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We have considered a wide range of research methods for manipulating and measuring brain–behavior interactions. Tables 7-1 and 7-2 summarize these methods, including goals and examples of each method. How do researchers choose among them all? Their main consideration is their research question. Ultimately, that question is behavioral, but many steps lie along the route to understanding behavior.

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Some researchers focus on morphology (structure) in postmortem tissue. This approach allows detailed analysis of both macro and micro structure, depending on the method chosen. Identifying brain pathology, as in Parkinson disease, can lead to insights about the causes and nature of a disorder.

Other investigators focus more on the ways neurons generate electrical activity in relation to behavior or on functional changes in brain activity during specific types of cognitive processing. Both approaches are legitimate: the goal is gaining an understanding of brain–behavior relationships.

But investigators must consider practical issues, too. Temporal resolution (how quickly the measurement or image is obtained); spatial resolution (how accurate localization is in the brain); and the degree of invasiveness all are pertinent. It is impractical to consider MRI-based methods for studies of very young children, for example, because although the images are highly accurate, the participants must remain absolutely still for long periods.

Similarly, studies of brain-injured patients must take into account factors such as the subject’s ability to maintain attention for long periods—during neuropsychological testing or imaging studies, for example. And practical problems such as motor or language impairment may limit the types of methods that researchers can use.

Of course, cost is an ever-present practical consideration. Studying brain and behavior linkages by perturbing the brain are generally less costly than some imaging methods, many of which require expensive machinery. EEG, ERP, and fNIRS are noninvasive and relatively inexpensive to set up (less than $100,000). MRI-based methods, MEG, and PET are very expensive (more than $2 million) and therefore typically found only in large research centers or hospitals. Similarly, epigenetic studies can be very expensive if investigators consider the entire genome in a large number of biological samples.

Comparing Neuroscience Research Methods

Before you continue, check your understanding.

Question 1

Question 2

Question 3

Answers appear in the Self Test section of the book.