Different Phases Of Learning Research Articles

Participatory Action Research, Critical Adult Education, and the Work of D.E. Smith for Research Praxis

From 2017-2021, the Youth Action Research Revolution (YARR) team documented the institutional histories of young people experiencing homelessness in Canada. Interviews with youth focused on educational, child welfare, healthcare, and criminal justice institutions. Situated at the intersections of critical adult education (CAE), participatory action research (PAR), and Institutional Ethnography (IE), we outline our mobilization of IE to ground learning and action within our team. We document the different phases of learning that we undertook, as a means of illustrating how CAE, PAR, and IE can be mutually supportive frameworks for praxis and activist learning. We highlight our use of IE to bring illuminate and resist the institutionalizing processes at work in post-secondary contexts and reflect on the importance of mutual aid as essential to realizing the social justice potential of participatory research. We suggest that co-creating IE research with young adults with lived experiences of homelessness constitutes a unique opportunity to mobilize CAE values and tangibly support community research that seeks to positively influence the lives of those implicated by the problems we study together.

Rodent maze studies: from following simple rules to complex map learning.

More than 100years since the first maze designed for rodent research, researchers now have the choice of a variety of mazes that come in many different shapes and sizes. Still old designs get modified and new designs are introduced to fit new research questions. Yet, which maze is the most optimal to use or which training paradigm should be applied, remains up for debate. In this review, we not only provide a historical overview of maze designs and usages in rodent learning and memory research, but also discuss the possible navigational strategies the animals can use to solve each maze. Furthermore, we summarize the different phases of learning that take place when a maze is used as the experimental task. At last, we delve into how training and maze design can affect what the rodents are actually learning in a spatial task.

Leading for deeper learning: international perspectives

PurposeThis article draws upon evidence from a contemporary study of all-through schools (ATS) in three countries. ATS combine at least two stages of a child's education in a single establishment. Many admit children aged 3–19. Most children join the school at nursery or kindergarten level and continue there for their entire education before moving on to further or higher education. ATS are also called all-age, in some contexts, because they bring children of all ages together into the same school environment. Models of ATS vary internationally; hence, there is not one definition of an ATS. This article takes a comparative look at ATS in Iceland, Spain and Wales. The purpose of this article is to explore innovative pedagogies in ATS and to explore how far deeper learning occurs because of the integrated and inclusive model of schooling. The study focused on pedagogical practices in ATS and examined how far these innovative practices are considered by teachers to foster deeper learning outcomes.Design/methodology/approachThe article draws upon a three-year comparative research project that explored pedagogy, leadership and well-being in ATS. The article investigates pedagogy with a cross-cutting focus on enquiry and deeper learning from the perspective of leaders and teachers. Using focus groups and lesson observations, a qualitative case-study approach was utilised to gather evidence about the teaching and learning processes adopted in ATS. Semi-structured interviews were also conducted with school leaders. The analytical approach adopted was one of constant comparison with the prime aim of eliciting common themes across the data sets. In relation to the pedagogy theme and an exploration of pedagogical innovation, research questions included (1) How far do ATS foster innovative pedagogies?, (2) What are the leadership conditions that support innovative pedagogies? and (3) To what extent do innovative pedagogies promote deeper learning?FindingsWithin and across the three education systems under investigation, the study found that all-through schooling engages students in a positive learning environment and provides innovative pedagogical processes associated with deeper learning. The article provides evidence about how deeper learning functions in ATS from different parts of the world and reflects on the way deeper learning is promoted by leaders and teachers, resulting in deeper learning for students. The evidence from this study reinforces that opportunities for pedagogical innovation and deeper learning within ATS occur because of flatter structures, more fluidity between different phases of learning and greater cross-over of teacher expertise. The study also highlights how leadership is a critical factor in creating the conditions for collective professional practices that foster pedagogical innovations to secure deeper learning. Findings suggest that leading for deeper learning is fundamentally concerned with creating the conditions for innovative learning environments that are equitable, inclusive, diverse and cross age ranges.Originality/valueContemporary empirical studies of the deeper learning environments within ATS remain relatively rare; hence, this study provides new comparative and contemporary evidence that illuminates the nature of the pedagogical innovation and the leadership practices that support pedagogical innovation in these schools. It also highlights how professional collaboration and cross-phase working are at the heart of innovative pedagogies that support deeper learning. The study outlined in this article provides critical, new insights about pedagogical innovation and deeper learning within ATS settings.

Global Pandemic Prevention Continual Learning—Taking Online Learning as an Example: The Relevance of Self-Regulation, Mind-Unwandered, and Online Learning Ineffectiveness

Since the global COVID-19 pandemic began, online learning has gained increasing importance as learners are socially isolated by physical and psychological threats, and have to face the epidemic and take preventive measures to ensure non-stop learning. Based on socially situated cognition theory, this study focused on exploring the relevance of online learning ineffectiveness (OLI) predicted by self-regulated learning (SRL) in different phases of learning (preparation, performance, and self-reflection) and its interaction with mind-unwandered during the COVID-19 pandemic. The subjects of the study were senior general high and technical high school students. After completing the online questionnaire, the PLS-SEM method of the structural equation model was used to analyze the data. Results demonstrated that self-regulation in two phases of preparation (i.e., cognitive strategy and emotional adjustment) and performance (i.e., mission strategy and environmental adjustment) in SRL are positively related to mind-unwandered in online learning. Moreover, mind-unwandered in online learning was positively related to the self-reflection phase (i.e., time management and help-seeking) of SRL. Additionally, self-reflection of SRL was negatively related to online learning ineffectiveness. PLS assessments found that the preparation and performance sub-constructs of SRL were negatively related to online learning ineffectiveness mediated by mind-unwandered and self-reflection of SRL. The results suggest that teachers can enhance their students’ self-regulation in online learning, and assist them in being more mind-unwandered in online learning.

Effects of pituitary hormones deficiency from the specific pituitary lobes on learning, memory and survival behavior in the Wistar rat

The role of the different adenohypophyseal hormones (GH, PRL, ACTH, TSH, LH and FSH) and neurohypophyseal (AVP and OXY) hormones on animal behavior, memory and learning have been stablished, however the role of lobe‐specific hormones on these cerebral functions has been not completely dilucidated. Here we study the specific pituitary hormone deficiencies in hypophysectomized (HYPOX), with anterior lobectomized (AL) and neurointermediate lobectomized (NIL) rats, subject to novel object recognition (NOR), forced swim (FS) and prepulse inhibition (PPI) tests. For comparisons the intact control (IC) and sham operated (SHAM) groups were also included. The NOR test that evaluate different phases of learning and memory in rodents, showed that memory discrimination index (DI) significantly increased in the NIL group, indicating that AVP and OXY deficiency negatively affect the ability of short and medium‐term memory. The FS test assess survival and motivation behavior; results showed that AL, NIL and HYPOX groups induced a loss in motivation and will to survive (increased immobility time); these observations may be partially explained by: 1) the significant deficiency of metabolic hormones (GH, ACTH‐corticosterone, TSH‐thyroid hormones and LH‐FSH‐testosterone hormones) whose decrease also induced significant loss in both mass muscle and body weight in AL and HYPOX groups and, 2) the decreased survival and motivational behavior induced by the AVP and OXY deficiency (NIL‐induced), thus supporting the view of the motivational and survival role of these hormones. The IPP test evaluates the rat ability to respond to potentially harmful acoustic stimuli and long‐term memory; results showed that AL animals did not show any sign of learning (expressed as very low inhibition percentage), whereas, interestingly, the HYPOX group (without any pituitary hormones) the long‐term memory was not significantly affected. In conclusion these results support the important role of the several pituitary hormones mainly neurohypophyseal hormones (AVP and OXY) controlling important brain functions necessary for learning, memory, and survival. These experimental models will allow in the future to study specifically the role of each pituitary hormone on the different aspects of animal behavior such as memory, motivation, generosity, adaptation, among others.

A random matrix analysis of random Fourier features: beyond the Gaussian kernel, a precise phase transition, and the corresponding double descent* *This article is an updated version of: Liao Z, Couillet R and Mahoney M W 2020 A random matrix analysis of random Fourier features: beyond the Gaussian kernel, a precise phase transition, and the corresponding double descent Advances in

This article characterizes the exact asymptotics of random Fourier feature (RFF) regression, in the realistic setting where the number of data samples n, their dimension p, and the dimension of feature space N are all large and comparable. In this regime, the random RFF Gram matrix no longer converges to the well-known limiting Gaussian kernel matrix (as it does when N → ∞ alone), but it still has a tractable behavior that is captured by our analysis. This analysis also provides accurate estimates of training and test regression errors for large n, p, N. Based on these estimates, a precise characterization of two qualitatively different phases of learning, including the phase transition between them, is provided; and the corresponding double descent test error curve is derived from this phase transition behavior. These results do not depend on strong assumptions on the data distribution, and they perfectly match empirical results on real-world data sets.

Learning-Induced Shifts in Mice Navigational Strategies Are Unveiled by a Minimal Behavioral Model of Spatial Exploration.

Shifts in spatial patterns produced during the execution of a navigational task can be used to track the effects of the accumulation of knowledge and the acquisition of structured information about the environment. Here, we provide a quantitative analysis of mice behavior while performing a novel goal localization task in a large, modular arena, the HexMaze. To demonstrate the effects of different forms of previous knowledge we first obtain a precise statistical characterization of animals’ paths with sub-trial resolution and over different phases of learning. The emergence of a flexible representation of the task is accompanied by a progressive improvement of performance, mediated by multiple, multiplexed time scales. We then use a generative mathematical model of the animal behavior to isolate the specific contributions to the final navigational strategy. We find that animal behavior can be accurately reproduced by the combined effect of a goal-oriented component, becoming stronger with the progression of learning, and of a random walk component, producing choices unrelated to the task and only partially weakened in time.

Cell-type-specific asynchronous modulation of PKA by dopamine in learning.

SummaryReinforcement learning models postulate that dopamine (DA) releasing neurons (DANs) encode information about action and action outcome and provide a teaching signal to striatal spiny projection neurons (SPNs) in the form of DA release1. DA is thought to guide learning via dynamic and differential modulation of protein kinase A (PKA) in each class of SPN2. However, the real-time relationship between DA and SPN PKA remains untested in behaving animals. Here, we monitor the activity of DANs, extracellular DA levels, and net PKA activity in SPNs in the nucleus accumbens in mice during learning. We find positive and negative modulation of DA that evolves across training and is both necessary and sufficient to explain concurrent fluctuations in SPN PKA activity. The modulations of PKA in SPNs that express type-1 and type-2 DA receptors are dichotomous such that they are selectively sensitive to increases and decreases in DA, respectively, which occur at different phases of learning. Thus, PKA-dependent pathways in each class of SPNs are asynchronously engaged by positive or negative DA signals during learning.

Differences in practice behaviours between expert musicians and non-musicians when learning a basic surgical skill

Background: Researchers have hypothesized that years of daily practice on a musical instrument may lead to increased efficiency in practice behaviours during the learning of other fine motor skills [1]. Practice strategies in music have also been considered a suitable model for surgical training [2] and some believe that surgical outcomes might be improved by adopting musicians’ practice strategies [3].Objective: This study examines the practice behaviours of expert musicians attempting to learn a basic surgical skill, as a way to detect possible transfer of practice habits across domains. This paper investigates whether musicians differ from a control group in their selection and application of practice strategies, whether there are relationships between the choice of practice behaviours and performance scores, whether musicians progress more rapidly through the different phases of learning and, whether relationships exist between those who reach automaticity sooner and their choice of practice behaviours.Methods: Participants’ practice sessions during a knot-tying task (taught via instructional video) were video-recorded and treated according to the method of thematic analysis [4]. Coding was performed by two evaluators through an iterative process and statistical and descriptive analyses were conducted on practice behaviours. Information was also collected on instructional video navigation so that the use of replay, pause, rewind or fast-forward could be investigated.Results: Musicians and the control group participants favoured different practice behaviours; this was demonstrated in their choice of strategies, the importance they gave to each strategy, and the way they used the strategies over the two practice sessions. There was evidence that the group of expert musicians applied better practice strategies as the choice of practice behaviours correlated positively with performance scores and their capacity to reach automaticity.Conclusion: Our results suggest that music experts may be applying practice strategies developed during their music studies when learning a novel surgical skill. This raised the possibility that practice skills developed through years of dedicated work at their musical instrument, might be transferable when learning a motor skill in a different domain.

Neurotransmitters and neuromodulators involved in learning and memory

Learning and memory being highly specialized process of human brain involves complex interaction between neurotransmitters and cellular events. Over the years, the understandings of these processes have been evolving from psychological, neurophysiological, and pharmacological perspectives. The most widely appraised model of learning and memory involves attention, acquisition, storage and retrieval. Each of these events involve interplay of neurotransmitters such as dopamine, acetylcholine, norepinephrine, N-methyl-d-aspartic acid, gamma-aminobutyric acid, though preponderance of specific neurotransmitter have been documented. The formation of long-term memory involves cellular events with neuroplasticity. Further, dopamine is documented to play crucial role in the process of forgetting. Understanding of the processes of learning and memory not only facilitates drug discovery, but also helps to understand actions of several existing drugs. In addition, it would also help to enhance psychological interventions in children with learning disabilities. Thus, the review intends to summarize role of neurotransmitters and neuromodulators during different phases of learning and memory.

Self-regulated learning in a competency-based and flipped learning environment: learning strategies across achievement levels and years

ABSTRACT Background: The transition from a traditional lecture-based curriculum to a competency-based curriculum poses significant challenges to both students and faculty in medical schools, especially when the curriculum is implemented in a flipped learning environment. Self-regulated learning (SRL) has been proven to be beneficial for competency-based learning and flipped classroom learning, but medical educators cannot expect our entering medical students to bring in these learning skills automatically. Methods: This study took place in the Michigan State University College of Human Medicine. A new competency-based curriculum was implemented in the fall 2016, focusing on the integration of basic science and clinical experience. Participants in this study were 26 first- and second-year students. By interviewing each student about the learning strategies they use in independent learning before class, we investigated how students use SRL strategies in different phases of learning, and how their adoption of SRL strategies differ across self-perceived achievement groups and years. Results: We found that students frequently use strategies in the stages of planning and reflection, but less frequently during the learning or monitoring phase. Students who perceive themselves as high achieving, and students in their second year of medical school do use more learning strategies during the monitoring stage than their counterparts. Conclusions: Students who lack self-regulation strategies may fail to comprehend or connect ideas in their pre-class learning, which could lead to ineffective learning outcomes during in-class activities. Our study indicated that while medical students, who tend to be successful learners in their undergraduate study, were able to use learning strategies to plan and reflect on their learning, they need more explicit instruction in how to monitor their own learning.

Practice to preach self-regulation: Use of metacognitive strategies by medical teachers in their learning practices

Objective:To explore use of metacognitive skills by medical teachers in relation to Zimmerman’s model of self-regulation.Methods:A qualitative phenomenological study was conducted at Riphah International University from February 2017 to August 2017. A semi structured interview of ten medical teachers was planned to uncover the lived experiences of selected teachers to demonstrate how these teachers use metacognitive strategies in different phases of learning. Data was collected by asking five open ended questions after expert validation. Data was analyzed by using N-Vivo software.Results:Total eight themes were extracted. For prediction and planning three themes, brainstorming, making concept map and sufficient time required were isolated while teachers selected learning objectives and level of students for resource selection while for motivation theme selected was previous experience. Two themes, self- questioning to improve the learning and extra effort required to meet the timeline were isolated for monitoring and reflection during and after learning for evaluation of learning process.Conclusion:During forethought phase, medical teachers predict their learning process through learning objectives and plan after brainstorming to make a concept map and use suitable learning resources. During learning, they monitor learning process through self-questioning and put extra-effort to meet the deadlines. During and after learning, teachers reflect on their performance.

Conventional analysis of trial-by-trial adaptation is biased: Empirical and theoretical support using a Bayesian estimator.

Research on human motor adaptation has often focused on how people adapt to self-generated or externally-influenced errors. Trial-by-trial adaptation is a person’s response to self-generated errors. Externally-influenced errors applied as catch-trial perturbations are used to calculate a person’s perturbation adaptation rate. Although these adaptation rates are sometimes compared to one another, we show through simulation and empirical data that the two metrics are distinct. We demonstrate that the trial-by-trial adaptation rate, often calculated as a coefficient in a linear regression, is biased under typical conditions. We tested 12 able-bodied subjects moving a cursor on a screen using a computer mouse. Statistically different adaptation rates arise when sub-sets of trials from different phases of learning are analyzed from within a sequence of movement results. We propose a new approach to identify when a person’s learning has stabilized in order to identify steady-state movement trials from which to calculate a more reliable trial-by-trial adaptation rate. Using a Bayesian model of human movement, we show that this analysis approach is more consistent and provides a more confident estimate than alternative approaches. Constraining analyses to steady-state conditions will allow researchers to better decouple the multiple concurrent learning processes that occur while a person makes goal-directed movements. Streamlining this analysis may help broaden the impact of motor adaptation studies, perhaps even enhancing their clinical usefulness.

Robustness of STDP to spike timing jitter

In Hebbian plasticity, neural circuits adjust their synaptic weights depending on patterned firing. Spike-timing-dependent plasticity (STDP), a synaptic Hebbian learning rule, relies on the order and timing of the paired activities in pre- and postsynaptic neurons. Classically, in ex vivo experiments, STDP is assessed with deterministic (constant) spike timings and time intervals between successive pairings, thus exhibiting a regularity that differs from biological variability. Hence, STDP emergence from noisy inputs as occurring in in vivo-like firing remains unresolved. Here, we used noisy STDP pairings where the spike timing and/or interval between pairings were jittered. We explored with electrophysiology and mathematical modeling, the impact of jitter on three forms of STDP at corticostriatal synapses: NMDAR-LTP, endocannabinoid-LTD and endocannabinoid-LTP. We found that NMDAR-LTP was highly fragile to jitter, whereas endocannabinoid-plasticity appeared more resistant. When the frequency or number of pairings was increased, NMDAR-LTP became more robust and could be expressed despite strong jittering. Our results identify endocannabinoid-plasticity as a robust form of STDP, whereas the sensitivity to jitter of NMDAR-LTP varies with activity frequency. This provides new insights into the mechanisms at play during the different phases of learning and memory and the emergence of Hebbian plasticity in in vivo-like activity.

Novel Object Recognition Test for the Investigation of Learning and Memory in Mice

The object recognition test (ORT) is a commonly used behavioral assay for the investigation of various aspects of learning and memory in mice. The ORT is fairly simple and can be completed over 3 days: habituation day, training day, and testing day. During training, the mouse is allowed to explore 2 identical objects. On test day, one of the training objects is replaced with a novel object. Because mice have an innate preference for novelty, if the mouse recognizes the familiar object, it will spend most of its time at the novel object. Due to this innate preference, there is no need for positive or negative reinforcement or long training schedules. Additionally, the ORT can also be modified for numerous applications. The retention interval can be shortened to examine short-term memory, or lengthened to probe long-term memory. Pharmacological intervention can be used at various times prior to training, after training, or prior to recall to investigate different phases of learning (i.e., acquisition, early or late consolidation, or recall). Overall, the ORT is a relatively low-stress, efficient test for memory in mice, and is appropriate for the detection of neuropsychological changes following pharmacological, biological, or genetic manipulations.

Novel Object Recognition Test for the Investigation of Learning and Memory in Mice.

The object recognition test (ORT) is a commonly used behavioral assay for the investigation of various aspects of learning and memory in mice. The ORT is fairly simple and can be completed over 3 days: habituation day, training day, and testing day. During training, the mouse is allowed to explore 2 identical objects. On test day, one of the training objects is replaced with a novel object. Because mice have an innate preference for novelty, if the mouse recognizes the familiar object, it will spend most of its time at the novel object. Due to this innate preference, there is no need for positive or negative reinforcement or long training schedules. Additionally, the ORT can also be modified for numerous applications. The retention interval can be shortened to examine short-term memory, or lengthened to probe long-term memory. Pharmacological intervention can be used at various times prior to training, after training, or prior to recall to investigate different phases of learning (i.e., acquisition, early or late consolidation, or recall). Overall, the ORT is a relatively low-stress, efficient test for memory in mice, and is appropriate for the detection of neuropsychological changes following pharmacological, biological, or genetic manipulations.

An analysis of student engagement patterns in language learning facilitated by Web 2.0 technologies

AbstractRecent research indicates that Web 2.0 applications contribute to supporting a social constructivist approach for language learning. However, students encounter different types of barrier associated with technologies and learning tasks, which can cause disengagement during different phases of learning. Thus, based on flow theory and the strategic motivation framework, this study aims to investigate students’ motivation and their engagement patterns while participating in Web 2.0 digital storytelling activities. The participants are 24 elementary school students of a suburban school in northern Taiwan. Over 19 weeks of observations on students aged 9–10 years in a third-grade classroom, data were collected through three sources: surveys, students’ digital stories, and English tests. The analysis of the data showed that motivation was a dynamic process, initially low but increasing in later phases. A dynamic pattern was also identified in the students’ flow perceptions, which included two cycles of disengagement and reengagement. Students encountered different challenges that led to disengagement phases, which highlighted the need for specific types of learning support in elementary school contexts. In addition, the participants’ vocabulary and oral fluency were found to have been enhanced by the end of the study. The implications for educational practice are discussed and the direction for future studies addressed.

Chapter 2 - The Organization of Plasticity in the Cerebellar Cortex: From Synapses to Control

The cerebellum is thought to play a critical role in procedural learning, but the relationship between this function and the underlying cellular and synaptic mechanisms remains largely speculative. At present, at least nine forms of long-term synaptic and nonsynaptic plasticity (some of which are bidirectional) have been reported in the cerebellar cortex and deep cerebellar nuclei. These include long-term potentiation (LTP) and long-term depression at the mossy fiber-granule cell synapse, at the synapses formed by parallel fibers, climbing fibers, and molecular layer interneurons on Purkinje cells, and at the synapses formed by mossy fibers and Purkinje cells on deep cerebellar nuclear cells, as well as LTP of intrinsic excitability in granule cells, Purkinje cells, and deep cerebellar nuclear cells. It is suggested that the complex properties of cerebellar learning would emerge from the distribution of plasticity in the network and from its dynamic remodeling during the different phases of learning. Intrinsic and extrinsic factors may hold the key to explain how the different forms of plasticity cooperate to select specific transmission channels and to regulate the signal-to-noise ratio through the cerebellar cortex. These factors include regulation of neuronal excitation by local inhibitory networks, engagement of specific molecular mechanisms by spike bursts and theta-frequency oscillations, and gating by external neuromodulators. Therefore, a new and more complex view of cerebellar plasticity is emerging with respect to that predicted by the original "Motor Learning Theory," opening issues that will require experimental and computational testing.

Sleep deprivation impairs spatial retrieval but not spatial learning in the non-human primate grey mouse lemur.

A bulk of studies in rodents and humans suggest that sleep facilitates different phases of learning and memory process, while sleep deprivation (SD) impairs these processes. Here we tested the hypothesis that SD could alter spatial learning and memory processing in a non-human primate, the grey mouse lemur (Microcebus murinus), which is an interesting model of aging and Alzheimer's disease (AD). Two sets of experiments were performed. In a first set of experiments, we investigated the effects of SD on spatial learning and memory retrieval after one day of training in a circular platform task. Eleven male mouse lemurs aged between 2 to 3 years were tested in three different conditions: without SD as a baseline reference, 8 h of SD before the training and 8 h of SD before the testing. The SD was confirmed by electroencephalographic recordings. Results showed no effect of SD on learning when SD was applied before the training. When the SD was applied before the testing, it induced an increase of the amount of errors and of the latency prior to reach the target. In a second set of experiments, we tested the effect of 8 h of SD on spatial memory retrieval after 3 days of training. Twenty male mouse lemurs aged between 2 to 3 years were tested in this set of experiments. In this condition, the SD did not affect memory retrieval. This is the first study that documents the disruptive effects of the SD on spatial memory retrieval in this primate which may serve as a new validated challenge to investigate the effects of new compounds along physiological and pathological aging.

Ventral tegmental area inactivation suppresses the expression of CA1 long term potentiation in anesthetized rat.

The hippocampus receives dopaminergic projections from the ventral tegmental area (VTA). Modulatory effect of dopamine on hippocampal long term potentiation (LTP) has been studied before, but there are conflicting results and some limitations in previous reports. Most of these studies show a significant effect of dopamine on the late phase of LTP in CA1 area of the hippocampus, while few reports show an effect on the early phase. Moreover, they generally manipulated dopamine receptors in the hippocampus and there are few studies investigating influence of the VTA neural activity on hippocampal LTP in the intact brain. Besides, VTA neurons contain other neurotransmitters such as glutamate and GABA that may modify the net effect of dopamine. In this study we examined the effect of VTA reversible inactivation on the induction and maintenance of early LTP in the CA1 area of anesthetized rats, and also on different phases of learning of a passive avoidance (PA) task. We found that inactivation of the VTA by lidocaine had no effect on CA1 LTP induction and paired-pulse facilitation, but its inactivation immediately after tetanic stimulation transiently suppressed the expression of LTP. Blockade of the VTA 20 min after tetanic stimulation had no effect on the magnitude of LTP. Moreover, VTA inactivation immediately after training impaired memory in the passive avoidance task, while its blockade before or 20 min after training produced no memory deficit. It can be concluded that VTA activity has no effect on CA1 LTP induction and acquisition of PA task, but involves in the expression of LTP and PA memory consolidation.