Oyster-I (Oy1): Fungal Electrical Dynamics
- Oyster-I (Oy1) is a mycelial system of Pleurotus ostreatus that exhibits spatially distributed, burst-based electrical signaling with clear directional biases.
- A star-shaped eight-channel differential electrode array enabled detailed analysis of angular spiking patterns, burst clustering, and propagation delays.
- The findings highlight local coupling, slow propagation, and dynamic reconfiguration of active sectors, underscoring spatial heterogeneity in fungal physiological signaling.
Oyster-I (Oy1) denotes the oyster mushroom, Pleurotus ostreatus, treated as a living electrical substrate; in the principal study on this subject, it refers specifically to mycelium colonising a wood-shavings substrate and recorded with a star-shaped differential electrode array. In that setting, Oy1 exhibits spontaneous electrical activity that is spatially structured, directionally anisotropic, burst-based, weakly but locally coupled, and capable of very slow propagation across the colony. These observations support the interpretation of the fungal network as a spatially extended excitable medium with slow distributed electrical signalling and signal integration (Adamatzky, 13 Jan 2026).
1. Biological identity and scope
In the Oy1 usage relevant here, the organism is oyster mushroom mycelium, Pleurotus ostreatus, growing through a wood-shavings substrate. The emphasis is not on isolated cells, extracts, or a detached electrophysiological preparation, but on a colonised fungal-substrate system in which spontaneous extracellular potential differences can be recorded over multiple spatial sectors. The central problem is the spatial organisation of fungal electrical activity: not merely whether spikes occur, but whether they are directionally biased, clustered, locally coupled, and propagative.
A central implication of this framing is that Oy1 is not treated as an electrically homogeneous medium. The reported activity varies by sector, changes across sessions, and does not reduce to a single global oscillation. This suggests that fungal electrical dynamics in P. ostreatus should be analysed as a distributed network phenomenon rather than as a scalar time series from a nominally uniform biological sample.
The term Oy1 should therefore be understood here as a specific experimental instantiation of Pleurotus ostreatus electrical physiology: spontaneous signalling in mycelium colonising wood shavings, resolved angularly around a central region rather than along a single imposed axis. That distinction is methodologically important because much of the interpretation depends on spatial anisotropy rather than on the existence of spikes alone.
2. Star-shaped recording architecture
The defining methodological feature is a star-shaped eight-channel differential electrode array inserted into the colonised substrate. Sixteen electrodes were inserted and paired into eight differential recording channels arranged radially around a central region. This geometry was chosen specifically to avoid imposing a preferred linear axis, unlike standard line-electrode setups, and to obtain angular resolution of electrical activity around the colony (Adamatzky, 13 Jan 2026).
| Channel direction | Electrode pair |
|---|---|
| North | 1–2 |
| North-East | 3–4 |
| East | 5–6 |
| South-East | 7–8 |
| South | 9–10 |
| South-West | 11–12 |
| West | 13–14 |
| North-West | 15–16 |
The array was designed to detect directional asymmetries in spike rate and amplitude, sector-specific bursting, correlations between neighboring versus distant sectors, and propagation delays between sectors. Because the channels are defined by compass sectors around a central region, the data admit polar representations of activity and delay structure rather than only pairwise linear comparisons.
The recordings used a Pico ADC-24 high-resolution data logger with galvanically isolated differential inputs, 24-bit ADC resolution, input impedance of about , and a sampling rate of 1 sample per second. Continuous recordings extended up to five days, and three independent recording sessions were analysed. Signals were detrended before analysis to remove slow baseline drift. The differential configuration was used to reduce common-mode noise and to emphasize local potential differences generated in the mycelium.
This instrumentation constrains the temporal scale of inference. Because the sampling rate was 1 Hz, the analysis is intrinsically tuned to slow fungal dynamics rather than fine fast transients. A plausible implication is that the reported phenomena concern colony-scale physiological signalling on timescales of seconds to hours, not unresolved high-frequency microevents.
3. Event definitions and analytical framework
Spike detection was performed by adaptive thresholding on each channel. A spike was defined as a contiguous excursion above a channel-specific threshold, where the threshold was set as a fixed multiple of signal dispersion above baseline, and the event had to persist for at least tens of seconds. Detected spikes were characterised by timing and peak amplitude (Adamatzky, 13 Jan 2026).
Burst detection grouped spikes into clusters separated by quiescent intervals exceeding a fixed temporal gap. Operationally, spikes close together in time were assigned to the same burst, whereas long silent gaps defined separate bursts. This yields a mesoscopic description of activity in which the basic unit is not merely an isolated spike but a clustered episode of electrical recruitment.
Inter-channel coupling was quantified using Pearson correlation coefficients computed on normalised, detrended signals. The analysis used a correlation matrix and mean correlation as a function of spatial separation . This is important because the central question is whether electrical activity is globally coherent or spatially constrained. The reported decay of correlation with separation is thus not an incidental statistic but a principal test of locality.
Propagation was assessed by choosing a reference channel and, for each burst onset, finding the first subsequent spike in each other channel within a predefined temporal window. Burst onset in the reference channel served as the temporal origin, delays were measured at the 1 Hz sampling rate, and results were summarised by median delay and interquartile range. A match rate was also defined as the fraction of reference burst onsets followed by at least one spike in a given channel within the analysis window.
Taken together, these definitions establish a hierarchy of observables: spike statistics describe local event production; bursts describe temporal clustering; correlations describe continuous cofluctuation; and propagation delays plus match rates describe event-triggered recruitment across sectors. The framework is therefore explicitly spatiotemporal rather than purely descriptive.
4. Directional spiking, amplitudes, and bursting
The most prominent result is strong directional heterogeneity. When data were pooled across sessions, spike rates differed by more than an order of magnitude between directions, with strong inter-session variability. Some directions were consistently highly active, whereas others were weakly active or nearly silent; however, the identity of the dominant directions could shift between sessions, indicating dynamic reconfiguration of electrically active regions. The polar plot showed a lobed angular distribution rather than a circularly uniform one, confirming directional preference (Adamatzky, 13 Jan 2026).
Spike amplitudes were also highly heterogeneous. Reported values ranged from a few millivolts to several tens of millivolts, with rare spikes exceeding that and reaching over 100 mV. The pooled amplitude distribution was heavy-tailed: most spikes were low-to-moderate amplitude, while rare large events contributed disproportionately to the upper tail. Directional differences were substantial, with some channels showing narrow, low-amplitude distributions and others broader distributions with strong upper tails. Notably, some low-rate directions still produced rare high-amplitude spikes, indicating episodic recruitment rather than sustained oscillation.
The temporal structure of spiking was non-random. Spike trains were clustered into bursts, and the inter-spike interval histograms showed short intervals concentrated at the lower end together with much longer gaps between clusters. Even the shortest inter-spike intervals were on the order of minutes rather than seconds. This rules out simple independent Poisson-like spiking and indicates temporal clustering. Burst size, defined as the number of spikes per burst, and burst duration, reported in seconds, were highly heterogeneous across sectors: bursts ranged from short transient events to extended trains lasting many minutes.
These observations collectively argue against a picture of fungal electrical activity as unstructured noise or uniformly distributed oscillation. Instead, Oy1 displays sector-specific burst dynamics whose dominant directions and amplitudes can reconfigure over time. This suggests a colony state that is both spatially differentiated and temporally labile.
5. Local coupling and slow directional propagation
The inter-channel coupling analysis showed partial, local coupling rather than global synchrony. The correlation matrix had its highest values near the diagonal, meaning that neighboring channels were more correlated, whereas distant channel pairs showed weak or negligible correlations. Correlation strength decreased systematically with channel separation . The authors emphasised that this pattern is inconsistent with common-mode noise, global drift, or system-wide oscillation, and instead supports spatially constrained coupling in the mycelial network (Adamatzky, 13 Jan 2026).
Propagation analysis further sharpened the spatial picture. Delays were measured from burst onset in a reference channel to the first subsequent spike in other channels, pooled across experiments. Recruitment spanned several orders of magnitude, from seconds in some directions to thousands of seconds in others; descriptively, the slowest sectors responded on timescales of tens of minutes to hours. Delay distributions were broad, heavy-tailed, and highly variable across events.
The propagation maps were strongly anisotropic. Some directions responded quickly, whereas others showed prolonged delays. Match rate also varied by direction: some sectors were reliably recruited after reference bursts, while others had low match rates, implying weak coupling or sparse connectivity. The reported patterns were reproducible within sessions but differed across sessions, indicating changing dominant pathways.
Two misconceptions are directly addressed by these results. First, the data do not support rapid neural-like conduction: the relevant propagation occurs over seconds to minutes to hours. Second, the data do not support whole-colony synchrony: coupling is local and directional, not uniformly global. Oy1 therefore behaves neither like a passive noisy substrate nor like a centrally coordinated fast-conduction network.
6. Interpretation, related Pleurotus electrophysiology, and unresolved issues
The principal interpretation is that Oy1 behaves as a spatially extended excitable medium. The evidential basis includes spike-like electrical events, bursts separated by quiescence, directional anisotropy, local rather than global correlation, slow state-dependent propagation, and session-to-session reconfiguration of active sectors (Adamatzky, 13 Jan 2026). The reported activity is interpreted as reflecting distributed physiological processes such as nutrient transport, metabolic switching, ionic fluxes, and local excitability in hyphal networks. The study explicitly argues against uniform stochastic noise, global synchrony, and rapid neural-like conduction.
This interpretation is continuous with earlier Pleurotus ostreatus electrophysiology, but also more spatially explicit. In a cortisol-stimulation study on P. ostreatus grown on hemp-based substrates, fungal electrical responses were analysed as spike events that changed after chemical triggering, with a marked reduction in spike count after cortisol exposure and accompanying changes in complexity and entropy metrics; that work framed fungal tissue as a responsive biosensing material rather than a passive electrical medium (Dehshibi et al., 2021). In a separate cyclic-voltammetry study on grey oyster mushroom fruit bodies grown on wood shavings, the tissue exhibited hysteretic, history-dependent electrical response, frequency dependence, current spiking or oscillation near zero voltage, and a nonzero baseline response at nominal , leading the authors to describe the fruit body not as a pure ideal memristor but as a mem-fractor with mixed memory behavior (Beasley et al., 2020). Relative to those studies, the star-array work on Oy1 extends the literature from response existence to spatiotemporal organisation.
A plausible implication is that fungal electrical signalling should be studied across multiple organisational levels: local spike generation, burst recruitment, mesoscale directional coupling, and colony-scale pathway reconfiguration. The claim is not that fungal mycelium implements neural signalling, but that it supports slow distributed electrical signalling and signal integration across space and time.
Several limitations bound current inference. Only three recording sessions were analysed. Sampling was 1 Hz, so fine fast dynamics could not be resolved. Propagation inference relied on first subsequent spike timing rather than direct causal mapping. Correlation does not prove direct structural connectivity. No external perturbations were applied in the star-array study, so the observations concern spontaneous activity only. For that reason, the present evidence is foundational rather than exhaustive: it establishes that Oy1 has preferred electrically active sectors, sector-specific burst dynamics, local communication between nearby regions, anisotropic propagation pathways, and dynamic reconfiguration over time, while leaving the mechanistic linkage to hyphal architecture, nutrient gradients, and metabolic demand for future work.
In fungal physiology, biohybrid sensing, unconventional computing, and distributed information processing in organisms without central control, Oy1 thus occupies a specific position: a Pleurotus ostreatus mycelial system in which electrical activity is not merely detectable, but demonstrably spatially organised.
