Learning Objectives

Cognitive neuroscientists employ tools to look inside the brain of participants while they are actively engaged in a mental process. This is no simple feat, and the field of cognitive neuroscience has grown with the advent of techniques that can measure activity in the functioning human brain. These methods vary in popularity, cost, complexity, spatial resolution, and temporal resolution. Each technique has advantages and disadvantages and takes years to master. This chapter briefly describes the most widely used techniques in cognitive neuroscience that will be referred to throughout this book. Section 2.1 briefly reviews the behavioral measures that allow for the interpretation of brain activation results. Section 2.2 discusses techniques with high spatial resolution, such as fMRI, which is the most popular method. fMRI measures the increases in blood flow that occur in active brain regions. This technique has excellent spatial resolution but has poor temporal resolution because the blood flow response is slow. Section 2.3 focuses on techniques with high temporal resolution, such as event-related potentials (ERPs). ERPs measure voltages (i.e., potentials) on the scalp that directly reflect the underlying brain activity. This technique has excellent temporal resolution and limited spatial resolution. In section 2.4, techniques with excellent spatial resolution and excellent temporal resolution are described. These include combined fMRI and ERPs as well as depth electrode recording from patients who have electrodes implanted in their brains for clinical reasons. Section 2.5 considers evidence from patients with brain lesions and cortical deactivation methods such as transcranial magnetic stimulation (TMS). Both of these methods have limited spatial resolution and poor temporal resolution; however, they can assess whether a brain region is necessary for a given cognitive process.