Memory retrieval improvement by Heteropterys aphrodisiaca in aging rats

Few data exists about the pharmacological properties of Heteropterys aphrodisiaca O. Mach. (Malpighiaceae), which is native to the scrubland regions of Brazil. The present study investigated the effects of oral treatment with H. aphrodisiaca extract (BST0298) on the learning and memory of young (3-6 months) and aged (21-23 months) rats, and compared the in vitro antioxidant activity of three lots collected in different years. An improvement in the number of sessions to learn the task was observed in the left/right discrimination test in aged rats treated for 45 days with 25 mg/kg (7.0 ± 0.5; p=0.005) or 50 mg/kg (7.6 ± 0.6; p=0.012) compared with control old rats (11.0 ± 1.6). On the other hand, pre-treatment did not improve the performance of scopolamine-treated mice in the passive avoidance test. The in vitro malondialdehyde test showed that all three different extracts presented similar antioxidant activity. The flavonoids astilbin, isoastilbin and neoastilbin were isolated from the extract and may contribute to the biological activity. These results suggest that repeated treatment with H. aphrodisiaca improves learning and memory, probably by a non-muscarinic mechanism.Existem poucos dados disponíveis sobre as propriedades farmacológicas da Heteropterys aphrodisiaca O. Mach. (Malpighiaceae), nativa da região do pantanal brasileiro. O presente estudo investigou o efeito do tratamento oral com um extrato de H. aphrodisiaca (BST0298) sobre a memória e aprendizagem de ratos jovens (3-6 meses) e idosos (21-23 meses) e comparou a atividade antioxidante in vitro de três lotes, coletados em diferentes anos. Melhora quanto ao número de sessões necessárias para aprender a tarefa foi observada no teste de discriminação direita/esquerda em ratos idosos tratados por 45 dias com doses de 25 mg/kg (7,0 ± 0,5; p=0,005) e 50 mg/kg (7,6 ± 0,6; p=0,012) comparados com ratos idosos controle (11,0 ± 1,6). Por outro lado, o pré-tratamento com o extrato não melhorou o desempenho de camundongos tratados com escopolamina no teste da esquiva passiva. Em relação à avaliação da atividade antioxidante in vitro pelo teste do malonodialdeído, os três lotes analisados apresentaram atividade antioxidante semelhante. Os flavonóides astilbina, isoastilbina e neoastilbina foram isolados do extrato e podem contribuir para a atividade biológica. Estes resultados sugerem que a administração repetida de H. aphrodisiaca melhora a memória e aprendizagem provavelmente por um mecanismo não muscarínico

Orbitofrontal cortex inactivation impairs early reversal learning in male rats during a sexually motivated task

This study analyzes whether inactivation of the orbitofrontal cortex (OFC) affects early discrimination or reversal learning during a T maze motivated task. Male rats received saline solution or one doses of tetrodotoxin (TTX) bilaterally into the OFC, and were permitted to have an intromission with a receptive female to induce a sexually motivated state. Discrimination and reversal sessions consisted of seven trials each to accomplish the non-overtrained condition. Each arm of the T maze was associated to different external cues. Subjects were sexually reinforced whenever they reached the receptive female box, and returned to the start-box if not. Spontaneous motor activity was not altered. Rats with OFC inactivated did not present alteration during discrimination. Males with higher doses of TTX had a deficit in the number of correct responses and increased number of trials without response during reversal learning. These data agrees with other studies and indicates that an intact OFC is essential for the adequate manifestation of reversal learning during its early phase in motivated tasks. However, disagrees with other findings about early perseverative responses, pointing out to a critical role of this structure in enhancing performance through incentive value re-assignment of predicted outcome cues. © Intern. Jour. Psych. Psychol. Ther

Orbitofrontal cortex inactivation impairs early reversal learning in male rats during a sexually motivated task

This study analyzes whether inactivation of the orbitofrontal cortex (OFC) affects early discrimination or reversal learning during a T maze motivated task. Male rats received saline solution or one doses of tetrodotoxin (TTX) bilaterally into the OFC, and were permitted to have an intromission with a receptive female to induce a sexually motivated state. Discrimination and reversal sessions consisted of seven trials each to accomplish the non-overtrained condition. Each arm of the T maze was associated to different external cues. Subjects were sexually reinforced whenever they reached the receptive female box, and returned to the start-box if not. Spontaneous motor activity was not altered. Rats with OFC inactivated did not present alteration during discrimination. Males with higher doses of TTX had a deficit in the number of correct responses and increased number of trials without response during reversal learning. These data agrees with other studies and indicates that an intact OFC is essential for the adequate manifestation of reversal learning during its early phase in motivated tasks. However, disagrees with other findings about early perseverative responses, pointing out to a critical role of this structure in enhancing performance through incentive value re-assignment of predicted outcome cues. � Intern. Jour. Psych. Psychol. Ther

Glucocorticoids in the dorsomedial striatum modulate the consolidation of spatial but not procedural memory

Item does not contain fulltextGlucocorticoid hormones are known to influence widely interconnected brain networks, thereby enhancing the consolidation of memory of several types of training experiences. In this network, the dorsal striatum plays an important role in transforming goal-directed behavior into habitual behavior. Many studies have shown that the dorsolateral striatum (DLS) enables the formation of stimulus-response associations that are needed for procedural learning. In contrast, the dorsomedial striatum (DMS) is predominantly involved in influencing goal-directed behaviors via interactions with the dorsal hippocampus and medial prefrontal cortex. To date, most studies that have supported a functional dissociation of the dorsal striatum in memory have focused on the behavioral deficits produced by lesions or temporary inactivation of different striatal regions. Few studies have investigated the effect of pharmacological activation of the DMS in modulating memory of distinct kinds of spatial navigation. Therefore, in the present study corticosterone (CORT) was administered into the DMS immediately after training on either a place or cue water-maze task to investigate possible effects on the consolidation of spatial and procedural memory. Our findings indicate that CORT (5, 10 and 20 ng) enhanced 24-h retention of place training, without affecting retention of cue training. However, CORT administration after place and cue training did not shift the selection from a procedural to a spatial navigation strategy in a place-cue competition test. These findings support the functional heterogeneity of the dorsal striatum and suggest that the DMS can modulate the consolidation of allocentric spatial information via glucocorticoid action

Glucocorticoid administration into the dorsolateral but not dorsomedial striatum accelerates the shift from a spatial toward procedural memory

Item does not contain fulltextGlucocorticoid stress hormones are known to enhance the consolidation of hippocampus-dependent spatial and contextual memory. Recent findings indicate that glucocorticoids also enhance the consolidation of procedural memory that relies on the dorsal striatum. The dorsal striatum can be functionally subdivided into the dorsolateral striatum (DLS), which is primarily implicated in shaping procedural memories, and the dorsomedial striatum (DMS), which is engaged in spatial memory. Here, we investigated the hypothesis that posttraining glucocorticoid administration into the DLS promotes the formation of a procedural memory that will normally take place only with extensive training. Male Wistar rats were trained to find a reward in a cross maze that can be solved through either place or response learning. Rats received four trials per day for 5days, a probe trial on Day 6, further training on Days 7-13, and an additional probe trial on Day 14. On Days 2-4 of training, they received posttraining infusions of corticosterone (10 or 30ng) or vehicle into either the DLS or DMS. Rats treated with vehicle into either the DLS or DMS displayed place learning on Day 6 and response learning on Day 14, indicating a shift in control of learned behavior toward a habit-like procedural strategy with extended training. Rats administered corticosterone (10ng) into the DLS displayed response learning on both Days 6 and 14, indicating an accelerated shift to response learning. In contrast, corticosterone administered posttraining into the DMS did not significantly alter the shift from place to response learning. These findings indicate that glucocorticoid administration into the DLS enhances memory consolidation of procedural learning and thereby influences the timing of the switch from the use of spatial/contextual memory to habit-like procedural memory to guide behavior

Effects of GABA antagonists on inhibitory avoidance

Experimental data indicate that GABA is involved in memory processes. However there are marked inconsistencies in the reported effects of interference with GABA synaptic activity on memory consolidation of aversively-motivated tasks. Both amnesia and improvement of performance have been reported after treatment with GABA antagonists. These contradictory effects could be explained by procedural differences in training. To test for this possibility rats were trained in passive avoidance using two levels of footshock and injected with a wide range of doses of picrotoxin and bicuculline. Picrotoxin did not modify the conditioned response while bicuculline induced amnesia only with the lower doses at both low and high footshock intensities. It was concluded that GABA is involved in memory consolidation, and that the conflicting results in the literature are indeed due, in part, to procedural differences, and also to the mode of action of these drugs. Zapotitlán 1993

Технология разработки программного обеспечения : учеб. пособие

В учебном пособии доступно и наглядно рассмотрены жизненный цикл программных средств, стратегии разработки и реализующие их модели жизненного цикла, процедура выбора модели жизненного цикла для конкретного проекта. Описаны классические и современные методологии и технологии анализа и проектирования программных средств. Приведены основы организации и классификация CASE-средств. Учебное пособие предназначено для студентов высших учебных заведений, чья специализация связана с программным обеспечением, а также для специалистов в области разработки программного обеспечения

Protective effect of under-reinforcement of passive avoidance against scopolamine-induced amnesia

Administration of antimuscarinic drugs induces amnesia of aversively motivated behaviors. However, when relatively high intensities of footshock are used during training (over-reinforcement), animals become protected against such amnesic state. Moreover, the protective effect is established in a none-or-all fashion i.e., within a series of increasing intensities a minute augmentation of footshock intensity is sufficient to reach the protective threshold. In the present experiment it was found that very low intensities of aversive stimulation (under-reinforcement), sufficient to produce learning, also protected animals from scopolamine-induced amnesia. These results suggest that acetylcholine is critically involved in memory consolidation of passive avoidance, but only within a limited range of training intensities. � 1993

Corticosterone in the dorsolateral striatum facilitates the extinction of stimulus-response memory

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Effects of central muscarinic blockade on passive avoidance: Anterograde amnesia, state dependency, or both?

It was recently reported that administration of relatively high intensities of footshock (overreinforcement) during training of passive avoidance protected animals against the amnesic effect of scopolamine, injected 5 min after training. This was interpreted in terms of a lesser involvement of acetylcholine in memory consolidation. An alternative explanation was that overreinforcement accelerated the consolidation process, which could have taken place before the injection of scopolamine. To test for this possibility, male Wistar rats were injected with 4, 8, or 12 mg/kg of scopolamine, 5 min before training with low or high levels of footshock and then tested for retention of the task. Scopolamine induced the expected memory deficit after the low-intensity footshock; after overreinforcement the higher doses of scopolamine induced state dependency, while no deficits were produced with the lower dose. It was concluded that: (a) acetylcholine is indeed involved in memory consolidation of passive avoidance; (b) scopolamine interacts with high footshock levels to produce state dependency; and (c) when relatively low doses of scopolamine are used in conditions of overreinforcement, protection against scopolamine-induced amnesia becomes evident. Zapotitlán 1994 Academic Press, Inc