The Brain Module 4

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The BrainModule 4
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The Brain Stem (old brain)

• Automatic survival functions
• Medulla heart rate and breathing
• Thalamus sensory switchboard
• Reticular Formation arousal

Thalamus
Reticular Formation
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Cerebellum

• The little brain attached to the rear of the
  brainstem. It helps coordinate voluntary
  movements and balance.

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The Limbic System

• The Limbic System Just above the brain stem
  controls emotions such as fear, aggression and
  drives for food and sex
• hippocampus,
• amygdala
• hypothalamus.

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Imaging Techniques

• Electroencephalogram (EEG) electrical waves
• Positron Emission Tomography (PET Scan) records
  radioactive glucose during tasks
• Magnetic Resonance Imaging (MRI) magnetic fields
  and radio waves distinguishes brain tissues

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MRI Images
Enlarged ventricles of schizophrenia
Subject lying
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Structure of the Cortex

• Two hemispheres, four lobes separated by
  prominent fissures.
• frontal lobe (forehead),
• parietal lobe
• (top to rear head),
• occipital lobe (back head)
• temporal lobe (side of head).

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Functions of the Cortex

• Motor Cortex rear of the frontal lobes controls
  voluntary movements.
• Sensory Cortex (parietal cortex) receives
  information from skin surface and sense organs.

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Visual Function

• The functional MRI scan shows the visual cortex
  is active as the subject looks at faces.

Courtesy of V.P. Clark, K. Keill, J. Ma. Maisog,
S. Courtney, L.G. Ungerleider, and J.V. Haxby,
National Institute of Mental Health
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Auditory Function

• The functional MRI scan shows the auditory cortex
  is active in patients who hallucinate.

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Specialization Integration

• Brain activity when hearing, seeing, and speaking
  words

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Association Areas

• More intelligent animals have increased
  uncommitted or association areas of the cortex.

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Language

• Aphasia language impairment,
• Brocas area (impaired speaking)
• Wernickes area (impaired understanding).

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Specialization Integration

• Brain activity when hearing, seeing, and speaking
  words

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The Brains Plasticity

• The brain is sculpted by our genes but also by
  our experiences.
• Plasticity refers to the brains ability to
  modify itself after some types of injury or
  illness.

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Our Divided Brain

• Left hemisphere processes reading, writing,
  speaking, mathematics, and comprehension skills.
  In the 1960s, it was termed as the dominant
  brain.
• Right hemisphere spatial skills, perceptual
  tasks, creativity

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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
Courtesy of Terence Williams, University of Iowa
Martin M. Rother
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With the corpus callosum severed, objects (apple)
presented in the right visual field can be named.
Objects (pencil) in the left visual field cannot.
Split Brain Patients
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Testing the Divided Brain