Fear conditioning

  • Article
    | Open Access

    Scintillators emit visible luminescence when irradiated with X-rays and may enable remote optogenetic control of neurons deep in the brain. The authors inject an inorganic scintillator to activate and inhibit midbrain dopamine neurons in freely moving mice by X-ray irradiation to modulate place preference behavior.

    • Takanori Matsubara
    • , Takayuki Yanagida
    •  & Takayuki Yamashita
  • Article
    | Open Access

    Cellular activity level at the time of learning is thought to be a critical factor to determine which neurons are recruited to encode memory. Here, the authors show that competitive synaptic plasticity mechanisms influence which neurons will encode a fear memory.

    • Yire Jeong
    • , Hye-Yeon Cho
    •  & Jin-Hee Han
  • Article
    | Open Access

    Changes in poly-unsaturated free fatty acids (FFAs) have been associated with LTP. Here, using lipidomics analysis the authors characterise FFA changes in the rat brain associated with fear conditioning, and demonstrate that increases in saturated FFAs represent the major change.

    • Tristan P. Wallis
    • , Bharat G. Venkatesh
    •  & Frédéric A. Meunier
  • Article
    | Open Access

    The Tachykinin 2 (Tac2) pathway in the central amygdala is sufficient and necessary for modulating fear memory consolidation. The authors show that silencing Tac2 neurons in the amygdala of male mice reduces fear expression, while fear expression in female mice is increased when manipulations are made during proestrus.

    • A. Florido
    • , E. R. Velasco
    •  & R. Andero
  • Article
    | Open Access

    How thalamic sensory relays participate in plasticity upon associative fear learning and stable long-term sensory coding remains unknown. The authors show that auditory thalamus neurons exhibit heterogeneous plasticity patterns after learning while population level encoding of auditory stimuli remains stable across days.

    • James Alexander Taylor
    • , Masashi Hasegawa
    •  & Jan Gründemann
  • Article
    | Open Access

    The vCA1-BA projection is enriched in shock responsive neurons, which are necessary for fear memory encoding and become correlated with a network of neurons during retrieval. Here the authors show that the magnitude of vCA1 correlated activity is proportional to memory strength and requires the shock response during encoding.

    • Jessica C. Jimenez
    • , Jack E. Berry
    •  & Rene Hen
  • Article
    | Open Access

    The neuronal pathway that signals the positive or negative value of memories is not well understood. Here, the authors report that an excitatory projection from the ventral tegmental area to the dorsal hippocampus carries the valence information, contributing, especially in females, to the recurrence of fear and to drug seeking behavior.

    • Yuan Han
    • , Yi Zhang
    •  & Jelena Radulovic
  • Article
    | Open Access

    Learned conditioned fear associations can be weakened (extinction learning), but extinction is less effective if performed too soon after the original fear conditioning. Here, the authors show that persistent activation of CRF-expressing neurons in the central amygdala is involved in the early fear extinction deficit.

    • Yong S. Jo
    • , Vijay Mohan K. Namboodiri
    •  & Larry S. Zweifel
  • Article
    | Open Access

    The success of extinction learning is not predictive of long-term retrieval of an extinction memory. Using fMRI to study consolidation of fear extinction in human subjects, the authors show that reactivation in the ventromedial prefrontal cortex during memory retrieval predicts extinction memory retrieval, and that increasing dopaminergic signaling increases the number of these activations.

    • A. M. V. Gerlicher
    • , O. Tüscher
    •  & R. Kalisch
  • Article
    | Open Access

    Emotional memory can change when retrieved, yet the conditions under which this can occur are not fully described. Here, authors show that taking a pill of propranolol taken during a specific time window can change the expression of fear memory in a person, and that sleep is necessary to forget learned fear.

    • Merel Kindt
    •  & Marieke Soeter
  • Article
    | Open Access

    When perceiving new stimuli, organisms need to distinguish between threats versus harmless stimuli. Here, the authors find a set of cells in the lateral amygdala that is required to discriminate or generalize new auditory stimuli based on similarity to previously fear-associate sounds.

    • Anna Grosso
    • , Giulia Santoni
    •  & Benedetto Sacchetti
  • Article
    | Open Access

    Zona incerta (ZI) is an inhibitory subthalamic nucleus with diverse connectivity yet its functional importance has not been extensively studied. Here the authors report that ZI receives mPFC input and can modulate both innate and learned defensive behaviors via its inhibitory projection to the PAG.

    • Xiao-lin Chou
    • , Xiyue Wang
    •  & Huizhong Whit Tao
  • Article
    | Open Access

    Previous work has documented a slow form of memory generalization although a rapid one is demanded. Here the authors elucidate the role of the interhemispheric CA1-CA1 projection in a form of rapid generalization of contextual fear memory via gradual potentiation of these synapses over 24 h.

    • Heng Zhou
    • , Gui-Jing Xiong
    •  & Lin Xu
  • Article
    | Open Access

    Intra-hippocampal circuits are essential for associating a background context with behaviorally salient stimuli and involve cholinergic modulation at SST+ interneurons. Here the authors show that the salience of the background context memory is modulated through muscarinic activation of NPY+ hilar perforant path associated interneurons and NPY signaling in the dentate gyrus.

    • Syed Ahsan Raza
    • , Anne Albrecht
    •  & Oliver Stork
  • Article
    | Open Access

    Though humans often learn about negative outcomes from observing the response of others, the neurochemistry underlying this learning is unknown. Here, authors show that blocking opioid receptors enhances social threat learning and describe the brain regions underlying this effect.

    • Jan Haaker
    • , Jonathan Yi
    •  & Andreas Olsson
  • Article
    | Open Access

    Amygdala and hippocampus are involved in processing motivationally salient stimuli but the precise circuit dynamics of the interaction is not understood. Here the authors show that in response to fearful faces in humans, theta/alpha oscillations in the amygdala modulate hippocampal activity dynamics.

    • Jie Zheng
    • , Kristopher L. Anderson
    •  & Jack J. Lin
  • Article
    | Open Access

    Flexible fear-related responses may be advantageous in adolescence. Here the authors use microprisms to image prefrontal cortical spine maturation across development and report that plasticity in adolescent fear extinction responses is associated with dynamic reorganization in the amygdalahippocampal-PFC circuit.

    • Siobhan S. Pattwell
    • , Conor Liston
    •  & Francis S. Lee
  • Article
    | Open Access

    The auditory cortex Te2 represents a key node for the assignment of the affective value to sensory stimuli in rodents. Using pharmacogenetic manipulations, this study shows that in Te2 there are neurons which respond to the emotional valence of sounds and their inactivation impairs emotional memories retrieval.

    • Anna Grosso
    • , Marco Cambiaghi
    •  & Benedetto Sacchetti
  • Article
    | Open Access

    Voxel-based morphometry (VBM) involves comparisons of high resolution structural images of the brain between groups, but what causes changes in the VBM signal is unclear. Here the authors perform a VBM study of Thy1-YFP mice following auditory fear conditioning and propose that the signal changes can be partially explained by increases in dendritic spine density.

    • O. P. Keifer Jr
    • , R. C. Hurt
    •  & K. J. Ressler
  • Article
    | Open Access

    The ability of animals to respond to life-threatening stimuli is critical for survival, yet the neural circuits mediating innate defensive behaviors are not well understood. Here, the authors reveal a novel collicular–thalamic–amygdala circuit critical for innate defensive responses to visual threats.

    • Pengfei Wei
    • , Nan Liu
    •  & Liping Wang
  • Article
    | Open Access

    Cholinergic signalling modulates learning and memory; however, its influence on learning-induced synaptic plasticity is less clear. Mitsushima et al.show that acetylcholine simultaneously strengthens both excitatory and inhibitory synapses onto CA1 pyramidal neurons following an inhibitory avoidance task.

    • Dai Mitsushima
    • , Akane Sano
    •  & Takuya Takahashi
  • Article |

    Memory retrieval followed by extinction training has been shown to erase fear memories. Flavellet al. show that this approach also erases appetitive memories in rats and results from a modification of memory reconsolidation, which could be useful for the treatment of drug addiction.

    • Charlotte R. Flavell
    • , David J. Barber
    •  & Jonathan L.C. Lee