Pattern Separation Research Articles

Discrimination of mnemonic similarity is associated with short-term and long-term memory precision.

Remembering specific memories with precision relies on the differentiation of similar memory contents - a process commonly referred to as pattern separation and behaviorally operationalized as lure discrimination in the mnemonic similarity task. Although pattern separation is typically investigated in the context of long-term memory (LTM), recent research extends these findings to short-term memory (STM) within a mixture model framework, emphasizing the distinction between memory quality and quantity. According to this framework, pattern separation is associated with memory precision across STM and LTM, regardless of the overall memory likelihood. However, these associations among memory quality measures may persist without the mixture model assumption. In an alternative model, a unitary memory strength measure quantified as a discrimination score (d') may also capture the association between pattern separation and memory quality, as pattern separation has been previously linked with strength-based memory performance. We tested these possibilities based on individual differences among 132 participants who underwent tasks measuring mnemonic pattern separation and STM/LTM quality. We found that behavioral estimates of pattern separation are significantly correlated with STM and LTM precision, irrespective of the likelihood of STM/LTM recall success. However, these associations are absent when considering the correlation between pattern separation and memory strength under a unitary model framework. By leveraging individual differences to constrain our understanding of cognitive models, our data unravel the intricate relationship between pattern separation and memory quality across timescales. These findings may therefore contribute to identifying sensitive behavioral measures for detecting subtle memory deficits in older adults or clinical populations.

Pattern separation during encoding and Subsequent Memory Effect

Memory retrieval has been extensively studied in relation to the encoding processes that precede access to stored information. Event related potentials (ERP) research has compared brain potentials elicited during the study phase of successful and unsuccessful retrieval, finding greater activation for the subsequent retrieval information. In this work we were interested in exploring the neural markers associated to subsequent recognition when similar memories are subsequently encoded. We used a Subsequent Memory paradigm in which we manipulated the number of similar items within a category (2 or 6) that participants encoded. Manipulating the number of similar encoded items within a category allowed us to test whether encoding markers of subsequent recognition depend solely on memory trace strength or, on the contrary, successful recognition is influenced by subsequently presented similar memories, and consequently may not be reflected in higher activation in such cases. After a 20-minute period, participants performed a recognition task providing one of a three-option judgement: “old”, “similar” and “new”, which allowed us to test if the amplitude of ERP waveforms varied based on the similarity judgement of the unrecognized encoded item. We did not observe a significant parietal subsequent memory effect, however, old hits and similar false alarms were both significantly different from similar correct rejections and old false alarms in ERP retrieval. These findings suggest that differences in brain responses between conditions are specifically related to the retrieval process and not the encoding process, indicating potential differential effects on memory during retrieval. Moreover, it is also possible that differences in brain responses develop or change over the rest time between phases, influencing how these conditions manifest across different stages of information processing.

Retirement through rose-colored glasses: greater positivity bias in retired relative to working older adults

Abstract Retirement has been associated with declines in memory beyond typical age-related memory decline. This may impact the ability to remember distinct events, as older adults (OA) are susceptible to interference in memory across experiences with overlapping features. Impaired hippocampal pattern separation, a computation that allows for the disambiguation of similar experiences as unique events, is thought to underlie age-related impairment in memory. Furthermore, positive experiences tend to be better remembered than neutral or negative experiences in aging. Socioemotional selectivity theory suggests that awareness of a limited remaining lifespan leads OA to prioritize emotionally fulfilling experiences, often leading to a bias towards positive information compared to negative or neutral information. However, the potential role of retirement in contributing to these age-related changes in memory has yet to be examined. Memory measures that tax hippocampal pattern separation may be more sensitive to memory impairment in retirement compared to standard memory measures. Retirement may exacerbate awareness of reduced remaining time, such that retired OA may experience a greater positivity bias in memory than their working peers. Here, we utilized an emotional memory task that taxes hippocampal pattern separation to examine memory in age-matched retired and working OA. We found that retired OA show selective impairments for memories with high interference and a greater positivity bias in memory compared to their working peers. These findings suggest that retirement may accelerate age-related memory changes, including greater susceptibility to interference as well as a bias toward remembering positive relative to neutral information.

Alterable Robotic Skin Using Material Gene Expression Modulation

AbstractRobotic skins that integrate artificial tactile sensing elements can substantially complement the perception dimension of social robots, presenting an indispensable part in human‐robot interaction (HRI). However, existing design frameworks compromise between versatility and sustainability due to the restricted range of characteristics available for a single constituent. Here an alterable robotic skin constructed from homogeneous sensing units are proposed, capable of cyclically realtering their inherent characteristics across a wide spectrum. Necessary characteristics to achieve positioning and pressure sensing subunits can be encoded in the feature motifs and extracted through condition‐induced differentiation, showcasing a remarkable resemblance to the gene expression in the living system. By virtue of this, up to 100‐fold differences in feature parameters are achieved, including modulus, surface state, and conductivity, to drive the target attribute coupling. The trans‐temporal reconstruction of materials enables the superb customization of functional building blocks, advancing the flexible separation and combination of different touch modes, including location, pressure, duration, and motion pattern. As a proof of concept, the alterable robotic skin is demonstrated that integrates a position‐sensing layer and a pressure‐sensing layer. It can accurately distinguish and recognize multi‐dimensional touch motions based on less‐channel data, which showcases an efficient haptic interaction application.

Shock Wave and Aeroelastic Coupling in Overexpanded Nozzle

The growing demand for increasing the engine power of a liquid rocket is driving the development of high-power De-Laval nozzles, which is primarily achieved by increasing the expansion ratio. A high-expansion-ratio for De-Laval nozzles can cause flow separation, resulting in unsteady, asymmetric forces that can limit nozzle life. To enhance nozzle performance, various separation control methods have been proposed, but no methods have been fully implemented thus far due to the uncertainties associated with simulating flow phenomena. A numerical study of a high-area-ratio rocket engine is performed to analyze the aeroelastic performance of its structure under flow separation conditions. Based on numerical methodology, the flow inside a rocket nozzle (the VOLVO S1) is analyzed, and different separation patterns are comprehensively discussed, including both free shock separation (FSS) and restricted shock separation (RSS). Since the location of the flow separation point strongly depends on the turbulence model, both the single transport equation and two-transport-equation turbulence models are simulated, and the findings are compared with the experimental results. Therefore, the Spalart–Allmaras (SA) turbulence model is the ideal choice for this rocket nozzle geometry. A wavelet is used to analyze the amplitude frequencies from 0 to 100 Hz under various pressure fluctuation conditions. Based on a clear understanding of the flow field, an aeroelastic coupling method is carried out with loosely coupled computational fluid dynamics (CFD)/computational structural dynamics (CSD). Some insights into the aeroelasticity of the nozzle under separated flow conditions are obtained. The simulation results show the significant impact of the structural response on the inherent pressure pulsation characteristics resulting from flow separation.

Phylogeographic structure of Italian Formica pratensis (Retzius 1783) populations in the framework of the species Eurasian range

AbstractThe phylogeography and demographical history of Italian Formica pratensis populations were examined and compared with the Eurasian-wide dataset available for this species and the other red wood ant species Formica lugubris. Forty-eight workers belonging to eight populations from both Alps and Apennines were analysed sequencing a 1.5-kilobase mitochondrial DNA fragment, including the cytochrome b gene and part of the NADH dehydrogenase subunit 6 gene. A total of 127 sequences were screened, scoring 53 different haplotypes amongst all specimens, with five new haplotypes discovered in the Italian populations. All the Italian haplotypes clustered in a monophyletic clade, underlining a clear phylogeographical separation of this group from the other Eurasian groups and suggesting a glacial separate forest refugia and different post-glacial colonisation patterns. The haplotypes from the Alps and the Apennines showed a high genetic proximity, pointing out an ancient (Pleistocene) wide distribution of this species across all these areas and common ancestral lineages. No shared haplotypes were scored between Northern and Central Apennine populations, but the low inter-population genetic distance indicated similar post-glacial selective processes acting on these groups. The diversity we recorded may be influenced by the actual fragmentation of F. pratensis populations across its entire Eurasian range, and by the limited geographical origin and sample dimension of the dataset analysed. Future studies with a more extensive sampling in the Alps and Eastern Europe are needed to confirm our result.

Geometric separability of mesoscale patterns in embedding representation and visualization of multidimensional data and complex networks

Geometric separability of mesoscale patterns in embedding representation and visualization of multidimensional data and complex networks

Experience of Euclidean geometry sculpts the development and dynamics of rodent hippocampal sequential cell assemblies

Euclidean space is the fabric of the world we live in. Whether and how geometric experience shapes our spatial-temporal representations of the world remained unknown. We deprived male rats of experience with crucial features of Euclidean geometry by rearing them inside spheres, and compared activity of large hippocampal neuronal ensembles during navigation and sleep with that of cuboid cage-reared controls. Sphere-rearing from birth permitted emergence of accurate neuronal ensemble spatial codes and preconfigured and plastic time-compressed neuronal sequences. However, sphere-rearing led to diminished individual place cell tuning, more similar neuronal mapping of different track ends/corners, and impaired pattern separation and plasticity of multiple linear tracks, coupled with reduced preconfigured sleep network repertoires. Subsequent experience with multiple linear environments over four days largely reversed these effects. Thus, early-life experience with Euclidean geometry enriches the hippocampal repertoire of preconfigured neuronal patterns selected toward unique representation and discrimination of multiple linear environments.

The longitudinal behavioral effects of acute exposure to galactic cosmic radiation in female C57BL/6J mice: Implications for deep space missions, female crews, and potential antioxidant countermeasures.

Galactic cosmic radiation (GCR) is an unavoidable risk to astronauts that may affect mission success. Male rodents exposed to 33-beam-GCR (33-GCR) show short-term cognitive deficits but reports on female rodents and long-term assessment are lacking. We asked: What are the longitudinal behavioral effects of 33-GCR on female mice? Also, can an antioxidant/anti-inflammatory compound (CDDO-EA) mitigate the impact of 33-GCR? Mature (6-month-old) C57BL/6J female mice received CDDO-EA (400 μg/g of food) or a control diet (vehicle, Veh) for 5 days and Sham-irradiation (IRR) or whole-body 33-GCR (0.75Gy) on the 4th day. Three-months post-IRR, mice underwent two touchscreen-platform tests: (1) location discrimination reversal (tests behavior pattern separation and cognitive flexibility, abilities reliant on the dentate gyrus) and (2) stimulus-response learning/extinction. Mice then underwent arena-based behavior tests (e.g. open field, 3-chamber social interaction). At the experiment's end (14.25-month post-IRR), an index relevant to neurogenesis was quantified (doublecortin-immunoreactive [DCX+] dentate gyrus immature neurons). Female mice exposed to Veh/Sham vs. Veh/33-GCR had similar pattern separation (% correct to 1st reversal). There were two effects of diet: CDDO-EA/Sham and CDDO-EA/33-GCR mice had better pattern separation vs. their respective control groups (Veh/Sham, Veh/33-GCR), and CDDO-EA/33-GCR mice had better cognitive flexibility (reversal number) vs. Veh/33-GCR mice. One radiation effect/CDDO-EA countereffect also emerged: Veh/33-GCR mice had slower stimulus-response learning (days to completion) vs. all other groups, including CDDO-EA/33-GCR mice. In general, all mice showed normal anxiety-like behavior, exploration, and habituation to novel environments. There was also a change relevant to neurogenesis: Veh/33-GCR mice had fewer DCX+ dentate gyrus immature neurons vs. Veh/Sham mice. Our study implies space radiation is a risk to a female crew's longitudinal mission-relevant cognitive processes and CDDO-EA is a potential dietary countermeasure for space-radiation CNS risks.

Barcode activity in a recurrent network model of the hippocampus enables efficient memory binding.

Forming an episodic memory requires binding together disparate elements that co-occur in a single experience. One model of this process is that neurons representing different components of a memory bind to an "index" - a subset of neurons unique to that memory. Evidence for this model has recently been found in chickadees, which use hippocampal memory to store and recall locations of cached food. Chickadee hippocampus produces sparse, high-dimensional patterns ("barcodes") that uniquely specify each caching event. Unexpectedly, the same neurons that participate in barcodes also exhibit conventional place tuning. It is unknown how barcode activity is generated, and what role it plays in memory formation and retrieval. It is also unclear how a memory index (e.g. barcodes) could function in the same neural population that represents memory content (e.g. place). Here, we design a biologically plausible model that generates barcodes and uses them to bind experiential content. Our model generates barcodes from place inputs through the chaotic dynamics of a recurrent neural network and uses Hebbian plasticity to store barcodes as attractor states. The model matches experimental observations that memory indices (barcodes) and content signals (place tuning) are randomly intermixed in the activity of single neurons. We demonstrate that barcodes reduce memory interference between correlated experiences. We also show that place tuning plays a complementary role to barcodes, enabling flexible, contextually-appropriate memory retrieval. Finally, our model is compatible with previous models of the hippocampus as generating a predictive map. Distinct predictive and indexing functions of the network are achieved via an adjustment of global recurrent gain. Our results suggest how the hippocampus may use barcodes to resolve fundamental tensions between memory specificity (pattern separation) and flexible recall (pattern completion) in general memory systems.

Cellulose acetate electrophoretic separation of serum and urine proteins in Nigerian children with autism spectrum disorders

BackgroundAutism spectrum disorder (ASD) is a neurodevelopmental disorder (NDD) characterized by social communication challenges and restricted, repetitive behaviors. While genetic and environmental factors are known to contribute to ASD, the role of the immune system remains unclear. This study investigated the separation patterns of serum and urine proteins in Nigerian children with ASD compared to typically developing children and children with other NDDs.MethodsForty-seven participants aged 3–8 years were recruited, including 16 children diagnosed with ASD and 16 children with other NDDs, both according to DSM-5 criteria, along with 15 neurotypical children. Blood and urine samples were collected for protein analysis. Total protein and albumin levels were measured in both serum and urine using established methods. Protein separation in serum and urine was performed using cellulose acetate electrophoresis, followed by densitometry analysis of the electrophoretic patterns.ResultsThe results revealed no significant differences in total serum protein levels and most protein fractions between the groups. However, children with other NDDs exhibited significantly lower levels of alpha-2 globulin compared to neurotypical children. Conversely, both ASD and NDD groups showed significantly higher gamma globulin levels compared to the control group. Interestingly, spot urine protein levels were significantly higher in children with ASD compared to neurotypical children.ConclusionThe observed changes in alpha-2 and gamma globulin levels suggest potential immune system involvement in ASD and other NDDs. The higher urine protein excretion in the ASD group warrants further investigation to explore the potential of urinary protein biomarkers for ASD diagnosis.

3M: Measuring Vital Signs With Markov-Gauss Model.

Measuring vital signs (VS) contained in the echoes is crucial to the analyses of breathing and heartbeat signals using medical radar. Although many advanced signal processing algorithms have been developed for radar-based VS measurement and make some improved progress, existing schemes cannot achieve a good estimation of echo phases modulated by the respiratory and cardiac activities with high accuracy or low computation, and thus resulting in serious performance degradation on the subsequent separation of breathing and heartbeat patterns as well as the assessment of breathing rate (BR), heart rate (HR), and heart rate variability (HRV). In this paper, we propose a simple yet effective method to measure VS for medical radar, named 3M method. Specifically, our method firstly introduces the Markov-Gauss model to obtain the recursive expression of the echo phases carrying VS, and secondly derive a simple observation equation (SOE) to reflect the relationship between the observed signal and VS of radar measurement. Thirdly, the aforementioned Markov-Gauss model and SOE are fused by Kalman filter to measure VS with accurate estimation. The 3M method demonstrates an elegant structure, low complexity and excellent features introduced by Kalman filter. Simulation results show the superiority of 3M over other methods. Then, we conduct extensive experiments with insightful visualizations to validate the effectiveness of the 3M method. Comparative results on different scenarios illustrate that the 3M method not only achieves state-of-the-art VS measurement performance but also expresses robust properties to HRV analysis.

An Information-Geometric Formulation of Pattern Separation and Evaluation of Existing Indices.

Pattern separation is a computational process by which dissimilar neural patterns are generated from similar input patterns. We present an information-geometric formulation of pattern separation, where a pattern separator is modeled as a family of statistical distributions on a manifold. Such a manifold maps an input (i.e., coordinates) to a probability distribution that generates firing patterns. Pattern separation occurs when small coordinate changes result in large distances between samples from the corresponding distributions. Under this formulation, we implement a two-neuron system whose probability law forms a three-dimensional manifold with mutually orthogonal coordinates representing the neurons' marginal and correlational firing rates. We use this highly controlled system to examine the behavior of spike train similarity indices commonly used in pattern separation research. We find that all indices (except scaling factor) are sensitive to relative differences in marginal firing rates, but no index adequately captures differences in spike trains that result from altering the correlation in activity between the two neurons. That is, existing pattern separation metrics appear (A) sensitive to patterns that are encoded by different neurons but (B) insensitive to patterns that differ only in relative spike timing (e.g., synchrony between neurons in the ensemble).

Enhancing spatial memory and pattern separation: Long-term effects of stimulant treatment in individuals with ADHD

This study explores the under-researched domain of long-term stimulant treatment in children and adolescents diagnosed with attention deficit hyperactivity disorder (ADHD). The necessity for extended treatment duration, often accompanied by safety concerns and side effects leading to treatment discontinuation, underscores the significance of this investigation. Concurrently, comparative studies have revealed adverse impacts on vulnerable regions within the hippocampal formation, accompanied by behavioral perturbations. We employed computerized tests and virtual reality to assess spatial memory, pattern separation, and object recognition memory in a cohort of children diagnosed with ADHD receiving stimulant treatment. We compared their performance to a group of neurotypical peers. Our findings indicate that the ADHD group exhibited a lower performance in spatial memory, pattern separation, and object recognition memory than ND group. Intriguingly, a positive relationship emerged between the duration of stimulant treatment and performance in these variables. Notably, this improvement was not immediate to MPH treatment but becomes significant after 24 months of treatment. In contrast to previous comparative investigations, our study did not reveal a detrimental impact on spatial navigation, object recognition memory, or pattern separation, despite the known interplay of these cognitive processes with the hippocampal formation. These results shed new light on the nuanced effects of stimulant treatment in ADHD, underscoring the need for a more comprehensive understanding of long-term treatment outcomes.

13C CSA Tensors and Orientational Order of Model and Dimer Mesogens Comprising of Phenyl Benzoate.

A Model mesogen and its symmetrical Dimer made up of phenyl benzoate core unit are investigated by 13C NMR spectroscopy. The existence of layer order in smectic A and smectic C phases of Dimer mesogen is established by powder X-ray diffraction. The chemical shift anisotropy (CSA) tensors of Model mesogen are determined by 2D separation of undistorted powder patterns by effortless recoupling (SUPER) experiment and are utilized for calculating the order parameters employing the alignment-induced chemical shifts (AIS). Additionally, 2D separated local field (SLF) NMR is availed for extracting 13C-1H dipolar couplings for both mesogens and used for computing the order parameters. A good agreement in the order parameters calculated from 13C-1H dipolar couplings and AIS is observed. Accordingly, the main order parameter (Szz) for the phenyl rings of the Model mesogen is found to be in the range 0.54 - 0.82, and for the Dimer mesogen, the values span 0.64 - 0.82 across mesophases. Since the phenyl benzoate core unit is frequently employed structural moiety for constructing the main chain as well as side chain liquid crystalline polymers and liquid crystalline elastomers, the CSA tensors reported here will be of immense utility for the structural characterization of these materials.

FDA-approved cannabidiol [Epidiolex®] alleviates Gulf War Illness-linked cognitive and mood dysfunction, hyperalgesia, neuroinflammatory signaling, and declined neurogenesis

BackgroundChronic Gulf War Illness (GWI) is characterized by cognitive and mood impairments, as well as persistent neuroinflammation and oxidative stress. This study aimed to investigate the efficacy of Epidiolex®, a Food and Drug Administration (FDA)-approved cannabidiol (CBD), in improving brain function in a rat model of chronic GWI.MethodsSix months after exposure to low doses of GWI-related chemicals [pyridostigmine bromide, N,N-diethyl-meta-toluamide (DEET), and permethrin (PER)] along with moderate stress, rats with chronic GWI were administered either vehicle (VEH) or CBD (20 mg/kg, oral) for 16 weeks. Neurobehavioral tests were conducted on 11 weeks after treatment initiation to evaluate the performance of rats in tasks related to associative recognition memory, object location memory, pattern separation, and sucrose preference. The effect of CBD on hyperalgesia was also examined. The brain tissues were processed for immunohistochemical and molecular studies following behavioral tests.ResultsGWI rats treated with VEH exhibited impairments in all cognitive tasks and anhedonia, whereas CBD-treated GWI rats showed improvements in all cognitive tasks and no anhedonia. Additionally, CBD treatment alleviated hyperalgesia in GWI rats. Analysis of hippocampal tissues from VEH-treated rats revealed astrocyte hypertrophy and increased percentages of activated microglia presenting NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) complexes as well as elevated levels of proteins involved in NLRP3 inflammasome activation and Janus kinase/signal transducers and activators of the transcription (JAK/STAT) signaling. Furthermore, there were increased concentrations of proinflammatory and oxidative stress markers along with decreased neurogenesis. In contrast, the hippocampus from CBD-treated GWI rats displayed reduced levels of proteins mediating the activation of NLRP3 inflammasomes and JAK/STAT signaling, normalized concentrations of proinflammatory cytokines and oxidative stress markers, and improved neurogenesis. Notably, CBD treatment did not alter the concentration of endogenous cannabinoid anandamide in the hippocampus.ConclusionsThe use of an FDA-approved CBD (Epidiolex®) has been shown to effectively alleviate cognitive and mood impairments as well as hyperalgesia associated with chronic GWI. Importantly, the improvements observed in rats with chronic GWI in this study were attributed to the ability of CBD to significantly suppress signaling pathways that perpetuate chronic neuroinflammation.

Predictions enable top-down pattern separation in the macaque face-processing hierarchy

Distinguishing faces requires well distinguishable neural activity patterns. Contextual information may separate neural representations, leading to enhanced identity recognition. Here, we use functional magnetic resonance imaging to investigate how predictions derived from contextual information affect the separability of neural activity patterns in the macaque face-processing system, a 3-level processing hierarchy in ventral visual cortex. We find that in the presence of predictions, early stages of this hierarchy exhibit well separable and high-dimensional neural geometries resembling those at the top of the hierarchy. This is accompanied by a systematic shift of tuning properties from higher to lower areas, endowing lower areas with higher-order, invariant representations instead of their feedforward tuning properties. Thus, top-down signals dynamically transform neural representations of faces into separable and high-dimensional neural geometries. Our results provide evidence how predictive context transforms flexible representational spaces to optimally use the computational resources provided by cortical processing hierarchies for better and faster distinction of facial identities.

Locus coeruleus activation 'resets' hippocampal event representations and separates adjacent memories.

Memories reflect the ebb and flow of experiences, capturing unique and meaningful events from our lives. Using a combination of functional magnetic resonance imaging (fMRI), neuromelanin imaging, and pupillometry, we show that arousal and locus coeruleus (LC) activation transform otherwise continuous experiences into distinct episodic memories. As sequences unfold, encountering a context shift, or event boundary, triggers arousal and LC processes that predict later memory separation. Boundaries furthermore promote temporal pattern separation within left hippocampal dentate gyrus, which correlates with heightened LC responses to those same transition points. We also find that a neurochemical index of prolonged LC activation correlates with diminished arousal responses at boundaries, suggesting a connection between elevated LC output and impaired event processing. These findings align with the idea that arousal processes initiate a neural and memory 'reset' in response to significant changes, constructing the very episodes that define everyday memory.

From Shared RE to a Shared Digital RE Strategy: Navigating the Post-Digital Transformation of RE Organizations—Results of a Swiss Participatory Research Project

Religious adult education, characterized as non-formal religious education (RE) that has often been established over many decades, is frequently marked by patterns of institutional separation, local conditions and denominational divisions. This is also the case in Switzerland, where in each canton various church academies and RE organizations generally offer their respective programs along both denominational and cantonal lines. The increasing digitalization of society, and consequently of education, alters the original situation for these actors, both on an individual and organizational level. This article discusses the challenges of religious adult education in navigating the post-digital pivot. It addresses the issues of changing forms of teaching and learning, dealing with shifts in authority, and the growing need for collaboration and shared strategies among RE organizations in post-digital society. A participatory research project involving nearly 60 Swiss RE organizations investigated how these organizations are dealing with digitalization, analyzing the perspectives of the organizational leaders, the teachers, and learners through mixed methods. The findings provide insights into factors influencing the intent to offer or use digital RE courses, as well as factors contributing to the readiness to cooperate in the digital educational field.

Petrophysical and petrographic data correlation and the discrimination of magmatic environments and processes in Santos Basin, offshore SE Brazil

The igneous rocks in the context of oil & gas exploratory sedimentary basins have been a paradigm and challenge for industry and academia due to the difficulty of reconnaissance and interpretation using indirect methods, e.g. geophysical data. We presented the combination of the petrographic and well log data of distinct magmatic sections from wells of Santos Basin, SE Brazil. Effusive and explosive felsic rocks, mafic volcanic subaerial and subaqueous and plutonic mafic rocks were recognized by petrography and petrophysics proprieties data, as radioactive (GR), electric resistivity (R), acoustic property (Δt), porosity (Φ) and density (ρ), showed different patterns along sections. This enables the division on magmatic subsections and allowed the recognition of rock types and igneous setting. The compositional influences are clearly distinguished by GR, as felsic and mafic rocks, presence of amygdales in mafic effusive rocks and inter-pillow intervals in subaqueous environments, can interfere with GR patterns. In plutonic environment, GR can show evidence of magmatic differentiation. Δt and Φ are directly proportional with similar pattern and both are inversely proportional to R and ρ. Felsic rocks, effusive or explosive, and inter-pillow intervals makes Φ and ρ curves closer. Less dense and more porous rocks, as explosive, tend to imprint the Φ and ρ pattern to the left of the log. Welding processes are distinguished by gradual decrease of Φ and increase of ρ. Otherwise, denser mafic rocks, volcanic or plutonic, tend to show separate Φ and ρ curves on the right of the log, while amygdaloidal portions are lighter and more porous than the massive one, showing the separate pattern on the left. The subaqueous mafic volcanic rocks imprint GR, ρ and Φ intermediate patterns between mafic massive and amygdaloidal. The recognition of the type of magmatic rock, the environment and the physical properties can aid to improve not only the decisions of exploration and production but also the elaboration of a geodynamic context for offshore sedimentary basins.