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De Corte BJ, Farley SJ, Heslin KA, Parker KL, Freeman JH. The dorsal hippocampus' role in context-based timing in rodents. Neurobiol Learn Mem 2022; 194:107673. [PMID: 35985617 DOI: 10.1016/j.nlm.2022.107673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 08/05/2022] [Accepted: 08/11/2022] [Indexed: 01/13/2023]
Abstract
To act proactively, we must predict when future events will occur. Individuals generate temporal predictions using cues that indicate an event will happen after a certain duration elapses. Neural models of timing focus on how the brain represents these cue-duration associations. However, these models often overlook the fact that situational factors frequently modulate temporal expectations. For example, in realistic environments, the intervals associated with different cues will often covary due to a common underlying cause. According to the 'common cause hypothesis,' observers anticipate this covariance such that, when one cue's interval changes, temporal expectations for other cues shift in the same direction. Furthermore, as conditions will often differ across environments, the same cue can mean different things in different contexts. Therefore, updates to temporal expectations should be context-specific. Behavioral work supports these predictions, yet their underlying neural mechanisms are unclear. Here, we asked whether the dorsal hippocampus mediates context-based timing, given its broad role in context-conditioning. Specifically, we trained rats with either hippocampal or sham lesions that two cues predicted reward after either a short or long duration elapsed (e.g., tone-8 s/light-16 s). Then, we moved rats to a new context and extended the long cue's interval (e.g., light-32 s). This caused rats to respond later to the short cue, despite never being trained to do so. Importantly, when returned to the initial training context, sham rats shifted back toward both cues' original intervals. In contrast, lesion rats continued to respond at the long cue's newer interval. Surprisingly, they still showed contextual modulation for the short cue, responding earlier like shams. These data suggest the hippocampus only mediates context-based timing if a cue is explicitly paired and/or rewarded across distinct contexts. Furthermore, as lesions did not impact timing measures at baseline or acquisition for the long cue's new interval, our data suggests that the hippocampus only modulates timing when context is relevant.
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Affiliation(s)
- Benjamin J De Corte
- Department of Psychiatry, Columbia University, New York, NY, USA; New York State Psychiatric Institute, New York, NY, USA
| | - Sean J Farley
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, IA, USA
| | - Kelsey A Heslin
- Department of Neuroscience and the Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Krystal L Parker
- Department of Psychiatry, The University of Iowa, Iowa City, IA, USA
| | - John H Freeman
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, IA, USA.
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2
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Yaeger JDW, Krupp KT, Summers TR, Summers CH. Contextual generalization of social stress learning is modulated by orexin receptors in basolateral amygdala. Neuropharmacology 2022; 215:109168. [PMID: 35724928 PMCID: PMC9285878 DOI: 10.1016/j.neuropharm.2022.109168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/07/2022] [Accepted: 06/14/2022] [Indexed: 01/22/2023]
Abstract
Fear-associated memories and behavior are often expressed in contexts/environments distinctively different from those in which they are created. This generalization process contributes to psychological disorders, particularly PTSD. Stress-related neurocircuits in the basolateral amygdala (BLA) receive inputs from hypothalamic orexin (Orx) neurons, which mediate neuronal activity by targeting orexin 1 (Orx1R) and orexin 2 (Orx2R) receptors via opposing functions. In BLA, inhibition of Orx1R or activation of Orx2R ameliorate stress responsiveness and behavior. We discovered that most Orx1R+ cells also express CamKIIα, while a majority of Orx2R+ cells are colocalized with GAD67. Further, Orx1R gene Hcrtr1 expression was positively correlated, and Orx2R gene Hcrtr2 expression was negatively correlated, with freezing in a phenotype-dependent fashion (Escape vs Stay) in the Stress Alternatives Model (SAM). The SAM consists of 4-days of social interaction between test mice and novel larger aggressors. Exits positioned at opposite ends of the SAM oval arena provide opportunities to actively avoid aggression. By Day 2, mice commit to behavioral phenotypes: Escape or Stay. Pharmacologically manipulating Orx receptor activity in the BLA, before Day 3 of the SAM, was followed with standard tests of anxiety: Open Field (OF) and Elevated Plus Maze (EPM). In Stay mice, freezing in response to social conflict and locomotion during SAM interaction (not home cage locomotion) were generalized to OF, and blocked by intra-BLA Orx1R antagonism, but not Orx2R antagonism. Moreover, patterns of social avoidance for Escape and Stay mice were recapitulated in OF, with generalization mediated by Orx1R and Orx2R antagonism, plus Orx2R stimulation.
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Affiliation(s)
- Jazmine D W Yaeger
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA; Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA; Veterans Affairs Research Service, Sioux Falls VA Health Care System, Sioux Falls, SD, 57105, USA; Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, 57104, USA
| | - Kevin T Krupp
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA; Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA
| | - Tangi R Summers
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA; Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA; Veterans Affairs Research Service, Sioux Falls VA Health Care System, Sioux Falls, SD, 57105, USA
| | - Cliff H Summers
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA; Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA; Veterans Affairs Research Service, Sioux Falls VA Health Care System, Sioux Falls, SD, 57105, USA.
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3
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Learning-induced biases in the ongoing dynamics of sensory representations predict stimulus generalization. Cell Rep 2022; 38:110340. [PMID: 35139386 DOI: 10.1016/j.celrep.2022.110340] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 11/16/2021] [Accepted: 01/14/2022] [Indexed: 11/22/2022] Open
Abstract
Sensory stimuli have long been thought to be represented in the brain as activity patterns of specific neuronal assemblies. However, we still know relatively little about the long-term dynamics of sensory representations. Using chronic in vivo calcium imaging in the mouse auditory cortex, we find that sensory representations undergo continuous recombination, even under behaviorally stable conditions. Auditory cued fear conditioning introduces a bias into these ongoing dynamics, resulting in a long-lasting increase in the number of stimuli activating the same subset of neurons. This plasticity is specific for stimuli sharing representational similarity to the conditioned sound prior to conditioning and predicts behaviorally observed stimulus generalization. Our findings demonstrate that learning-induced plasticity leading to a representational linkage between the conditioned stimulus and non-conditioned stimuli weaves into ongoing dynamics of the brain rather than acting on an otherwise static substrate.
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4
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Pajser A, Foster C, Gaeddert B, Pickens CL. Extended operant training increases infralimbic and prelimbic cortex Fos regardless of fear conditioning experience. Behav Brain Res 2021; 414:113476. [PMID: 34302878 PMCID: PMC8428778 DOI: 10.1016/j.bbr.2021.113476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 07/11/2021] [Accepted: 07/16/2021] [Indexed: 12/28/2022]
Abstract
Extended fear training can lead to initially low fear expression that grows over time, termed fear incubation. Conversely, a single fear conditioning session typically results in high fear initially that is sustained over time. Fear expression decreases across extended training, suggesting that a fear extinction-like process might be responsible for low fear observed soon after training. Because of the prominent role medial prefrontal cortex (mPFC) plays in fear conditioning and extinction, we decided to examine Fos expression resulting from a cued fear retrieval test to gain insight into possible mechanisms involved in extended training fear incubation. Male Long-Evans rats received 1 or 10 days of tone-shock pairings or tone-only exposure (while lever-pressing for food). Two days after the end of fear training, rats received a cued fear test, with perfusions timed to visualize Fos expression during test. As expected, the limited fear conditioning group exhibited higher fear in the test than any of the other groups (as measured with conditioned suppression of lever-pressing). Interestingly, we found that extended training animals (whether they received tone-shock pairings or tone-only exposure) expressed higher levels of Fos in both prelimbic and infralimbic cortices than limited training animals. There was no association between fear expression and mPFC Fos expression. These results suggest we may have visualized Fos expression related to operant overtraining rather than conditioned fear related processes. Further research is needed to determine the neurobiological basis of extended training fear incubation and to determine processes represented by the pattern of Fos expression we observed.
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Affiliation(s)
- Alisa Pajser
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, 66506, USA
| | - Christian Foster
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, 66506, USA
| | - Brooke Gaeddert
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, 66506, USA
| | - Charles L Pickens
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, 66506, USA.
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5
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Pajser A, Fisher H, Pickens CL. Pre-training naltrexone increases conditioned fear learning independent of adolescent alcohol consumption history. Physiol Behav 2021; 229:113212. [PMID: 33069685 DOI: 10.1016/j.physbeh.2020.113212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/26/2020] [Accepted: 10/14/2020] [Indexed: 11/27/2022]
Abstract
Our previous research has shown a relationship between low voluntary alcohol consumption and high conditioned fear in male Long Evans rats. Here, we examined whether differences in the endogenous opioid systems might be responsible for these differences. Rats received 6 weeks of chronic intermittent to 20% alcohol (v/v) or water-only from PND 26-66. Based on their consumption during the last 2 weeks of alcohol access, the alcohol-access rats were divided into high drinking (>2.5 g/kg/24-h) or low drinking (<2 g/kg/24-h). Rats were then given injections of the preferential mu opioid receptor antagonist naltrexone (1 mg/kg, s.c.) or the selective kappa opioid receptor antagonist LY2456302 (10 mg/kg, s.c.) prior to fear conditioning and were then tested for conditioned fear 2 days later. Pre-training naltrexone increased conditioned suppression of lever-pressing during training and testing, with no differences between high versus low alcohol drinkers or between water-only versus alcohol access groups (averaged across drinking levels). There was no effect of LY2456302 on conditioned fear in any comparison. We also found no differences between high and low alcohol drinkers and no reliable effect of prior alcohol access (averaged across drinking levels) on conditioned fear. Our experiment replicates and extends previous demonstrations that a preferential MOR antagonist can increase fear learning using conditioned suppression of lever-pressing as a fear measure. However, additional research is needed to determine the cause of the differences in conditioned fear that we previously observed (as they were not observed in the current experiments).
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Affiliation(s)
- Alisa Pajser
- Department of Psychological Sciences, Kansas State University, Manhattan, KS 66506, USA
| | - Hayley Fisher
- Department of Psychological Sciences, Kansas State University, Manhattan, KS 66506, USA
| | - Charles L Pickens
- Department of Psychological Sciences, Kansas State University, Manhattan, KS 66506, USA.
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Abstract
The generalization of learned behavior has been extensively investigated, but accounting for variance in generalized responding remains a challenge. Based on recent advances, we demonstrate that the inclusion of perceptual measures in generalization research may lead to a better understanding of both intra- and interindividual differences in generalization. We explore various ways through which perceptual variability can influence generalized responding. We investigate its impact on the ability to discriminate between stimuli and how similarity between stimuli may be variable, rather than fixed, because of it. Subsequently, we argue that perceptual variations can yield different learning experiences and that interindividual differences in generalized responding may be understood from this perspective. Finally, we point to the role of memory and decision-making within this context. Throughout this paper, we argue that accounting for perception in current generalization protocols will improve the precision of obtained generalization gradients and the ability to infer latent mechanisms. This can inspire future attempts to use generalization gradients as a (clinical) predictor or to relate them to individual traits and neural correlates and, ultimately, may lead to new theoretical and clinical insights.
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7
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Xie H, Wu D, Gao X, Wang N, Xiao Z. Auditory Fear Conditioning Alters Sensitivity of the Medial Prefrontal Cortex but this is not based on Frequency-dependent Integration. Neuroscience 2020; 442:237-252. [PMID: 32505746 DOI: 10.1016/j.neuroscience.2020.05.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 11/27/2022]
Abstract
Although many studies have shown that the prelimbic (PL) cortex of the mPFC is involved in the formation of conditioned freezing behavior, few have considered the acoustic response characteristics of PL cortex. Importantly, the change in auditory response characteristics of the PL cortex after conditional fear learning is largely unknown. Here we used in vivo cell-attached recordings targeting the mPFC during the waking state. We confirmed that the mPFC of adult C57 mice have neurons that respond to noise and tone in the waking state, especially in the PL cortex. Interestingly, the data also confirmed that these neurons responded well to the intensity of sound but did not have frequency topological distribution characteristics. Furthermore, we found that the number of c-fos positive neurons in the PL cortex increased significantly after auditory fear conditioning. The auditory-induced local field potential recordings and in vivo cell-attached recordings demonstrated that the PL cortex was more sensitive to the auditory conditioned stimulus after the acquisition of conditioned fear. The proportion of neurons responding to noise was significantly increased, and the signal to noise ratio of the spikes were also increased. These data reveal that PL neurons themselves responded to the main information (sound intensity), while the secondary information (frequency) response was almost negligible after auditory fear conditioning. This phenomenon may be the functional basis for handling this type of emotional memory, and this response characteristic is thought to be emotional sensitization but does not change the nature of this response.
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Affiliation(s)
- Haiting Xie
- Department of Physiology, School of Basic Medical Sciences, Key Laboratory of Psychiatric Disorders of Guangdong Province, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou 510515, China; Department of Neurology, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Duobin Wu
- Department of Neurology, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Xiaoya Gao
- Department of Neurology, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Ningqian Wang
- Department of Physiology, School of Basic Medical Sciences, Key Laboratory of Psychiatric Disorders of Guangdong Province, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou 510515, China.
| | - Zhongju Xiao
- Department of Physiology, School of Basic Medical Sciences, Key Laboratory of Psychiatric Disorders of Guangdong Province, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou 510515, China.
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8
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Divergence in cortical representations of threat generalization in affective versus perceptual circuitry in childhood: Relations with anxiety. Neuropsychologia 2020; 142:107416. [PMID: 32173623 DOI: 10.1016/j.neuropsychologia.2020.107416] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/22/2020] [Accepted: 02/29/2020] [Indexed: 01/16/2023]
Abstract
Children at risk for anxiety display elevated threat sensitivity and may inaccurately classify safe stimuli as threatening, a process known as overgeneralization. Little is known about whether such overgeneralization might stem from altered sensory representations of stimuli resembling threat, especially in youth. Here we implement representational similarity analysis of fMRI data to examine the similarity of neural representations of threat versus ambiguous or safe stimuli in threat and perceptual neurocircuitry among children at varying levels of anxiety traits. Three weeks after completing threat conditioning and extinction, children underwent an fMRI extinction recall task, during which they viewed the extinguished threat cue (CS+), safety cue (CS-) and generalization stimuli (GS) consisting of CS-/CS+ blends. Multivoxel BOLD signal patterns were measured in seven regions of interest: four affective areas (ventromedial prefrontal cortex (vmPFC), anterior insular cortex (AIC), dorsomedial prefrontal cortex (dmPFC), and amygdala) and three perceptual areas (inferior temporal cortex (ITC) and visual areas V1 and V4). Compared to low anxious children, children with high trait anxiety evidenced less neural pattern differentiation between the CS+ and similar GS, particularly in the vmPFC. Together, these results demonstrate the utility of multivariate neuroimaging approaches in arbitrating the relative contributions of perceptual versus affective sources to threat generalization.
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9
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Bakkum A, Donelan JM, Marigold DS. Challenging balance during sensorimotor adaptation increases generalization. J Neurophysiol 2020; 123:1342-1354. [PMID: 32130079 DOI: 10.1152/jn.00687.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
From reaching to walking, real-life experience suggests that people can generalize between motor behaviors. One possible explanation for this generalization is that real-life behaviors often challenge our balance. We propose that the exacerbated body motions associated with balance-challenged whole body movements increase the value to the nervous system of using a comprehensive internal model to control the task. Because it is less customized to a specific task, a more comprehensive model is also a more generalizable model. Here we tested the hypothesis that challenging balance during adaptation would increase generalization of a newly learned internal model. We encouraged participants to learn a new internal model using prism lenses that created a new visuomotor mapping. Four groups of participants adapted to prisms while performing either a standing-based reaching or precision walking task, with or without a manipulation that challenged balance. To assess generalization after the adaptation phase, participants performed a single trial of each of the other groups' tasks without prisms. We found that both the reaching and walking balance-challenged groups showed significantly greater generalization to the equivalent, nonadapted task than the balance-unchallenged groups. Additionally, we found some evidence that all groups generalized across tasks, for example, from walking to reaching and vice versa, regardless of balance manipulation. Overall, our results demonstrate that challenging balance increases the degree to which a newly learned internal model generalizes to untrained movements.NEW & NOTEWORTHY Real-life experience indicates that people can generalize between motor behaviors. Here we show that challenging balance during the learning of a new internal model increases the degree of generalization to untrained movements for both reaching and walking tasks. These results suggest that the effects of challenging balance are not specific to the task but instead apply to motor learning more broadly.
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Affiliation(s)
- Amanda Bakkum
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - J Maxwell Donelan
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Daniel S Marigold
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
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10
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Dennis-Tiwary TA, Roy AK, Denefrio S, Myruski S. Heterogeneity of the Anxiety-Related Attention Bias: A Review and Working Model for Future Research. Clin Psychol Sci 2019; 7:879-899. [PMID: 33758680 DOI: 10.1177/2167702619838474] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The anxiety-related attention bias (AB) has been studied for several decades as a clinically-relevant output of the dynamic and complex threat detection-response system. Despite research enthusiasm for the construct of AB, current theories and measurement approaches cannot adequately account for the growing body of mixed, contradictory, and null findings. Drawing on clinical, neuroscience, and animal models, we argue that the apparent complexity and contradictions in the empirical literature can be attributed to the field's failure to clearly conceptualize AB heterogeneity and the dearth of studies in AB that consider additional cognitive mechanisms in anxiety, particularly disruptions in threat-safety discrimination and cognitive control. We review existing research and propose a working model of AB heterogeneity positing that AB may be best conceptualized as multiple subtypes of dysregulated processing of and attention to threat anchored in individual differences in threat-safety discrimination and cognitive control. We review evidence for this working model and discuss how it can be used to advance knowledge of AB mechanisms and inform personalized prevention and intervention approaches.
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Affiliation(s)
- Tracy A Dennis-Tiwary
- Hunter College, The City University of New York, Department of Psychology, New York, NY.,The Graduate Center, The City University of New York, Department of Psychology, New York, NY
| | - Amy Krain Roy
- Fordham University, Department of Psychology, Bronx, NY.,New York University Langone School of Medicine, Department of Child and Adolescent Psychiatry, New York, NY
| | - Samantha Denefrio
- The Graduate Center, The City University of New York, Department of Psychology, New York, NY.,Hunter College, The City University of New York, Department of Psychology, New York, NY
| | - Sarah Myruski
- Hunter College, The City University of New York, Department of Psychology, New York, NY
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11
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Abstract
Fear expressed toward threat-associated stimuli is an adaptive behavioral response. In contrast, the generalization of fear responses toward nonthreatening cues is a maladaptive and debilitating dimension of trauma- and anxiety-related disorders. Expressing fear to appropriate stimuli and suppressing fear generalization require integration of relevant sensory information and motor output. While thalamic and subthalamic brain regions play important roles in sensorimotor integration, very little is known about the contribution of these regions to the phenomenon of fear generalization. In this study, we sought to determine whether fear generalization could be modulated by the zona incerta (ZI), a subthalamic brain region that influences sensory discrimination, defensive responses, and retrieval of fear memories. To do so, we combined differential intensity-based auditory fear conditioning protocols in mice with C-FOS immunohistochemistry and designer receptors exclusively activated by designer drugs (DREADDs)-based manipulation of neuronal activity in the ZI. C-FOS immunohistochemistry revealed an inverse relationship between ZI activation and fear generalization: The ZI was less active in animals that generalized fear. In agreement with this relationship, chemogenetic inhibition of the ZI resulted in fear generalization, while chemogenetic activation of the ZI suppressed fear generalization. Furthermore, targeted stimulation of GABAergic cells in the ZI reduced fear generalization. To conclude, our data suggest that stimulation of the ZI could be used to treat fear generalization in the context of trauma- and anxiety-related disorders.
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12
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Ramsaran AI, Schlichting ML, Frankland PW. The ontogeny of memory persistence and specificity. Dev Cogn Neurosci 2019; 36:100591. [PMID: 30316637 PMCID: PMC6969236 DOI: 10.1016/j.dcn.2018.09.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/06/2018] [Accepted: 09/25/2018] [Indexed: 02/01/2023] Open
Abstract
Interest in the ontogeny of memory blossomed in the twentieth century following the initial observations that memories from infancy and early childhood are rapidly forgotten. The intense exploration of infantile amnesia in subsequent years has led to a thorough characterization of its psychological determinants, although the neurobiology of memory persistence has long remained elusive. By contrast, other phenomena in the ontogeny of memory like infantile generalization have received relatively less attention. Despite strong evidence for reduced memory specificity during ontogeny, infantile generalization is poorly understood from psychological and neurobiological perspectives. In this review, we examine the ontogeny of memory persistence and specificity in humans and nonhuman animals at the levels of behavior and the brain. To this end, we first describe the behavioral phenotypes associated with each phenomenon. Looking into the brain, we then discuss neurobiological mechanisms in the hippocampus that contribute to the ontogeny of memory. Hippocampal neurogenesis and critical period mechanisms have recently been discovered to underlie amnesia during early development, and at the same time, we speculate that similar processes may contribute to the early bias towards memory generalization.
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Affiliation(s)
- Adam I Ramsaran
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, M5S 3G3, Canada
| | | | - Paul W Frankland
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, M5S 3G3, Canada; Department of Physiology, University of Toronto, Toronto, M5S 1A8, Canada; Institute of Medical Science, University of Toronto, Toronto, M5S 1A8, Canada; Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, M5G 1M1, Canada.
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13
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Abstract
The processing and regulation of fear is one of the key components of posttraumatic stress disorder (PTSD). Fear can involve both acute and potential threats that can manifest in different behaviors and result from activity within different neural nodes and networks. Fear circuits have been studied extensively in animal models for several decades and in human neuroimaging research for almost 20 years. Therefore, the centrality of fear processing to PTSD lends the disorder to be more tractable to investigation at the level of brain and behavior, and provides several observable phenotypes that can be linked to PTSD symptoms. Moreover, psychophysiological metrics of fear conditioning offer tools that can be used to shift diagnostic paradigms in psychiatry toward neurobiology-consistent with a Research Domain Criteria approach to PTSD. In general, mammalian fear processing can be divided into fear learning (or acquisition), during which an association develops between previously neutral stimuli and aversive outcomes, and fear extinction, in which the latter associations are suppressed by a new form of learning. This review describes translational research in both fear acquisition and extinction, along with their relevance to PTSD and PTSD treatment, focusing specifically on the empirical value and potential clinical utility of psychophysiological methods.
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14
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Individual differences in voluntary alcohol consumption are associated with conditioned fear in the fear incubation model. Behav Brain Res 2019; 362:299-310. [PMID: 30664887 DOI: 10.1016/j.bbr.2019.01.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/24/2018] [Accepted: 01/14/2019] [Indexed: 12/31/2022]
Abstract
Previous research in male Long Evans rats has shown a relationship between low voluntary alcohol consumption and high conditioned fear after a single training session. Here, we determined whether chronic intermittent access (CIA) to alcohol during adolescence/early adulthood or during adulthood would alter or be associated with auditory-cued conditioned fear levels using an extended training fear incubation procedure. This training procedure leads to low fear soon after training that grows over one month. Rats received 6 weeks of CIA to 20% alcohol or water from PND 26-66. Ten or eleven days later, the rats began behavioral testing that included 10 sessions of tone-shock pairings. Rats then received 4 weeks of CIA exposure during the 1-month fear incubation period and were tested for conditioned fear 6 days after the end of alcohol access. We found no evidence that voluntary alcohol consumption during adolescence/early adulthood or adulthood altered fear expression. However, we found that rats that consumed more alcohol during early adulthood (PND 54-66) had lower fear than low-consumption rats on day 1 of conditioned fear training and in the day 2 and 1-month tests. This extends associations we previously found between individual differences in alcohol consumption and conditioned fear to a different fear conditioning procedure. Combined with our previous data that show that the rate of instrumental extinction is associated with both alcohol consumption and conditioned fear, these data provide further support for the generality and reliability of a pair of phenotypes that encompass a wide variety of learning traits.
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15
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Thome J, Hauschild S, Koppe G, Liebke L, Rausch S, Herzog JI, Müller-Engelmann M, Steil R, Priebe K, Hermans D, Schmahl C, Bohus M, Lis S. Generalisation of fear in PTSD related to prolonged childhood maltreatment: an experimental study. Psychol Med 2018; 48:2223-2234. [PMID: 29282161 DOI: 10.1017/s0033291717003713] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Fear responses are particularly intense and persistent in post-traumatic stress disorder (PTSD), and can be evoked by unspecific cues that resemble the original traumatic event. Overgeneralisation of fear might be one of the underlying mechanisms. We investigated the generalisation and discrimination of fear in individuals with and without PTSD related to prolonged childhood maltreatment. METHODS Sixty trauma-exposed women with (N = 30) and without (N = 30) PTSD and 30 healthy control participants (HC) underwent a fear conditioning and generalisation paradigm. In a contingency learning procedure, one of two circles of different sizes was associated with an electrical shock (danger cue), while the other circle represented a safety cue. During generalisation testing, online risk ratings, reaction times and fear-potentiated startle were measured in response to safety and danger cues as well as to eight generalisation stimuli, i.e. circles of parametrically varying size creating a continuum of similarity between the danger and safety cue. RESULTS The increase in reaction times from the safety cue across the different generalisation classes to the danger cue was less pronounced in PTSD compared with HC. Moreover, PTSD participants expected higher risk of an aversive event independent of stimulus types and task. CONCLUSIONS Alterations in generalisation constitute one part of fear memory alterations in PTSD. Neither the accuracy of a risk judgement nor the strength of the induced fear was affected. Instead, processing times as an index of uncertainty during risk judgements suggested a reduced differentiation between safety and threat in PTSD.
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Affiliation(s)
- Janine Thome
- Institute for Psychiatric and Psychosomatic Psychotherapy,Central Institute of Mental Health Mannheim,Medical Faculty Mannheim,Heidelberg University,Mannheim,Germany
| | - Sophie Hauschild
- Institute for Psychiatric and Psychosomatic Psychotherapy,Central Institute of Mental Health Mannheim,Medical Faculty Mannheim,Heidelberg University,Mannheim,Germany
| | - Georgia Koppe
- Department of Theoretical Neuroscience,Central Institute of Mental Health Mannheim,Medical Faculty Mannheim,Heidelberg University,Mannheim,Germany
| | - Lisa Liebke
- Institute for Psychiatric and Psychosomatic Psychotherapy,Central Institute of Mental Health Mannheim,Medical Faculty Mannheim,Heidelberg University,Mannheim,Germany
| | - Sophie Rausch
- Institute for Psychiatric and Psychosomatic Psychotherapy,Central Institute of Mental Health Mannheim,Medical Faculty Mannheim,Heidelberg University,Mannheim,Germany
| | - Julia I Herzog
- Department of Psychosomatic Medicine and Psychotherapy,Central Institute of Mental Health Mannheim,Medical Faculty Mannheim,Heidelberg University,Mannheim,Germany
| | - Meike Müller-Engelmann
- Department of Clinical Psychology and Intervention,Institute of Psychology,Goethe University Frankfurt,Frankfurt,Germany
| | - Regina Steil
- Department of Clinical Psychology and Intervention,Institute of Psychology,Goethe University Frankfurt,Frankfurt,Germany
| | - Kathlen Priebe
- Department of Psychology,Faculty of Life Sciences,Humboldt University Berlin,Berlin,Germany
| | - Dirk Hermans
- Faculty of Psychology and Educational Sciences,Leuven University,Leuven,Belgium
| | - Christian Schmahl
- Department of Psychosomatic Medicine and Psychotherapy,Central Institute of Mental Health Mannheim,Medical Faculty Mannheim,Heidelberg University,Mannheim,Germany
| | - Martin Bohus
- Institute for Psychiatric and Psychosomatic Psychotherapy,Central Institute of Mental Health Mannheim,Medical Faculty Mannheim,Heidelberg University,Mannheim,Germany
| | - Stefanie Lis
- Institute for Psychiatric and Psychosomatic Psychotherapy,Central Institute of Mental Health Mannheim,Medical Faculty Mannheim,Heidelberg University,Mannheim,Germany
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16
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Pollack GA, Bezek JL, Lee SH, Scarlata MJ, Weingast LT, Bergstrom HC. Cued fear memory generalization increases over time. Learn Mem 2018; 25:298-308. [PMID: 29907637 PMCID: PMC6004064 DOI: 10.1101/lm.047555.118] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 04/13/2018] [Indexed: 01/04/2023]
Abstract
Fear memory is a highly stable and durable form of memory, even over vast (remote) time frames. Nevertheless, some elements of fear memory can be forgotten, resulting in generalization. The purpose of this study is to determine how cued fear memory generalizes over time and measure underlying patterns of cortico-amygdala synaptic plasticity. We established generalization gradients at recent (1-d) and remote (30-d) retention intervals following auditory cued fear conditioning in adult male C57BL/6 mice. Results revealed a flattening of the generalization gradient (increased generalization) that was dissociated from contextual fear generalization, indicating a specific influence of time on cued fear memory performance. This effect reversed after a brief exposure to the novel stimulus soon after learning. Measurements from cortico-amygdala imaging of the activity-regulated cytoskeletal Arc/arg 3.1 (Arc) protein using immunohistochemistry after cued fear memory retrieval revealed a stable pattern of Arc expression in the dorsolateral amygdala, but temporally dynamic expression in the cortex. Over time, increased fear memory generalization was associated with a reduction in Arc expression in the agranular insular and infralimbic cortices while discrimination learning was associated with increased Arc expression in the prelimbic cortex. These data identify the dorsolateral amygdala, medial prefrontal, and insular cortices as loci for synaptic plasticity underlying cued fear memory generalization over time.
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Affiliation(s)
- Gabrielle A Pollack
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Jessica L Bezek
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Serena H Lee
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Miranda J Scarlata
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Leah T Weingast
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
| | - Hadley C Bergstrom
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York 12604 USA
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17
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Pajser A, Breen M, Fisher H, Pickens CL. Individual differences in conditioned fear are associated with levels of adolescent/early adult alcohol consumption and instrumental extinction. Behav Brain Res 2018; 349:145-157. [PMID: 29694912 DOI: 10.1016/j.bbr.2018.04.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/28/2018] [Accepted: 04/15/2018] [Indexed: 12/31/2022]
Abstract
Previous research has shown a relationship between alcohol exposure and conditioned fear, but the nature of this relationship remains unclear. We determined whether chronic intermittent access to alcohol during adolescence and early adulthood would alter or be associated with the level of conditioned fear to an auditory cue in male Long Evans rats. Rats received 6 weeks of chronic intermittent access to 20% alcohol or water from PND 26-66 and began behavioral testing 10 days later. We found no evidence that voluntary alcohol consumption altered fear. However, we found that rats that consumed more alcohol had lower fear, as measured with conditioned suppression of lever-pressing and conditioned freezing to an auditory cue. We have previously shown that higher levels of alcohol consumption are correlated with faster instrumental extinction learning. Therefore, we determined whether instrumental extinction would be directly associated with conditioned fear in rats never given alcohol access. As predicted, we found that rats that exhibited faster instrumental extinction also exhibited lower conditioned fear, as measured with conditioned suppression of lever-pressing and conditioned freezing. Our results suggest that at least part of the relationship between alcohol consumption levels and fear learning differences may be due to pre-existing individual differences. In addition, our finding that conditioned fear and instrumental extinction abilities (both separately associated with alcohol consumption levels) are associated with each other suggests that alcohol consumption levels may be a marker that can distinguish two separate phenotypes that encompass a wide variety of learning traits.
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Affiliation(s)
- Alisa Pajser
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, 66506, USA
| | - Morgan Breen
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, 66506, USA
| | - Hayley Fisher
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, 66506, USA
| | - Charles L Pickens
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, 66506, USA.
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18
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Xiao C, Liu Y, Xu J, Gan X, Xiao Z. Septal and Hippocampal Neurons Contribute to Auditory Relay and Fear Conditioning. Front Cell Neurosci 2018; 12:102. [PMID: 29713265 PMCID: PMC5911473 DOI: 10.3389/fncel.2018.00102] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/28/2018] [Indexed: 01/30/2023] Open
Abstract
The hippocampus has been thought to process auditory information. However, the properties, pathway, and role of hippocampal auditory responses are unclear. With loose-patch recordings, we found that hippocampal neurons are mainly responsive to noise and are not tonotopically organized. Their latencies are shorter than those of primary auditory cortical (A1) neurons but longer than those of medial septal (MS) neurons, suggesting that hippocampal auditory information comes from MS neurons rather than from A1 neurons. Silencing the MS blocks both hippocampal auditory responses and memory of auditory fear conditioning trained with noise and tone. Auditory fear conditioning was associated with some cues but not with a specific frequency of sound, as demonstrated by animals trained with noise, 2.5-, 5-, 10-, 15-, or 30-kHz tones, and tested with these sounds. Therefore, the noise responses of hippocampal neurons have identified a population of neurons that can be associated with auditory fear conditioning.
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Affiliation(s)
- Cuiyu Xiao
- Key Laboratory of Psychiatric Disorders of Guangdong Province, Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yun Liu
- Key Laboratory of Psychiatric Disorders of Guangdong Province, Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jian Xu
- Key Laboratory of Psychiatric Disorders of Guangdong Province, Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xiong Gan
- Key Laboratory of Psychiatric Disorders of Guangdong Province, Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zhongju Xiao
- Key Laboratory of Psychiatric Disorders of Guangdong Province, Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
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19
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Koban L, Kusko D, Wager TD. Generalization of learned pain modulation depends on explicit learning. Acta Psychol (Amst) 2018; 184:75-84. [PMID: 29025685 DOI: 10.1016/j.actpsy.2017.09.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 08/28/2017] [Accepted: 09/19/2017] [Indexed: 11/30/2022] Open
Abstract
The experience of pain is strongly influenced by contextual and socio-affective factors, including learning from previous experiences. Pain is typically perceived as more intense when preceded by a conditioned cue (CSHIGH) that has previously been associated with higher pain intensities, compared to cues associated with lower intensities (CSLOW). In three studies (total N=134), we tested whether this learned pain modulation generalizes to perceptually similar cues (Studies 1 and 2) and conceptually similar cues (Study 3). The results showed that participants report higher pain when heat stimulation was preceded by novel stimuli that were either perceptually (Studies 1 and 2) or conceptually (Study 3) similar to the previously conditioned CSHIGH. In all three studies, the strength of this generalization effect was strongly correlated with individual differences in explicitly learned expectations. Together, these findings suggest an important role of conscious expectations and higher-order conceptual inference during generalization of learned pain modulation. We discuss implications for the understanding of placebo and nocebo effects as well as for chronic pain and anxiety.
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Affiliation(s)
- Leonie Koban
- Department of Psychology and Neuroscience, University of Colorado Boulder, United States; Institute of Cognitive Science, University of Colorado Boulder, United States.
| | - Daniel Kusko
- Department of Psychology and Neuroscience, University of Colorado Boulder, United States; Institute of Cognitive Science, University of Colorado Boulder, United States
| | - Tor D Wager
- Department of Psychology and Neuroscience, University of Colorado Boulder, United States; Institute of Cognitive Science, University of Colorado Boulder, United States
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20
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Abstract
Most behaviors in mammals are directly or indirectly guided by prior experience and therefore depend on the ability of our brains to form memories. The ability to form an association between an initially possibly neutral sensory stimulus and its behavioral relevance is essential for our ability to navigate in a changing environment. The formation of a memory is a complex process involving many areas of the brain. In this chapter we review classic and recent work that has shed light on the specific contribution of sensory cortical areas to the formation of associative memories. We discuss synaptic and circuit mechanisms that mediate plastic adaptations of functional properties in individual neurons as well as larger neuronal populations forming topographically organized representations. Furthermore, we describe commonly used behavioral paradigms that are used to study the mechanisms of memory formation. We focus on the auditory modality that is receiving increasing attention for the study of associative memory in rodent model systems. We argue that sensory cortical areas may play an important role for the memory-dependent categorical recognition of previously encountered sensory stimuli.
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Affiliation(s)
- Dominik Aschauer
- Institute of Physiology, Focus Program Translational Neurosciences (FTN), University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Simon Rumpel
- Institute of Physiology, Focus Program Translational Neurosciences (FTN), University Medical Center, Johannes Gutenberg University, Mainz, Germany.
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21
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Dunsmoor JE, Kroes MCW, Braren SH, Phelps EA. Threat intensity widens fear generalization gradients. Behav Neurosci 2017; 131:168-175. [PMID: 28221081 PMCID: PMC5354976 DOI: 10.1037/bne0000186] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Research in nonhuman animals reveals threat-sensitive generalization of defensive behavior that favors widespread generalization when threat intensity is high and limited generalization (i.e., specificity) when threat intensity is low. Here, we used Pavlovian fear conditioning to systematically investigate whether threat intensity widens behavioral generalization gradients to stimuli that decreasingly resemble a learned threat cue. Using a between-subjects design, volunteers underwent fear conditioning with a tone paired with either a high-intensity or low-intensity aversive stimulus prior to a test of fear generalization to novel tones. Results showed no effect of threat intensity on initial acquisition of conditioned fear. However, volunteers who underwent fear conditioning with a high-intensity aversive stimulus exhibited widespread generalization of autonomic arousal (skin conductance responses) as compared to volunteers who received a low-intensity aversive stimulus. These results show a transition from normal (selective) to overgeneralized fear as threat intensity increases, and have implications for understanding overgeneralization characteristic of trauma- and stress-related disorders. (PsycINFO Database Record
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Affiliation(s)
- Joseph E. Dunsmoor
- Psychology Department and Center for Neural Sciences, New York University, New York, NY, 10003, USA
| | - Marijn C. W. Kroes
- Psychology Department and Center for Neural Sciences, New York University, New York, NY, 10003, USA
| | - Stephen H. Braren
- Psychology Department, Hunter College, City University of New York, New York, NY, 10065, USA
| | - Elizabeth A. Phelps
- Psychology Department and Center for Neural Sciences, New York University, New York, NY, 10003, USA
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
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22
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Kaczkurkin AN, Burton PC, Chazin SM, Manbeck AB, Espensen-Sturges T, Cooper SE, Sponheim SR, Lissek S. Neural Substrates of Overgeneralized Conditioned Fear in PTSD. Am J Psychiatry 2017; 174:125-134. [PMID: 27794690 PMCID: PMC7269602 DOI: 10.1176/appi.ajp.2016.15121549] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Heightened generalization of fear from an aversively reinforced conditioned stimulus (CS+, a conditioned danger cue) to resembling stimuli is widely accepted as a pathogenic marker of posttraumatic stress disorder (PTSD). Indeed, a distress response to benign stimuli that "resemble" aspects of the trauma is a central feature of the disorder. To date, the link between overgeneralization of conditioned fear and PTSD derives largely from clinical observations, with limited empirical work on the subject. This represents the first effort to examine behavioral and brain indices of generalized conditioned fear in PTSD using systematic methods developed in animals known as generalization gradients: the gradual decline in conditioned responding as the presented stimulus gradually differentiates from CS+. METHOD Gradients of conditioned fear generalization were assessed using functional MRI and behavioral measures in U.S. combat veterans who served in Iraq or Afghanistan and had PTSD (N=26), subthreshold PTSD (N=19), or no PTSD (referred to as trauma control subjects) (N=17). Presented stimuli included rings of graded size, with extreme sizes serving as CS+ (paired with shock) and as a nonreinforced conditioned stimulus (CS-, a conditioned safety cue), and with intermediate sizes forming a continuum of similarity between CS+ and CS-. Generalization gradients were assessed as response slopes from CS+, through intermediate ring sizes, to CS-, with less steep slopes indicative of stronger generalization. RESULTS Relative to trauma control subjects, PTSD patients showed stronger conditioned generalization, as evidenced by less steep generalization gradients in both behavioral risk ratings and brain responses in the left and right anterior insula, left ventral hippocampus, dorsolateral and dorsomedial prefrontal cortex, and caudate nucleus. Severity of PTSD symptoms across the three study groups was positively correlated with levels of generalization at two such loci: the right anterior insula and left ventral hippocampus. CONCLUSIONS The results point to evidence of brain-based markers of overgeneralized fear conditioning related to PTSD. These findings provide further understanding of a central yet understudied symptom of trauma-related psychopathology.
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Affiliation(s)
| | - Philip C. Burton
- Department of Psychology, University of Minnesota, Minneapolis, MN
| | - Shai M. Chazin
- Department of Psychology, University of Minnesota, Minneapolis, MN
| | | | | | - Samuel E. Cooper
- Department of Psychology, University of Minnesota, Minneapolis, MN
| | | | - Shmuel Lissek
- Department of Psychology, University of Minnesota, Minneapolis, MN
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23
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Wigestrand MB, Schiff HC, Fyhn M, LeDoux JE, Sears RM. Primary auditory cortex regulates threat memory specificity. Learn Mem 2017; 24:55-58. [PMID: 27980076 PMCID: PMC5159661 DOI: 10.1101/lm.044362.116] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 10/24/2016] [Indexed: 01/26/2023]
Abstract
Distinguishing threatening from nonthreatening stimuli is essential for survival and stimulus generalization is a hallmark of anxiety disorders. While auditory threat learning produces long-lasting plasticity in primary auditory cortex (Au1), it is not clear whether such Au1 plasticity regulates memory specificity or generalization. We used muscimol infusions in rats to show that discriminatory threat learning requires Au1 activity specifically during memory acquisition and retrieval, but not during consolidation. Memory specificity was similarly disrupted by infusion of PKMζ inhibitor peptide (ZIP) during memory storage. Our findings show that Au1 is required at critical memory phases and suggest that Au1 plasticity enables stimulus discrimination.
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Affiliation(s)
- Mattis B Wigestrand
- Center for Neuroscience, New York University, New York, New York 10003, USA
- Department of Molecular Biosciences, University of Oslo, 0371 Oslo, Norway
| | - Hillary C Schiff
- Center for Neuroscience, New York University, New York, New York 10003, USA
| | - Marianne Fyhn
- Department of Molecular Biosciences, University of Oslo, 0371 Oslo, Norway
| | - Joseph E LeDoux
- Center for Neuroscience, New York University, New York, New York 10003, USA
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962, USA
| | - Robert M Sears
- Center for Neuroscience, New York University, New York, New York 10003, USA
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962, USA
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24
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Nair SS, Paré D, Vicentic A. Biologically based neural circuit modelling for the study of fear learning and extinction. NPJ SCIENCE OF LEARNING 2016; 1:16015. [PMID: 29541482 PMCID: PMC5846682 DOI: 10.1038/npjscilearn.2016.15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/09/2016] [Accepted: 09/19/2016] [Indexed: 05/25/2023]
Abstract
The neuronal systems that promote protective defensive behaviours have been studied extensively using Pavlovian conditioning. In this paradigm, an initially neutral-conditioned stimulus is paired with an aversive unconditioned stimulus leading the subjects to display behavioural signs of fear. Decades of research into the neural bases of this simple behavioural paradigm uncovered that the amygdala, a complex structure comprised of several interconnected nuclei, is an essential part of the neural circuits required for the acquisition, consolidation and expression of fear memory. However, emerging evidence from the confluence of electrophysiological, tract tracing, imaging, molecular, optogenetic and chemogenetic methodologies, reveals that fear learning is mediated by multiple connections between several amygdala nuclei and their distributed targets, dynamical changes in plasticity in local circuit elements as well as neuromodulatory mechanisms that promote synaptic plasticity. To uncover these complex relations and analyse multi-modal data sets acquired from these studies, we argue that biologically realistic computational modelling, in conjunction with experiments, offers an opportunity to advance our understanding of the neural circuit mechanisms of fear learning and to address how their dysfunction may lead to maladaptive fear responses in mental disorders.
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Affiliation(s)
- Satish S Nair
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO, USA
| | - Denis Paré
- Center for Molecular and Behavioral Neuroscience, Rutgers University—Newark, Newark, NJ, USA
| | - Aleksandra Vicentic
- Division of Neuroscience and Basic Behavioral Science, National Institute of Mental Health, Rockville, MD, USA
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25
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Bergstrom HC. The neurocircuitry of remote cued fear memory. Neurosci Biobehav Rev 2016; 71:409-417. [PMID: 27693699 DOI: 10.1016/j.neubiorev.2016.09.028] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 09/25/2016] [Accepted: 09/27/2016] [Indexed: 11/16/2022]
Abstract
Memories of threatening, fear-evoking events can persist even over a lifetime. While fear memory is widely considered to be a highly persistent and durable form of memory, its circuits are not. This article reviews the dynamic temporal representation of remote fear memory in the brain, at the level of local circuits and distributed networks. Data from the study of Pavlovian cued fear conditioning suggests memory retrieval remains amygdala-dependent, even over protracted time scales, all the while interconnected cortical and subcortical circuits are newly recruited and progressively reorganized. A deeper understanding into how the neurocircuitry of cued fear memory reorganizes with the passage of time will advance our ongoing search for the elusive physical changes representing fear memories in the brain. Considering that persistent, pathological fear memories are a hallmark feature of post-traumatic stress disorder (PTSD), the behavioral and circuit-level study of remote cued fear memory retrieval adds a key element towards a systems understanding of PTSD.
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Affiliation(s)
- Hadley C Bergstrom
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, NY 12604, United States.
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26
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Abstract
Oscillatory activity in the gamma-band range has been related both to gestalt perception and to cognitive functions such as attention, learning, and memory. After giving a brief account of recent findings from electroencephalography and intracortical recordings, the present review will focus on spectral activity in the magnetoencephalogram. Here, gamma-band effects are topographically more local and involve higher frequencies than in the electroencephalogram. Bottom-up-driven auditory spatial mismatch detection elicits gamma-band activity over posterior parietal cortex, whereas auditory pattern mismatch processing leads to gamma-band enhancements over anterior temporal and inferior frontal regions. These topographies support representations of auditory spatial and pattern information in the putative dual auditory “where” and “what” pathways, respectively. During top-down-guided auditory spatial and pattern-working memory tasks, prefrontal gamma-band increases are observed in addition to activations over putative auditory stream areas. Moreover, stimulus maintenance in working memory is accompanied by coherence increases between sensory and prefrontal regions. Gamma-band topographies in magnetoencephalogram are highly comparable with hemodynamic brain imaging studies but yield additional information on the temporal dynamics of activations and connectivity patterns. In summary, magnetoencephalographic gammaband activity revealed both local synchronization patterns and cortico-cortical interactions accompanying cognitive processes at a good spatial and high temporal resolution.
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Affiliation(s)
- Jochen Kaiser
- MEG-Center, Institute of Medical Psychology and Behavioral Neurobiology, Eberhard-Karls-University of Tübingen, Germany.
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27
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Kim D, Samarth P, Feng F, Pare D, Nair SS. Synaptic competition in the lateral amygdala and the stimulus specificity of conditioned fear: a biophysical modeling study. Brain Struct Funct 2016; 221:2163-82. [PMID: 25859631 PMCID: PMC4600426 DOI: 10.1007/s00429-015-1037-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 03/31/2015] [Indexed: 12/20/2022]
Abstract
Competitive synaptic interactions between principal neurons (PNs) with differing intrinsic excitability were recently shown to determine which dorsal lateral amygdala (LAd) neurons are recruited into a fear memory trace. Here, we explored the contribution of these competitive interactions in determining the stimulus specificity of conditioned fear associations. To this end, we used a realistic biophysical computational model of LAd that included multi-compartment conductance-based models of 800 PNs and 200 interneurons. To reproduce the continuum of spike frequency adaptation displayed by PNs, the model included three subtypes of PNs with high, intermediate, and low spike frequency adaptation. In addition, the model network integrated spatially differentiated patterns of excitatory and inhibitory connections within LA, dopaminergic and noradrenergic inputs, extrinsic thalamic and cortical tone afferents to simulate conditioned stimuli as well as shock inputs for the unconditioned stimulus. Last, glutamatergic synapses in the model could undergo activity-dependent plasticity. Our results suggest that plasticity at both excitatory (PN-PN) and di-synaptic inhibitory (PN-ITN and, particularly, ITN-PN) connections are major determinants of the synaptic competition governing the assignment of PNs to the memory trace. The model also revealed that training-induced potentiation of PN-PN synapses promotes, whereas that of ITN-PN synapses opposes, stimulus generalization. Indeed, suppressing plasticity of PN-PN synapses increased, whereas preventing plasticity of interneuronal synapses decreased the CS specificity of PN recruitment. Overall, our results indicate that the plasticity configuration imprinted in the network by synaptic competition ensures memory specificity. Given that anxiety disorders are characterized by tendency to generalize learned fear to safe stimuli or situations, understanding how plasticity of intrinsic LAd synapses regulates the specificity of learned fear is an important challenge for future experimental studies.
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Affiliation(s)
- D Kim
- Electrical and Computer Engineering, University of Missouri, Columbia, MO, 65211, USA
| | - P Samarth
- Electrical and Computer Engineering, University of Missouri, Columbia, MO, 65211, USA
| | - F Feng
- Electrical and Computer Engineering, University of Missouri, Columbia, MO, 65211, USA
| | - D Pare
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ, 07102, USA
| | - Satish S Nair
- Electrical and Computer Engineering, University of Missouri, Columbia, MO, 65211, USA.
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28
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Laufer O, Israeli D, Paz R. Behavioral and Neural Mechanisms of Overgeneralization in Anxiety. Curr Biol 2016; 26:713-22. [PMID: 26948881 DOI: 10.1016/j.cub.2016.01.023] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 01/07/2016] [Accepted: 01/11/2016] [Indexed: 10/22/2022]
Abstract
Overgeneralization of dangerous stimuli is a possible etiological account for anxiety disorders, yet the underlying behavioral and neural origins remain vague. Specifically, it is unclear whether this is a choice behavior in an unsafe environment ("better safe than sorry") or also a fundamental change in how the stimulus is perceived. We show that anxiety patients have wider generalization for loss-conditioned tone when compared to controls and do so even in a safe context that requires a different behavioral policy. Moreover, patients overgeneralized for gain-conditioned tone as well. Imaging (fMRI) revealed that in anxiety only, activations during conditioning in the dACC and the putamen were correlated with later overgeneralization of loss and gain, respectively, whereas valence distinction in the amygdala and hippocampus during conditioning mediated the difference between loss and gain generalization. During generalization itself, neural discrimination based on multivoxel patterns in auditory cortex and amygdala revealed specific stimulus-related plasticity. Our results suggest that overgeneralization in anxiety has perceptual origins and involves affective modulation of stimulus representations in primary cortices and amygdala.
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Affiliation(s)
- Offir Laufer
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - David Israeli
- The Jerusalem Mental Health Center and the Hebrew University, Jerusalem 91120, Israel
| | - Rony Paz
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel.
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29
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Feng F, Samarth P, Paré D, Nair SS. Mechanisms underlying the formation of the amygdalar fear memory trace: A computational perspective. Neuroscience 2016; 322:370-6. [PMID: 26944604 DOI: 10.1016/j.neuroscience.2016.02.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 02/19/2016] [Accepted: 02/24/2016] [Indexed: 12/24/2022]
Abstract
Recent experimental and modeling studies on the lateral amygdala (LA) have implicated intrinsic excitability and competitive synaptic interactions among principal neurons (PNs) in the formation of auditory fear memories. The present modeling studies, conducted over an expanded range of intrinsic excitability in the network, revealed that only excitable PNs that received tone inputs participate in the competition. Strikingly, the number of model PNs integrated into the fear memory trace remained constant despite the much larger range considered, and model runs highlighted several conditioning-induced tone responsive characteristics of the various PN populations. Furthermore, these studies showed that although excitation was important, disynaptic inhibition among PNs is the dominant mechanism that keeps the number of plastic PNs stable despite large variations in the network's excitability. Finally, we found that the overall level of inhibition in the model network determines the number of projection cells integrated into the fear memory trace.
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Affiliation(s)
- F Feng
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO, USA
| | - P Samarth
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO, USA
| | - D Paré
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - S S Nair
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, MO, USA.
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Hersman S, Rodriguez Barrera V, Fanselow M. Assigning Function to Adult-Born Neurons: A Theoretical Framework for Characterizing Neural Manipulation of Learning. Front Syst Neurosci 2016; 9:182. [PMID: 26778981 PMCID: PMC4700131 DOI: 10.3389/fnsys.2015.00182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/07/2015] [Indexed: 12/26/2022] Open
Abstract
Neuroscientists are concerned with neural processes or computations, but these may not be directly observable. In the field of learning, a behavioral procedure is observed to lead to performance outcomes, but differing inferences on underlying internal processes can lead to difficulties in interpreting conflicting results. An example of this challenge is how many functions have been attributed to adult-born granule cells in the dentate gyrus. Some of these functions were suggested by computational models of the properties of these neurons, while others were hypothesized after manipulations of adult-born neurons resulted in changes to behavioral metrics. This review seeks to provide a framework, based in learning theory classification of behavioral procedures, of the processes that may be underlying behavioral results after manipulating procedure and observing performance. We propose that this framework can serve to clarify experimental findings on adult-born neurons as well as other classes of neural manipulations and their effects on behavior.
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Affiliation(s)
- Sarah Hersman
- Department of Psychology, University of California, Los AngelesLos Angeles, CA, USA
| | | | - Michael Fanselow
- Department of Psychology, University of California, Los AngelesLos Angeles, CA, USA
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los AngelesLos Angeles, CA, USA
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Neural circuits and mechanisms involved in fear generalization: Implications for the pathophysiology and treatment of posttraumatic stress disorder. Neurosci Biobehav Rev 2016; 60:31-42. [DOI: 10.1016/j.neubiorev.2015.10.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 09/15/2015] [Accepted: 10/20/2015] [Indexed: 12/14/2022]
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Dunning JP, Hajcak G. Gradients of Fear Potentiated Startle During Generalization, Extinction, and Extinction Recall--and Their Relations With Worry. Behav Ther 2015; 46:640-51. [PMID: 26459844 DOI: 10.1016/j.beth.2015.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/08/2015] [Accepted: 06/23/2015] [Indexed: 11/30/2022]
Abstract
It is well established that fear conditioning plays a role in the development and maintenance of anxiety disorders. Moreover, abnormalities in fear generalization, extinction, and extinction recall have also been associated with anxiety. The present study used a generalization paradigm to examine fear processing during phases of generalization, extinction, and extinction recall. Specifically, participants were shocked following a CS+ and were also presented with stimuli that ranged in perceptual similarity to the CS+ (i.e., 20%, 40%, or 60% smaller or larger than the CS+) during a fear generalization phase. Participants were also presented with the same stimuli during an extinction phase and an extinction recall phase 1week later; no shocks were presented during extinction or recall. Lastly, participants completed self-report measures of worry and trait anxiety. Results indicated that fear potentiated startle (FPS) to the CS+ and GS±20% shapes was present in generalization and extinction, suggesting that fear generalization persisted into extinction. FPS to the CS+ was also evident 1 week later during extinction recall. Higher levels of worry were associated with greater FPS to the CS+ during generalization and extinction phases. Moreover, individuals high in worry had fear response gradients that were steeper during both generalization and extinction. This suggests that high levels of worry are associated with greater discriminative fear conditioning to threatening compared to safe stimuli and less fear generalization to perceptually similar stimuli.
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Fear Generalization and Anxiety: Behavioral and Neural Mechanisms. Biol Psychiatry 2015; 78:336-43. [PMID: 25981173 DOI: 10.1016/j.biopsych.2015.04.010] [Citation(s) in RCA: 267] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 04/01/2015] [Accepted: 04/14/2015] [Indexed: 01/02/2023]
Abstract
Fear can be an adaptive emotion that helps defend against potential danger. Classical conditioning models elegantly describe how animals learn which stimuli in the environment signal danger, but understanding how this learning is generalized to other stimuli that resemble aspects of a learned threat remains a challenge. Critically, the overgeneralization of fear to harmless stimuli or situations is a burden to daily life and characteristic of posttraumatic stress disorder and other anxiety disorders. Here, we review emerging evidence on behavioral and neural mechanisms of generalization of emotional learning with the goal of encouraging further research on generalization in anxiety disorders. We begin by placing research on fear generalization in a rich historical context of stimulus generalization dating back to Pavlov, which lays the foundation for theoretical and experimental approaches used today. We then transition to contemporary behavioral and neurobiological research on generalization of emotional learning in humans and nonhuman animals and discuss the factors that promote generalization on the one hand from discrimination on the other hand.
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Montes-Lourido P, Vicente AF, Bermudez MA, Gonzalez F. Neural activity in monkey amygdala during performance of a multisensory operant task. J Integr Neurosci 2015; 14:309-23. [PMID: 26246438 DOI: 10.1142/s021963521550020x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this paper, we study the potential involvement of monkey amygdala in the evaluation of value encoding of visual and auditive stimuli associated with reward or no reward. We recorded the activity of 93 extracellular neurons from the monkey right amygdala, while performing a multisensory operant task. The activity of 78 task-related neurons was studied. Of these, 13 neurons (16%) responded to the value of visual stimuli, 22 neurons (28%) responded after the presentation of visual stimuli, 22 neurons (28%) showed an inhibition around the lever-pressing and were classified as action related neurons and 22 neurons (28%) responded after reward delivery. These findings suggest that neurons in the amygdala play a role in encoding value and processing visual information, participate in motor regulation and are sensitive to reward. The activity of these neurons did not change in the evaluation of auditive stimuli. These data support the hypothesis that amygdala neurons are specific to each sensory modality and that different groups of amygdala neurons process visual and auditive information.
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Affiliation(s)
- Pilar Montes-Lourido
- * Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela E-15782, Spain
| | - Ana F Vicente
- * Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela E-15782, Spain
| | - Maria A Bermudez
- * Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela E-15782, Spain
| | - Francisco Gonzalez
- * Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela E-15782, Spain.,† Department of Surgery, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.,‡ Service of Ophthalmology and IDIS, Complejo Hospitalario Universitario de Santiago de Compostela, E-15706 Santiago de Compostela, Spain
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Melzer N, Budde T, Stork O, Meuth SG. Limbic Encephalitis: Potential Impact of Adaptive Autoimmune Inflammation on Neuronal Circuits of the Amygdala. Front Neurol 2015; 6:171. [PMID: 26284026 PMCID: PMC4522870 DOI: 10.3389/fneur.2015.00171] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/20/2015] [Indexed: 12/31/2022] Open
Abstract
Limbic encephalitis is characterized by adaptive autoimmune inflammation of the gray matter structures of the limbic system. It has recently been identified as a major cause of temporal lobe epilepsy accompanied by progressive declarative – mainly episodic – memory disturbance as well as a variety of rather poorly defined emotional and behavioral changes. While autoimmune inflammation of the hippocampus is likely to be responsible for declarative memory disturbance, consequences of autoimmune inflammation of the amygdala are largely unknown. The amygdala is central for the generation of adequate homoeostatic behavioral responses to emotionally significant external stimuli following processing in a variety of parallel neuronal circuits. Here, we hypothesize that adaptive cellular and humoral autoimmunity may target and modulate distinct inhibitory or excitatory neuronal networks within the amygdala, and thereby strongly impact processing of emotional stimuli and corresponding behavioral responses. This may explain some of the rather poorly understood neuropsychiatric symptoms in limbic encephalitis.
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Affiliation(s)
- Nico Melzer
- Department of Neurology, University of Münster , Münster , Germany
| | - Thomas Budde
- Institute of Physiology I, University of Münster , Münster , Germany
| | - Oliver Stork
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg , Magdeburg , Germany
| | - Sven G Meuth
- Department of Neurology, University of Münster , Münster , Germany ; Department of Neuropathophysiology, Institute of Physiology I, University of Münster , Münster , Germany
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Auditory cortex directs the input-specific remodeling of thalamus. Hear Res 2015; 328:1-7. [PMID: 26143340 DOI: 10.1016/j.heares.2015.06.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/10/2015] [Accepted: 06/23/2015] [Indexed: 01/09/2023]
Abstract
Input-specific remodeling is observed both in the primary auditory cortex (AI) and the ventral division of the medial geniculate body of the thalamus (MGBv) through motivation such as learning. Here, we show the role of AI in the MGBv remodeling induced by the electrical stimulation (ES) of the central division of the inferior colliculus (ICc). For the MGBv neurons with frequency tunings different from those of electrically stimulated ICc neurons, their frequency tunings shifted towards the tunings of the ICc neurons. AI neurons also showed this input-specific remodeling after ES of the ICc (ESICc). Interestingly, the input-specific remodeling of MGBv was eliminated when the AI was inactivated using cortical application of muscimol. For the MGBv neurons tuned to the same frequency as the stimulated ICc neurons, their tunings were kept but their responses were facilitated after the ESICc. In contrast to the input-specific tuning shifts, this facilitation was rarely impacted by the AI inactivation. Thus, we conclude that AI directs the input-specific remodeling of MGBv induced by ESICc. It is suggested that the tuning shift in the MGBv primarily takes place in the AI and is relayed to the MGBv through the corticofugal system while the MGBv mainly highlights the frequency information emphasized in ICc.
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Abstract
Auditory cortex is necessary for the perceptual detection of brief gaps in noise, but is not necessary for many other auditory tasks such as frequency discrimination, prepulse inhibition of startle responses, or fear conditioning with pure tones. It remains unclear why auditory cortex should be necessary for some auditory tasks but not others. One possibility is that auditory cortex is causally involved in gap detection and other forms of temporal processing in order to associate meaning with temporally structured sounds. This predicts that auditory cortex should be necessary for associating meaning with gaps. To test this prediction, we developed a fear conditioning paradigm for mice based on gap detection. We found that pairing a 10 or 100 ms gap with an aversive stimulus caused a robust enhancement of gap detection measured 6 h later, which we refer to as fear potentiation of gap detection. Optogenetic suppression of auditory cortex during pairing abolished this fear potentiation, indicating that auditory cortex is critically involved in associating temporally structured sounds with emotionally salient events.
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Resnik J, Paz R. Fear generalization in the primate amygdala. Nat Neurosci 2014; 18:188-90. [PMID: 25531573 DOI: 10.1038/nn.3900] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 11/16/2014] [Indexed: 12/13/2022]
Abstract
Broad generalization of negative memories is a potential etiology for anxiety disorders, yet the underlying mechanisms remain unknown. We developed a non-human primate model that replicates behavioral observations in humans and identifies specific changes in tuning properties of amygdala neurons: the width of auditory tuning increases with the distance of its center from the conditioned stimulus. This center-width relationship can account for better detection and at the same time explain the wide stimulus generalization.
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Affiliation(s)
- Jennifer Resnik
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Rony Paz
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
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39
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Ghosh S, Chattarji S. Neuronal encoding of the switch from specific to generalized fear. Nat Neurosci 2014; 18:112-20. [DOI: 10.1038/nn.3888] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/29/2014] [Indexed: 12/14/2022]
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Lissek S, van Meurs B. Learning models of PTSD: Theoretical accounts and psychobiological evidence. Int J Psychophysiol 2014; 98:594-605. [PMID: 25462219 DOI: 10.1016/j.ijpsycho.2014.11.006] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 10/29/2014] [Accepted: 11/10/2014] [Indexed: 12/18/2022]
Abstract
Learning abnormalities have long been centrally implicated in posttraumatic psychopathology. Indeed, of all anxiety disorders, PTSD may be most clearly attributable to discrete, aversive learning events. In PTSD, such learning is acquired during the traumatic encounter and is expressed as both conditioned fear to stimuli associated with the event and more general over-reactivity-or failure to adapt-to intense, novel, or fear-related stimuli. The relatively straightforward link between PTSD and these basic, evolutionarily old, learning processes of conditioning, sensitization, and habituation affords models of PTSD comprised of fundamental, experimentally tractable mechanisms of learning that have been well characterized across a variety of mammalian species including humans. Though such learning mechanisms have featured prominently in explanatory models of psychological maladjustment to trauma for at least 90years, much of the empirical testing of these models has occurred only in the past two decades. The current review delineates the variety of theories forming this longstanding tradition of learning-based models of PTSD, details empirical evidence for such models, attempts an integrative account of results from this literature, and specifies limitations of, and future directions for, studies testing learning models of PTSD.
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Affiliation(s)
- Shmuel Lissek
- University of Minnesota-Twin Cities Campus, Department of Psychology, 75 East River Road, Minneapolis, MN 55455, United States.
| | - Brian van Meurs
- University of Minnesota-Twin Cities Campus, Department of Psychology, 75 East River Road, Minneapolis, MN 55455, United States
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Hegoburu C, Parrot S, Ferreira G, Mouly AM. Differential involvement of amygdala and cortical NMDA receptors activation upon encoding in odor fear memory. ACTA ACUST UNITED AC 2014; 21:651-5. [PMID: 25403452 PMCID: PMC4236412 DOI: 10.1101/lm.036558.114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Although the basolateral amygdala (BLA) plays a crucial role for the acquisition of fear memories, sensory cortices are involved in their long-term storage in rats. However, the time course of their respective involvement has received little investigation. Here we assessed the role of the glutamatergic N-methyl-d-aspartate (NMDA) receptors in the BLA and olfactory cortex at discrete moments of an odor fear conditioning session. We showed that NMDA receptors in BLA are critically involved in odor fear acquisition during the first association but not during the next ones. In the cortex, NMDA receptor activation at encoding is not necessary for recent odor fear memory while its role in remote memory storage needs further investigation.
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Affiliation(s)
- Chloé Hegoburu
- Centre de Recherche en Neurosciences de Lyon, INSERM U1028, CNRS UMR5292, University Lyon1, Lyon, France
| | - Sandrine Parrot
- Centre de Recherche en Neurosciences de Lyon, INSERM U1028, CNRS UMR5292, University Lyon1, Lyon, France
| | - Guillaume Ferreira
- INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France Université de Bordeaux, Nutrition et Neurobiologie Intégrée, Bordeaux, France
| | - Anne-Marie Mouly
- Centre de Recherche en Neurosciences de Lyon, INSERM U1028, CNRS UMR5292, University Lyon1, Lyon, France
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42
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Kindt M. A behavioural neuroscience perspective on the aetiology and treatment of anxiety disorders. Behav Res Ther 2014; 62:24-36. [DOI: 10.1016/j.brat.2014.08.012] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 08/18/2014] [Accepted: 08/18/2014] [Indexed: 01/06/2023]
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Norrholm SD, Jovanovic T, Briscione MA, Anderson KM, Kwon CK, Warren VT, Bosshardt L, Bradley B. Generalization of fear-potentiated startle in the presence of auditory cues: a parametric analysis. Front Behav Neurosci 2014; 8:361. [PMID: 25368559 PMCID: PMC4201100 DOI: 10.3389/fnbeh.2014.00361] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/29/2014] [Indexed: 11/13/2022] Open
Abstract
Intense fear responses observed in trauma-, stressor-, and anxiety-related disorders can be elicited by a wide range of stimuli similar to those that were present during the traumatic event. The present study investigated the experimental utility of fear-potentiated startle paradigms to study this phenomenon, known as stimulus generalization, in healthy volunteers. Fear-potentiated startle refers to a relative increase in the acoustic startle response to a previously neutral stimulus that has been paired with an aversive stimulus. Specifically, in Experiment 1 an auditory pure tone (500 Hz) was used as the conditioned stimulus (CS+) and was reinforced with an unconditioned stimulus (US), an airblast to the larynx. A distinct tone (4000 Hz) was used as the nonreinforced stimulus (CS−) and was never paired with an airblast. Twenty-four hours later subjects underwent Re-training followed by a Generalization test, during which subjects were exposed to a range of generalization stimuli (GS) (250, 1000, 2000, 4000, 8000 Hz). In order to further examine the point at which fear no longer generalizes, a follow-up experiment (Experiment 2) was performed where a 4000 Hz pure tone was used as the CS+, and during the Generalization test, 2000 and 8000 Hz were used as GS. In both Experiment 1 and 2 there was significant discrimination in US expectancy responses on all stimuli during the Generalization Test, indicating the stimuli were perceptually distinct. In Experiment 1, participants showed similar levels of fear-potentiated startle to the GS that were adjacent to the CS+, and discriminated between stimuli that were 2 or more degrees from the CS+. Experiment 2 demonstrated no fear-potentiated startle generalization. The current study is the first to use auditory cues to test generalization of conditioned fear responses; such cues may be especially relevant to combat posttraumatic stress disorder (PTSD) where much of the traumatic exposure may involve sounds.
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Affiliation(s)
- Seth Davin Norrholm
- Atlanta Veterans Affairs Medical Center, Mental Health Service Line Decatur, GA, USA ; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine Atlanta, GA, USA
| | - Tanja Jovanovic
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine Atlanta, GA, USA
| | - Maria A Briscione
- Atlanta Veterans Affairs Medical Center, Mental Health Service Line Decatur, GA, USA ; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine Atlanta, GA, USA
| | - Kemp M Anderson
- Atlanta Veterans Affairs Medical Center, Mental Health Service Line Decatur, GA, USA ; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine Atlanta, GA, USA
| | - Cliffe K Kwon
- Atlanta Veterans Affairs Medical Center, Mental Health Service Line Decatur, GA, USA ; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine Atlanta, GA, USA
| | - Victor T Warren
- Atlanta Veterans Affairs Medical Center, Mental Health Service Line Decatur, GA, USA ; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine Atlanta, GA, USA
| | - Lauren Bosshardt
- Atlanta Veterans Affairs Medical Center, Mental Health Service Line Decatur, GA, USA ; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine Atlanta, GA, USA
| | - Bekh Bradley
- Atlanta Veterans Affairs Medical Center, Mental Health Service Line Decatur, GA, USA ; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine Atlanta, GA, USA
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Sterpenich V, Piguet C, Desseilles M, Ceravolo L, Gschwind M, Van De Ville D, Vuilleumier P, Schwartz S. Sleep sharpens sensory stimulus coding in human visual cortex after fear conditioning. Neuroimage 2014; 100:608-18. [DOI: 10.1016/j.neuroimage.2014.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/28/2014] [Accepted: 06/04/2014] [Indexed: 11/15/2022] Open
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Blockade of CB1 receptors prevents retention of extinction but does not increase low preincubated conditioned fear in the fear incubation procedure. Behav Pharmacol 2014; 25:23-31. [PMID: 24346290 DOI: 10.1097/fbp.0000000000000020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We recently developed a procedure to study fear incubation, in which rats given 100 tone-shock pairings over 10 days show low fear 2 days after conditioned fear training and high fear after 30 days. Notably, fear 2 days after 10 sessions of fear conditioning is lower than fear seen 2 days after a single session of fear conditioning, suggesting that fear is suppressed. Here, we investigate the potential role of CB1 receptor activation by endocannabinoids in this fear suppression. We subjected rats to 10 days of fear conditioning and then administered systemic injections of the CB1 receptor antagonist SR141716 before a conditioned fear test was conducted 2 days later under extinction conditions. A second test was conducted without any injections on the following day (3 days after training) to examine retention of fear extinction. SR141716 injections did not increase fear expression 2 days after extended fear conditioning or affect within-session extinction; however, it impaired retention of between-session fear extinction in the day 3 test. These data suggest that CB1 receptor activation does not suppress fear soon after extended fear conditioning in the fear incubation task. The data also add to the existing literature on the role of CB1 receptors in extinction of conditioned fear.
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46
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Ren HM, Ren J, Liu W. Recognition and control of the progression of age-related hearing loss. Rejuvenation Res 2014; 16:475-86. [PMID: 23915327 DOI: 10.1089/rej.2013.1435] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Recent breakthroughs have provided notable insights into both the pathogenesis and therapeutic strategies for age-related hearing loss (ARHL). Simultaneously, these breakthroughs enhance our knowledge about this neurodegenerative disease and raise the question of whether the disorder is preventable or even treatable. Discoveries relating to ARHL have revealed a unique link between ARHL and the underlying pathologies. Therefore, we need to better understand the pathogenesis or the mechanism of ARHL and learn how to take full advantage of various therapeutic strategies to prevent the progression of ARHL.
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Affiliation(s)
- Hong Miao Ren
- Department of Otolaryngology Head and Neck Surgery, the Second Xiangya Hospital, Central South University , Changsha, Hunan, P.R. China
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Lissek S, Kaczkurkin AN, Rabin S, Geraci M, Pine DS, Grillon C. Generalized anxiety disorder is associated with overgeneralization of classically conditioned fear. Biol Psychiatry 2014; 75:909-15. [PMID: 24001473 PMCID: PMC3938992 DOI: 10.1016/j.biopsych.2013.07.025] [Citation(s) in RCA: 282] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/26/2013] [Accepted: 07/18/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND Meta-analytic results of fear-conditioning studies in the anxiety disorders implicate generalization of conditioned fear to stimuli resembling the conditioned danger cue as one of the more robust conditioning markers of anxiety pathology. Due to the absence of conditioning studies assessing generalization in generalized anxiety disorder (GAD), results of this meta-analysis do not reveal whether such generalization abnormalities also apply to GAD. The current study fills this gap by behaviorally and psychophysiologically assessing levels of conditioned fear generalization across adults with and without GAD. METHODS Twenty-two patients with a DSM-IV-Text Revision diagnosis of GAD and 26 healthy comparison subjects were recruited and tested. The employed generalization paradigm consisted of quasi-randomly presented rings of gradually increasing size, with extreme sizes serving as conditioned danger cues (CS+) and conditioned safety cues. The rings of intermediary size served as generalization stimuli, creating a continuum of similarity between CS+ and conditioned safety cues across which to assess response slopes, referred to as generalization gradients. Primary outcome variables included slopes for fear-potentiated startle (electromyography) and self-reported risk ratings. RESULTS Behavioral and psychophysiological findings demonstrated overgeneralization of conditioned fear among patients with GAD. Specifically, generalization gradients were abnormally shallow among GAD patients, reflecting less degradation of the conditioned fear response as the presented stimulus differentiated from the CS+. CONCLUSIONS Overgeneralization of conditioned fear to safe encounters resembling feared situations may contribute importantly to the psychopathology of GAD by proliferating anxiety cues in the individual's environment that are then capable of evoking and maintaining anxiety and worry associated with GAD.
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Affiliation(s)
- Shmuel Lissek
- Intramural Research Program, National Institute of Mental Health, Bethesda, Maryland; Department of Psychology, University of Minnesota, Minneapolis, Minnesota.
| | | | - Stephanie Rabin
- Department of Psychology, Drexel University, Philadelphia, Pennsylania
| | - Marilla Geraci
- Intramural Research Program, National Institute of Mental Health, Bethesda, Maryland
| | - Daniel S Pine
- Intramural Research Program, National Institute of Mental Health, Bethesda, Maryland
| | - Christian Grillon
- Intramural Research Program, National Institute of Mental Health, Bethesda, Maryland
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Decreased anxiety-like behavior and Gαq/11-dependent responses in the amygdala of mice lacking TRPC4 channels. J Neurosci 2014; 34:3653-67. [PMID: 24599464 DOI: 10.1523/jneurosci.2274-13.2014] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Transient receptor potential (TRP) channels are abundant in the brain where they regulate transmission of sensory signals. The expression patterns of different TRPC subunits (TRPC1, 4, and 5) are consistent with their potential role in fear-related behaviors. Accordingly, we found recently that mutant mice lacking a specific TRP channel subunit, TRPC5, exhibited decreased innate fear responses. Both TRPC5 and another member of the same subfamily, TRPC4, form heteromeric complexes with the TRPC1 subunit (TRPC1/5 and TRPC1/4, respectively). As TRP channels with specific subunit compositions may have different functional properties, we hypothesized that fear-related behaviors could be differentially controlled by TRPCs with distinct subunit arrangements. In this study, we focused on the analysis of mutant mice lacking the TRPC4 subunit, which, as we confirmed in experiments on control mice, is expressed in brain areas implicated in the control of fear and anxiety. In behavioral experiments, we found that constitutive ablation of TRPC4 was associated with diminished anxiety levels (innate fear). Furthermore, knockdown of TRPC4 protein in the lateral amygdala via lentiviral-mediated gene delivery of RNAi mimicked the behavioral phenotype of constitutive TRPC4-null (TRPC4(-/-)) mouse. Recordings in brain slices demonstrated that these behavioral modifications could stem from the lack of TRPC4 potentiation in neurons in the lateral nucleus of the amygdala through two Gαq/11 protein-coupled signaling pathways, activated via Group I metabotropic glutamate receptors and cholecystokinin 2 receptors, respectively. Thus, TRPC4 and the structurally and functionally related subunit, TRPC5, may both contribute to the mechanisms underlying regulation of innate fear responses.
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Sui L, Huang S, Peng B, Ren J, Tian F, Wang Y. Deep brain stimulation of the amygdala alleviates fear conditioning-induced alterations in synaptic plasticity in the cortical–amygdala pathway and fear memory. J Neural Transm (Vienna) 2014; 121:773-82. [DOI: 10.1007/s00702-014-1183-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 02/21/2014] [Indexed: 11/28/2022]
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50
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Abstract
The ability to distinguish danger from safety is crucial for survival. On the other hand, anxiety disorders can result from failures to dissociate safe cues from those that predict dangerous outcomes. The amygdala plays a major role in learning and signaling danger, and recently, evidence accumulates that it also acquires information to signal safety. Traditionally, safety is explored by paradigms that change the value of a previously dangerous cue, such as extinction or reversal; or by paradigms showing that a safe cue can inhibit responses to another danger-predicting cue, as in conditioned-inhibition. In real-life scenarios, many cues are never paired or tested with danger and remain neutral all along. A detailed study of neural responses to unpaired conditioned-stimulus (CS-) can therefore indicate whether information on safety-by-comparison is also acquired in the amygdala. We designed a multiple-CS study, with CS- from both visual and auditory modalities. Using discriminative aversive-conditioning, we find that responses in the primate amygdala develop for CS- of the same modality and of a different modality from that of the aversive CS+. Moreover, we find that responses are comparable in proportion, sign (increase/decrease), onset, and magnitude. These results indicate that the primate amygdala actively acquires signals about safety, and strengthen the hypothesis that failure in amygdala processing can result in failure to distinguish dangerous cues from safe ones and lead to maladaptive behaviors.
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