Behavioral Endocrinology Techniques and Concepts

Flashcards covering essential techniques, historical experiments, analytical levels, and molecular methods in behavioral endocrinology.

Berthold's Experiment

A foundational endocrinology experiment involving three groups of adult roosters (castrated, reimplanted testes, and transplanted testes) demonstrating that testicular transplantation restored normal male development and behavior without requiring nerve reattachment, proving testes release a blood-borne hormone.

Hormone

A chemical signaling molecule synthesized in the endoplasmic reticulum, processed in the Golgi, and secreted into the blood to travel long distances to specific target cell receptors, requiring a minimum threshold concentration to trigger non-linear behavioral and physiological responses.

Neurotransmitter

A chemical messenger stored in presynaptic vesicles that fuses with the membrane upon the influx of calcium ions ($\text{Ca}^{2+}$) to cross a small synaptic distance and bind to postsynaptic cell receptors.

Comparative Approach

A research methodology of studying simpler animal models to gain insights into human biology and behavior, offering high replicability while requiring care not to overlook species-specific connections.

Immediate Causation

A level of behavioral analysis focusing on the underlying physiological or hormonal mechanisms directly driving a specific behavior (e.g., a zebra finch singing due to high blood estrogen concentration).

Development (Level of Analysis)

A level of behavioral analysis examining how individual experience, learning, or maturation (e.g., undergoing puberty or learning a song from a father) shapes behavior.

Evolutionary Approach

A level of behavioral analysis investigating how a behavior has evolved across generations through natural selection within a lineage of common ancestral species.

Adaptive Function

A level of behavioral analysis addressing how a specific behavior increases an individual's evolutionary fitness to survive and reproduce in its environment.

Radioimmunoassay (RIA)

An assay technique utilizing radioactive labeling and standard curves to quantify hormone concentrations, characterized by an inverse relationship where lower color binding indicates higher hormone concentration.

Enzyme Immunoassay (EIA / ELISA)

A quantitative assay technique (used in test strips like hCG pregnancy tests) where hormone binding to antibody-linked enzymes causes a measurable color change.

Western Blot

A laboratory technique used to measure protein presence, in which homogenized tissue proteins (carrying a negative charge) are separated by gel electrophoresis along a voltage gradient and detected with specific antibodies.

Southern Blot

A molecular biology blot technique using gel electrophoresis and labeled molecular probes to identify specific target DNA sequences.

Northern Blot

A molecular biology blot technique that separates nucleic acids by gel electrophoresis and utilizes probes to detect specific target RNA sequences.

Immunohistochemistry

Also referred to as immunocytochemistry, a technique using dye-labeled antibodies to visualize the precise cellular or tissue localization of specific hormones or proteins.

In Situ Hybridization

A technique using radiolabeled or dye-labeled cDNA probes applied to tissue sections to detect and localize specific mRNA transcripts to determine where genes are being expressed.

Autoradiography

A technique used to map hormone receptor sites in tissue by injecting a radiolabeled hormone and applying film, which darkens where the hormone binds.

Transgenic Animals

Organisms whose genome has been modified through the artificial insertion, alterion, or deletion of specific genetic material.

Knockout Animals

A subtype of transgenic animals (typically mice) in which a specific target gene has been intentionally inactivated or completely deleted to study its loss of function.

RNA Interference (RNAi)

A gene-silencing technique in which introduced small RNA molecules bind to and destroy target mRNA, temporarily blocking the expression of specific hormones or receptors.

Viral Gene Transduction

A genetic manipulation technique utilizing engineered viral vectors (e.g., modified common cold virus) injected into target brain regions to introduce genes and alter expression in nearby neurons.

Gene Arrays

Microarrays containing probe sets for multiple genes that bind extracted, fluorescently tagged mRNA to assess the presence, absence, and relative expression level of transcripts.

Single Unit Recording

A neurophysiological technique using fine microelectrodes positioned near individual neurons to record changes in electrical activity during behavioral or hormonal conditions.

Electrical Stimulation

A method of applying electric current via electrodes to activate neurons in a target brain region, noted for being non-specific because it stimulates all nearby cell types.

Optogenetics

A technique using light-sensitive ion channels expressed in specific neuronal populations to selectively activate or inhibit neural circuits using specific light wavelengths.

Optogenetic Inhibition

The selective suppression or silencing of neuronal firing within targeted neural circuits using light-activated inhibitory constructs.

Calcium Imaging

A technique using fluorescent sensors to detect increases in intracellular calcium ($\text{Ca}^{2+}$) ions, serving as a readout for action potential firing and neuronal activity.

Homozygous ob Mice

Mutant mice lacking functional genes for encoding leptin, resulting in severe hyperphagia, overeating, and obesity.

Leptin

A hormone produced in white and brown adipose tissue that acts on hypothalamic receptors to reduce food intake and regulate body weight.