, DIFFERENT INTERNEURON SUBSETS: parvalbumin cells produce LITTLE TO NO RESPONSE to distal-layer stimulation and fire strongly to this one, so the two inputs ACTIVATE DIFFERENT SUBSETS OF INTERNEURONS Quotation withheld because this record is not cleared for redistribution. and the selectivity was already known for the other pathway - specific subsets can be POTENTLY ACTIVATED while others are ONLY WEAKLY AFFECTED OR NOT AFFECTED AT ALL Quotation withheld because this record is not cleared for redistribution. NOT ALL SUBTYPES ARE EQUALLY AFFECTED: parvalbumin cells fire at higher frequencies than the other two classes, and the responsive cells span several morphological subtypes within each class Quotation withheld because this record is not cleared for redistribution. THE SAME PHARMACOLOGICAL TEST GIVES OPPOSITE ANSWERS FOR THE TWO RESPONSE TYPES: the potassium channel blocker rescues the excitatory response and CANNOT rescue the inhibitory one, which is what makes one monosynaptic and the other disynaptic Quotation withheld because this record is not cleared for redistribution. with a geometric argument doing the work the pharmacology cannot - the light was confined to the deep layers, so the terminals there MUST be the source and not the distal ones Quotation withheld because this record is not cleared for redistribution. and a delay difference used the same way - the interneuron delay is SIGNIFICANTLY SHORTER than the pyramidal one, which is the wrong direction for a relayed response Quotation withheld because this record is not cleared for redistribution. MORE THAN HALF THE INHIBITION MEASURED RATHER THAN ATTRIBUTED: silencing one interneuron class during the same stimulation removed GREATER THAN 50% of the response amplitude Quotation withheld because this record is not cleared for redistribution. AND THE UNTESTED PATHWAY IS THE VULNERABLE ONE: tau accumulates in the terminals of THIS pathway BUT NOT the other, so the input nobody had recorded from may be the one that fails first in Alzheimer's disease Quotation withheld because this record is not cleared for redistribution. with an open question left open - it is UNKNOWN whether the projection neurons whose firing tracks theta contribute to this pathway at all Quotation withheld because this record is not cleared for redistribution. claim_type: mechanism a second reading reaching the same value. Recorded: mechanism — note: a second reading reaching the same value from a different sentence. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. method: optogenetic activation confined to one layer, so that the responses cannot come from the same axons' terminals elsewhere a second reading DIFFERING from the recorded value. Recorded: electrophysiology — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. phenomenon: two anatomically separate entorhinal inputs converging on the same target region by different routes a second reading DIFFERING from the recorded value. Recorded: entorhinal alvear pathway input to hippocampal CA1 — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. extends → Milstein et al. (2015) Quotation withheld because this record is not cleared for redistribution. extends → Milstein et al. (2015) Quotation withheld because this record is not cleared for redistribution. supports → feedforward inhibition as the principal effect of entorhinal input on CA1 pyramidal cells Quotation withheld because this record is not cleared for redistribution. contradicts → the assumption that the two entorhinal pathways engage the same interneuron population differs in: alvear pathway terminals in the SO appear to be capable of activating different subsets of interneurons relative to TA inputs Quotation withheld because this record is not cleared for redistribution. reconciles → the disagreement about whether entorhinal stimulation drives CA1 pyramidal cells, by noting the in vitro literature is consistent where the in vivo one is not differs in: Quotation withheld of CA1 PCs Quotation withheld because this record is not cleared for redistribution. critiques → earlier comparisons of the two pathways' strengths, which stimulated a site that activates three inputs at once differs in: THE AXIS IS WHAT THE STIMULATION SITE ACTUALLY ACTIVATES. 'These data may seem to suggest that the TA pathway input is stronger than the alvear pathway ... However, STIMULATION IN THE SLM WOULD ACTIVATE MORE THAN JUST TA SYNAPTIC TERMINALS.' The earlier comparison is not disputed as a measurement - it is disputed as an ATTRIBUTION, because the electrode reaches more than the pathway it was taken to test. Quotation withheld because this record is not cleared for redistribution. predicts → that this pathway contributes to theta rhythm generation through perisomatic interneurons Quotation withheld because this record is not cleared for redistribution. supports → the early vulnerability of this specific input in Alzheimer's disease, from the reported tau distribution Quotation withheld because this record is not cleared for redistribution. pyramidal —contrasted-with→ interneuron pyramidal interneuron strength of the relation: 1 · note: the inputs land on BOTH, which is why the question of what the pathway does could not be answered from anatomy alone Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span shown is the abstract opening; the pyramidal/interneuron contrast is elsewhere. Quotation withheld because this record is not cleared for redistribution. PV —contrasted-with→ VIP PV VIP strength of the relation: 1 · note: more than 70% of PV and VIP cells showed responses and less than 20% of the third class Quotation withheld because this record is not cleared for redistribution. stimulation —causes→ suprathreshold stimulation suprathreshold strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span reports suprathreshold activation following stimulation in some studies; causes is loose. Quotation withheld because this record is not cleared for redistribution. PV —distinct-from→ SLM PV SLM strength of the relation: 1 · note: THE SAME TARGET, TWO INPUTS, DIFFERENT INTERNEURON SUBSETS - PV cells produce LITTLE TO NO RESPONSE to distal-layer stimulation and fire strongly to this one Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but PV interneurons produce little or no response to SLM STIMULATION; distinct-from 'SLM' is loose. Quotation withheld because this record is not cleared for redistribution. alvear —causes→ interneuron alvear interneuron strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span says alvear terminals appear capable of activating interneuron subsets; causes is loose. Quotation withheld because this record is not cleared for redistribution. PV —contrasted-with→ GIN PV GIN strength of the relation: 1 · note: NOT ALL SUBTYPES EQUALLY AFFECTED - PV cells fire at higher frequencies than the other two classes Quotation withheld because this record is not cleared for redistribution. theta —causes→ excitation theta excitation strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span says theta-burst stimulation elicited excitation; 'theta' names the stimulation pattern. Quotation withheld because this record is not cleared for redistribution. IPSC —operationalised-as→ inhibition IPSC inhibition strength of the relation: 1 Audit 2026-09-28: DOUBTFUL - read against its span and kept, but IPSCs are a measure of inhibition; operationalised-as is loose. Quotation withheld because this record is not cleared for redistribution. PV —causes→ IPSC PV IPSC strength of the relation: 1 · note: MORE THAN HALF THE INHIBITION MEASURED RATHER THAN ATTRIBUTED - silencing one class during the same stimulation removed GREATER THAN 50% of the response amplitude Quotation withheld because this record is not cleared for redistribution. EPSP —distinct-from→ suprathreshold EPSP suprathreshold strength of the relation: 1 · note: subthreshold responses in pyramidal cells EVEN UNDER ROBUST THETA BURST STIMULATION, against suprathreshold responses in the interneurons Quotation withheld because this record is not cleared for redistribution. GIN —is-a→ interneuron GIN interneuron strength of the relation: 1 · note: and the conclusion states the asymmetry plainly - the subset activated here APPEARS TO BE DIFFERENT from those activated by the other pathway Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span shown does not name GIN cells. Quotation withheld because this record is not cleared for redistribution. Shapiro-Wilk normality test Shapiro-Wilk normality test Quotation withheld because this record is not cleared for redistribution. repeated measures ANOVA repeated measures ANOVA Quotation withheld because this record is not cleared for redistribution. one-sample t-test one-sample t-test Quotation withheld because this record is not cleared for redistribution. two-way ANOVA two-way ANOVA Quotation withheld because this record is not cleared for redistribution. p-value p-value 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. Friedman test Friedman test Quotation withheld because this record is not cleared for redistribution. nonparametric tests nonparametric tests Quotation withheld because this record is not cleared for redistribution. action potential frequency action potential frequency Quotation withheld because this record is not cleared for redistribution. Theta burst activation of the alvear pathway never drove CA1 pyramidal cells to spike; the inputs produced only subthreshold EPSPs. Quotation withheld because this record is not cleared for redistribution. The same alvear stimulation that fails to spike pyramidal cells does excite interneurons, which then inhibit the pyramidal cells disynaptically. Quotation withheld because this record is not cleared for redistribution. Parvalbumin interneurons are the most responsive target of the alvear input, firing at higher rates than VIP or somatostatin (GIN) interneurons. Quotation withheld because this record is not cleared for redistribution. Interneuron subtypes differ sharply in whether they respond at all, with O-LM/GIN cells largely unresponsive. Quotation withheld because this record is not cleared for redistribution. Optogenetically silencing PV interneurons removed more than half of the alvear-driven inhibitory current in pyramidal cells, showing PV cells carry most of the feedforward inhibition. Quotation withheld because this record is not cleared for redistribution. Alvear inputs onto CA1 pyramidal basal dendrites showed a low probability of transmitter release. Quotation withheld because this record is not cleared for redistribution. The alvear pathway appears to affect CA1 mainly through feedforward inhibition via select interneuron subtypes. Quotation withheld because this record is not cleared for redistribution. A MAJOR INPUT PATHWAY WITH NO PHYSIOLOGY ATTACHED TO IT: a MAJOR EXCITATORY INPUT to hippocampal CA1, YET NOTHING IS KNOWN ABOUT ITS PHYSIOLOGICAL IMPACT Quotation withheld because this record is not cleared for redistribution. and it is not a minor route - in rodent it CARRIES MOST of the entorhinal input to dorsal CA1, and its effect HAS NOT, TO OUR KNOWLEDGE, BEEN REPORTED Quotation withheld because this record is not cleared for redistribution. with the gap dated - the synaptic boutons were described in 1996 and THE PHYSIOLOGICAL IMPACT OF THE SYNAPSES IN THE SO HAS NOT BEEN INVESTIGATED Quotation withheld because this record is not cleared for redistribution. THE REGION STUDIED WAS CHOSEN BY THE TOOLS THAT EXISTED: the target was chosen BY VIRTUE OF THE TRANSGENIC MICE AVAILABLE Quotation withheld because this record is not cleared for redistribution. A DISAGREEMENT DIVIDED BY PREPARATION: SOME GROUPS observed monosynaptic suprathreshold activation in vivo, WHEREAS OTHER GROUPS observed only subthreshold events Quotation withheld because this record is not cleared for redistribution. whether in vivo stimulation excites CA1 pyramidal cells above threshold is disputed, while ex vivo stimulation has consistently given subthreshold responses Quotation withheld because this record is not cleared for redistribution. THE COMPARISON EVERYONE WOULD WANT COULD NOT BE MADE BEFORE: stimulating the distal layer activates three inputs at once, so A DIRECT COMPARISON BETWEEN THE STRENGTHS OF THE TWO WAS NOT POSSIBLE WITH PREVIOUS STUDIES Quotation withheld because this record is not cleared for redistribution. TWO INPUTS, DIFFERENT INTERNEURON SUBSETS: PV interneurons have been demonstrated to produce LITTLE TO NO RESPONSE to SLM stimulation, and alvear pathway terminals appear capable of activating DIFFERENT SUBSETS OF INTERNEURONS relative to TA inputs Quotation withheld because this record is not cleared for redistribution. with the selectivity already known for the other pathway - specific subsets POTENTLY ACTIVATED while others are ONLY WEAKLY AFFECTED OR NOT AFFECTED AT ALL Quotation withheld because this record is not cleared for redistribution. NOT ALL SUBTYPES ARE EQUALLY AFFECTED: PV cells fire at higher frequencies than the other two classes, and the responsive cells span several morphological subtypes within each class Quotation withheld because this record is not cleared for redistribution. THE SAME PHARMACOLOGICAL TEST GIVES OPPOSITE ANSWERS FOR THE TWO RESPONSE TYPES: the potassium channel blocker rescues the excitatory response and CANNOT rescue the inhibitory one Quotation withheld because this record is not cleared for redistribution. with a geometric argument doing what pharmacology cannot - the light was confined to the deep layers, so the terminals there MUST be the source Quotation withheld because this record is not cleared for redistribution. and a delay difference used the same way - the interneuron delay is SIGNIFICANTLY SHORTER than the pyramidal one Quotation withheld because this record is not cleared for redistribution. MORE THAN HALF THE INHIBITION MEASURED RATHER THAN ATTRIBUTED: silencing one interneuron class removed GREATER THAN 50% of the response amplitude Quotation withheld because this record is not cleared for redistribution. subthreshold responses in pyramidal cells EVEN UNDER ROBUST THETA BURST STIMULATION, against suprathreshold responses in the interneurons Quotation withheld because this record is not cleared for redistribution. AND THE UNTESTED PATHWAY IS THE VULNERABLE ONE: tau accumulates in the terminals of THIS pathway BUT NOT the other Quotation withheld because this record is not cleared for redistribution. with an open question left open - it is UNKNOWN whether the projection neurons whose firing tracks theta contribute to this pathway at all Quotation withheld because this record is not cleared for redistribution. and individual projection neurons do NOT correlate well with the population field potential but DO fire coherently with their own internal theta Quotation withheld because this record is not cleared for redistribution. the two pathways' terminals look alike where it can be measured - both facilitating, both indicative of a low probability release synapse Quotation withheld because this record is not cleared for redistribution. and the conclusion states the asymmetry plainly - the subset activated here APPEARS TO BE DIFFERENT from those activated by the other pathway Quotation withheld because this record is not cleared for redistribution. alvear pathway alvear pathway Quotation withheld because this record is not cleared for redistribution. temporo-ammonic (TA) pathway temporo-ammonic (TA) pathway Quotation withheld because this record is not cleared for redistribution. alvear alvear Quotation withheld because this record is not cleared for redistribution. monosynaptic monosynaptic Quotation withheld because this record is not cleared for redistribution. disynaptic disynaptic Quotation withheld because this record is not cleared for redistribution. release probability release probability Quotation withheld because this record is not cleared for redistribution. IPSC amplitudes IPSC amplitudes Quotation withheld because this record is not cleared for redistribution. burst action potential frequencies burst action potential frequencies Quotation withheld because this record is not cleared for redistribution. stimulation stimulation Quotation withheld because this record is not cleared for redistribution. theta theta Quotation withheld because this record is not cleared for redistribution. synaptic delay synaptic delay Quotation withheld because this record is not cleared for redistribution. greater than 50% — Reduction in alvear-driven inhibitory postsynaptic current in CA1 pyramidal cells when PV interneurons were optogenetically silenced Quotation withheld because this record is not cleared for redistribution. 85% / 25% / 30% — Proportion of GIN, PV and VIP interneurons respectively that gave no response at all to alvear stimulation Quotation withheld because this record is not cleared for redistribution. greater than 70% / less than 20% — Fraction of PV and VIP interneurons versus O-LM cells that showed alvear excitatory synaptic responses Quotation withheld because this record is not cleared for redistribution. 41 of 49 — Pyramidal neurons that responded at all to optogenetic alvear stimulation Quotation withheld because this record is not cleared for redistribution. 17 of 28 — Responsive stratum oriens interneurons that reached spike threshold during theta burst stimulation Quotation withheld because this record is not cleared for redistribution. 16 of 37 — VIP-expressing interneurons that fired action potentials to theta burst stimulation of the alvear pathway Quotation withheld because this record is not cleared for redistribution. 39 — Total interneurons recorded with somata in CA1 stratum oriens Quotation withheld because this record is not cleared for redistribution. greater than 70% ... less than 20% — the share of two interneuron classes that responded against the third - the number that turns 'drives interneurons' into 'drives these interneurons' Quotation withheld because this record is not cleared for redistribution. greater than 50% — the share of the inhibitory response removed by silencing one interneuron class - a contribution measured by subtraction rather than inferred from which cells fired hardest Quotation withheld because this record is not cleared for redistribution. approximately 3 ms ... approximately 2 ms — the synaptic delays of alvear inputs, supporting the monosynaptic nature of alvear inputs onto PC basal dendrites in the deep layers of hippocampal CA1 value source note: THE VALUE DRAWS ON THE PAPER BEYOND THIS QUOTE: part of it is printed elsewhere in the paper, not in this quote ('alvear inputs onto CA1 interneurons was approximately 2 ms…'). Quotation withheld because this record is not cleared for redistribution.

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