Microdissection of Mouse Brain into Functionally and Anatomically Different Regions.

The brain is the command center for the mammalian nervous system and an organ with enormous structural complexity. Protected within the skull, the brain consists of an outer covering of grey matter over the hemispheres known as the cerebral cortex. Underneath this layer reside many other specialized structures that are essential for multiple phenomenon important for existence. Acquiring samples of specific gross brain regions requires quick and precise dissection steps. It is understood that at the microscopic level, many sub-regions exist and likely cross the arbitrary regional boundaries that we impose for the purpose of this dissection. Mouse models are routinely used to study human brain functions and diseases. Changes in gene expression patterns may be confined to specific brain areas targeting a particular phenotype depending on the diseased state. Thus, it is of great importance to study regulation of transcription with respect to its well-defined structural organization. A complete understanding of the brain requires studying distinct brain regions, defining connections, and identifying key differences in the activities of each of these brain regions. A more comprehensive understanding of each of these distinct regions may pave the way for new and improved treatments in the field of neuroscience. Herein, we discuss a step-by-step methodology for dissecting the mouse brain into sixteen distinct regions. In this procedure, we have focused on male mouse C57Bl/6J (6-8 week old) brain removal and dissection into multiple regions using neuroanatomical landmarks to identify and sample discrete functionally-relevant and behaviorally-relevant brain regions. This work will help lay a strong foundation in the field of neuroscience, leading to more focused approaches in the deeper understanding of brain function.

Early Life Stress Alters Adult Inflammatory Responses in a Mouse Model for Depression.

Increased levels of pro-inflammatory cytokines and hypothalamic pituitary axis (HPA) activity are strongly associated with depression. Childhood stress and trauma predispose individuals for increased inflammatory tone and major depression in later life, suggesting that early life reprogramming of the stress/immune axis may be involved in the pathogenesis of depression. In this study, we are using a short duration neonatal maternal separation stress (MS) paradigm in mice to test if early life stress can impact plasma and brain inflammatory tone into adulthood. We use ELISA assays to investigate levels of the pro-inflammatory cytokines IL-1beta, IL-2, IL-6 and TNF-alpha, in both plasma and brain tissue of mice exposed to MS (STR), their unseparated littermates (LMC) and unhandled age matched controls (AMC). Cytokine levels are assessed in male and female adult mice with and without a bacterial lipopolysaccharide (LPS) induced immune challenge. We present evidence that stress exposure, during the first week of life, predisposes both male and female mice for increased inflammatory cytokine secretion, peripherally and in brain tissue, upon adult exposure to lipopolysaccharide (LPS).