Psychology

Mini Quiz 2 AP Describe the Nervous system. Describe the Peripheral nervous system Autonomic Sympathetic Parasympathetic

Mini Quiz Psychology What is a split brain, and what does it reveal about brain functioning?

Electric Impulses This microelectrode is being used to record the electrical impulses generated by a single cell in the brain of a monkey.

he was drinking from while the image was obtained. SCANNING THE BRAIN The PET scanner on the left will detect biochemical activity in specific brain areas. In the adjacent PET scans, arrows and the color red indicate areas of highest activity and violet indicates areas of lowest activity during different tasks. At the right, an MRI shows a child’s brain—and the bottle he was drinking from while the image was obtained.

This cross-section depicts the brain as if it were split in half. The view is of the inside surface of the right half, and shows the structures described in the notes.

Thalamus and Hypothalamus

Structures of the limbic system play an important role in memory and emotion. The notes describes two of these structures, the amygdala and the hippocampus. The hypothalamus is also often included as part of the limbic system.

On the left is Phineas Gage’s skull and a cast of his head On the left is Phineas Gage’s skull and a cast of his head. You can see where an iron rod penetrated his skull, altering his behavior and personality dramatically. The exact location of the brain damage remained controversial for almost a century and a half, until Hanna and Antonio Damasio and their colleagues (1994) used measurements of Gage’s skull and MRIs of normal brains to plot possible trajectories of the rod. The reconstruction on the right shows that the damage occurred in an area of the prefrontal cortex associated with emotional processing and rational decision making.

Each cerebral hemisphere receives information from the eyes about the opposite side of the visual field. Thus, if you stare directly at the corner of a room, everything to the left of the juncture is represented in your right hemisphere and vice versa. This is so because half the axons in each optic nerve cross over (at the optic chiasm) to the opposite side of the brain. Normally, each hemisphere immediately shares its information with the other one, but in split-brain patients, severing the corpus callosum prevents such communication.

DIVIDED BRAIN, DIVIDED VIEW When split-brain patients were shown composite photographs (a) and were then asked to pick out the face they had seen from a series of intact photographs (b), they said they had seen the face on the right side of the composite—yet they pointed with their left hands to the face that had been on the left. Because the two cerebral hemispheres could not communicate, the verbal left hemisphere was aware of only the right half of the picture, and the relatively mute right hemisphere was aware of only the left half (c).

Human Brain

GENDER AND THE BRAIN When women and men listened to a John Grisham thriller read aloud, they showed activity in the left temporal lobe, but women also showed some activity in the right temporal lobe (Phillips et al., 2001). (Because of the orientation of these MRI images, the left hemisphere is seen on the right and vice versa.) Along with other evidence, these results suggest a sex difference in lateralization on tasks involving language.