Food-attraction conditioning in the snail,Helix pomatia

Adult pulmonate snails (Helix pomatia) were released equidistant between two types of food, carrot and potato, respectively. Naive snails moved in different directions and did not locate either food above chance, although both foods were readily eaten upon direct contact. After a single carrot feeding episode, 75% of the carrot-fed snails moved directly towards the carrot and ate it. Conversely, potato-fed snails located the potato in 67% of the cases. Snails that were fed apple or lettuce behaved like naive animals, with the majority of animals (75% in both cases) locating neither the carrot nor the potato.The ability of snails to locate this particular food after a single feeding episode was maintained for at least 11 days, provided that the snails were not exposed to other foods in the interim. If the animals were fed a different food (but still tested for food-finding ability to the initially conditioned food) their orientation preference decreased gradually over a period of 5 days.Although the snails' orientation is based upon olfactory cues, exposure to food odor alone is not sufficient to enable food-finding; additional feeding related stimuli are necessary.These findings indicate that Helix do not possess a predisposition for the foods tested, and further suggest that processes underlying food-finding and food selection are strongly influenced by learning experiences. The conditioning phenomenon underlying food-finding behavior has been called Food-Attraction Conditioning, and appears to be a crucial link between the ecologies of learning and foraging behaviors. The accessibility of the snail's nervous system should permit neuronal analysis of the mechanisms underlying such a unique and complex learning phenomenon.     

β-Endorphin like immunoreactivity of brain,pituitary gland and plasma of rats submitted to postnatal protein malnutrition: Effect of behavioral training

Wistar-derived rats were raised and maintained either on a normal- (25% casein) or on a low-protein (8% casein) diet until the age of 100 to 114 days. Both diets were isocaloric and contained an adequate supply of salts and vitamins. There were gross differences in body, brain and pituitary weight between the two groups. In addition, the brain and pituitary content of β-endorphin like immunoreactivity was lower in the protein malnourished rats, and three different forms of training (50 tone-footshock shuttle avoidance trials; 50 tones alone (habituation); 50 footshocks alone) caused a depletion of brain β-endorphin like immunoreactivity in the normal, but not in the malnourished rats. Footshock stimulation caused, in addition, a pituitary decrease and a plasma increase of β-endorphin like immunoreactivity, also restricted to the normal diet group. Performance in the habituation and in the shuttle avoidance tasks was similar in the two groups, despite the different responsiveness of their brain and pituitary β-endorphin systems to training and/or stimulation. In view of the possible involvement of these systems in learning suggested by these and by previous data, it seems likely that the neurohumoral regulation of habituation and avoidance learning may be different in rats submitted to protein malnutrition when compared to controls.     

Die Anwendung einer ‘deduktiven Methode syntaxonomischer Klassifikation’ bei der Bearbeitung der strassenbegleitenden Pflanzengesellschaften Nordostböhmens

Zusammenfassung In der vorgelegten Arbeit wurde die sogenante deduktive Klassifikationsmethode der anthropogenen Pflanzengesellschaften behandelt. Diese Methode geht vom System der höheren Vegetationseinheiten der Braun-Blanquet Schule aus. Sie ermöglicht die syntaxonomische Bearbeitung zahlreicher anthropogener Gesellschaften unserer Kulturlandschaft, die nur aus Arten mit breiterer ökologischer und zönologischer Amplitude zusammengesetzt sind, und zwar ohne unerwünschte Verwechslung der Bestimmungsmerkmale einzelner Rangstufen des Systems (Klassen-, Ordnungs-, Verbands- und Assoziationskenn-und trennarten). Die Grundprinzipien der Methode wurden schon früher von Kopecký & Hejný (1971, 1973, 1974) und Kopecký (1976) erläutert. Die vorliegende Arbeit bringt eine präzisierte Auslegung der Methode auf Grund neuer Erfahrungen, die bei der Bearbeitung der spontan entstandenen strassenbegleitenden Gesellschaften derMolinio-Arrhenatheretea Tx. 1937 in Nordostböhmen gewonnen wurden. Aus dem reichen Aufnahmematerial werden nur einige Aufnahmen der Basalgesellschaften mitAlopecurus pratensis und der von ihnen abgeleiteten Derivatgesellschaften mitDactylis glomerata undAgropyron repens fur die anschauliche Demonstration der Methode beigegeben (Tab. 1 und 2). Die Aufnahmen der übrigen Gesellschafts-typen werden in einer anderen Arbeit (Kopecký 1978) veröffentlicht.

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Summary Use of a so-called deductive method in syntaxonomic classification of roadside plant communities in NE Bohemia.The present paper explains the so-called deductive method of syntaxonomic classification of plant communities, derived from the system of syntaxa of higher rank of the Braun-Blanquet approach. This method enables the synthesis of vegetations units of the varied anthropogenic plant communities in the man-made landscape, and their arrangement within the existing system, without changing the classification and determination criteria of both the higher and lower syntaxa in this system. Basic principles of this method have been outlined earlier by Kopecký & Hejný (1971, 1973, 1974) and Kopecký (1976). Following the newly obtained data and experience, this paper brings further details and more precise explanation of the method. Recently, the deductive method has been applied to the classification of turf communities which spontaneously develop along the roads in NE Bohemia. In order to illustrate the principles of the method, selected relevés of basal communities withAlopecurus pratensis (Table 1), and respective communities derived from these basal communities (Table 2) are presented. A complete set of vegetation relevés of all other roadside communities will be published elsewhere (Kopecký 1978).

Die wissenschaftlichen Pflanzennamen sind nach Rothmaler et al. (1966) angeführt.     

Endogenous opiates: 1979

Since the discovery in 1971 of opiate receptors and later of the opiate-like peptides, there has been widespread interest in determining their exact localization, number and kinds, nature, and physiological and pharmacological functions. Between 1971 and 1978, vast amounts of research investigated these problem areas, but in 1979 alone the literature on the opiate peptides nearly doubled. This review is the second of an annual series and summarizes the highlights of the work published during 1979.     

Endogenous opiates: 1980

Vast amounts of research have been done that have attempted to delineate the pharmacological and physiological effects of the endogenous opiate peptides. A great deal of knowledge has also been accumulated in a limited time span concerning the types and locations of the opiate receptors and peptides, as well as their functions. In 1980, reports were made concerning the effects of these peptides on analgesia, on tolerance and dependence, on activity, on learning and memory, on schizophrenia and other types of emotional disturbances, and on physiological responses such as eating and drinking, cardiovascular responses, and sexual function. Additional understanding was also gained concerning their interactions with neurotransmitters, other neuropeptides, and hormones. These and other studies published only in 1980 are reviewed in this paper, which is the third of an annual series.     

Comparison of learning in related generalist and specialist eucoilid parasitoids

Effects of learning in two microhabitat specialists, Leptopilina boulardia Barbotin et al. and L. fimbriata Kieffer were compared to previous and new results of learning in the microhabitat generalist L. heterotoma Thomson. Females were given one or more oviposition experiences on hosts in different types of substrate. In all species oviposition experience affected the choice for a substrate, although this effect of learning was considerably less in L. fimbriata compared to the other two species. Patch times, known to be highly determined by experience in the generalist L. heterotoma, were much less flexible in the specialists. L. boulardi and L. fimbriata have fixed patch times on their natural substrate and have variable patch times on other substrates only. In all three species one oviposition affected the choice for a substrate. Additional ovipositions showed no different effect. An accumulative effect of the number of ovipositions on patch times was found in L. heterotoma only. Retention of the learning effect was only studied in L. boulardi, and was shown to be similar to that reported for L. heterotoma, i.e. two to three days. Although learning was found in both the generalist and the specialist species studied, it seems to affect their foraging behaviour differently.     

Identification of marker genes in Alzheimer's disease using a machine-learning model

Alzheimer''s Disease (AD) is one of the most common causes of dementia, mostly affecting the elderly population. Currently, there is no proper diagnostic tool or method available for the detection of AD. The present study used two distinct data sets of AD genes, which could be potential biomarkers in the diagnosis. The differentially expressed genes (DEGs) curated from both datasets were used for machine learning classification, tissue expression annotation and co-expression analysis. Further, CNPY3, GPR84, HIST1H2AB, HIST1H2AE, IFNAR1, LMO3, MYO18A, N4BP2L1, PML, SLC4A4, ST8SIA4, TLE1 and N4BP2L1 were identified as highly significant DEGs and exhibited co-expression with other query genes. Moreover, a tissue expression study found that these genes are also expressed in the brain tissue. In addition to the earlier studies for marker gene identification, we have considered a different set of machine learning classifiers to improve the accuracy rate from the analysis. Amongst all the six classification algorithms, J48 emerged as the best classifier, which could be used for differentiating healthy and diseased samples. SMO/SVM and Logit Boost further followed J48 to achieve the classification accuracy.     

Rapid Communication Chronic Ingestion of Ethanol Up-Regulates NMDAR1 Receptor Subunit Immunoreactivity in Rat Hippocampus

We examined the effects of chronic ethanol exposure on the levels of N -methyl-D-aspartate receptor subunit 1 (NMDAR1) protein, an essential component of N -methyl-D-aspar- tate glutamate receptors, in rat brain. By immunoblotting procedures using a specific antibody for the NMDAR1 subunit, we found that ethanol dramatically up-regulated (by 65%) NMDAR1 immunoreactivity in the hippocampus but not in the nucleus accumbens, cerebral cortex, or striatum. In contrast, ethanol did not alter the levels of glutamate receptor subunit (GLUR) 1 or GLUR2 protein, subunits that make up the α-amino-3-hydroxy-5-methy4-isoxazole propionic acid glutamate receptor, in the hippocampus. Because ethanol can potentially influence many different neurotransmitter systems, we examined whether chronic treatment with several psychotropic drugs with different pharmacological profiles (cocaine, haloperidol, SCH 23390, imipramine, and morphine) could mimic the effect of ethanol. None of these agents increased hippocampal NMDAR1 subunit immunoreactivity after chronic administration. Increased NMDAR1 subunit levels in the hippocampus after chronic ethanol exposure may represent an important neurochemical substrate for some of the features associated with ethanol dependence and withdrawal.     

Vasopressin analog delays extinction of classically conditioned bradycardia

Albino rabbits were subjected to Pavlovian (classical) conditioning and extinction of concomitant heart rate and eyeblink responses. Sixty minutes before each of three extinction sessions animals were treated with 5 or 20 μg/kg of deamino-dicarba-arginine-8-vasopressin or saline. Vasopressin treatment delayed extinction of bradycardiac conditioned responses but did not affect concomitant eyeblink conditioned responses. It was concluded that classically conditioned autonomic responses may be useful tools for studying the effects of peptides on learning.