行動神経科学入門

Behavioral neuroscience is the study of how the nervous system guides behavior in humans and animals. Researchers investigate how functional areas and networks of the brain correlate to specific behaviors and disease states. The field combines methods ranging from animal training techniques to neuroimaging experiments to understand the relationship between brain activity and observable behavior.

In 1848, railroad foreman Phineas Gage survived an accident in which an iron rod drove through his skull. After the injury, he exhibited severe personality changes, demonstrating that damage to the frontal lobe profoundly impacts behavior. This case provided early evidence that specific brain regions control behavior, refuting earlier theories like Descartes' pineal gland hypothesis.

Neural correlates are specific brain regions whose activation is responsible for a given function or behavior. Behavioral neuroscientists study neural correlates to understand how different brain areas enable movement, learning, memory, motivation, and higher cognitive processes. Identifying these correlates helps researchers address behavioral problems and neurological diseases like addiction and post-traumatic stress disorder.

The Skinner box is an apparatus developed by B.F. Skinner in the 1930s to study how punishment and reward reinforce behavior in animals. In this device, animals learn that pressing a lever produces a food reward or other stimulus. Researchers use the Skinner box to investigate operant conditioning and how neuroactive substances influence motivation and behavioral responses to rewards.

Functional magnetic resonance imaging measures blood flow signals correlated to neuronal activation, creating statistical maps of active brain regions during specific tasks. Developed by Seiji Ogawa in 1990, fMRI revolutionized neuroscience by allowing researchers to visualize brain activity over time in human subjects. This non-invasive technique enables investigation of higher cognitive processes like decision-making and language without direct brain manipulation.

Researchers investigate learning and memory using maze designs such as T-arm or Morris water maze apparatus, in which animals must find and remember the path to exit. These behavioral tests reveal how the brain creates and retains memories. The hippocampus and amygdala are key neural correlates for memory formation, particularly for fearful stimuli relevant to treating post-traumatic stress disorder.

Electroencephalography is a non-invasive technique where electrodes placed on the scalp measure the brain's electrical activity during specific functions. EEG can reveal abnormal electrical patterns correlated with neurological and psychiatric diseases such as dementia and Alzheimer's disease. This method allows researchers to study disease states and cognitive processes without the need for invasive procedures or complex imaging equipment.