Tutorial 2 Flashcards
What does electrophysiology refer to?
The electrical potentials generated in nerve cells and muscles
What techniques measure electrical activity in the brain?
- Micro-electrode recordings
- Electroencephalography (EEG)
- Magnetoencephalography (MEG)
- Electromyography (EMG)
What are micro-electrode recordings used for?
Measuring action potentials and post-synaptic potentials from brain tissue
What is a limitation of micro-electrode recordings in humans?
They are highly invasive and can only be performed during brain surgery
What does EEG measure?
Electrical activity from the scalp based on Local Field Potentials (LFPs)
What are Local Field Potentials (LFPs)?
Transient deficits or surpluses of electrical charges outside neurons due to ion movement
What are Event-Related Potentials (ERPs)?
Stimulus-induced changes in EEG that are averaged over multiple segments
What do the components of an ERP signal represent?
Departures and returns from the baseline signal, indicating psychological processes
How are ERP components labeled?
By their polarity and order, or by polarity and timing (e.g., N1, P300)
What is the ‘inverse problem’ in EEG?
Determining the brain sources of EEG/ERP data from scalp measurements
What is the primary limitation of EEG in localizing brain activity?
The inverse problem does not have a unique solution
What does structural MRI measure?
The magnetic signal from hydrogen atoms in the body
What is Blood Oxygen Level Dependent (BOLD) contrast?
The difference in MRI signal between more and less metabolically active brain regions
What is a key advantage of BOLD fMRI over PET?
Superior spatial and temporal resolution
What is a limitation of fMRI related to patient conditions?
Cannot scan individuals with metal implants or claustrophobia
What is neuropsychology?
The study of the consequences of anatomically-selective brain damage
What is a single dissociation in neuropsychology?
Showing that damage to a brain region impairs performance in condition A relative to condition B
What is a double-dissociation?
Demonstrating that damage to another brain region leads to greater impairment in condition B than condition A
What is Transcranial Magnetic Stimulation (TMS)?
The application of a magnetic field to the head to induce electrical currents in neurons
What are the possible neurophysiological effects of TMS?
- Excitatory
- Inhibitory
What is a challenge in using TMS for cognitive research?
Ruling out effects of noise and sensations caused by the stimulation
What is the spatial resolution of TMS?
Relatively high, but confined to the cortex
What is one limitation of TMS regarding stimulation depth?
Cannot stimulate deeper brain structures like the hippocampus or amygdala
