COGNITIVE SCIENCE 17

What’s A Brain?

Part 2

Jaime A. Pineda, Ph.D.

Brain Quiz• What did the right hemisphere say to the left hemisphere when they

could not agree on anything?– “Let’s split”

• What do you call a group of brains that form a singing group in school?– A glia club

• What do you get when you cross a thought with a light?– A bright idea

• What is the brain’s favorite television channel?– The Neural Network

• What do neurons use to talk to each other?– Cell-ular phones

• What did the Hollywood director say after making a movie about myelin?– “That’s a wrap”

Principles of Brain Organization• Subdivided into 3 primary

and 5 secondary regions

– Forebrain• Telencephalon (endbrain) • Diencephalon (interbrain)

– Midbrain• Mesencephalon

– Hindbrain• Metencephalon • Myelencephalon

Neural plate > neural tube

Principles (cont.)

• Brain contains an interconnected system of ventricles

Brain contains a protective covering (meninges)

Principles (cont.)

CerebralSpinalFluid (CSF)

Hydrocephalus

Principles (cont.)

• Brain is composed of two hemispheres connected by a set of fibers (corpus callosum)

• 200-250 million fibers• Monotremes and

marsupials do not have a corpus callosum

• Agenesis and split brain patients

Principles (cont.)

• Cortex is subdivided into four major external lobes (plus the internal limbic lobe)

Limbic lobe

Found only in the medial view of the brain.

Its major responsibilities include olfaction and emotions

Principles (cont.)• Cortex is subdivided into areas of specialized function

Principles (cont.)• Some areas of cortex (primarily sensory and motor areas) are topographically mapped.

V1 (retinotopic) A1 (tonotopic) M1 (mototopic) S1 (somatotopic)

Anterior-Posterior Organization

Dorsal-Ventral Organization

Left-Right Organization