Cognitive neuroscientists can directly examine brain structure and activity using which of the following imaging techniques?

Introduction / Context:
This psychology and neuroscience question asks about tools that cognitive neuroscientists use to study the brain. Imaging techniques have transformed our understanding of how the brain supports memory, attention, language, and other mental functions by allowing researchers to see structure and activity in living humans.

Given Data / Assumptions:

• The question focuses on imaging techniques that allow direct examination of brain structure or metabolic activity.
• PET stands for positron emission tomography, and MRI stands for magnetic resonance imaging.
• Other options mention gamma imaging and electroencephalography, which relate to brain measurements but are phrased in a broad way.

Concept / Approach:
Positron emission tomography (PET) uses small amounts of radioactive tracers to measure metabolic processes in the brain, such as glucose use or blood flow. Regions that are more active during tasks show higher tracer uptake. Magnetic resonance imaging (MRI) uses strong magnetic fields and radio waves to produce detailed images of brain structures. A related technique, functional MRI, measures changes in blood oxygen levels as a proxy for neural activity during tasks. Cognitive neuroscientists frequently use PET and MRI because they provide detailed maps of where in the brain certain functions are localised. Electroencephalography (EEG) records electrical activity at the scalp and is valuable for tracking timing of brain events but has lower spatial resolution compared to imaging methods like PET and MRI.

Step-by-Step Solution:

Verification / Alternative check:
Look at any introductory cognitive neuroscience or biological psychology textbook. The early chapters usually introduce MRI, functional MRI, and PET scans as primary imaging tools for studying brain structure and function. Diagrams show colourful images of brain slices with highlighted areas that become active during cognitive tasks. These texts may also discuss other tools such as EEG or magnetoencephalography, but PET and MRI are consistently highlighted as central imaging techniques in the field.

Why Other Options Are Wrong:

Gamma imaging and electroencephalography is not the best answer because gamma imaging is not a standard term used in cognitive neuroscience surveys, and electroencephalography focuses on timing and electrical signals more than detailed structural imaging.

Electroencephalography and PET is incomplete because EEG measures electrical activity at the scalp with good temporal resolution but relatively poor spatial resolution compared with MRI. The question asks about techniques that examine the brain, often understood as structural and metabolic images, which are more clearly linked to PET and MRI together.

MRI and electroencephalography is also incomplete because, although both are used in research, the classic pair often mentioned in basics of cognitive neuroscience is PET and MRI for imaging structure and metabolic activity.

Common Pitfalls:
Students may confuse methods that measure brain activity over time with those that provide detailed images of where activity occurs. Electroencephalography is excellent for timing but less precise for localisation, while MRI and PET are primarily used for spatial mapping. Another pitfall is to assume that any combination of brain related techniques is equally correct. In exam style questions, the pair PET and MRI is commonly used to represent the main imaging methods introduced at the basic level.

Final Answer:
Cognitive neuroscientists commonly examine brain structure and metabolic activity using the imaging techniques PET and MRI.