Brain Hemispheres Study Unit 2

Hemispheric Specialization Corpus Callosum (Video) Fibers that connect the two hemispheres Allow close communication between left and right hemisphere Each hemisphere appears to specialize in certain function

Neural Plasticity (Click for Video) The brain can be changed, both structurally and chemically, by experience Rat studies show that an “enriched” environment leads to larger neurons with more connections Has also been shown in humans Recent research has uncovered evidence of neurogenesis, or the production of new brain cells, in human brains

Neural Plasticity Collateral Sprouting – Process where healthy neurons will grow new branches when near damaged cells. Substitution of Function – A damaged region of brain is taken over by another area Neurogenesis – New neurons are generated within the brain

Fun with your Hemispheres Rotate your dominant hand in one direction while at the same time rotating the opposite foot in the other direction. No problem since controlled by two hemispheres Now, rotate your dominant hand in one direction while at the same time rotating the foot on the same side in the other direction.

Our Divided Brain Our brain is divided into two hemispheres. The left hemisphere processes reading, writing, speaking, mathematics, and comprehension skills. In the 1960s, it was termed as the dominant brain. OBJECTIVE 19| Describe split-brain research, and explain how it helps us to understand the functions of our left and right hemispheres.

Which face is happier?

Which face was happier?

Right Hemisphere

Hemispheric Specialization People with intact brains also show left-right hemispheric differences in mental abilities. A number of brain scan studies show normal individuals engage their right brain when completing a perceptual task and their left brain when carrying out a linguistic task.

Splitting the Brain A procedure in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them. Corpus Callosum

Split Brain Patients With the corpus callosum severed, objects (apple) presented in the right visual field can be named. Objects (pencil) in the left visual field cannot.

Brain Organization & Handedness Is handedness inherited? Yes. Archival and historic studies, as well as modern medical studies, show that the right hand is preferred. This suggests genes and/or prenatal factors influence handedness. OBJECTIVE 20| Discuss the relationship among brain organization, handedness, and mortality.

Is it Alright to be Left Handed? The percentage of left-handed individuals decreases sharply in samples of older people (Coren, 1993).

Is it Alright to be Left Handed? Being left handed is difficult in a right-handed world.