Picture the brain as two boxing gloves put next to each other, hands crossed, thumbs facing in gaze direction and palms facing down. Look at the picture from the side. The fat thumbs on each side are the temporal lobes. The temporal lobes are crucial sites for language, speech, memory, object recognition and emotion. Abnormalities in the temporal lobes can cause problems to any of these functions.
For years scientists believed stuttering was a result of social phobia. It turns out to originate in an abnormality in the temporal lobes, the centers for speech and language, reports Tulane University neuroscientist Dr. Anne Foundas in Science Daily. Foundas and colleagues looked a 16 stutterers and 16 controls and found that the temporal lobes of the stutterers were significantly enlarged and sometimes had an irregular shape. This may indicate that stutterers have a larger capacity for learning and processing language than non-stutterers.
A strong immune system seems essential to a healthy life. But researchers have now discovered that it could put people at the risk for developing Alzheimer's. Alzheimer's occurs when amyloid-beta protein forms plaques in the temporal lobe's hippocampus, a center crucial to memory. The plaques cause the hippocampus neurons to become inactive and die off. The researchers, who reported their results in the March 3, 2010, issue of "PLoS ONE," found that amyloid-beta protein promotes brain inflamation but apparently also helps to fight infections in the brain.
Temporal Lobe Stroke
A stroke or other similar damage in the temporal lobes of the brain can impair abilities to identify sounds. According to a review article published in the June 2009 issue of "Nature Neuroscience," language is processed in two different auditory streams: the "what" stream and the "how/where" stream. Both auditory streams begin in the auditory cortex in the temporal lobes. Some of the information then proceeds through the outside of the temporal lobes, which calculate the identity of the sounds. Another portion of the information runs through the parietal lobe, which calculates sound location, motion through space and provides feedback in speech.
Brain Shrinkage in Men
The temporal and frontal lobes shrink with age but the shrinkage is more pronounced in elderly men, reports Henry Ford psychiatrist Dr. Edward Coffey in Science Daily. Coffey and his team scanned the brains of 330 subjects over the age of 66. They found excess cerebrospinal fluid on the outside of the temporal and frontal lobes of the male study participants. An increase in cerebrospinal fluid is a strong indicator of an atrophy of the underlying areas, says Coffey, the study's principal investigator.
Temporal Lobe Epilepsy
Temporal lobe epilepsy occurs when neurons in the temporal lobes become hyperactive and start firing uncontrollably. This can spread to the whole brain leading to a global seizure, which leads to a collapse, uncontrollable spasms and a loss of consciousness. Temporal lobectomy is a surgical procedure that removes the anterior and medial parts of the temporal lobe. It relives the intensity of seizures in up to 75 percent of patients but requires removing 30g or more of cerebral tissue. In a classical review in the "Journal of the Royal Society of Medicine", C. E. Polkey reports that a temporal lobectomy can lead to numerous neurological conditions ranging from visual field deficits to psychotic disorders. Despite the severe consequences of removing a large portion of the brain, temporal lobectomy is still performed in the United States when drug therapeutic approaches fail.
- Science Daily: Study Ties Stuttering To Anatomical Differences In The Brain
- "PLoS ONE"; The Alzheimer's Disease-Associated Amyloid β-Protein Is an Antimicrobial Peptide; Soscia, et al.; March, 2010
- "Nature Neuroscience"; Maps and streams in the auditory cortex: nonhuman primates illuminate human speech processing; Rauschecker & Scott; June 2009
- Science Daily: Male Brain Ages Faster Than Female, Henry Ford Research Shows
- "Journal of the Royal Society of Medicine"; Effects of anterior temporal lobectomy apart from the relief of seizures: a study of 40 patients; Polkey; May 1983