Brain Landmarks
The lobe at the back of the brain that processes visual information, including colors and shapes
occipital lobe
Also called the soma, this part of a neuron contains the nucleus
cell body
Brain waves are detected with this device, abbreviated EEG
electroencephalograph
This part of the eye regulates how much light enters by changing the size of the pupil
iris
Along with sweet, sour, salty, and bitter, this taste quality is named for the Japanese word for "savory"
umami
This thick bundle of nerve fibers is the largest one bridging the brain's two cerebral hemispheres
corpus callosum
When the summed signals at the dendrites reach threshold voltage, the neuron fires this electrical impulse down its axon
action potential
Produced mainly in the parietal and occipital lobes when you're relaxed with eyes closed, these waves run 8 to 13 Hz
alpha waves
Making up about 95 percent of photoreceptors, these cells let you see in dim light
rods
This is the only sensory system that sends information directly to the cerebral cortex without first passing through the thalamus
This curved structure in the temporal lobes encodes new memories
hippocampus
These glial cells are the brain's main "immune cells," working mainly as phagocytes
microglia
Occurring during deep sleep, these very slow waves have frequencies below 3.5 Hz
delta waves
This small pitted area at the center of the retina is where cones are most densely packed
fovea
Neurologists use this test, the minimum distance at which two points on the skin feel like two stimuli, to measure touch sensitivity
two-point discrimination
The midbrain, pons, and medulla together make up this structure
brainstem
The brain's most common excitatory neurotransmitter, it acts on AMPA and NMDA receptors
glutamate
The visual cortex sends signals back to the thalamus in this two-way circuit
thalamocortical loop
The eardrum passes its vibrations along these three tiny middle-ear bones
mallus, incus, and stapes
These sensory fibers respond to stimuli that can cause tissue damage
nocireceptors
Tucked underneath the occipital lobe, this second-largest part of the brain contains over half of the brain's neurons
cerebellum
In mammals, a resting neuron's membrane potential is about this many millivolts
−70 mV
Controlled locally by the spinal cord or subcortical regions, these circuits trigger action before thought and never reach the cortex
reflex loops
Damage to this region of the left auditory cortex, as from a stroke, leaves a person able to hear speech but unable to understand it
Wernicke's Area
The cortex sends pain messages to this brainstem region, which activates descending pathways that modulate pain and trigger endorphin release
periaqueductal gray matter