BMB Lesson 8

Somatic Intervention

manipulating the body (brain) may affect behavior

Behavioral intervention

manipulating behavior may have an affect on the body and the brain

Correlation

measures how closely the body and measures covary

control group

identical to the experimental group except that they do not experience any alteration or treatment

within-subject experiments

the control group is the same set of subjects tested before alteration or treatment

between-subjects experiments

the experimental group is compared to a serrate control group that has been treated identically except for the manipulation

independent variable

the structure or function that is being altered

- what you manipulate

dependent variable

the response that is measured such as a behavior

- what you measure

Computerized axial tomography ( CAT to CT)

A measure of X -ray absorption at several positions around the head and it maps tissue density

- generate anatomical map

-looks at organization of grey and white matter and ventricles

-DETECTS STRUCTURAL CHANGES IN THE BRAIN

Magnetic resonance imagining (MRI)

provides higher resolution images than CT

- also valuable for detecting structural changes

- more detailed than a CT but it is more expensive so it is less used

Functional MRI (fMRI)

detects changes in brain metabolism (oxygen use) in ACTIVE brain areas

- measured indirectly

-shows how brain structures collaborate

( brain activity causes more blood flow to that area which supplies more oxygen so we can determine what areas of the brain are active with an fmri)

Position emission tomography (PET)

-gives image of brain activity

- uses RADIOACTIVE chemicals injected into the blood stream and maps their destination by the radioactive emissions

- identifies which brain regions contribute to specific functions

- concerns about RADIATION EXPOSURE so this limits the number of scans from one person in a reasonable time frame

Electroencephalogram (EEG)

- a recording of spontaneous brain potentials (brain waves)

- when the action potential is propagated down the axon, it creates an electric current

- EEG caps measure the electrical fields created by groups of neurons firing together

- distinguishes between sleep states and provides data for diagnosing seizures

MEG

- similar to an EEG

- noninvasive/ records direct ensemble neural activity

- measures the tiny magnetic fields given off by active neurons during cognitive processing

- EXCELLENT TEMPORAL RESOLUTION

transcranial magnetic stimulation (TMS)

- NOT a measure of neural activity but provides a experimental probe to alter neural activity

- applies a brief strong magnetic field that alters neural activity by activating or deactivating brain structures

Stereotaxic surgery

- a device used during surgery for precise placement of a fine wire or small injunction needle for targeting electrical current or a chemical solution into a specific region of the brain

ex:

- neural lesions

- electrode implantation

-micro-infusions

Optogenetics

- opsin genes inserted into a particular type or neuron

- can use light to polarize or depolarize cells

- superior temporal resolution

Channelrhodopsin

excite neurons

Halorhodopsins

inhibit neurons

DREADDs

designer receptors exclusively activated by designer drugs

- g-protein coupled receptors that are designed to be activated by a drug called CNO

-Superior SPATIAL resolution

Nissal stains

uses basic dyes to show nissl bodies which are rich in RNA

Golgi stains

visualizes neurons with a metallic (silver)

Immunohistochemistry (IHC)

visualizes proteins using antibodies to detect specific proteins in tissue samples

In-situ hybridization

visualizes mRNA in tissue using a labeled nucleic acid probe