The role of schools as an opportunity for transmission of local knowledge about useful Restinga plants: experiences in southeastern Brazil

Background The study of cultural transmission can help identify processes that influence knowledge systems dynamics and evolution, especially during childhood and youth, which are fundamental phases in acquiring survival skills. In this sense, we use the knowledge about useful restinga plants (Brazilian coastal vegetation) as an analytical model to describe, compare, and analyze cultural transmission during youth, while factoring in origin, in the Cabo Frio region, southeastern Brazil. We tested (1) whether transmission of knowledge is conservative, (2) whether immigration events define the transmission modes, (3) whether teaching is the most important social transmission cognitive process, and (4) which type of stimulus/context is most important for the knowledge transmission process. Methods Questionnaires and free listings were applied to 150 high school students aged between 15 and 20 to obtain information about socioeconomic characteristics, useful plant knowledge, and cultural transmission. We analyzed the distribution of knowledge according to the informant’s origin and evaluated the models, processes, and context with which this information was transmitted. The chi-square test was used to determine the association between origin, plant knowledge, and transmission as well as to reveal the most important models, modes, and processes during youth. Results Informants provided 299 plant citations ($$ \overline{x} $$ x ¯ = 1.75; s = 1.73) related to 37 species. The categories of the most cited uses were edible (93) and medicinal (32). Statistical results showed that origin did not influence knowledge distribution and transmission. In addition, although the most relevant mode was the conservative (vertical) one, the one-to-many diffuse mode (teacher) was highlighted. The new environmental context for immigrants did not influence transmission, the main transmission process was teaching, and the learning contexts were predominantly school-related. Conclusion Plant knowledge in youth was related to local edible and medicinal plants, indicating adaptive knowledge linked to material demands for survival. While the initial models for cultural transmission are family (vertical), during the development phase of juveniles, other actors become models (one-to-many). In addition, the nature of the information (survival demand) and age are more relevant to cultural transmission than the socio-environmental context.

Adaptive Behavior and the Role of Primary Somatosensory Cortex

ABSTRACTBehavioral experience and flexibility are crucial for survival in a constantly changing environment. What are the neuronal processes that selectively transform dynamic sensory information into an appropriate behavioral response, and how do these processes adapt to changes in the environment? Here, we use voltage imaging to measure signals in primary somatosensory cortex (S1) during sensory learning and behavioral adaptation in the mouse. We found that in response to changing sensory stimulus statistics, mice adopt a task strategy that modifies their detection behavior in a context dependent manner as to maintain reward expectation. Correspondingly, neuronal activity in S1 shifts from simply representing stimulus properties to adaptively representing stimulus context in an experience dependent manner. Our results suggest that neuronal signals in S1 are part of an adaptive and dynamic framework that facilitates flexible behavior as an individual gains experience.

Cortical subnetworks encode context of visual stimulus

Cortical processing of sensory events is significantly influenced by context. For instance, a repetitive or redundant visual stimulus elicits attenuated cortical responses, but if the same stimulus is unexpected or “deviant”, responses are augmented. This contextual modulation of sensory processing is likely a fundamental function of neural circuits, yet an understanding of how it is computed is still missing. Using holographic two-photon calcium imaging in awake animals, here we identify three distinct, spatially intermixed ensembles of neurons in mouse primary visual cortex which differentially respond to the same stimulus under separate contexts, including a subnetwork which selectively responds to deviant events. These non-overlapping ensembles are distributed across layers 2-5, though deviance detection is more common in superficial layers. Contextual preferences likely arise locally since they are not present in bottom up inputs from the thalamus or top-down inputs from prefrontal cortex. The functional parcellation of cortical circuits into independent ensembles that encode stimulus context provides a circuit basis underlying cortically based perception of novel or redundant stimuli, a key deficit in many psychiatric disorders.One Sentence SummaryVisual cortex represents deviant and redundant stimuli with separate subnetworks.

Distributed plasticity drives visual habituation learning in larval zebrafish

Habituation is a simple form of learning, where animals learn to reduce their responses to repeated innocuous stimuli. While habituation is simple in concept, its exact implementation in the vertebrate brain is not clear. It could occur via a single plasticity event at a singular site in the circuit, or alternatively via more complex strategies that combine multiple mechanisms at various processing stages and sites. Here, we use a visual habituation assay in larval zebrafish, where larvae habituate to sudden reductions in illumination (dark flashes). We find that 8 different components of this response habituate, including the probability of executing a response, its latency, and measures of its magnitude. Through behavioural analyses, we find that habituation of these different behavioural components occurs independently of each other and at different locations in the circuit. Further, we use genetic and pharmacological manipulations to show that habituation of different behavioural components are molecularly distinct. These results are consistent with a model by which visual habituation originates from the combination of multiple independent processes, which each act to adapt specific components of behaviour. This may allow animals to more specifically habituate behaviour based on stimulus context or internal state.

Natural echolocation sequences evoke echo-delay selectivity in the auditory midbrain of the FM bat, Eptesicus fuscus

Echolocating bats must process temporal streams of sonar sounds to represent objects along the range axis. Neuronal echo-delay tuning, the putative mechanism of sonar ranging, has been characterized in the inferior colliculus (IC) of the mustached bat, an insectivorous species that produces echolocation calls consisting of constant frequency and frequency modulated (FM) components, but not in species that use FM signals alone. This raises questions about the mechanisms that give rise to echo-delay tuning in insectivorous bats that use different signal designs. To investigate whether stimulus context may account for species differences in echo-delay selectivity, we characterized single-unit responses in the IC of awake passively listening FM bats, Eptesicus fuscus, to broadcasts of natural sonar call-echo sequences, which contained dynamic changes in signal duration, interval, spectrotemporal structure, and echo-delay. In E. fuscus, neural selectivity to call-echo delay emerges in a population of IC neurons when stimulated with call-echo pairs presented at intervals mimicking those in a natural sonar sequence. To determine whether echo-delay selectivity also depends on the spectrotemporal features of individual sounds within natural sonar sequences, we studied responses to computer-generated echolocation signals that controlled for call interval, duration, bandwidth, sweep rate, and echo-delay. A subpopulation of IC neurons responded selectively to the combination of the spectrotemporal structure of natural call-echo pairs and their temporal patterning within a dynamic sonar sequence. These new findings suggest that the FM bat’s fine control over biosonar signal parameters may modulate IC neuronal selectivity to the dimension of echo-delay. NEW & NOTEWORTHY Echolocating bats perform precise auditory temporal computations to estimate their distance to objects. Here, we report that response selectivity of neurons in the inferior colliculus of a frequency modulated bat to call-echo delay, or target range tuning, depends on the temporal patterning and spectrotemporal features of sound elements in a natural echolocation sequence. We suggest that echo responses to objects at different distances are gated by the bat’s active control over the spectrotemporal patterning of its sonar emissions.

Auditory Mismatch Negativity and P300a Elicited by the “Optimal” Multi-feature Paradigm in Early Schizophrenia

The mismatch negativity (MMN) is an EEG-derived event-related potential (ERP) elicited by any violation of a predicted auditory “rule,” regardless of whether one is attending to the stimuli and is thought to reflect updating of the stimulus context. Redirection of attention toward a rare, distracting stimulus event, however, can be measured by the subsequent P3a component of the P300. Chronic schizophrenia patients exhibit robust MMN deficits, as well as reductions in P3a amplitude. While, the substantial literature on the MMN in first-episode and early phase schizophrenia in this population reports reduced amplitudes, there also exist several contradictory studies. Conversely, P3a reduction in this population is relatively consistent, although the literature investigating this is small. The primary goal of this study was to contribute to our understanding of whether auditory change detection mechanisms are altered in early phase schizophrenia and, if so, under what conditions. Event-related potentials elicited by duration, frequency, gap, intensity, and location deviants (as elicited by the “optimal” multi-feature paradigm) were recorded in 14 early phase schizophrenia (EP) patients and 17 healthy controls (HCs). Electrical activity was recorded from 15 scalp electrodes. MMN/P3a amplitudes and latencies for each deviant were compared between groups and were correlated with clinical measures in EPs. There were no significant group differences for MMN amplitudes or latencies, though EPs did exhibit reduced P3a amplitudes to gap and duration deviants. Furthermore, PANSS (Positive and Negative Syndrome Scale) positive symptom scores were correlated with intensity MMN latencies and duration P3a amplitudes in EPs. These findings suggest that MMNs may not be as robustly reduced in early phase schizophrenia (relative to chronic illness), but that alterations may be more likely in patients with increased positive symptomatology. Furthermore, these findings offer further support to previous work suggesting that the understudied P3a may have good complementary utility as a marker of early cortical dysfunction in psychosis.

A unifying motif for spatial and directional surround suppression

In the visual system, the response to a stimulus in a neuron’s receptive field can be modulated by stimulus context, and the strength of these contextual influences vary with stimulus intensity. Recent work has shown how a theoretical model, the stabilized supralinear network (SSN), can account for such modulatory influences, using a small set of computational mechanisms. While the predictions of the SSN have been confirmed in primary visual cortex (V1), its computational principles apply with equal validity to any cortical structure. We have therefore tested the generality of the SSN by examining modulatory influences in the middle temporal area (MT) of the macaque visual cortex, using electrophysiological recordings and pharmacological manipulations. We developed a novel stimulus that can be adjusted parametrically to be larger or smaller in the space of all possible motion directions. We found, as predicted by the SSN, that MT neurons integrate across motion directions for low-contrast stimuli, but that they exhibit suppression by the same stimuli when they are high in contrast. These results are analogous to those found in visual cortex when stimulus size is varied in the space domain. We further tested the mechanisms of inhibition using pharmacologically manipulations of inhibitory efficacy. As predicted by the SSN, local manipulation of inhibitory strength altered firing rates, but did not change the strength of surround suppression. These results are consistent with the idea that the SSN can account for modulatory influences along different stimulus dimensions and in different cortical areas.Significance StatementVisual neurons are selective for specific stimulus features in a region of visual space known as the receptive field, but can be modulated by stimuli outside of the receptive field. The SSN model has been proposed to account for these and other modulatory influences, and tested in V1. As this model is not specific to any particular stimulus feature or brain region, we wondered whether similar modulatory influences might be observed for other stimulus dimensions and other regions. We tested for specific patterns of modulatory influences in the domain of motion direction, using electrophysiological recordings from MT. Our data confirm the predictions of the SSN in MT, suggesting that the SSN computations might be a generic feature of sensory cortex.

School Partnerships

This chapter examines how schools that establish rich and sustaining partnerships with local communities enhance opportunities for urban environmental education. It considers “socioecological refrains” that incorporate stewardship, pedagogy, interrelationships, and heritage and highlight the role played by schools in shaping sustainable cities through urban environmental education. These refrains promote a connectedness to place through the use of the local environment to stimulate learning, the development of curricula and pedagogies that embrace the development of sustainable cities, and the establishment of links with the community to foster relationships, stewardship, and resiliency. Case studies from Canada, Australia, China, and Spain are presented to illustrate these refrains and to show initiatives at work such as green schools. The chapter demonstrates that urban schools can use local environments to serve as stimulus, context, and content for teaching and learning about sustainability.