Wild plants eaten in childhood: a retrospective of Estonia in the 1970s–1990s

In this ethnobotanical study, the authors provide the first quantitative analysis of the use of wild edible plants in Estonia, describing the domains and assessing the food importance of different species. The information was collected using free‐listing written questionnaires and concerned plants used by the respondents in their childhood. As part of a major study, this article covers the responses of professionals with some botanical education at vocational or university level, to ensure the greatest possible reliability without using voucher specimens. Fifty‐eight respondents provided information on the use of 137 plant taxa, corresponding to approximately 6% of the native and naturalized vascular plants of Estonia. According to use frequency, the most typical wild food plant of Estonia is a fruit, eaten raw as a snack. The results clearly signal that the majority of famine and food shortage plants had already been forgotten by the end of the 20^th century, but new plants have been introduced as green vegetables for making salads. Despite changes in the nomenclature of the plants, the use of wild food plants in Estonia was still thriving at the turn of the 20^th century, covering many domains already forgotten in urbanized modern Europe. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172 , 239–253.     

Between an ugly truth and a perfect lie: Wiping off fearful memories using beta-adrenergic receptors antagonists

Psychiatric disorders such as anxiety, phobias, and post-traumatic stress disorder are considered of high global prevalence. Currently, a therapeutic approach to treat these disorders using beta-blockers, which antagonize the beta-adrenergic receptors (B1, B2, and B3) is being studied. This approach claims that beta-blockers, such as propranolol, inhibit fear memory reconsolidation. However, there are several studies refuting such claims by discrediting their experimental design and pointing out both the drugs pharmacokinetic properties and confounding factors. In this review, we explore the different effects of central beta-adrenergic agonists and antagonists on the fear memory consolidation providing mixed-evidence, limitations, and future directions.     

On the resilience of remote traumatic memories against exposure therapy‐mediated attenuation

How to attenuate traumatic memories has long been the focus of intensive research efforts, as traumatic memories are extremely persistent and heavily impinge on the quality of life. Despite the fact that traumatic memories are often not readily amenable to immediate intervention, surprisingly few studies have investigated treatment options for remote traumata in animal models. The few that have unanimously concluded that exposure therapy‐based approaches, the most successful behavioral intervention for the attenuation of recent forms of traumata in humans, fail to effectively reduce remote fear memories. Here, we provide an overview of these animal studies with an emphasis on why remote traumatic memories might be refractory to behavioral interventions: A lack of neuroplasticity in brain areas relevant for learning and memory emerges as a common denominator of such resilience. We then outline the findings of a recent study in mice showing that by combining exposure therapy‐like approaches with small molecule inhibitors of histone deacetylases (HDACis), even remote memories can be persistently attenuated. This pharmacological intervention reinstated neuroplasticity to levels comparable to those found upon successful attenuation of recent memories. Thus, HDACis—or any other agent capable of heightening neuroplasticity—in conjunction with exposure therapy‐based treatments might constitute a promising approach to overcome remote traumata.     

Desert ant navigation: how miniature brains solve complex tasks

This essay presents and discusses the state of the art in studies of desert ant (Cataglyphis) navigation. In dealing with behavioural performances, neural mechanisms, and ecological functions these studies ultimately aim at an evolutionary understanding of the insect's navigational toolkit: its skylight (polarization) compass, its path integrator, its view-dependent ways of recognizing places and following landmark routes, and its strategies of flexibly interlinking these modes of navigation to generate amazingly rich behavioural outputs. The general message is that Cataglyphis uses path integration as an egocentric guideline to acquire continually updated spatial information about places and routes. Hence, it relies on procedural knowledge, and largely context-dependent retrieval of such knowledge, rather than on all-embracing geocentred representations of space.This revised version was published online in July 2003 with corrections to the text of the sections "Skylight compass" and "Path integration".     

Homing in the field cricket,Gryllus campestris

Homing ability of the cricket Gryllus campestriswas experimentally studied in the field after passive and active displacements. Whatever the weather conditions and the nature of the displacement, crickets (18/18) home directly when they are located between 5 and 15 cm from their burrow by performing real-time orientation. When moved by the experimenter between 15 and 55 cm away from home, some crickets (26/43) can retrieve their burrow by systematic searching only after winding inward trips but they get lost (0/18) beyond 55 cm. After self-generated movements between 5 and 85 cm away from home, crickets (33/35) return to their burrow under blue sky, but they cannot home as well under overcast sky (22/34 from 5 to 65 cm and 0/5 beyond). The volatile memory orientation system allowing path integration is based on the polarized skylight of the sun.     

Modeling spatial–temporal operations with context-dependent associative memories

We organize our behavior and store structured information with many procedures that require the coding of spatial and temporal order in specific neural modules. In the simplest cases, spatial and temporal relations are condensed in prepositions like “below” and “above”, “behind” and “in front of”, or “before” and “after”, etc. Neural operators lie beneath these words, sharing some similarities with logical gates that compute spatial and temporal asymmetric relations. We show how these operators can be modeled by means of neural matrix memories acting on Kronecker tensor products of vectors. The complexity of these memories is further enhanced by their ability to store episodes unfolding in space and time. How does the brain scale up from the raw plasticity of contingent episodic memories to the apparent stable connectivity of large neural networks? We clarify this transition by analyzing a model that flexibly codes episodic spatial and temporal structures into contextual markers capable of linking different memory modules.     

A Genetic Algorithm with Conformational Memories for Structure Prediction of Polypeptides

Abstract

We have developed an iterative hybrid algorithm (HA) to predict the 3D structure of peptides starting from their amino acid sequence. The HA is made of a modified genetic algorithm (GA) coupled to a local optimizer. Each HA iteration is carried out in two phases. In the first phase several GA runs are performed upon the entire peptide conformational space. In the second phase we used the manifestation of what we have called conformational memories, that arises at the end of the first phase, as a way of reducing the peptide conformational space in subsequent HA iterations. Use of conformational memories speeds up and refines the localization of the structure at the putative Global Energy Minimum (GEM) since conformational barriers are avoided. The algorithm has been used to predict successfully the putative GEM for Met- and Leu-enkephalin, and to obtain useful information regarding the 3D structure for the 8mer of polyglycine and the 16 residue (AAQAA)₃Y peptide. The number of fitness function evaluations needed to locate the putative GEMs are fewer than those reported for other heuristic methods. This study opens the possibility of using Genetic Algorithms in high level predictions of secondary structure of polypeptides.     

药物成瘾记忆的神经生物机制及临床干预方法

药物成瘾者戒断后的持久复吸是治疗药物成瘾的难点.成瘾者出现持续复吸的重要原因是由于成瘾记忆的长期存在.成瘾物质的长期反复使用导致前额叶-边缘多巴胺系统结构和功能的适应性改变,这种改变是成瘾记忆形成的神经基础.本文从学习记忆的角度来理解成瘾形成,介绍了成瘾记忆的初始形成阶段、习惯化阶段和成瘾行为维持阶段及其相应的神经基础.回顾了近年来成瘾记忆的临床干预方法,包括消退干预方法、增强消退干预的多情境干预方法,以及直接干预消除成瘾记忆的记忆再巩固干预方法,并总结了虚拟现实、神经调控技术在成瘾记忆干预中的应用.对记忆再巩固干预方法与虚拟现实、神经调控技术相结合干预成瘾记忆进行展望,为药物成瘾的临床干预和治疗提供了新方法、新思路.     

Reduced order multiport parallel and multidirectional neural associative memories

This paper proposes multiport parallel and multidirectional intraconnected associative memories of outer product type with reduced interconnections. Some new reduced order memory architectures such as k-directional and k-port parallel memories are suggested. These architectures are, also, very suitable for implementation of spatio-temporal sequences and multiassociative memories. It is shown that in the proposed memory architectures, a substational reduction in interconnections is achieved if the actual length of original N-bit long vectors is subdivided into k sublengths. Using these sublengths, submemory matrices, T _s or W _s , are computed, which are then intraconnected to form k-port parallel or k-directional memories. The subdivisions of N-bit long vectors into k sublengths save of interconnections. It is shown, by means of an example, that more than 80% reduction in interconnections is achieved. Minimum limit in bits on k as well as maximum limit on subdivisions in k is determined. The topologies of reduced interconnectivity developed in this paper are symmetric in structure and can be used to scale up to larger systems. The underlying principal of construction, storage and retrieval processes of such associative memories has been analyzed. The effect of complexity of different levels of reduced interconnectivity on the quality of retrieval, signal to noise ratio, and storage capacity has been investigated. The model possesses analogies to biological neural structures and digital parallel port memories commonly used in parallel and multiprocessing systems.