The Johnson Lab in the department of Psychiatry and interdepartmental
Neuroscience program seeks to address fundamental questions in the neurobiology
of fear memory with the aim of providing vital basic knowledge into the way the
brain encodes normal and pathological fear memories.
Normal fear
memory and fear responses are an essential part of any persons or animals
survival mechanism. Using fear memory an organism can learn to associate and
remember new threats with physical danger. Fear pathology includes the anxiety
disorders and post traumatic stress disorder (PTSD). Anxiety and PTSD can be
characterized by pathology in fear memory where responses are amplified and
become debilitating. These disorders can thus be thought of as either pathology
of the acquisition of fear memory or as pathology in the expression of an
otherwise normal fear memory.
Knowledge of where and how the brain
processes fear and fear learning has greatly increased in the last few decades
driven by the work of LeDoux, Davis, Pare, Fanslow, Phelps, Maren and many
others. This research has identified neural circuits that mediate synaptic
plasticity at input synapses to the lateral amygdala (LA). However, knowledge of
the cellular encoding of fear memory within the LA network is crucially lacking.
The Johnson Lab seeks to quantify the neural circuits of the LA and also the
organization of fear memories encoded by groups of LA neurons. The lab has
coined this approach the study of the Micro Anatomy of Fear.
In addition
the Johnson Lab also seeks to directly understand the microanatomy of how stress
interacts with the fear system. One of the key mechanisms of the stress response
is regulation of the HPA axis including modulation of adrenal steroids. The
Johnson lab also investigates the microanatomy of glucorticoid receptors and
their regulation of LA network behavior.
The Johnson lab studies the
microanatomy of fear using Pavlovian Fear Conditioning as a principal behavioral
model. Brains subject to Pavlovian conditioning are studied using 3-dimensional
reconstruction of LA neural networks. 3D mapping is performed using computerized
mapping with Neurolucida (Microbrightfield, VT). Anatomical and
electrophysiological data is obtained from neurons and networks using
immunocytochemistry and whole cell patch clamp and extra cellular field
recordings. Structural data is obtained using transmitted light, fluorescent and
electron microscopy.
For further information including current paid and
volunteer research opportunities please contact:
email: mailto:Luke.Johnson@usuhs.mil
Contact Information
Uniformed Services University of the Health Sciences
4301 Jones Bridge
Road
Bethesda, Maryland 20814