Understanding Stress by Neuroscience

ABSTRACT

Stress can be defined generally as reponses to stressors on the body or in a definition more focused on the central nervous system, it can be defined as alterations in neuro-psychological homeostatic processes. There is a psychological aspect to stress, related to issues such as memory, emotion, arousal, and also a biological aspect which included activation of specific brain and endocrine circuits. This article reviews a series of neurobiological mechanisms aimed at understanding what are pathways by which stress is perceived, processed, and transduced into a neuroendocrine response. Multiple brain structures are involved in the organization of responses to stressful stimuli. Among them the hypothalamus, septohippocampal structures, amygdala, cingulate and prefrontal cortices, hindbrain regions such as the brainstem catecholamine cell body group (A2/C2 cell groups in the nucleus of the tractus solitaris; A1/C1 cell groups in the ventrolateral medulla; A6 cell groups in the locus ceruleus), the parabrachial nucleus, cuneiform nucleus, and dorsal raphe nucleus are prominent structures. We reviewed with the focus on the classic stress circuits the limbic- hypothalamic-pituitary- adrenal axis (LHPA) and locus ceruleus-norepinephrine (LC-NE) system. Our review indicates that the LHPA stress circuit and LC- NE system are the complex systems with multiple control mechanisms and that these mechanisms are altered in pathological states, such as chronic stress and depression. The holistic features described in this reviews can provide insight into the nature and location of brain circuits and neurotransmitter receptors involved in stress and the treatment of stress-related disorders.