Introduction to Psychology

Introduction to Psychology of 97 chemicals, including neurotransmitters, can be delivered directly and their effects on behavior studied. A specific region of the brain can also be stimulated by a mild electric current. Electrical Recording- Because electrodes can record brain activity as well as stimulate it, scientists can measure the activity of large groups of neurons through a series of large electrodes placed on the scalp. This method is known as electroencephalography (EEG). Clinicians use the EEG to detect abnormal electrical patterns that signal the presence of brain pathology. Brain Imaging- The newest tools of discovery are imaging techniques that permit neuroscientists to look into the living brain. A CT scan (computerized axil tomography) uses x-ray techniques to study brain structures. A MRI (magnetic resonance imaging) creates images based on how atoms in living tissue respond to a magnetic pulse delivered by the device. Whereas CT scans and MRIs provide pictures of brain structures, PET scans (positron-emission tomography) measure brain activity, including metabolism, blood flow, and neurotransmitter activity. Split-brain- The visual system’s anatomy made studies of split-brain subjects possible. Images entering the eye are reversed by the lens. This led to the development of simple ways to test the functions of two hemispheres after the corpus callosumwas cut and the patients had recovered from their surgery. The results showed that in some ways the operation had created two minds in one body. The results of split-brain research were so dramatic that they led some people to promote the concept of brain functions as being highly localized and restricted to one hemisphere or the other. Hemispheres- The brain is divided structurally into the hindbrain, the midbrain, and the forebrain. This organization reflects the evolution of increasingly complex brain structures related to behavioral capabilities. Hindbrain- The hindbrain is the lowest and most primitive level of the brain. As the spinal cord enters the brain, it enlarges to form the structures that compose the stalk-like brain stem. Attached to the brain stem is the other major portion of the hindbrain, the cerebellum. Midbrain- Lying just above the hindbrain, the midbrain contains clusters of sensory and motor neurons. The sensory portion of the midbrain contains important relay centers for the visual and auditory systems. Here, nerve impulses from the eyes and ears are organized and sent to the forebrain structures involved in visual and auditory perception. The midbrain also contains motor neurons that control eye movement. Forebrain- The forebrain is the brain’s most advanced portion, from an evolutionary standpoint. Its major structure, the cerebrum, consists of two large hemispheres, a left side and a right side, that wrap around the brain stem. The outer portion of the forebrain has a thin covering, or cortex. Within are a number of important structures buried in the central regions of the hemispheres. The two cerebral hemispheres work in coordination with each other, and they appear to have different functions and abilities. The left hemisphere commands language and mathematical abilities; and positive emotions are linked to the left side. The right hemisphere controls spatial abilities but has a generally limited ability to communicate through speech; and negative emotions are linked to the right side of the brain. The brain normally operates as a highly integrated system. © 2015 Achieve Page 21