Assessing translational applicability of perineuronal net dysfunction in Alzheimer's disease across species.

In the context of aging and age-associated neurodegenerative disorders, the brain's extracellular matrix (ECM) serves as a critical regulator for neuronal health and cognitive function. Within the extracellular space, proteoglycans and their glycosaminoglycan attachments play essential roles in forming, stabilizing, and protecting neural circuits throughout neurodevelopment and adulthood. Recent studies in rodents reveal that chondroitin sulfate-glycosaminoglycan (CS-GAG) containing perineuronal nets (PNNs) exhibit both structural and compositional differences throughout the brain. While animal studies are illuminating, additional research is required to translate these interregional PNN/CS-GAG variations to human brain tissue. In this perspective article, we first investigate the translational potential for interregional CS-GAG variances across species as novel targets for region-specific therapeutic development. We specifically focus on the observation that alterations in brain PNN-associated CS-GAGs have been linked with the progression of Alzheimer's disease (AD) neuropathology in humans, but these changes have not been fully recapitulated in rodent models of this disease. A second highlight of this perspective article investigates whether AD-associated shifts in CS-GAGs in humans may be dependent on region-specific baseline differences in CS-GAG sulfation patterning. The current findings begin to disentangle the intricate relationships between the interregional differences in brain PNN/CS-GAG matrices across species, while emphasizing the need to better understand the close relationship between dementia and changes in brain CS-GAG sulfation patterns in patients with AD and related dementias.

Bioprospecting of extremophilic perchlorate-reducing bacteria: report of promising Bacillus spp. isolated from sediments of the bay of Cartagena, Colombia.

Three extremophile bacterial strains (BBCOL-009, BBCOL-014 and BBCOL-015), capable of degrading high concentrations of perchlorate at a range of pH (6.5 to 10.0), were isolated from Colombian Caribbean Coast sediments. Morphological features included Gram negative strain bacilli with sizes averaged of 1.75 × 0.95, 2.32 × 0.65 and 3.08 × 0.70 µm, respectively. The reported strains tolerate a wide range of pH (6.5 to 10.0); concentrations of NaCl (3.5 to 7.5% w/v) and KClO4- (250 to 10000 mg/L), reduction of KClO4- from 10 to 25%. LB broth with NaCl (3.5-30% w/v) and KClO4- (250-10000 mg/L) were used in independent trials to evaluate susceptibility to salinity and perchlorate, respectively. Isolates increased their biomass at 7.5 % (w/v) NaCl with optimal development at 3.5 % NaCl. Subsequently, ClO4- reduction was assessed using LB medium with 3.5% NaCl and 10000 mg/L ClO4-. BBCOL-009, BBCOL-014 and BBCOL-015 achieved 10%, 17%, and 25% reduction of ClO4-, respectively. The 16 S rRNA gene sequence grouped them as Bacillus flexus T6186-2, Bacillus marisflavi TF-11 (T), and Bacillus vietnamensis 15 - 1 (T) respectively, with < 97.5% homology. In addition, antimicrobial resistance to ertapenem, vancomycine, amoxicillin clavulanate, penicillin, and erythromycin was present in all the isolates, indicating their high adaptability to stressful environments. The isolated strains from marine sediments in Cartagena Bay, Colombia are suitable candidates to reduce perchlorate contamination in different environments. Although the primary focus of the study of perchlorate-reducing and resistant bacteria is in the ecological and agricultural realms, from an astrobiological perspective, perchlorate-resistant bacteria serve as models for astrobiological investigations.

Near-field potentials index local neural computations more accurately than population spiking.

Local field potentials (LFP) are low-frequency extracellular voltage fluctuations thought to primarily arise from synaptic activity. However, unlike highly localized neuronal spiking, LFP is spatially less specific. LFP measured at one location is not entirely generated there due to far-field contributions that are passively conducted across volumes of neural tissue. We sought to quantify how much information within the locally generated, near-field low-frequency activity (nfLFP) is masked by volume-conducted far-field signals. To do so, we measured laminar neural activity in primary visual cortex (V1) of monkeys viewing sequences of multifeatured stimuli. We compared information content of regular LFP and nfLFP that was mathematically stripped of volume-conducted far-field contributions. Information content was estimated by decoding stimulus properties from neural responses via spatiotemporal multivariate pattern analysis. Volume-conducted information differed from locally generated information in two important ways: (1) for stimulus features relevant to V1 processing (orientation and eye-of-origin), nfLFP contained more information. (2) in contrast, the volume-conducted signal was more informative regarding temporal context (relative stimulus position in a sequence), a signal likely to be coming from elsewhere. Moreover, LFP and nfLFP differed both spectrally as well as spatially, urging caution regarding the interpretations of individual frequency bands and/or laminar patterns of LFP. Most importantly, we found that population spiking of local neurons was less informative than either the LFP or nfLFP, with nfLFP containing most of the relevant information regarding local stimulus processing. These findings suggest that the optimal way to read out local computational processing from neural activity is to decode the local contributions to LFP, with significant information loss hampering both regular LFP and local spiking. Author's Contributions: Conceptualization, D.A.T., J.A.W, and A.M.; Data Collection, J.A.W., M.A.C., K.D.; Formal Analysis, D.A.T. and J.A.W.; Data Visualization, D.A.T. and J.A.W.; Original Draft, D.A.T., J.A.W., and A.M.; Revisions and Final Draft, D.A.T., J.A.W., M.A.C., K.D., M.T.W., A.M.B., and A.M. Competing Interests: The authors declare no conflicts of interest.

Taquicardia ventricular asociada a mutación en el gen de ankirina B / Ventricular tachycardia associated to a mutation in the ankyrin B gen

Resumen Se presenta el caso de una mujer de 14 años, con taquicardiomiopatía secundaria a taquicardia ventricular. Se evidenció la presencia de una variante de significado incierto en el gen ANK2, por lo que se consideró un posible síndrome de ankirina B. La paciente fue tratada con éxito a través de ablación con radiofrecuencia. Tras dicho procedimiento, tuvo recuperación completa de su función ventricular izquierda y resolución de los complejos ventriculares prematuros y los episodios de taquicardia ventricular.

Abstract We report a case of a 14-year-old with tachycardiomyopathy due to ventricular tachycardia. A variant of uncertain significance of the ANK2 gene was identified, which is suggestive of a possible ankyrin-B syndrome. The patient underwent a successful radiofrequency ablation. After the procedure, the patient completely recovered her left ventricular function and there was resolution of the premature ventricular complexes and ventricular tachycardia.

Visual Influences on Auditory Behavioral, Neural, and Perceptual Processes: A Review.

In a naturalistic environment, auditory cues are often accompanied by information from other senses, which can be redundant with or complementary to the auditory information. Although the multisensory interactions derived from this combination of information and that shape auditory function are seen across all sensory modalities, our greatest body of knowledge to date centers on how vision influences audition. In this review, we attempt to capture the state of our understanding at this point in time regarding this topic. Following a general introduction, the review is divided into 5 sections. In the first section, we review the psychophysical evidence in humans regarding vision's influence in audition, making the distinction between vision's ability to enhance versus alter auditory performance and perception. Three examples are then described that serve to highlight vision's ability to modulate auditory processes: spatial ventriloquism, cross-modal dynamic capture, and the McGurk effect. The final part of this section discusses models that have been built based on available psychophysical data and that seek to provide greater mechanistic insights into how vision can impact audition. The second section reviews the extant neuroimaging and far-field imaging work on this topic, with a strong emphasis on the roles of feedforward and feedback processes, on imaging insights into the causal nature of audiovisual interactions, and on the limitations of current imaging-based approaches. These limitations point to a greater need for machine-learning-based decoding approaches toward understanding how auditory representations are shaped by vision. The third section reviews the wealth of neuroanatomical and neurophysiological data from animal models that highlights audiovisual interactions at the neuronal and circuit level in both subcortical and cortical structures. It also speaks to the functional significance of audiovisual interactions for two critically important facets of auditory perception-scene analysis and communication. The fourth section presents current evidence for alterations in audiovisual processes in three clinical conditions: autism, schizophrenia, and sensorineural hearing loss. These changes in audiovisual interactions are postulated to have cascading effects on higher-order domains of dysfunction in these conditions. The final section highlights ongoing work seeking to leverage our knowledge of audiovisual interactions to develop better remediation approaches to these sensory-based disorders, founded in concepts of perceptual plasticity in which vision has been shown to have the capacity to facilitate auditory learning.

Stimulus Feature-Specific Information Flow Along the Columnar Cortical Microcircuit Revealed by Multivariate Laminar Spiking Analysis.

Most of the mammalian neocortex is comprised of a highly similar anatomical structure, consisting of a granular cell layer between superficial and deep layers. Even so, different cortical areas process different information. Taken together, this suggests that cortex features a canonical functional microcircuit that supports region-specific information processing. For example, the primate primary visual cortex (V1) combines the two eyes' signals, extracts stimulus orientation, and integrates contextual information such as visual stimulation history. These processes co-occur during the same laminar stimulation sequence that is triggered by the onset of visual stimuli. Yet, we still know little regarding the laminar processing differences that are specific to each of these types of stimulus information. Univariate analysis techniques have provided great insight by examining one electrode at a time or by studying average responses across multiple electrodes. Here we focus on multivariate statistics to examine response patterns across electrodes instead. Specifically, we applied multivariate pattern analysis (MVPA) to linear multielectrode array recordings of laminar spiking responses to decode information regarding the eye-of-origin, stimulus orientation, and stimulus repetition. MVPA differs from conventional univariate approaches in that it examines patterns of neural activity across simultaneously recorded electrode sites. We were curious whether this added dimensionality could reveal neural processes on the population level that are challenging to detect when measuring brain activity without the context of neighboring recording sites. We found that eye-of-origin information was decodable for the entire duration of stimulus presentation, but diminished in the deepest layers of V1. Conversely, orientation information was transient and equally pronounced along all layers. More importantly, using time-resolved MVPA, we were able to evaluate laminar response properties beyond those yielded by univariate analyses. Specifically, we performed a time generalization analysis by training a classifier at one point of the neural response and testing its performance throughout the remaining period of stimulation. Using this technique, we demonstrate repeating (reverberating) patterns of neural activity that have not previously been observed using standard univariate approaches.

Revision of the Amphibolips species of the 'nassa' complex from Mexico and central America (Hymenoptera: Cynipidae).

The cynipid gall wasp species of Amphibolips (Cynipidae: Cynipini) belonging to the "nassa" complex are reviewed for Mexico and Central America. Five new species are described: A. bassae Cuesta-Porta Pujade-Villar n. sp., A. bromus Pujade-Villar Cuesta-Porta n. sp., A. kinseyi Cuesta-Porta Pujade-Villar n. sp., A. rulli Pujade-Villar Cuesta-Porta n. sp., and A. turulli Pujade-Villar Cuesta-Porta n. sp. Amphibolips quercuspomiformis (Bassett) comb. nov. is redescribed and Amphibolips malinche Nieves-Aldrey Maldonado is proposed as a new synonym of A. hidalgoensis Pujade-Villar Melika. The validity of A. dampfi is discussed. Diagnostic characters, distribution, host-plant relationships, and biology are provided. Also new diagnostic characters and new distribution data for earlier described species are given. Keys to adults and galls for all known "nassa" complex species from Mexico and Central America are presented.

Synergus Hartig species group (Hymenoptera: Cynipidae: Synergini) with partially smooth mesopleurae from the New World.

Inquiline oak gall wasps from the genus Synergus Hartig (Hymenoptera: Cynipidae: Synergini) that occur in the New World should be classified into the following morphological groups: i) species with the radial cell of fore wings open; ii) species with the radial cell of fore wings closed and mesopleurae completely sculptured, always with transversal striae covering its surface; iii) species with the radial cell of fore wings closed and mesopleurae partially smooth, with the speculum always shiny and not sculptured. The latter group, which appears to be unique to the New World's fauna, is the focus of this study. An exhaustive taxonomical revision of all the Synergus species within this morphological group is carried out for the first time after the initial treatment by Lobato-Vila Pujade-Villar (2017). Redescriptions, images and new distribution and biological data are provided. A new species from Mexico, Synergus aurofacies Lobato-Vila Pujade-Villar, sp. nov., is here formally described and illustrated. Synergus variegatus McCracken Egbert, 1922 is a junior synonym of S. flavens McCracken Egbert, 1922 syn. nov.; S. profusus McCracken Egbert, 1922 is a junior synonym of S. pacificus McCracken Egbert, 1922 syn. nov.; and S. flavus Kieffer, 1904 and S. varicolor Fullaway, 1911 are junior synonyms of S. pomiformis (Ashmead, 1885) syn. nov. A key to species of this group is provided. The morphological traits of the species with partially smooth mesopleurae are discussed.

A New Genus of Oak Gall Wasp, Striatoandricus Pujade-Villar (Hymenoptera: Cynipidae: Cynipini) from America with Descriptions of Two New Mexican Species.

A new genus of cynipid oak gall wasp, Striatoandricus Pujade-Villar (Hymenoptera: Cynipidae: Cynipini), is described. Striatoandricus gen. nov. includes four previously described species, Andricus nievesaldreyi n. comb., A. georgei n. comb., A. maesi n. comb., and A. barriosi n. comb., which induce pubescent leaves or twig galls on Quercus belonging to Quercus section. Two new species from México are also described: S. cuixarti Pujade-Villar n. sp. and S. sanchezi Pujade-Villar n. sp. in Quercus section. Descriptions of the genus and diagnostic characters, including DNA sequence data, are presented. This new genus is supported by both morphological and molecular data.

Selective Enhancement of Object Representations through Multisensory Integration.

Objects are the fundamental building blocks of how we create a representation of the external world. One major distinction among objects is between those that are animate versus those that are inanimate. In addition, many objects are specified by more than a single sense, yet the nature by which multisensory objects are represented by the brain remains poorly understood. Using representational similarity analysis of male and female human EEG signals, we show enhanced encoding of audiovisual objects when compared with their corresponding visual and auditory objects. Surprisingly, we discovered that the often-found processing advantages for animate objects were not evident under multisensory conditions. This was due to a greater neural enhancement of inanimate objects-which are more weakly encoded under unisensory conditions. Further analysis showed that the selective enhancement of inanimate audiovisual objects corresponded with an increase in shared representations across brain areas, suggesting that the enhancement was mediated by multisensory integration. Moreover, a distance-to-bound analysis provided critical links between neural findings and behavior. Improvements in neural decoding at the individual exemplar level for audiovisual inanimate objects predicted reaction time differences between multisensory and unisensory presentations during a Go/No-Go animate categorization task. Links between neural activity and behavioral measures were most evident at intervals of 100-200 ms and 350-500 ms after stimulus presentation, corresponding to time periods associated with sensory evidence accumulation and decision-making, respectively. Collectively, these findings provide key insights into a fundamental process the brain uses to maximize the information it captures across sensory systems to perform object recognition.SIGNIFICANCE STATEMENT Our world is filled with ever-changing sensory information that we are able to seamlessly transform into a coherent and meaningful perceptual experience. We accomplish this feat by combining different stimulus features into objects. However, despite the fact that these features span multiple senses, little is known about how the brain combines the various forms of sensory information into object representations. Here, we used EEG and machine learning to study how the brain processes auditory, visual, and audiovisual objects. Surprisingly, we found that nonliving (i.e., inanimate) objects, which are more difficult to process with one sense alone, benefited the most from engaging multiple senses.

Biology and Life Stages of Pine Spittle Bug Ocoaxo assimilis Walker (Hemiptera: Cercopidae).

The first records of outbreaks of the Pine Spittle bug Ocoaxo assimilis Walker were recently identified from Puebla, Mexico, which promoted more than 2600 ha of forest foliar fall. Beyond the taxonomic and distribution information of this species, the basic traits of its biology remain unknown. This study aims to describe some biological aspects of O. assimilis, in a natural pine forest at Nicolás Bravo, Puebla (NB). Using morphological characteristics and a phylogenetic analysis of a fragment of cytochrome oxidase subunit I mtDNA (COI), immature instars with adults were studied; the instar number was determined by means of a multivariate analysis of 19 morphological characteristics of 121 specimens. The systematic sampling to evaluate the occurrence of nymphal specimens during a year, plus host selection experiments, allowed for determination of the abundance over time, voltism, and host preferences. Phylogenetic analysis of the COI supported that both nymphs and adults collected in NB correspond to O. assimilis. Principal coordinate analysis supported the existence of five nymphal stages. Field sampling and host selection experiments indicated that this species displays a single generation per year, is associated with the rainy season, and that specimens from the three first nymphal stages feed on roots of eight host species (one grass, four herbaceous species, one bush, and two trees). From the fourth instar, the insects feed on pine roots to complete their development, and when they are adults, they migrate to needles of young or mature pine stands of Pinus pseudostrobus to feed and reproduce.

Novel procedure for generating continuous flash suppression: Seurat meets Mondrian.

Continuous flash suppression (CFS) entails presentation of a stationary target to one eye and an animated sequence of arrays of geometric figures, the mask, to the other eye. The prototypical CFS sequence comprises different sized rectangles of various colors, dubbed Mondrians. Presented as a rapid, changing sequence to one eye, Mondrians or other similarly constructed textured arrays can abolish awareness of the target viewed by the other eye for many seconds at a time, producing target suppression durations much longer than those associated with conventional binocular rivalry. We have devised an animation technique that replaces meaningless Mondrian figures with recognizable visual objects and scenes as inducers of CFS, allowing explicit manipulation of the visual semantic content of those masks. By converting each image of these CFS sequences into successively presented objects or scenes each comprised of many small, circular patches of color, we create pointillist CFS sequences closely matched in terms of their spatio-temporal power spectra. Randomly rearranging the positions of the pointillist patches scrambles the images so they are no longer recognizable. CFS sequences comprising a stream of different objects produces more robust interocular suppression than do sequences comprising a stream of different scenes, even when the two categories of CFS are matched in root mean square contrast and spatial frequency content. Factors promoting these differences in CFS potency could range from low-level, image-based features to high-level factors including attention and recognizability. At the same time, object- and scene-based CFS sequences, when themselves suppressed from awareness, do not differ in their durations of suppression, implying that semantic content of those images comprising CFS sequences are not registered during suppression. The pointillist technique itself offers a potentially useful means for examining the impact of high-level image meaning on aspects of visual perception other than interocular suppression.

Primera descripción de Sclerotium coffeicola en caoba africana en México / First description of Sclerotium coffeicola on African mahogany in Mexico

Una enfermedad foliar fue detectada en la plantación comercial de Khaya senegalensis con 3 anos de edad, en la localidad de Huimanguillo (Tabasco, México). Mediante la caracterización morfológica y molecular, y por el cumplimiento de los postulados de Koch, se determinó que el agente causal corresponde al hongo Sclerotium coffeicola. Este es el primer reporte de S. coffeicola causando mancha foliar en caoba africana en México.

A foliar disease was detected in the commercial plantation of Khaya senegalen with three years of age in Huimanguillo, Tabasco, Mexico. Through the morphological and molecular characterization and the compliance of the Koch's postulates, it was concluded that the causal agent corresponds to the fungus Sclerotium coffeicola. This is the first report of S. coffeicola causing leaf spot on African mahogany in Mexico.

[First description of Sclerotium coffeicola on African mahogany in Mexico]. / Primera descripción de Sclerotium coffeicola en caoba africana en México.

A foliar disease was detected in the commercial plantation of Khaya senegalensis with three years of age in Huimanguillo, Tabasco, Mexico. Through the morphological and molecular characterization and the compliance of the Koch's postulates, it was concluded that the causal agent corresponds to the fungus Sclerotium coffeicola. This is the first report of S. coffeicola causing leaf spot on African mahogany in Mexico.

A Rotational Cylindrical fMRI Phantom for Image Quality Control.

PURPOSE: A novel phantom for image quality testing for functional magnetic resonance imaging (fMRI) scans is described. METHODS: The cylindrical, rotatable, ~4.5L phantom, with eight wedge-shaped compartments, is used to simulate rest and activated states. The compartments contain NiCl2 doped agar gel with alternating concentrations of agar (1.4%, 1.6%) to produce T1 and T2 values approximating brain grey matter. The Jacard index was used to compare the image distortions for echo planar imaging (EPI) and gradient recalled echo (GRE) scans. Contrast to noise ratio (CNR) was compared across the imaging volume for GRE and EPI. RESULTS: The mean T2 for the two agar concentrations were found to be 106.5±4.8, 94.5±4.7 ms, and T1 of 1500±40 and 1485±30 ms, respectively. The Jacard index for GRE was generally found to be higher than for EPI (0.95 versus 0.8). The CNR varied from 20 to 50 across the slices and echo times used for EPI scans, and from 20 to 40 across the slices for the GRE scans. The phantom provided a reproducible CNR over 25 days. CONCLUSIONS: The phantom provides a quantifiable signal change over a head-size imaging volume with EPI and GRE sequences, which was used for image quality assessment.

Emerging Object Representations in the Visual System Predict Reaction Times for Categorization.

Recognizing an object takes just a fraction of a second, less than the blink of an eye. Applying multivariate pattern analysis, or "brain decoding", methods to magnetoencephalography (MEG) data has allowed researchers to characterize, in high temporal resolution, the emerging representation of object categories that underlie our capacity for rapid recognition. Shortly after stimulus onset, object exemplars cluster by category in a high-dimensional activation space in the brain. In this emerging activation space, the decodability of exemplar category varies over time, reflecting the brain's transformation of visual inputs into coherent category representations. How do these emerging representations relate to categorization behavior? Recently it has been proposed that the distance of an exemplar representation from a categorical boundary in an activation space is critical for perceptual decision-making, and that reaction times should therefore correlate with distance from the boundary. The predictions of this distance hypothesis have been born out in human inferior temporal cortex (IT), an area of the brain crucial for the representation of object categories. When viewed in the context of a time varying neural signal, the optimal time to "read out" category information is when category representations in the brain are most decodable. Here, we show that the distance from a decision boundary through activation space, as measured using MEG decoding methods, correlates with reaction times for visual categorization during the period of peak decodability. Our results suggest that the brain begins to read out information about exemplar category at the optimal time for use in choice behaviour, and support the hypothesis that the structure of the representation for objects in the visual system is partially constitutive of the decision process in recognition.

Representational dynamics of object vision: the first 1000 ms.

Human object recognition is remarkably efficient. In recent years, significant advancements have been made in our understanding of how the brain represents visual objects and organizes them into categories. Recent studies using pattern analyses methods have characterized a representational space of objects in human and primate inferior temporal cortex in which object exemplars are discriminable and cluster according to category (e.g., faces and bodies). In the present study we examined how category structure in object representations emerges in the first 1000 ms of visual processing. In the study, participants viewed 24 object exemplars with a planned categorical structure comprised of four levels ranging from highly specific (individual exemplars) to highly abstract (animate vs. inanimate), while their brain activity was recorded with magnetoencephalography (MEG). We used a sliding time window decoding approach to decode the exemplar and the exemplar's category that participants were viewing on a moment-to-moment basis. We found exemplar and category membership could be decoded from the neuromagnetic recordings shortly after stimulus onset (<100 ms) with peak decodability following thereafter. Latencies for peak decodability varied systematically with the level of category abstraction with more abstract categories emerging later, indicating that the brain hierarchically constructs category representations. In addition, we examined the stationarity of patterns of activity in the brain that encode object category information and show these patterns vary over time, suggesting the brain might use flexible time varying codes to represent visual object categories.

Contribución al conocimiento etnomicológico de los hongos comestibles silvestres de mercados regionales y comunidades de la Sierra Nevada (México) / Contribution to ethnomycological knowledge of wild edible mushrooms from regional markets and communities of Sierra Nevada (Mexico)

En el presente trabajo se estudiaron 67 especies de hongos comestibles silvestres, 65 de ellas comercializadas en cuatro mercados regionales y varias en comunidades rurales, todas en la región de la Sierra Nevada, ubicada ésta en parte de las entidades del Estado de México, Puebla y Tlaxcala, al E y NE de la Ciudad de México. Se determinó el valor diferencial de importancia etnomicológica de las especies identificadas, por medio de la medición del valor de venta, así como de la presencia y la temporalidad de los hongos en los mercados, a lo largo de un año, en 1998. Se registró la preferencia de los hongos comestibles en una encuesta en 10 comunidades de la región, durante 1999. De los hongos considerados, Hebeloma fastibile fue la especie con mayor valor de importancia etnomicológica en los mercados y Lyophyllum decastes en las comunidades.

In this study, 67 species of wild edible mushrooms were studied, 65 of them were sold in four regional markets and some of them in communities, all on the Sierra Nevada found in the states of Mexico, Puebla, and Tlaxcala, at E and NE of Mexico City. The differential value of ethnomycological importance of the identified species was determined in terms of selling price as well as the presence and seasonality of the mushrooms, throughout one year, in 1998. Also, preference for the edible mushrooms mentioned was recorded through a survey of 10 communities in this region, during 1999. Of the mushrooms identified, Hebeloma fastibile was the species of highest value in terms of ethnomycological importance in the markets and Lyophyllum decastes was in the communities.

Contribuição ao conhecimento etnomicológico dos cogumelos comestiveis silvestres de mercados regionais e comunidades da Serra Nevada (México).

No presente trabalho se estudaram 67 espécies de cogumelos comestíveis silvestres, 65 delas comercializadas em quatro mercados regionais e varias em comunidades rurais, todas na região da Serra Nevada, situada esta em parte das entidades do Estado de México, Puebla e Tlaxcala, al E e NE da Cidade do México. Determinou-se o valor diferencial de importância etnomicológica das espécies identificadas, por meio da medição do valor de venda, assim como da presença e a temporalidade dos cogumelos nos mercados, ao longo de um ano, em 1998. Registrou-se a preferência dos cogumelos comestíveis em uma encosta em 10 comunidades da região, durante 1999. Dos cogumelos considerados, Hebeloma fastibile foi a espécie com maior valor de importância etnomicológica nos mercados e Lyophyllum decastes nas comunidades.