The temporal lobes are located behind and below the frontal lobes. A brain seen from the side looks like a boxing glove with the thumb sticking out in the direction of the viewer. The temporal lobes are where the thumbs would be. The left temporal lobe is a central area for sound and speech. It also finishes work done by the visual system. Among other things, it adds shape to blobs of colors to form recognizable objects.
Temporal Lobe Epilepsy
The temporal lobe not only misfires during a seizure, it also causes the rest of the brain to misfire, says Yale medical researcher Hal Blumenfeld, M.D. Global brain malfunction normally causes a loss of consciousness--a dangerous condition for people driving a car or walking down stairs. A localized seizure in the temporal lobe can also lead to a very brief loss of consciousness, but localized seizures usually only manifest themselves as a blank stare or a moment of distraction--something most people won't even notice.
Attention-Deficit Hyperactivity Disorder
Attention-Deficit Hyperactivity Disorder (ADHD) is a neurological disorder that impairs people's ability to pay attention. A common form involves abnormal activity in the frontal and temporal lobe areas. Because ADHD often involves hyperactivity, it is one of its diagnostic criteria. But identifying the disorder on the basis of subjective observations of children's behavior is unreliable. Well-behaved, calm children can suffer from quite severe cases of the disorder, but go undiagnosed because they don't show any hyperactivity but simply are a bit slow to learn. Brain imaging provides a more reliable tool for diagnosing the disorder, says Stanford psychologist John Gabrieli. Brain imaging allows for a more precise identification of the implicated brain areas.
Visual Agnosia
Damages to higher visual and temporal lobe areas can cause visual agnosia, an inability to recognize shapes. Research on visual agnosia influenced David Milner and Mel Goodale's theory of the two visual streams. Because a patient with visual agnosia cannot quite see where an object begins or ends, but can grasp it accurately, vision for object recognition and vision for action must occur in separate parts of the brain, the researchers say. In 2009, Birmingham neuroscientist Harriet Allen discovered that the sense of touch, which plays an important role in grasping behavior, can activate the visual and temporal areas in visual agnosia patients. This result does not refute the disassociation hypothesis, but simply shows that touch is a multi-modal sense.
Herpes Simplex Encephalitis
The common herpes simplex virus that causes cold sores or genital herpes can also lead to encephalitis, an acute inflammation of the medial temporal lobe, says University of Liverpool researcher Juliet Holdstock. Symptoms and effects can be quite similar to those of meningitis. Medial temporal lobe damage typically result in retrograde amnesia--loss of memories acquired prior to the onset of the disease. The memory loss is usually partial. Patients don't always notice when they have partial retrograde memory loss, because human brains are very adept at filling in missing details with plausible events or material from different memories.
Schizophrenia
The white matter in the temporal lobe of people who are at risk for developing schizophrenia does not develop as fast as the white matter of healthy individuals, reports UCLA neuroscientist Katherine Karlsgodt in the June 2009 online edition of "Biological Psychiatry." The brain's white matter forms the main neural connections between different regions of the brain. Karlsgodt and her team used diffusion tensor imaging, which relies on water movement in mapping the brain's white matter, to track the development of a group of high-risk individuals and healthy controls. Unlike the control group, the risk group did not show an increase in integrity of white matter.
References
- Science Daily: Differences In Brain Function Found For Attention Deficit Disorder
- Science Daily: Brain's Object Recognition System Activated By Touch Alone
- Science Daily: Study Reveals Cause Of Loss Of Consciousness During Seizures
- Science Daily: Memory Function Varies After Damage To Key Area Of The Brain
- Science Daily: Alterations In Brain's White Matter Key To Schizophrenia, Study Shows
