The Experts below are selected from a list of 82332 Experts worldwide ranked by ideXlab platform

Robert M Sears - One of the best experts on this subject based on the ideXlab platform.

  • a Brainstem central amygdala circuit underlies defensive responses to learned threats
    Molecular Psychiatry, 2020
    Co-Authors: Walte T Pipe, Elena M Vazey, Gary Astonjones, Robert M Sears, Laure A Aniga, Joseph E Ledou
    Abstract:

    Norepinephrine (NE) plays a central role in the acquisition of aversive learning via actions in the lateral Nucleus of the amygdala (LA) [1, 2]. However, the function of NE in expression of aversively-conditioned responses has not been established. Given the role of the central Nucleus of the amygdala (CeA) in the expression of such behaviors [3–5], and the presence of NE axons projections in this Brain Nucleus [6], we assessed the effects of NE activity in the CeA on behavioral expression using receptor-specific pharmacology and cell- and projection-specific chemogenetic manipulations. We found that inhibition and activation of locus coeruleus (LC) neurons decreases and increases freezing to aversively conditioned cues, respectively. We then show that locally inhibiting or activating LC terminals in CeA is sufficient to achieve this bidirectional modulation of defensive reactions. These findings support the hypothesis that LC projections to CeA are critical for the expression of defensive responses elicited by conditioned threats.

  • a Brainstem central amygdala circuit underlies defensive responses to learned threats
    bioRxiv, 2019
    Co-Authors: Elena M Vazey, Gary Astonjones, Longnian Lin, Joseph E Ledoux, Robert M Sears
    Abstract:

    Norepinephrine (NE) plays a central role in the acquisition of aversive learning via actions in the lateral Nucleus of the amygdala (LA). However, the function of NE in expression of aversively-conditioned responses has not been established. Given the role of the central Nucleus of the amygdala (CeA) in the expression of such behaviors, and the presence of NE projections in this Brain Nucleus, we assessed the effects of NE activity in the CeA on behavioral expression using receptor-specific pharmacology and cell- and projection-specific chemogenetic manipulations. We found that inhibition and activation of locus coeruleus (LC) neurons decreases and increases freezing to aversively conditioned cues, respectively. We then show that locally inhibiting or activating LC terminals in CeA is sufficient to achieve this bidirectional modulation of defensive reactions. These findings support the hypothesis that LC projections to CeA are required for the expression of defensive responses elicited by conditioned threats.

Joseph E Ledou - One of the best experts on this subject based on the ideXlab platform.

  • a Brainstem central amygdala circuit underlies defensive responses to learned threats
    Molecular Psychiatry, 2020
    Co-Authors: Walte T Pipe, Elena M Vazey, Gary Astonjones, Robert M Sears, Laure A Aniga, Joseph E Ledou
    Abstract:

    Norepinephrine (NE) plays a central role in the acquisition of aversive learning via actions in the lateral Nucleus of the amygdala (LA) [1, 2]. However, the function of NE in expression of aversively-conditioned responses has not been established. Given the role of the central Nucleus of the amygdala (CeA) in the expression of such behaviors [3–5], and the presence of NE axons projections in this Brain Nucleus [6], we assessed the effects of NE activity in the CeA on behavioral expression using receptor-specific pharmacology and cell- and projection-specific chemogenetic manipulations. We found that inhibition and activation of locus coeruleus (LC) neurons decreases and increases freezing to aversively conditioned cues, respectively. We then show that locally inhibiting or activating LC terminals in CeA is sufficient to achieve this bidirectional modulation of defensive reactions. These findings support the hypothesis that LC projections to CeA are critical for the expression of defensive responses elicited by conditioned threats.

Gary Astonjones - One of the best experts on this subject based on the ideXlab platform.

  • a Brainstem central amygdala circuit underlies defensive responses to learned threats
    Molecular Psychiatry, 2020
    Co-Authors: Walte T Pipe, Elena M Vazey, Gary Astonjones, Robert M Sears, Laure A Aniga, Joseph E Ledou
    Abstract:

    Norepinephrine (NE) plays a central role in the acquisition of aversive learning via actions in the lateral Nucleus of the amygdala (LA) [1, 2]. However, the function of NE in expression of aversively-conditioned responses has not been established. Given the role of the central Nucleus of the amygdala (CeA) in the expression of such behaviors [3–5], and the presence of NE axons projections in this Brain Nucleus [6], we assessed the effects of NE activity in the CeA on behavioral expression using receptor-specific pharmacology and cell- and projection-specific chemogenetic manipulations. We found that inhibition and activation of locus coeruleus (LC) neurons decreases and increases freezing to aversively conditioned cues, respectively. We then show that locally inhibiting or activating LC terminals in CeA is sufficient to achieve this bidirectional modulation of defensive reactions. These findings support the hypothesis that LC projections to CeA are critical for the expression of defensive responses elicited by conditioned threats.

  • a Brainstem central amygdala circuit underlies defensive responses to learned threats
    bioRxiv, 2019
    Co-Authors: Elena M Vazey, Gary Astonjones, Longnian Lin, Joseph E Ledoux, Robert M Sears
    Abstract:

    Norepinephrine (NE) plays a central role in the acquisition of aversive learning via actions in the lateral Nucleus of the amygdala (LA). However, the function of NE in expression of aversively-conditioned responses has not been established. Given the role of the central Nucleus of the amygdala (CeA) in the expression of such behaviors, and the presence of NE projections in this Brain Nucleus, we assessed the effects of NE activity in the CeA on behavioral expression using receptor-specific pharmacology and cell- and projection-specific chemogenetic manipulations. We found that inhibition and activation of locus coeruleus (LC) neurons decreases and increases freezing to aversively conditioned cues, respectively. We then show that locally inhibiting or activating LC terminals in CeA is sufficient to achieve this bidirectional modulation of defensive reactions. These findings support the hypothesis that LC projections to CeA are required for the expression of defensive responses elicited by conditioned threats.

  • designer receptor manipulations reveal a role of the locus coeruleus noradrenergic system in isoflurane general anesthesia
    Proceedings of the National Academy of Sciences of the United States of America, 2014
    Co-Authors: Elena M Vazey, Gary Astonjones
    Abstract:

    Mechanisms driving emergence from general anesthesia are not well understood. The noradrenergic Brain Nucleus locus coeruleus (LC) modulates arousal and may have effects on general anesthetic state. Using virally delivered designer receptors to specifically control LC norepinephrine (NE) neurons, we investigated the causal relationship between LC-NE activity and general anesthetic state under isoflurane. Selective activation of LC-NE neurons produced cortical electroencephalography (EEG) activation under continuous deep isoflurane anesthesia. Specifically, LC-NE activation reduced burst suppression in EEG and drove a rightward shift in peak EEG frequency with reduced δ EEG power and increased θ EEG power, measures of cortical arousal. LC-NE activation also accelerated behavioral emergence from deep isoflurane anesthesia; this was prevented with β or α1 noradrenergic antagonists. Moreover, these adrenoreceptor antagonists alone were sufficient to markedly potentiate anesthetic duration when delivered centrally or peripherally. Induction of anesthesia also was retarded by LC-NE activation. Our results demonstrate that the LC-NE system strongly modulates the anesthetic state, and that changes in LC-NE neurotransmission alone can affect the emergence from isoflurane general anesthesia. Taken together, these findings extend our understanding of mechanisms underlying general anesthesia and cortical arousal, and have significant implications for optimizing the clinical safety and management of general anesthesia.

  • numerous gabaergic afferents to locus ceruleus in the pericerulear dendritic zone possible interneuronal pool
    The Journal of Neuroscience, 2004
    Co-Authors: Gary Astonjones, Yan Zhu, Patrick J Card
    Abstract:

    Most nuclei in the CNS are composed of principal neurons that project to other areas and interneurons that serve to integrate information among afferents. The noradrenergic Brain Nucleus locus ceruleus (LC) has appeared to be an exception to this general rule, because the LC is composed almost entirely of noradrenergic principal neurons. Here, we report that numerous small neurons in the peri-LC region become retrogradely labeled after focal injections of wheat germ agglutinin-apo (inactivated) horseradish peroxidase conjugated to colloidal gold, or pseudorabies virus (PRV), into the nuclear core of the rat LC. A substantial number of these neurons were routinely found within the dendritic field of the LC, in the area surrounding the compact cell-dense region classically defined as LC. Double labeling revealed that a large percentage of these cells stained for GABA. Ultrastructural analyses revealed axodendritic and axosomatic contacts between PRV-labeled afferents and LC neurons labeled with tyrosine hydroxylase immunohistochemistry. In addition, PRV-labeled neurons or axons were immunopositive for GABA in ultrastructural localizations. Analysis of the synaptology of immunopositive profiles demonstrated that these LC afferents in the peri-LC region receive several non-LC synaptic inputs. These results indicate that a population of small GABAergic neurons in the peri-LC dendritic zone may provide interneuronal integration for LC noradrenergic neurons.

David Crews - One of the best experts on this subject based on the ideXlab platform.

  • Effect of incubation temperature and androgens on dopaminergic activity in the leopard gecko, Eublepharis macularius.
    Developmental Neurobiology, 2007
    Co-Authors: Brian G. Dias, Ramona Sousan Ataya, David Rushworth, Jun Zhao, David Crews
    Abstract:

    Male leopard geckos that hatch from eggs incubated at a female-biased temperature (Tf) behave differently when compared with males hatching at a temperature which produces a male-biased sex ratio (Tm). We investigated the effect of incubation temperature and androgen implantation on aspects of the dopaminergic system of Tf and Tm males. Our data suggest that more dopamine (DA) is stored in the Nucleus accumbens of naive Tf males compared with naive Tm males when they encounter a receptive female conspecific across a barrier. No difference was measured in the preoptic area and the ventral tegmental area (VTA). This difference in intracellular DA levels in a motivation-related Brain Nucleus might be correlated with differences in sociosexual behavior observed between the two morphs. There were no differences in tyrosine hydroxylase (TH) expressing cell numbers in the VTA of cholesterol (CH)-implanted naive castrated Tf and Tm males. Only Tf males implanted with testosterone had significantly higher TH immunopositive cell numbers in the VTA compared with CH- and dihydrotestosterone-implanted Tf males. These data indicate that both the embryonic environment as well as the circulating hormonal milieu can modulate neurochemistry, which might in turn be a basis for individual variation in behavior. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007

  • Effect of Incubation Temperature and Androgens on Dopaminergic Activity in the Leopard Gecko,
    2006
    Co-Authors: Eublepharis Macularius, Brian G. Dias, Ramona Sousan Ataya, David Rushworth, Jun Zhao, David Crews
    Abstract:

    Male leopard geckos that hatch from eggs incubated at a female-biased temperature (T f) behave differently when compared with males hatching at a temperature which produces a male-biased sex ratio (T m). We investigated the effect of incubation temperature and androgen implantation on aspects of the dopaminergic system of Tf and Tm males. Our data suggest that more dopamine (DA) is stored in the Nucleus accumbens of naive Tf males compared with naïve Tm males when they encounter a receptive female conspecific across a barrier. No difference was measured in the preoptic area and the ventral tegmental area (VTA). This difference in intracellular DA levels in a motivationrelated Brain Nucleus might be correlated with differences in sociosexual behavior observed between the tw

Elena M Vazey - One of the best experts on this subject based on the ideXlab platform.

  • a Brainstem central amygdala circuit underlies defensive responses to learned threats
    Molecular Psychiatry, 2020
    Co-Authors: Walte T Pipe, Elena M Vazey, Gary Astonjones, Robert M Sears, Laure A Aniga, Joseph E Ledou
    Abstract:

    Norepinephrine (NE) plays a central role in the acquisition of aversive learning via actions in the lateral Nucleus of the amygdala (LA) [1, 2]. However, the function of NE in expression of aversively-conditioned responses has not been established. Given the role of the central Nucleus of the amygdala (CeA) in the expression of such behaviors [3–5], and the presence of NE axons projections in this Brain Nucleus [6], we assessed the effects of NE activity in the CeA on behavioral expression using receptor-specific pharmacology and cell- and projection-specific chemogenetic manipulations. We found that inhibition and activation of locus coeruleus (LC) neurons decreases and increases freezing to aversively conditioned cues, respectively. We then show that locally inhibiting or activating LC terminals in CeA is sufficient to achieve this bidirectional modulation of defensive reactions. These findings support the hypothesis that LC projections to CeA are critical for the expression of defensive responses elicited by conditioned threats.

  • a Brainstem central amygdala circuit underlies defensive responses to learned threats
    bioRxiv, 2019
    Co-Authors: Elena M Vazey, Gary Astonjones, Longnian Lin, Joseph E Ledoux, Robert M Sears
    Abstract:

    Norepinephrine (NE) plays a central role in the acquisition of aversive learning via actions in the lateral Nucleus of the amygdala (LA). However, the function of NE in expression of aversively-conditioned responses has not been established. Given the role of the central Nucleus of the amygdala (CeA) in the expression of such behaviors, and the presence of NE projections in this Brain Nucleus, we assessed the effects of NE activity in the CeA on behavioral expression using receptor-specific pharmacology and cell- and projection-specific chemogenetic manipulations. We found that inhibition and activation of locus coeruleus (LC) neurons decreases and increases freezing to aversively conditioned cues, respectively. We then show that locally inhibiting or activating LC terminals in CeA is sufficient to achieve this bidirectional modulation of defensive reactions. These findings support the hypothesis that LC projections to CeA are required for the expression of defensive responses elicited by conditioned threats.

  • designer receptor manipulations reveal a role of the locus coeruleus noradrenergic system in isoflurane general anesthesia
    Proceedings of the National Academy of Sciences of the United States of America, 2014
    Co-Authors: Elena M Vazey, Gary Astonjones
    Abstract:

    Mechanisms driving emergence from general anesthesia are not well understood. The noradrenergic Brain Nucleus locus coeruleus (LC) modulates arousal and may have effects on general anesthetic state. Using virally delivered designer receptors to specifically control LC norepinephrine (NE) neurons, we investigated the causal relationship between LC-NE activity and general anesthetic state under isoflurane. Selective activation of LC-NE neurons produced cortical electroencephalography (EEG) activation under continuous deep isoflurane anesthesia. Specifically, LC-NE activation reduced burst suppression in EEG and drove a rightward shift in peak EEG frequency with reduced δ EEG power and increased θ EEG power, measures of cortical arousal. LC-NE activation also accelerated behavioral emergence from deep isoflurane anesthesia; this was prevented with β or α1 noradrenergic antagonists. Moreover, these adrenoreceptor antagonists alone were sufficient to markedly potentiate anesthetic duration when delivered centrally or peripherally. Induction of anesthesia also was retarded by LC-NE activation. Our results demonstrate that the LC-NE system strongly modulates the anesthetic state, and that changes in LC-NE neurotransmission alone can affect the emergence from isoflurane general anesthesia. Taken together, these findings extend our understanding of mechanisms underlying general anesthesia and cortical arousal, and have significant implications for optimizing the clinical safety and management of general anesthesia.