Electrical Properties of Human Tissues and Cells: From Membrane Potential to Systemic Electrophysiology

Abstract

Narrative review · Preprint · Version 1.6 · Not peer reviewed · Not submitted to a journal. A consolidated reference for the measured passive and active electrical properties of human cells and tissues, from the membrane to the whole body. Each value is reported with the species, preparation, method and frequency range that attached to it at the point of measurement, and with the reported uncertainty where the source's indexed record supplies it — for the tissue resistivities of Table 2 it does not, and the manuscript says so rather than filling the gap. Quantitative statements were checked against the indexed record — the abstract-level record — of the source that reported them. That level confirms a number is reported as stated; it cannot confirm anything the abstract does not contain. Organising finding. The specific membrane capacitance of human neocortical layer 2/3 pyramidal neurons is approximately 0.5 µF/cm² — half the value its discoverers describe as the commonly accepted “universal” figure for biological membranes. The consequences are not a uniform factor of two and are not all in the same direction: because the membrane time constant is the measured quantity to which capacitance and resistance are jointly fitted, tau is approximately preserved while specific membrane resistance, input resistance and the dendritic space constant increase. The source’s own conclusion is that the low value enhances dendrite-to-soma charge transfer and axonal spike propagation. Contents. Membrane parameters and resting potential · excitable and non-excitable cells · passive tissue conductivity, resistivity and dielectric dispersion · skin · whole-body bioimpedance · ECG, EEG, EMG, EDA and their standards · measured applied fields in human cortex · endogenous fields in human tissue · a minimum specification for quoting a tissue electrical parameter · and a named list of the human measurements that do not currently exist. Three tables, three figures, 44 verified references. What this preprint does not do. It makes no therapeutic claim, evaluates no device, and describes no technology associated with the author. It computes no pooled estimate. Where only animal data exist — human skeletal muscle anisotropy, for example — it says so and declines to substitute them. Status. Version 1.0 of this manuscript was graded RED by an adversarial internal review and corrected; this is the corrected version, graded YELLOW. The change log is at §11.6, which carries thirteen rows: the three grounds on which v1.0 was graded RED — a physics error in the original framing of the membrane-capacitance argument, five findings from sources the manuscript otherwise relied on that it had omitted, and a competing-interests declaration asserting a property of the text that the text did not support — together with nine smaller defects and one correction made on the author's instruction. Three full-text extractions remain outstanding and are listed at §11.3; the 95% confidence intervals for Table 2 are the priority item and could not be obtained because the source is not open access. Version 1.6 (this version, 19 September 2026). No scientific content changes. The version 1.5 PDF carried a stray Markdown emphasis marker, printed literally at the end of the status banner on page 1. Deposited files cannot be replaced, so correcting it required a new version. Three things differ from version 1.5 and they are the whole of the difference: the marker is closed, §11.11 is added recording how it arose, and one sentence is added to the banner saying why this version exists. The defect was introduced by the version 1.5 edit itself — the edit whose purpose was to check that every quoted value in this manuscript holds against its source — and a check has since been added to the programme's pre-flight script so that an unclosed emphasis marker fails the build. Every value, interval, comparator, sample size, significance level, species label, frequency range, evidence grade, table, figure, legend, reference, declaration and conclusion is identical to version 1.5. The page count rises from 23 to 24 because §11.11 is there. Version 1.5 (19 September 2026). Every quoted value in this manuscript was checked against the indexed record of the source that reported it: 33 sentences carry both a quantity and a citation key, drawing on 26 of the 44 references, and all 26 were checked. Every magnitude, interval, comparator, sample size and significance level matches its source. Three defects were found, none of them a wrong number. (1) The squid-axon impedance result [A06] was reported as a fall in membrane resistance; the source's own abstract names the falling quantity "conductance" while giving it in ohm·cm², which are units of resistance. The reading here is what the units and the source's own analysis require, but that correction had been made silently, and it is now stated where the value is quoted. (2) A species label was carried across two adjacent sentences, so a rat corneal result [C07] sat under a guinea-pig label; the rat is now named. (3) The manuscript correctly declined to quote magnitudes from two foundational skin-impedance sources whose indexed records carry no abstract [B09, B10], but still drew two qualitative characterisations from them; those are now marked as resting on the full texts and listed in §11.2. Two limits of the method are stated rather than implied: the indexed record cannot confirm units, because its text strips superscripts; and extraction was pattern-based over sentences, so a value whose citation key sits outside the sentence may not have been captured. No finding, value, table, figure or conclusion changes. The change log is §11.10. The full verification record — the extracted quantity-bearing sentences, the per-manuscript checks, the register of universal self-descriptive claims and the pre-flight script — is deposited at the dataset concept DOI 10.5281/zenodo.22831175, version 1.3 of 19 September 2026. §11.10 said the record was deposited with this manuscript before it was; publishing it made the sentence true, and the gap is recorded here rather than closed quietly. Version 1.4 (19 September 2026). A second declaration is corrected, and again no science changes. Version 1.3's Use-of-AI-tools statement said every quantitative value was verified against the indexed record of "the primary source". That is false, and this manuscript's own contents refute it: the eight tissue resistivities of Table 2 are drawn from a meta-analysis of review studies [B06], and the table grades every one of those rows B — published evidence, not primary measurement — for exactly that reason. The declaration also cited §1.3 as its authority while §1.3 and §11.5 both say only "the source that reported it". It now states what the paper actually did and names the Table 2 exception. §11.9 records it, including how it was found: by reading the type field of all 44 cited sources in the deposited database, which showed 17 of them are not primary measurements. That claim had been flagged as unverified earlier the same day, and flagging was not the same as checking — it sat one query away from being disproved. Version 1.3 (19 September 2026) corrected the Data-and-materials declaration, which had claimed the deposited bibliography carries "the indexed identifier of every source"; one cited source, a textbook, carries neither a PMID nor a DOI, and the deposit did not then contain five of the sources cited here at all. §11.8 records that. The remaining verification claim, in the abstract and §11.5, was checked in the same pass and holds as written. Competing interests. The author is an electronics engineer, founder and Director of Rohera Healthcare & Technology Pvt. Ltd., Pune, India, and a named inventor on a patent family relating to electrical stimulation technology. He therefore holds a financial and intellectual interest in the field of applied bioelectricity. No device, product, patent or framework associated with the author or the company is described, evaluated, named or referred to anywhere in the manuscript. Full declaration, including the passages a sceptical reader should scrutinise, is in the Declarations section. Funding. Self-funded. This work received no external, grant or institutional funding; the costs were borne by the author and his companies, and the company provided no funding specific to this manuscript and had no role in its design, conduct, analysis, drafting or the decision to submit. Self-funding is declared here because it is itself a competing interest: no external sponsor reviewed, constrained or independently verified this work. Version 1.2. A second adversarial internal pass over version 1.1 found a further set of defects, all corrected here and listed in §11.7. The most serious: the abstract claimed an uncertainty column and a level of verification the tables do not deliver; the evidence-grading scheme used labels it had not defined and graded reviews and consensus documents as primary measurements; and §9’s headline comparison of endogenous wound fields to applied cortical fields omitted the three facts that weaken it. The manuscript now also states why §4 contains no parameter values, and records a second failed attempt to obtain the confidence intervals that Table 2 needs — no figure has been invented to fill that gap.