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Xu Z, Geron E, Pérez-Cuesta LM, Bai Y, Gan WB. Generalized extinction of fear memory depends on co-allocation of synaptic plasticity in dendrites. Nat Commun 2023; 14:503. [PMID: 36720872 PMCID: PMC9889816 DOI: 10.1038/s41467-023-35805-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 01/03/2023] [Indexed: 02/02/2023] Open
Abstract
Memories can be modified by new experience in a specific or generalized manner. Changes in synaptic connections are crucial for memory storage, but it remains unknown how synaptic changes associated with different memories are distributed within neuronal circuits and how such distributions affect specific or generalized modification by novel experience. Here we show that fear conditioning with two different auditory stimuli (CS) and footshocks (US) induces dendritic spine elimination mainly on different dendritic branches of layer 5 pyramidal neurons in the mouse motor cortex. Subsequent fear extinction causes CS-specific spine formation and extinction of freezing behavior. In contrast, spine elimination induced by fear conditioning with >2 different CS-USs often co-exists on the same dendritic branches. Fear extinction induces CS-nonspecific spine formation and generalized fear extinction. Moreover, activation of somatostatin-expressing interneurons increases the occurrence of spine elimination induced by different CS-USs on the same dendritic branches and facilitates the generalization of fear extinction. These findings suggest that specific or generalized modification of existing memories by new experience depends on whether synaptic changes induced by previous experiences are segregated or co-exist at the level of individual dendritic branches.
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Affiliation(s)
- Zhiwei Xu
- Institute of Neurological and Psychiatric Disorders, Shenzhen Bay Laboratory, Shenzhen, 518132, China
- Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Erez Geron
- Skirball Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Luis M Pérez-Cuesta
- Skirball Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, 10016, USA
| | - Yang Bai
- Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Wen-Biao Gan
- Institute of Neurological and Psychiatric Disorders, Shenzhen Bay Laboratory, Shenzhen, 518132, China.
- Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
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2
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García-Rosales F, López-Jury L, González-Palomares E, Cabral-Calderín Y, Hechavarría JC. Fronto-Temporal Coupling Dynamics During Spontaneous Activity and Auditory Processing in the Bat Carollia perspicillata. Front Syst Neurosci 2020; 14:14. [PMID: 32265670 PMCID: PMC7098971 DOI: 10.3389/fnsys.2020.00014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 02/28/2020] [Indexed: 11/17/2022] Open
Abstract
Most mammals rely on the extraction of acoustic information from the environment in order to survive. However, the mechanisms that support sound representation in auditory neural networks involving sensory and association brain areas remain underexplored. In this study, we address the functional connectivity between an auditory region in frontal cortex (the frontal auditory field, FAF) and the auditory cortex (AC) in the bat Carollia perspicillata. The AC is a classic sensory area central for the processing of acoustic information. On the other hand, the FAF belongs to the frontal lobe, a brain region involved in the integration of sensory inputs, modulation of cognitive states, and in the coordination of behavioral outputs. The FAF-AC network was examined in terms of oscillatory coherence (local-field potentials, LFPs), and within an information theoretical framework linking FAF and AC spiking activity. We show that in the absence of acoustic stimulation, simultaneously recorded LFPs from FAF and AC are coherent in low frequencies (1-12 Hz). This "default" coupling was strongest in deep AC layers and was unaltered by acoustic stimulation. However, presenting auditory stimuli did trigger the emergence of coherent auditory-evoked gamma-band activity (>25 Hz) between the FAF and AC. In terms of spiking, our results suggest that FAF and AC engage in distinct coding strategies for representing artificial and natural sounds. Taken together, our findings shed light onto the neuronal coding strategies and functional coupling mechanisms that enable sound representation at the network level in the mammalian brain.
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Affiliation(s)
| | - Luciana López-Jury
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt, Germany
| | | | - Yuranny Cabral-Calderín
- Research Group Neural and Environmental Rhythms, MPI for Empirical Aesthetics, Frankfurt, Germany
| | - Julio C. Hechavarría
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt, Germany
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3
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Sangha S, Diehl MM, Bergstrom HC, Drew MR. Know safety, no fear. Neurosci Biobehav Rev 2020; 108:218-230. [PMID: 31738952 PMCID: PMC6981293 DOI: 10.1016/j.neubiorev.2019.11.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 09/27/2019] [Accepted: 11/11/2019] [Indexed: 02/08/2023]
Abstract
Every day we are bombarded by stimuli that must be assessed for their potential for harm or benefit. Once a stimulus is learned to predict harm, it can elicit fear responses. Such learning can last a lifetime but is not always beneficial for an organism. For an organism to thrive in its environment, it must know when to engage in defensive, avoidance behaviors and when to engage in non-defensive, approach behaviors. Fear should be suppressed in situations that are not dangerous: when a novel, innocuous stimulus resembles a feared stimulus, when a feared stimulus no longer predicts harm, or when there is an option to avoid harm. A cardinal feature of anxiety disorders is the inability to suppress fear adaptively. In PTSD, for instance, learned fear is expressed inappropriately in safe situations and is resistant to extinction. In this review, we discuss mechanisms of suppressing fear responses during stimulus discrimination, fear extinction, and active avoidance, focusing on the well-studied tripartite circuit consisting of the amygdala, medial prefrontal cortex and hippocampus.
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Affiliation(s)
- Susan Sangha
- Department of Psychological Sciences and Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, USA.
| | - Maria M Diehl
- Department of Psychological Sciences, Kansas State University, Manhattan, KS, USA.
| | - Hadley C Bergstrom
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, NY, USA.
| | - Michael R Drew
- Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Austin, TX, USA.
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4
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Wang H, Chen J, Xu X, Sun WJ, Chen X, Zhao F, Luo MH, Liu C, Guo Y, Xie W, Zhong H, Bai T, Tian Y, Mao Y, Ye C, Tao W, Li J, Farzinpour Z, Li J, Zhou JN, Wang K, He J, Chen L, Zhang Z. Direct auditory cortical input to the lateral periaqueductal gray controls sound-driven defensive behavior. PLoS Biol 2019; 17:e3000417. [PMID: 31469831 PMCID: PMC6742420 DOI: 10.1371/journal.pbio.3000417] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 09/12/2019] [Accepted: 08/14/2019] [Indexed: 01/10/2023] Open
Abstract
Threatening sounds can elicit a series of defensive behavioral reactions in animals for survival, but the underlying neural substrates are not fully understood. Here, we demonstrate a previously unexplored neural pathway in mice that projects directly from the auditory cortex (ACx) to the lateral periaqueductal gray (lPAG) and controls noise-evoked defensive behaviors. Electrophysiological recordings showed that the lPAG could be excited by a loud noise that induced an escape-like behavior. Trans-synaptic viral tracing showed that a great number of glutamatergic neurons, rather than GABAergic neurons, in the lPAG were directly innervated by those in layer V of the ACx. Activation of this pathway by optogenetic manipulations produced a behavior in mice that mimicked the noise-evoked escape, whereas inhibition of the pathway reduced this behavior. Therefore, our newly identified descending pathway is a novel neural substrate for noise-evoked escape and is involved in controlling the threat-related behavior. Threatening sounds can evoke a defensive behavior in animals to avoid potential harm. This study identifies a novel neural pathway in mice that projects directly from the auditory cortex to the lateral periaqueductal gray and controls defense-like behaviors evoked by a loud noise, supporting the notion that such behaviors are controlled by multiple neural circuits.
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Affiliation(s)
- Haitao Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Jiahui Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Xiaotong Xu
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Wen-Jian Sun
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Xi Chen
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Fei Zhao
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Min-Hua Luo
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Chunhua Liu
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yiping Guo
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Wen Xie
- Department of Psychology, Anhui Mental Health Center, Hefei, China
| | - Hui Zhong
- Department of Psychology, Anhui Mental Health Center, Hefei, China
| | - Tongjian Bai
- Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yanghua Tian
- Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yu Mao
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
- Department of Anesthesiology, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Chonghuan Ye
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Wenjuan Tao
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Jie Li
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Zahra Farzinpour
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Juan Li
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Jiang-Ning Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
| | - Kai Wang
- Department of Neurology, the First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Jufang He
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Lin Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
- * E-mail: (ZZ); (LC)
| | - Zhi Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, University of Science and Technology of China, Hefei, China
- * E-mail: (ZZ); (LC)
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5
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Guo L, Walker WI, Ponvert ND, Penix PL, Jaramillo S. Stable representation of sounds in the posterior striatum during flexible auditory decisions. Nat Commun 2018; 9:1534. [PMID: 29670112 PMCID: PMC5906458 DOI: 10.1038/s41467-018-03994-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/27/2018] [Indexed: 11/09/2022] Open
Abstract
The neuronal pathways that link sounds to rewarded actions remain elusive. For instance, it is unclear whether neurons in the posterior tail of the dorsal striatum (which receive direct input from the auditory system) mediate action selection, as other striatal circuits do. Here, we examine the role of posterior striatal neurons in auditory decisions in mice. We find that, in contrast to the anterior dorsal striatum, activation of the posterior striatum does not elicit systematic movement. However, activation of posterior striatal neurons during sound presentation in an auditory discrimination task biases the animals' choices, and transient inactivation of these neurons largely impairs sound discrimination. Moreover, the activity of these neurons during sound presentation reliably encodes stimulus features, but is only minimally influenced by the animals' choices. Our results suggest that posterior striatal neurons play an essential role in auditory decisions, and provides a stable representation of sounds during auditory tasks.
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Affiliation(s)
- Lan Guo
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, OR, 97403, USA
| | - William I Walker
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Nicholas D Ponvert
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Phoebe L Penix
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, OR, 97403, USA
| | - Santiago Jaramillo
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, OR, 97403, USA.
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6
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Differential Recruitment of Auditory Cortices in the Consolidation of Recent Auditory Fearful Memories. J Neurosci 2017; 36:8586-97. [PMID: 27535907 DOI: 10.1523/jneurosci.0561-16.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 06/23/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Memories of frightening events require a protracted consolidation process. Sensory cortex, such as the auditory cortex, is involved in the formation of fearful memories with a more complex sensory stimulus pattern. It remains controversial, however, whether the auditory cortex is also required for fearful memories related to simple sensory stimuli. In the present study, we found that, 1 d after training, the temporary inactivation of either the most anterior region of the auditory cortex, including the primary (Te1) cortex, or the most posterior region, which included the secondary (Te2) component, did not affect the retention of recent memories, which is consistent with the current literature. However, at this time point, the inactivation of the entire auditory cortices completely prevented the formation of new memories. Amnesia was site specific and was not due to auditory stimuli perception or processing and strictly related to the interference with memory consolidation processes. Strikingly, at a late time interval 4 d after training, blocking the posterior part (encompassing the Te2) alone impaired memory retention, whereas the inactivation of the anterior part (encompassing the Te1) left memory unaffected. Together, these data show that the auditory cortex is necessary for the consolidation of auditory fearful memories related to simple tones in rats. Moreover, these results suggest that, at early time intervals, memory information is processed in a distributed network composed of both the anterior and the posterior auditory cortical regions, whereas, at late time intervals, memory processing is concentrated in the most posterior part containing the Te2 region. SIGNIFICANCE STATEMENT Memories of threatening experiences undergo a prolonged process of "consolidation" to be maintained for a long time. The dynamic of fearful memory consolidation is poorly understood. Here, we show that 1 d after learning, memory is processed in a distributed network composed of both primary Te1 and secondary Te2 auditory cortices, whereas, at late time intervals, memory processing is concentrated in the most posterior Te2 cortex. Together, our data reveal that the consolidation of fearful memories related to simple auditory stimuli requires the auditory cortex, provided that the inactivation encompasses both the primary and the secondary components of the cortex, and that different regions of the auditory cortex play complementary but different roles in these processes.
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7
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Abstract
Lattice-like structures known as perineuronal nets (PNNs) are key components of the extracellular matrix (ECM). Once fully crystallized by adulthood, they are largely stable throughout life. Contrary to previous reports that PNNs inhibit processes involving plasticity, here we report that the dynamic regulation of PNN expression in the adult auditory cortex is vital for fear learning and consolidation in response to pure tones. Specifically, after first confirming the necessity of auditory cortical activity for fear learning and consolidation, we observed that mRNA levels of key proteoglycan components of PNNs were enhanced 4 hr after fear conditioning but were no longer different from the control groups 24 hr later. A similar pattern of regulation was observed in numbers of cells surrounded by PNNs and area occupied by them in the auditory cortex. Finally, the removal of auditory cortex PNNs resulted in a deficit in fear learning and consolidation.
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Delamater AR, Westbrook RF. Psychological and neural mechanisms of experimental extinction: a selective review. Neurobiol Learn Mem 2014; 108:38-51. [PMID: 24104049 PMCID: PMC3946186 DOI: 10.1016/j.nlm.2013.09.016] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/24/2013] [Accepted: 09/26/2013] [Indexed: 11/24/2022]
Abstract
The present review examines key psychological concepts in the study of experimental extinction and implications these have for an understanding of the underlying neurobiology of extinction learning. We suggest that many of the signature characteristics of extinction learning (spontaneous recovery, renewal, reinstatement, rapid reacquisition) can be accommodated by the standard associative learning theory assumption that extinction results in partial erasure of the original learning together with new inhibitory learning. Moreover, we consider recent behavioral and neural evidence that supports the partial erasure view of extinction, but also note shortcomings in our understanding of extinction circuits as these relate to the negative prediction error concept. Recent work suggests that common prediction error and stimulus-specific prediction error terms both may be required to explain neural plasticity both in acquisition and extinction learning. In addition, we suggest that many issues in the content of extinction learning have not been fully addressed in current research, but that neurobiological approaches should be especially helpful in addressing such issues. These include questions about the nature of extinction learning (excitatory CS-No US, inhibitory CS-US learning, occasion setting processes), especially as this relates to studies of the micro-circuitry of extinction, as well as its representational content (sensory, motivational, response). An additional understudied problem in extinction research is the role played by attention processes and their underlying neural networks, although some research and theory converge on the idea that extinction is accompanied by attention decrements (i.e., habituation-like processes).
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Affiliation(s)
- Andrew R Delamater
- Brooklyn College of the City University of New York, USA; University of New South Wales, Australia.
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Bieszczad KM, Weinberger NM. Extinction reveals that primary sensory cortex predicts reinforcement outcome. Eur J Neurosci 2012; 35:598-613. [PMID: 22304434 DOI: 10.1111/j.1460-9568.2011.07974.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primary sensory cortices are traditionally regarded as stimulus analysers. However, studies of associative learning-induced plasticity in the primary auditory cortex (A1) indicate involvement in learning, memory and other cognitive processes. For example, the area of representation of a tone becomes larger for stronger auditory memories and the magnitude of area gain is proportional to the degree that a tone becomes behaviorally important. Here, we used extinction to investigate whether 'behavioral importance' specifically reflects a sound's ability to predict reinforcement (reward or punishment) vs. to predict any significant change in the meaning of a sound. If the former, then extinction should reverse area gains as the signal no longer predicts reinforcement. Rats (n = 11) were trained to bar-press to a signal tone (5.0 kHz) for water-rewards, to induce signal-specific area gains in A1. After subsequent withdrawal of reward, A1 was mapped to determine representational areas. Signal-specific area gains, estimated from a previously established brain-behavior quantitative function, were reversed, supporting the 'reinforcement prediction' hypothesis. Area loss was specific to the signal tone vs. test tones, further indicating that withdrawal of reinforcement, rather than unreinforced tone presentation per se, was responsible for area loss. Importantly, the amount of area loss was correlated with the amount of extinction (r = 0.82, P < 0.01). These findings show that primary sensory cortical representation can encode behavioral importance as a signal's value to predict reinforcement, and that the number of cells tuned to a stimulus can dictate its ability to command behavior.
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Affiliation(s)
- Kasia M Bieszczad
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, Irvine, CA 92697-3800, USA
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Norrholm SD, Anderson KM, Olin IW, Jovanovic T, Kwon C, Warren VT, McCarthy A, Bosshardt L, Sabree J, Duncan EJ, Rothbaum BO, Bradley B. Versatility of fear-potentiated startle paradigms for assessing human conditioned fear extinction and return of fear. Front Behav Neurosci 2011; 5:77. [PMID: 22125516 PMCID: PMC3221285 DOI: 10.3389/fnbeh.2011.00077] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 10/31/2011] [Indexed: 11/13/2022] Open
Abstract
Fear conditioning methodologies have often been employed as testable models for assessing learned fear responses in individuals with anxiety disorders such as post-traumatic stress disorder (PTSD) and specific phobia. One frequently used paradigm is measurement of the acoustic startle reflex under conditions that mimic anxiogenic and fear-related conditions. For example, fear-potentiated startle is the relative increase in the frequency or magnitude of the acoustic startle reflex in the presence of a previously neutral cue (e.g., colored shape; termed the conditioned stimulus or CS+) that has been repeatedly paired with an aversive unconditioned stimulus (e.g., airblast to the larynx). Our group has recently used fear-potentiated startle paradigms to demonstrate impaired fear extinction in civilian and combat populations with PTSD. In the current study, we examined the use of either auditory or visual CSs in a fear extinction protocol that we have validated and applied to human clinical conditions. This represents an important translational bridge in that numerous animal studies of fear extinction, upon which much of the human work is based, have employed the use of auditory CSs as opposed to visual CSs. Participants in both the auditory and visual groups displayed robust fear-potentiated startle to the CS+, clear discrimination between the reinforced CS+ and non-reinforced CS−, significant extinction to the previously reinforced CS+, and marked spontaneous recovery. We discuss the current results as they relate to future investigations of PTSD-related impairments in fear processing in populations with diverse medical and psychiatric histories.
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Affiliation(s)
- Seth D Norrholm
- Trauma Recovery Program, Mental Health Service Line, Atlanta Veterans Affairs Medical Center Decatur, GA, USA
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Kim EJ, Kim ES, Covey E, Kim JJ. Social transmission of fear in rats: the role of 22-kHz ultrasonic distress vocalization. PLoS One 2010; 5:e15077. [PMID: 21152023 PMCID: PMC2995742 DOI: 10.1371/journal.pone.0015077] [Citation(s) in RCA: 143] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 10/18/2010] [Indexed: 11/17/2022] Open
Abstract
Background Social alarm calls alert animals to potential danger and thereby promote group survival. Adult laboratory rats in distress emit 22-kHz ultrasonic vocalization (USV) calls, but the question of whether these USV calls directly elicit defensive behavior in conspecifics is unresolved. Methodology/Principal Findings The present study investigated, in pair-housed male rats, whether and how the conditioned fear-induced 22-kHz USVs emitted by the ‘sender’ animal affect the behavior of its partner, the ‘receiver’ animal, when both are placed together in a novel chamber. The sender rats’ conditioned fear responses evoked significant freezing (an overt evidence of fear) in receiver rats that had previously experienced an aversive event but not in naïve receiver rats. Permanent lesions and reversible inactivations of the medial geniculate nucleus (MGN) of the thalamus effectively blocked the receivers’ freeezing response to the senders' conditioned fear responses, and this occurred in absence of lesions/inactivations impeding the receiver animals' ability to freeze and emit 22-kHz USVs to the aversive event per se. Conclusions/Significance These results—that prior experience of fear and intact auditory system are required for receiver rats to respond to their conspecifics' conditioned fear responses—indicate that the 22-kHz USV is the main factor for social transmission of fear and that learning plays a crucial role in the development of social signaling of danger by USVs.
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Affiliation(s)
- Eun Joo Kim
- Department of Psychology, University of Washington, Seattle, Washington, United States of America
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