Ch. 7 - Research Methods Flashcards
advances in microscopy (20th century)
light microscopes (magnitudes)
electron microscopes (detail)
multiphoton microscopes (living tissue)
histology (anatomy)
case of frozen addicts
1982 Santa Clara
George Carillo, heroin addict, appeared frozen in place
- caused by new synthetic heroin made by Barry Kidston
- tried to make MPPP
- ended up synthesizing MPTP
- MPTP -> MPP+ which kills neurons in the substantia nigra
hippocampus/learning rat study
3 groups of rats
- ADX rats (adrenal cortex removed): can’t distinguish different objects
- control rats: more time with new object
- ADX + enrich: unimpaired
swimming rat study
Morris 1981
rats used memory and visual markers to help find platform in a swimming pool of water.
skilled-reach rat study
Whishaw and Kolb, 2005
rats needed to learn how to shape their hands to fit through slots to reach food
- CAN BE USED TO STUDY STROKE RECOVER
- FINE MOTOR SKILLS
stimulation/inhibition brain manipulation: electrical
Wilder Penfield in the 1950s - live patients, stimulated the cerebral cortex
DBS: deep brain stimulation - used for mental health issues and disease, LAST RESORT option as it is very invasive.
TMS: transcranial magnetic stimulation - noninvasive but only target neocortex
stimulation/inhibition brain manipulation: drugs
used on animals only
administered through BBB or cannula
haloperidol: lowers dopamine
amphetamine: increases dopamine
PROS: TEMPORARY EFFECTS, AUTOMATIC CONTROL
CONS: INVASIVE
stimulation/inhibition brain manipulation: genes
used in animals only
knock out (loss of function) or knock-in (gain of function)
CRISPR-Cas9: uses an enzyme to cut away or knock out a gene
Optogenetics: uses light to manipulate the brain
- channelrhodopsin-2 (excitation - Na/K pump) or halorhodopsin (inhibition - Cl pump)
PROS: IMMEDIATE RESPONSE, RAPID REVERSAL
CONS: EXPENSIVE, HIGH EXPERTISE REQUIRED
brain lesions
stereotaxic apparatus
a patient has their head drilled/fixed to an apparatus while a surgeon performs targeting manually
whole animal manipulation
diet, exercise, socialization
electrical brain imaging: electrophysiology
microelectrodes are placed next to cells.
extracellular (vertebrates.
- PROS: live, less expertise
- CONS: yields less information
intracellular (invertebrates)
- PROS: high temporal and spatial resolution
- CONS: harmful, confined to neurons in dishes that will die inevitably
electrical brain imaging: electroencephalography (EEG)
electrodes are placed on the scalp to map out activity in the brain
** graded potentials only
PROS: simple, cheap, non-invasive
CONS: can’t detect action potentials
electrical brain imaging: event-related potentials (ERP)
complex EEG produce responses through discrete stimuli.
PROS: cheap, easy, non-invasive, high temporal resolution
CONS: noise (messy), low spatial resolution, can’t penetrate the brain, too vague
anatomical imaging: static methods
CT scans: “computed tomography”
- 3D, passes X-ray beams through the brain
- lighter colour = higher density
PROS: spatial resolution
CONS: radiation exposure
MRI scans: “magnetic resonance imaging”
- magnetic field measures emitted radiowaves from H+ atoms in the brain
- 1.5-3 Tesla
- darker colour = higher density
PROS: more detail (white and grey matter)
anatomical imaging: functional methods
fMRI:
- records brain O2 levels (increase when active)
PROS: spatial resolution
CONS: poor temporal resolution, costly, high expertise needed
PET scans: “positron emission tomography”
- unstable radioisotopes (missing a neutron) will emit positrons detected by cameras
PROS: good spatial resolution
CONS: poor temporal resolution, costly
