3.17 Reading: Invasive methods for investigating the brain

experimental ablation

the removal or destruction of a portion of the brain of a laboratory animal; presumably, the functions that can no longer be performed are the ones the region previously controlled (lesion study)

excitotoxic lesion

a brain lesion produced by intracerebral injection of an excitatory amino acid, such as kainic acid

sham lesion

a "placebo" procedure that duplicates all the steps of producing a brain lesion except for the one that actually causes the brain damage

stereotaxic surgery

brain surgery using a stereotaxic apparatus to position an electrode or cannula in a specified position of the brain.

bregma

the junction of the sagittal and coronal sutures of the skull; often used as a reference point for stereotaxic brain surgery

stereotaxic atlas

a collection of drawings of sections of the brain of a particular animal with measurements that provide coordinates for stereotaxic surgery

stereotaxic apparatus

a device that permits a surgeon to position an electrode or cannula into a specific part of the brain

fixative

a chemical such as formalin; used to prepare and preserve body tissue

formalin

the aqueous solution of formaldehyde gas; the most commonly used tissue fixative

microtome

an instrument that produces very thin slices of body tissues

scanning electron microscope

a microscope that provides 3D information about the shape of the surface of a small object

anterograde labeling method

a histological method that labels the axons and terminal buttons of neurons whose cell bodies are located in a particular region

phaseolus vulgaris leukoagglutinin (PHA-L)

a protein derived from kidney beans and used as an anterograde tracer; taken up by dendrites and cell bodies and carried to the ends of the axons

immunocytochemical method

a histological method that uses radioactive antibodies or antibodies bound with a dye molecule to indicate the presence of particular proteins of peptides

retrograde labeling method

a histological method that labels cell bodies that give rise to the terminal buttons that form synapses with cells in a particular region.

fluorogold

a dye that serves as a retrograde label; taken up by terminal buttons and carried back to the cell bodies.

transneuronal tracing method

a tracing method that identifies a series of neurons that form serial synaptic connections with each other, either in an anterograde or retrograde direction; involves infection of specific neurons with weakened forms of rabies or herpes viruses