5: The Research Methods of Biopsychology Flashcards
(35 cards)
Stereotaxic surgery…
Device inserted into target sites to investigate activity.
Stereotaxic atlas…
Locates brain structures for the device to be inserted.
Bregma…
Base point, like ‘North star’; top of the skull where sutures (skull bones) intersect.
Aspiration lesions…
Used for cortical tissue that is visible to the surgeon’s eye.
Radio frequency lesions…
Subcortical lesions. Current sent via stereotaxic electrode, which is sent to target site. Heat destroys tissue.
Cryogenic blockade…
Alternative to sectioning; a cryoprobe is used in target sight to freeze activity. Unlike sectioning, this is reversible = +ve.
Lidocaine…
Reversible microinjections, a type of local anaesthetic.
Electrical simulation…
Target sites are stimulated using bipolar electrode.
Intracellular unit recording…
Records activity in one neuron’s membrane potential. Intra- because it’s inside nerve cell.
Difficult to achieve in freely moving animals, so have to be immobilised.
Extracellular unit recording…
Records firing of a neuron via electrodes in neuron’s extracellular fluid.
Difficult to achieve in freely moving animals.
Multiple unit recording…
Larger electrode tip, so records signals from more neurons.
Graph - sum number of recorded action potentials per unit of time.
Intragastically…
Through a tube into the stomach.
Intraperitonically…
Injected into peritoneal cavity of abdomen, ‘IP’.
Subcutaneously…
Injected into fat just beneath skin, ‘SC’.
Intravenously…
Injected into large surface vein, ‘IV’.
Cannub…
A stereotaxic tube that directs drugs into brain. Surpasses blood-drain barrier.
Neurotoxins…
Microinjected into the brain to perform more accurate lesions.
Selective neurotoxins…
Kainic acid (used to kill intestinal worms) or ibotenic acid (from Amanita mushrooms); enter cell bodies of neurons to kill them.
6-Hydroxydopamine…
(6-OHDA) - selectively absorbed by dopamine and epinephrine neurons and destroys them.
2-Deoxyglucose (2-DG) technique…
2-DG is injected into animal’s brain, then activity is performed by them. The neurons involved absorb 2-DG (as it contains glucose - but it cannot be metabolised).
Then they are killed and an autopsy is performed on the brain.
Using an autoradiography the experimenter can locate traces of 2-DG and therefore what parts of the brain are involved in performed activity.
Density is colour-coded.
Cerebral dialysis…
Measures extracellular concentration of target neurochemicals without killing animal.
A tube is inserted into target brain structure and local extracellular chemicals diffuse into this.
Tube is collected and the solution receives a chromatograph, which records the chemical make-up of these fluids.
Immunocytochemistry…
Colours antibodies of interest in brain which then bind to particular enzymes found in target neurons (i.e. one that contains dopamine). The dye helps locate these neurons so that we know which parts of the brain and/or neurons produce certain chemicals.
In Situ hybridisation…
Locates target neuroproteins via artificial production of mRNA (hybrid RNA).
RNA is a messenger that is involved in synthesis of neuroproteins.
Therefore mRNA helps discover the location of neurons that produce target neuroprotein.
Gene knockout techniques…
Creates organisms devoid of a particular gene to investigate said gene’s role.
E.g. study of melanopsin knockout mice found that said gene helps regulate circadian rhythms. Found in retina (makes sense, as these rhythms are affected by light levels).
