The Experts below are selected from a list of 244827 Experts worldwide ranked by ideXlab platform

Edward Vela - One of the best experts on this subject based on the ideXlab platform.

  • Environmental Context-Dependent Memory: A review and meta-analysis
    Psychonomic Bulletin & Review, 2001
    Co-Authors: Steven M. Smith, Edward Vela
    Abstract:

    To address questions about human Memory’s dependence on the coincidental environmental contexts in which events occur, we review studies of incidental environmental Context-Dependent Memory in humans and report a meta-analysis. Our theoretical approach to the issue stems from Glenberg’s (1997) contention that introspective thought (e.g., remembering, conceptualizing) requires cognitive resources normally used to represent the immediate environment. We propose that if tasks encourage processing of noncontextual information (i.e., introspective thought) at input and/or at test, then both learning and Memory will be less dependent on the ambient environmental contexts in which those activities occur. The meta-analysis showed that across all studies, environmental context effects were reliable, and furthermore, that the use of noncontextual cues during learning (overshadowing) and at test (outshining), as well as mental reinstatement of appropriate context cues at test, all reduce the effect of environmental manipulations. We conclude that environmental Context-Dependent Memory effects are less likely to occur under conditions in which the immediate environment is likely to be suppressed.

Steven M. Smith - One of the best experts on this subject based on the ideXlab platform.

  • Environmental Context-Dependent Memory: A review and meta-analysis
    Psychonomic Bulletin & Review, 2001
    Co-Authors: Steven M. Smith, Edward Vela
    Abstract:

    To address questions about human Memory’s dependence on the coincidental environmental contexts in which events occur, we review studies of incidental environmental Context-Dependent Memory in humans and report a meta-analysis. Our theoretical approach to the issue stems from Glenberg’s (1997) contention that introspective thought (e.g., remembering, conceptualizing) requires cognitive resources normally used to represent the immediate environment. We propose that if tasks encourage processing of noncontextual information (i.e., introspective thought) at input and/or at test, then both learning and Memory will be less dependent on the ambient environmental contexts in which those activities occur. The meta-analysis showed that across all studies, environmental context effects were reliable, and furthermore, that the use of noncontextual cues during learning (overshadowing) and at test (outshining), as well as mental reinstatement of appropriate context cues at test, all reduce the effect of environmental manipulations. We conclude that environmental Context-Dependent Memory effects are less likely to occur under conditions in which the immediate environment is likely to be suppressed.

Oliver Stiedl - One of the best experts on this subject based on the ideXlab platform.

  • time dependent involvement of the dorsal hippocampus in trace fear conditioning in mice
    Hippocampus, 2005
    Co-Authors: Ilga Misane, Philip Tovote, Michael Meyer, Joachim Spiess, Sven Ove Ogren, Oliver Stiedl
    Abstract:

    Hippocampal and amygdaloid neuroplasticity are important substrates for Pavlovian fear conditioning. The hippocampus has been implicated in trace fear conditioning. However, a systematic investigation of the significance of the trace interval has not yet been performed. Therefore, this study analyzed the time-dependent involvement of N-methyl-D-aspartate (NMDA) receptors in the dorsal hippocampus in one-trial auditory trace fear conditioning in C57BL/6J mice. The NMDA receptor antagonist APV was injected bilaterally into the dorsal hippocampus 15 min before training. Mice were exposed to tone (conditioned stimulus [CS]) and footshock (unconditioned stimulus [US]) in the conditioning context without delay (0 s) or with CS-US (trace) intervals of 1-45 s. Conditioned auditory fear was determined 24 h after training by the assessment of freezing and computerized evaluation of inactivity in a new context; 2 h later, Context-Dependent Memory was tested in the conditioning context. NMDA receptor blockade by APV markedly impaired conditioned auditory fear at trace intervals of 15 s and 30 s, but not at shorter trace intervals. A 45-s trace interval prevented the formation of conditioned tone-dependent fear. Context-Dependent Memory was always impaired by APV treatment independent of the trace interval. The results indicate that the dorsal hippocampus and its NMDA receptors play an important role in auditory trace fear conditioning at trace intervals of 15-30-s length. In contrast, NMDA receptors in the dorsal hippocampus are unequivocally involved in contextual fear conditioning independent of the trace interval. The results point at a time-dependent role of the dorsal hippocampus in encoding of noncontingent explicit stimuli. Preprocessing of long CS-US contingencies in the hippocampus appears to be important for the final information processing and execution of fear memories through amygdala circuits. © 2005 Wiley-Liss, Inc.

  • strain and substrain differences in context and tone dependent fear conditioning of inbred mice
    Behavioural Brain Research, 1999
    Co-Authors: Oliver Stiedl, Jelena Radulovic, Ragna Lohmann, Karin Birkenfeld, Markki Palve, Jens Kammermeier, Farahnaz Sananbenesi, Joachim Spiess
    Abstract:

    The performance of C57BL/6J (6J), C57BL/6N (6N), DBA/2J (2J) and DBA/2N (2N) mice in context- and tone-dependent fear conditioning was determined 24 h after fear conditioning to evaluate and compare different behavioral measures as indices of emotional learning. Freezing, the change in activity and the size of the explored area were evaluated as behavioral parameters indicating fear. Additionally, the heart rate (HR) increase elicited by tone presentation was evaluated as an autonomic indicator of fear. During the Context-Dependent Memory test, freezing was high only in 6J and 6N mice, whereas a drop of activity and a reduced exploratory area was measured in all strains. During the tone-dependent Memory test, high freezing, low activity, reduced exploratory area and a strong HR increase were demonstrated only in 6N and 6J mice, whereas behavioral and HR changes of 2J and 2N mice were always low. In extinction tests, context- and tone-dependent freezing of 6J mice decayed significantly faster than the freezing of 6N mice, whereas in both substrains the conditioned tachycardia to tone extinguished similarly in the home cage. The data demonstrate that monitoring of additional behavioral measures besides freezing and autonomic measures is necessary to interpret differences in associative learning performance of mouse strains that could be related to a differential expression of fear.

Joachim Spiess - One of the best experts on this subject based on the ideXlab platform.

  • time dependent involvement of the dorsal hippocampus in trace fear conditioning in mice
    Hippocampus, 2005
    Co-Authors: Ilga Misane, Philip Tovote, Michael Meyer, Joachim Spiess, Sven Ove Ogren, Oliver Stiedl
    Abstract:

    Hippocampal and amygdaloid neuroplasticity are important substrates for Pavlovian fear conditioning. The hippocampus has been implicated in trace fear conditioning. However, a systematic investigation of the significance of the trace interval has not yet been performed. Therefore, this study analyzed the time-dependent involvement of N-methyl-D-aspartate (NMDA) receptors in the dorsal hippocampus in one-trial auditory trace fear conditioning in C57BL/6J mice. The NMDA receptor antagonist APV was injected bilaterally into the dorsal hippocampus 15 min before training. Mice were exposed to tone (conditioned stimulus [CS]) and footshock (unconditioned stimulus [US]) in the conditioning context without delay (0 s) or with CS-US (trace) intervals of 1-45 s. Conditioned auditory fear was determined 24 h after training by the assessment of freezing and computerized evaluation of inactivity in a new context; 2 h later, Context-Dependent Memory was tested in the conditioning context. NMDA receptor blockade by APV markedly impaired conditioned auditory fear at trace intervals of 15 s and 30 s, but not at shorter trace intervals. A 45-s trace interval prevented the formation of conditioned tone-dependent fear. Context-Dependent Memory was always impaired by APV treatment independent of the trace interval. The results indicate that the dorsal hippocampus and its NMDA receptors play an important role in auditory trace fear conditioning at trace intervals of 15-30-s length. In contrast, NMDA receptors in the dorsal hippocampus are unequivocally involved in contextual fear conditioning independent of the trace interval. The results point at a time-dependent role of the dorsal hippocampus in encoding of noncontingent explicit stimuli. Preprocessing of long CS-US contingencies in the hippocampus appears to be important for the final information processing and execution of fear memories through amygdala circuits. © 2005 Wiley-Liss, Inc.

  • strain and substrain differences in context and tone dependent fear conditioning of inbred mice
    Behavioural Brain Research, 1999
    Co-Authors: Oliver Stiedl, Jelena Radulovic, Ragna Lohmann, Karin Birkenfeld, Markki Palve, Jens Kammermeier, Farahnaz Sananbenesi, Joachim Spiess
    Abstract:

    The performance of C57BL/6J (6J), C57BL/6N (6N), DBA/2J (2J) and DBA/2N (2N) mice in context- and tone-dependent fear conditioning was determined 24 h after fear conditioning to evaluate and compare different behavioral measures as indices of emotional learning. Freezing, the change in activity and the size of the explored area were evaluated as behavioral parameters indicating fear. Additionally, the heart rate (HR) increase elicited by tone presentation was evaluated as an autonomic indicator of fear. During the Context-Dependent Memory test, freezing was high only in 6J and 6N mice, whereas a drop of activity and a reduced exploratory area was measured in all strains. During the tone-dependent Memory test, high freezing, low activity, reduced exploratory area and a strong HR increase were demonstrated only in 6N and 6J mice, whereas behavioral and HR changes of 2J and 2N mice were always low. In extinction tests, context- and tone-dependent freezing of 6J mice decayed significantly faster than the freezing of 6N mice, whereas in both substrains the conditioned tachycardia to tone extinguished similarly in the home cage. The data demonstrate that monitoring of additional behavioral measures besides freezing and autonomic measures is necessary to interpret differences in associative learning performance of mouse strains that could be related to a differential expression of fear.

Peter Gass - One of the best experts on this subject based on the ideXlab platform.

  • Memory retrieval after contextual fear conditioning induces c fos and junb expression in ca1 hippocampus
    Genes Brain and Behavior, 2003
    Co-Authors: Tatyana Strekalova, Bjorn Zorner, Christiane Zacher, G Sadovska, T Herdegen, Peter Gass
    Abstract:

    Using specific polyclonal antisera against c-Fos, JunB, c-Jun and JunD, we tried to identify the candidate transcription factors of the immediate early gene family which may contribute to the molecular processes during contextual Memory reconsolidation. For that purpose we analyzed the expression of these proteins in the hippocampus after contextual Memory retrieval in a mouse model of fear conditioning. A single exposure to a foot shock of 0.8 mA was sufficient to induce robust contextual fear conditioning in C57BI/6N mice. In these mice context dependent Memory retrieval evoked a marked induction of c-Fos and JunB, but not of c-Jun and JunD, in pyramidal CA1 neurons of the dorsal hippocampus. In contrast, mice exposed and re-exposed only to the context, without foot shock, did not show behavioral signs of contextual fear conditioning and exhibited significantly less expression of c-Fos and JunB in CA1 neurons. Mice which received a foot shock but were not re-exposed to the context revealed no immediate early gene induction. These results demonstrate that contextual Memory retrieval is associated with de novo synthesis of specific members of the Fos/Jun transcription factor family. Therefore we suggest that these genes may contribute to plasticity and reconsolidation accompanying the retrieval process. The specific activation of CA1 neurons during the retrieval of contextual fear associations supports the postulated concept of a mnemonic role of this hippocampal subsector during the retrieval of contextual informations.