Neurobiology of Fear Conditioning and Memory

Fear conditioning is a form of associative learning in which neutral cues become linked to aversive events, giving rise to robust and persistent memories. At its core lie specialised circuits encompassing the amygdala, hippocampus and medial prefrontal cortex, each contributing distinct operations in acquisition, consolidation and extinction. Within the basolateral amygdala, synaptic plasticity and molecular signalling cascades—such as BDNF-dependent MAPK activation and CREB-mediated gene transcription—solidify the memory trace or engram. The hippocampus contextualises fearful stimuli and supports the formation of detailed representations, while subdivisions of the prefrontal cortex exert top-down control to either maintain or suppress conditioned responses. Immediate-early genes mark activated ensembles, and interactions with glial cells refine long-term stability. Together, these mechanisms underpin adaptive responses to threat but, when dysregulated, contribute to anxiety disorders and post-traumatic stress. Advances in spatial transcriptomics, circuit mapping and behavioural paradigms are now illuminating the cellular architecture of fear memory and opening avenues for targeted interventions.

Research from Nature Portfolio

Recent studies have employed spatial and single-cell transcriptomics to map the cellular composition of fear engrams in the basolateral amygdala. Distinct neuronal subpopulations expressing neuropeptides and synaptic proteins were found to interact with nearby astrocytes, revealing a collaborative network essential for long-term memory persistence. Complementary work has constructed a comprehensive taxonomy of over a hundred amygdalar neuron types in conditioned mice, identifying those that up-regulate plasticity genes during learning and retrieval. Another investigation has delineated an insular cortex–basolateral amygdala circuit that encodes both negative valence and anxiety levels, demonstrating projection-specific optogenetic control over anxiety-related behaviours and clarifying how cortical inputs modulate fear responses.

Neurobiology of Fear Conditioning and Memory publication trend

The graph below shows the total number of articles in neurobiology of fear conditioning and memory across all publications each year (not limited to Nature Index journals).

Technical terms

Fear conditioning: Associative learning process linking neutral stimuli to aversive events, resulting in conditioned defensive responses.

Engram: A physical and molecular trace of a memory stored by changes in neuronal networks.

Synaptic plasticity: Activity-dependent strengthening or weakening of synapses underlying learning and memory.

Immediate-early genes (IEGs): Rapidly expressed genes such as Arc or c-fos used as markers of neuronal activation during learning.

Basolateral amygdala: Amygdalar subdivision crucial for encoding emotional valence and consolidating fear memories.

Long-term potentiation (LTP): A sustained increase in synaptic strength following high-frequency stimulation, serving as a cellular model for memory.

References

1. Spatial transcriptomics reveal neuron–astrocyte synergy in long-term memory. Nature (2024).
2. Neuronal types in the mouse amygdala and their transcriptional response to fear conditioning. Nature Neuroscience (2023).
3. Neural Circuits for Emotion. Annual Review of Neuroscience (2023).
4. Linking emotional valence and anxiety in a mouse insula-amygdala circuit. Nature Communications (2023).
5. The Role of the Medial Prefrontal Cortex in the Conditioning and Extinction of Fear. Frontiers in Behavioral Neuroscience (2015).
6. Role of Immediate-Early Genes in Synaptic Plasticity and Neuronal Ensembles Underlying the Memory Trace. Frontiers in Molecular Neuroscience (2016).