Pathophysiology: Neuroanatomy Part II

Functional Neuroanatomy

Brian J. Piper, Ph.D.

Goals

• Sensory– Vision– Audition– Touch

• Emotion• Motor• Language

Major Subdivisions of Brain

Sulci & Gyri

Gyri of the Cerebral Cortex (Lateral Surface)

Vision

Retina -> Optic Nerve -> Thalamus -> Occipital Cortex

Implications of Visual Wiring1. optic nerve

2. optic chiasm

3. optic tract

4. optic radiation

A. unilateral blindness

B. bitemporal hemianopsia

C. left homonymous hemianopsia

Beyond Occipital

where pathway

what pathway

AuditoryCochlea: Coiled, bony, fluid-filled tube in the inner ear that transforms sound vibrations to auditory signals.Carpet Explanation

http://www.youtube.com/watch?NR=1&feature=fvwp&v=FjbcAH3dL0s

Localization of Sound

1. Intensity differences2. Time differences

Vestibular

• Semicircular Canals: mediate balance & movement of head

Taste

Traditionally, taste sensations consisted of sweet, salty, sour, and bitter tastes.

Recently, receptors for a fifth taste have been discovered called “Umami”.

Sweet Sour Salty Bitter Umami(Fresh

Chicken)

Gustatory Receptors

• Sweet: sucrose• Sour: pH• Saltiness: NaCl• Bitter: organic (carbon)• Umami: Monosodium Glutamate• Fat: ?

Gustatory Pathways

SmellLike taste, smell is a chemical sense.

Odorants enter the nasal cavity to stimulate 5 million receptors to sense smell. Unlike taste, there are many different forms of

smell.

Touch & Motor Function

M S

Motor Homunculus

Motor Neurons

Medial Column Lateral Column

Brodal (2010). Central Nervous System. p. 282.L/M images from: http://quizlet.com/4690758/neuro-lab-flash-cards/

Sensory Homunculus

Phantom Limbs (0 to 4 min): http://www.youtube.com/watch?v=1mHIv5ToMTM

Limbic System: Emotional Brain

hypothalamus (#2)

Hypothalamus & Aggression

Stimulation of Medial Hypothalamus Stimulation of Perifornical Nucleus of Hypothalamus

Hypothalamus & Hunger

Amygdala Lesions: Kluver-Bucy Syndrome

Positron Emission Tomography

“Only left-handers are in their right mind.”

Right Left

Left 95%

Right 5%

Handedness

LanguageCenter

Left-handers are more likely to have their language center in their right cortex

Right Left

Left 95% 70%

Right 5% 30%

Handedness

LanguageCenter

Summary

Insula

Lesions of Insula

• Smoking following brain damage was examined in patients with insula damage.

Naqvi et al. (2007). Science, 315, 531-534.

Lesions of Insula

• Smoking following brain damage was examined in patients with insula damage.

• He quit because his “body forgot the urge to smoke”

Naqvi et al. (2007). Science, 315, 531-534.