History and Methods Flashcards
What is meant by In Vivo measurement?
A measurement taken from a living subject without taking a sample from them.
What does comparative and evolutionary psychology look at?
Comparing human and animal behaviour and biology to explain differences or similarities.
- Explains biological features or behaviour through evolutionary theories
What methods are used to try to understand the brain?
Neuropsychology
Brain Imaging
Brain Stimulation
What specifically does Neuropsychology do, in terms of trying to understand the brain?
Looks at the effects of brain damage on brain function
- By seeing what is affected, we can infer the function of the damaged brain region
Investigates what damaged brains can tell us about the building blocks of cognition and how they interact
Use case studies to compare brain-damaged groups with healthy controls
Use case studies to look for double dissociation among individuals with different brain damage
What are the two things that Brain Imaging can be used to look at?
Structure - size, shape, etc.
Function - activity
What are the two methods that Functional Brain Imaging can be split into?
Haemodynamic methods
- e.g. fMRI, PET
- Have superior spatial resolution compared to Electro- or Megneto- physiological methods
Electro- or Magneto- physiological methods
- Have superior temporal resolution to haemodynamic methods
What is an fMRI and how does it work?
Functional Magnetic Resonance Imagining
Measures oxygen in the blood & reports it as BOLD (Blood Oxygen Level Dependent) contrast
- shows difference between oxygenated and de-oxygenated blood, due to difference in magnetic properties
Assumes a stronger signal reflects greater demand for oxygenated blood, therefore more activity occurring in the more oxygen-rich region
What is a PET scan and how does it work?
Name a limitation
Positron Emission Tomography
Injected with radioactive tracer into biologically active molecule (normally type of glucose)
Concentration levels of tracer in brain are measured
Generally safe BUT is a little invasive
What is an EEG and how does it work?
Give a limitation
Electroencephalography
Records electrical activity of neurons through electrodes on scalp
- very large numbers of neurons have to be active synchronously in order to record activity
Exact source localisation is difficult (current travels differently through brain matter & skull of different texture and density
What methods of observing the brain fall under Brain Imaging?
fMRI
PET
EEG
What methods of brain observation fall under Brain Stimulation?
Optogenetics
Deep Brain Stimulation (DBS)
Transcranial Direct Current Stimulation (tDCS)
Transcranial Magnetic Stimulation (TMS)
How does Deep Brain Stimulation (DBS) work?
Give some advantages of DBS.
- Brain ‘pacemaker’ is implanted, which sends electrical signals to parts of brain that need stimulation
- Internal Pulse Generator is implanted under skin by clavicle. Sends out electrical pulse which travels up extension to the lead
- The lead is an insulated wire with electrodes, implanted in the to-be-stimulated brain region
Fully reversible
Precise localisation
Very few complications/side-effects
What is Deep Brain Stimulation commonly used to treat?
Parkinson’s Disease and Chronic Pain (in the US)
Evidence that it can be effective for treatment-resistant Depression and OCD
How does Transcranial Direct Current Stimulation (tDCS) work?
- Delivers direct current to a brain region through electrodes placed on scalp
- Battery powered device is used to deliver current, to ensure constant current
Anodal (+) current stimulation increases neuronal excitability of cortex below electrode & makes neurons more likely to fire
Cathodal (-) current stimulation decreases neuronal excitability of cortex below electrode, makes neurons less likely to fire
How does Transcranial Magnetic Stimulation (TMS) work?
- Applies rapidly changing electromagnetic fields to induce electrical currents
- When applied repeatedly (rTMS) can increase or decrease cortical excitability
- Low frequency stimulation inhibits
- High frequency stimulation activates
