Cerebral Lateralization and Functionality

Cerebral Lateralization and Functionality

Cerebral Lateralization and Functionality

Barbie Bittinger

PSY/240

12/10/2010

Cerebral Lateralization and Functionality

There are four methods of cerebral lateralization to study the different functionalities of the left and right hemispheres. This includes the sodium amytal test, the dichotic listening test, and functional brain imaging. Also, the relation between handedness and language lateralization is a method of cerebral lateralization.

In the sodium amytal test, a patient's language abilities are assessed by a neurosurgeon before going into surgery. In the sodium amytal test, sodium amytal is injected into the carotid artery on a side of the neck (Pinel, 2007). The injection anesthetizes the hemisphere on that side for a few minutes, thus allowing the capacities of the other hemisphere to be assessed (Pinel, 2007).

In the dichotic listening test "three pairs of spoken digits are presented through earphones; the digits of each pair are presented simultaneously, one to each ear" (Pinel, 2007, p. 445). For example, a subject might hear the sequence 3, 9, 2 through one ear and at the same time 1, 6, 4 through the other and the subject is then asked to report all of the digits (Pinel, 2007). The test reveals that most people have left-hemisphere dominance because they hear slightly more in the right ear.

In functional brain imaging, while the subject engages in some activity, such as reading, the activity of the brain is monitored by positron emission tomography (PET) or functional magnetic resonance imaging (fMRI) (Pinel, 2007).

The relation between handedness and language lateralization is a method of cerebral lateralization. Studies reveal that "the left hemisphere is dominant for language-related abilities in almost all dextral (right-handed) and in the majority of sinestrals (left-handed); they also indicate that sinestrals are more variable than dextrals with respect to language...