Methods and Strategies of Research

Question 1

What are the types of experimental ablation?

Answer 1

Lesion studies draw behavioral inferences from animals by studying the interconnectivity of brain tissue and functional differences between intact and lesioned brains

To produce brain lesions: aspiration (biopsy), knife cuts, radio-frequency lesions, CHEMICALS: excitotoxic lesions (kainic acid) and 6-ODHA (selectively toxic to DA neurons), reversible lesions: local anesthetic, muscimol, and placebo (sham) lesions

Question 2

What are the aspects of stereotaxic surgery?

Answer 2

Stereotaxic atlas: drawings of brain sections for locating structures
– Bregma: reference point
Stereotaxic apparatus: device for positioning electrode or cannula

Question 3

What are the different tests for brain imaging?

Answer 3

CT scan (computerized tomography): multiple x-ray scans compiled by computer
MRI (magnetic resonance imaging): energy of hydrogen activated by radio waves in a magnetic field, better spatial resolution
– diffusion tensor imaging: modification allows imaging of smaller tracts
PET scan (positron emission tomography): radioactie 2-DG taken up by active neurons
fMRI (functional MRI): shows areas of increased blood flow/brain activity/oxygen

Question 4

What tests are used to record neural activity?

Answer 4

EEG (electroencephalogram) – mass activity of neurons measured (macro electrodes)
micro electrodes using single-unit recordings

Question 5

What tests are used to record metabolic activity in animals?

Answer 5

Autoradiography: radioactive 2-DG is taken up by active neurons – brain sections show active areas
Fos: protein produced by active neurons – fos identifies active areas in brain sections

Question 6

What is used to stimulate neural activity?

Answer 6

Transcranial magnetic stimulation: human cortical stimulation with magnetic fields, used in research and as an antidepressant

behavioral effects include: problems of artificiality – cannot be produced by humans naturally

Question 7

What are the ways we study genetic methods?

Answer 7

Twin and adoption studies: compare trait concordance rate (correlation) of monozygotic (identical) to dizygotic (fraternal) twins or compare identical twins that were raised together or apart

Genomic studies: identify location of genes related to behavioral traits

Targeted mutations: knockout genes are used to create organisms that have defective gene related to particular protein related to behavior

Question 8

What are the non-invasive methods used to record physiological responses in humans?

Answer 8

CNS
– EEG and ERPs: P300 is what happens when you react to a novel stimulus or a salient stimulus

PNS
Somatic
–Electromyography (EMG: muscle): startle reflex, humans blink and rats jump
– Electrooculography (EOG: eye movements)

Autonomic
– pupillometry (pupil dilation)
– skin conductance (sweat gland)
– electrocardiogram (ECG)
– blood pressure and volume and respiration

Question 9

What are the behavioral paradigms?

Answer 9

Human neuropsychology
– performance tests (verbal, cognitive, spatial, perceptual-motor) e.g., Wisconsin card-sorting test for frontal lobe function

animal behavior paradigms
– radial arm maze (spatial ability)
– morris water maze (memory and spatial cognition) and studies Alzheimer’s
– open field test (anxiety and fear behavior)