60 Minutes - Invisible Wounds

Describe the impact of TBI and PTSD on soldiers in Iraq and Afghanistan.

a.Why was it so difficult to treat TBI?

b.Why is there a stigma associated with TBI?

c.How can technology revolutionize treatment of TBI?

What is Neuroscience?

How do we study the brain?

5 PRIMARY WAYS TO VIEW THE BRAIN

EEG

CT Scan

PET Scan

MRI

fMRI

Or an autopsy :(

EEG

EEG aka Electroencephalograph is a non-invasive way to measure brain wave activity aka neuronal activity

CT or CAT Scans - Computerized Axial Tomography

CT, or CAT scans, are special X-ray tests that produce cross-sectional images of the body using X-rays and a computer to make 3D images. CT uses X-rays to produce images.

Tomography allows us to slice a

3D image and understand the

internal image by creating a 2D

Picture - STRUCTURE

PET SCAN - Positron Emission Tomography - shows us function

Radioactive glucose is injected to see glucose functioning in the blood in the brain - look at the functioning of the brain - where is it taking place - color coded- FUNCTION

PET

MRI - MAGNETIC RESONANCE IMAGING

Uses magnetic pulse and radio waves to see the soft tissue of the brain - 2 dimensional view similar to an x-ray but allows you to see both soft tissue and the bones - STRUCTURE

fMRI - Functional Magnetic Resonance Imaging

• Measuring blood flow in the brain
• One can see what parts of the brain are being used and how much energy is being used
• Shows both function and structure of the brain

Transcranial Magnetic Stimulation (TMS)

TMS is a form of neurostimulation and is a non-invasive procedure in which a changing magnetic field is used to cause electric current to flow in a small targeted region of the brain via electromagnetic induction.

Intentional brain damage:

• performed on animals
• has yielded some insights, especially about less complex brain structures
• no longer necessary, as we now can chemically or magnetically deactivate brain areas to get similar information

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Lesions/Ablations

(injury or destruction of tissue)

Post Mortem Autopsy

Neuropathologist would look for

• Hematoma
• Degenerative brain disease
• Lacerations/ contusions

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Studying cases of brain damage

When a stroke or injury damages part of the brain, we have a chance to see the impact on the mind.

Why is Gage so important in the understanding of neuroscience?

Francis Gall - 19th cenury

Father of Phrenology

Phrenology is the belief that the shape of the human skull reflects the shape of the human brain beneath it, which is in turn shaped by certain personality traits. Studying a person's skull thus reveals his/her personality, abilities, and character:

• Phrenology yielded one big idea--that the brain might have different areas that do different things (localization of function).

Phrenology

(developed by Franz Gall in the early 1800’s):

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the study of bumps on the skull and their relationship to mental abilities and character traits

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THE THREE LAYERS OF THE BRAIN

- Cerebrum- cerebral cortex

The triune brain model is a theory developed in the 1960s to explain how the human brain has evolved – we don’t have one brain but three. These are all layered on top of each other, and were developed during different stages of evolution.

How does each one above represent the three layers of the brain?

SPECIALIZATION OF THE 4 LOBES

The Cerebral Cortex - The lobes consist of:

300 billion synaptic connections

The brain has left and right hemispheres

• outer grey “bark” structure that is wrinkled in order to create more surface area for 20+ billion neurons.
• inner white region—axons linking parts of the brain.
• 180+ billion glial cells, which feed and protect neurons and assist neural transmission.

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gray matter is the neurons located on the outside of the cerebrum - specialize in mental processing

white matter is neurons inside the cerebrum - communicating with the CNS/ PNS

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Fissure

Sulci

Groove

Gyri

Ridge

PARIETAL LOBE - Perception

The parietal lobe receives the sensory information from the skin and the tongue and processes sensory information from the ears (temporal lobe) and the eyes (occipital lobe). The major sensory inputs from the skin - touch, temperature and pain receptors.

Sensory Functions of the Cortex

• The sensory strip deals with information from touch stimuli.
• The occipital lobe deals with visual information.
• Auditory information is sent to the temporal lobe.

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SOMATOSENSORY CORTEX IN PARIETAL LOBE

Homunculus - little man

Motor strip aka cortex lies in the back of the frontal lobe

Somatosensory strip aka cortex lies in the front of the parietal lobe

Penfield’s mapped the cortical space by stimulating each area and the result is a visual representation of the cortical space devoted to each area.

What is activated in the brain?

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OCCIPITAL LOBE

The occipital lobe processes

visual input that is sent to the

brain from the retina.

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LGN - is an area on the thalamus, the relay center of the brain for sensory information

Sensory Functions of the Cortex

• The somatosensory strip deals with information from touch stimuli.
• The occipital lobe deals with visual information.
• Auditory information is sent to the temporal lobe.

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Every part of the body is represented in the primary motor cortex, and these representations are arranged somatotopically

The amount of brain matter devoted to any particular body part represents the amount of control that the primary motor cortex has over that body part.This disproportionate map of the body in the motor cortex is called the motor homunculus

The Lobes of the Cerebral Cortex:

• Frontal Lobes

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• Parietal Lobes
• Occipital Lobes
• Temporal Lobes

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CEO planning, involved in speaking and muscle movement and judgments

voluntary

include the sensory cortex

include the visual areas; they receive visual information from the opposite visual field

include the auditory processing areas

• The frontal lobes are active in “executive functions” such as judgment, planning, and inhibition of impulses.
• The frontal lobes are also active in the use of working memory and the processing of new memories.

Frontal Lobes

FRONTAL LOBE

• Motor Functions
• Higher Order Functions
• Planning
• Reasoning
• Judgement
• Impulse Control
• Memory

William Penfield

In the 1950s, Penfield was trying to treat patients with epilepsy. Before an epileptic seizure, he knew, patients experience an "aura," a warning that the seizure is about to occur.

Penfield thought if he could provoke this aura with a mild electric current on the brain, then he would have located the source of the seizure activity and could remove or destroy that bit of tissue. While patients were fully conscious, though anaesthetized, he opened their skulls and tried to pinpoint the source of their epilepsy.

Neurological Approach to Language

• Paul Broca & Tan
• Broca’s patients - production impaired but comprehension relatively intact
• Broca’s patients often had weakening of the right arm and leg

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Neurological Approach to Language

• Carl Wernicke
• 2 patients – fluent, but nonsensical sounds, words, sentences
• Damage in the posterior region of the temporal lobe

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APHASIA

Aphasia is an impairment of language, affecting the production or comprehension of speech and the ability to read or write.

Aphasia is always due to injury to the brain-most commonly from a stroke.

But may also arise from head trauma, from brain tumors, or from infections.

Neurological Approach to Language

• A disorder of language apparent in speech, in writing (agraphia) or in reading (alexia) produced by injury to brain areas specialized for these functions.
• Primary aphasia*** - due to problems with the language-processing mechanisms
• Secondary aphasia - due to memory impairments, attention disorders, or perceptual problems

Right Hemisphere Contribution to Language

• Prosody – the intonation pattern, or sound envelope, of an utterance (interpreting whether the tone is friendly, sarcastic, condescending or excited)
• “we need to talk” vs. “we need to talk”
• Narrative – ability to construct or understand a story line
• Inference – ability to “fill in the blanks”

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Aphasia - damage to the brain involving language

The limbic system's components are the

HIPPO - HAT

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hippocampus - New Memory and Learning

hypothalamus - Homeostasis, Circadian rhythms, Glucose Levels, Body temperature, motives and drives (hunger, thirst, sex)

amygdala - Emotional Responses / fear / aggression

thalamus - relay center for sensory processing to the cerebral cortex / ? focus / attention

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The Thalamus (“Inner Chamber”)

• The thalamus is the “sensory switchboard” or “router.”
• All sensory messages, except smell, are routed through the thalamus on the way to the cortex (higher, outer brain).
• The thalamus also sends messages from the cortex to the medulla and cerebellum.

The Amygdala

• Electrical stimulation of a cat’s amygdala provokes aggressive reactions.
• If you move the electrode very slightly and cage the cat with a mouse, the cat will cower in terror.

AMYGDALA

1. Lust
2. Curiosity
3. Emotional Intelligence
4. Fear - Link to anxiety/ binge drinking /bipolar disorder
5. Right side- negative (anxiety) / Left side - positive (reward)- Gender differences
6. Memory Consolidation - Emotional Memories

The Brainstem: Medulla Oblongata

• Medulla is the lower half of the brainstem controls involuntary movement The medulla contains the cardiac, respiration, and deals with autonomic functions, such as breathing, heart rate and blood pressure.

It is key to transferring neural messages from the brain to the spinal cord

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Reticular Formation

• The reticular formation is a nerve network in the pons of the brainstem involved with the physiological response to stress and panic
• It enables alertness, (arousal) from coma to wide awake because it is the principal site for brain synthesis of norepinephrine
• Associated with sleep disorder - narcolepsy/ anesthesia
• It also filters incoming sensory information. Prevents sensory overload and selective attention.

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PONS

This region of brainstem conducts signals from the brain down to the cerebellum and signals to the thalamus

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Innervates the trigeminal nerve-responsible for feeling in the face.

Innervates the muscles that are responsible for biting, chewing, and swallowing.

It helps allows the eyes to look from side to side, The facial nerve controls facial expressions, and the vestibulocochlear nerve allows sound to move from the ear to the brain.

Sleep Cycle - REM/ Sleep Paralysis

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ROLE OF THE PONS

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Cerebellum (“little brain”)

The cerebellum helps coordinate voluntary movement such as playing a sport.

The cerebellum has many other functions, including enabling nonverbal learning, balance and muscle memory.

CEREBRUM

The largest part of the brain.

It is divided into two hemispheres, or halves, called the cerebral hemispheres.

Areas within the cerebrum control muscle functions and also control speech, thought, emotions, reading, writing, and learning.

CEREBRAL CORTEX

The Cerebral Cortex is made up of tightly packed neurons and is the wrinkly, outermost layer that surrounds the brain. It is also responsible for higher thought processes including speech and decision making .

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The cortex is divided into four different lobes, the frontal, parietal, temporal, and occipital, which are each responsible for processing different types of sensory information.

Review of Brain Structures

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Association function of the cortex

More complex animals have more cortical space devoted to integrating/associating information

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Functions of the Brain: � The Motor and Sensory Strip

The primary motor cortex (M1) lies along the precentral gyrus (bump) in the posterior of the frontal lobe

It generates the signals that control the execution of movement.

Secondary motor areas are involved in motor planning.(smc)

Lesion in posterior frontal lobe (Broca’s Area)

Cerebral Dominance - Language

Temporal Lobe Association Areas

Some abilities managed by association areas in this “by the temples” lobe:

• recognizing specific faces
• managing sensory input related to sound, which helps the understanding of spoken words

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Temporal Lobe (Auditory and Visual)

The temporal lobe receives audio input from part of the thalamus that relays information from the ears. The inferior (lower) temporal lobe processes pattern recognition and the medial and anterior processes facial recognition (memory).

Functions of the Brain: � The Motor and Sensory Strips

← Axons receiving motor signals FROM the cortex

←Axons sending sensory information TO the cortex

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HOMUNCULUS

Neurological Bases for Visual Language Processing

• Brain damage can produce alexia or agraphia
• Alexia – inability to read
• Agraphia – inability to write

Dyslexia

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What is Dyslexia

Dyslexia is a congenital disturbance that involves the process of reading, in short we can say that the ability of reading gets disturbed.

What is Alexia

On the other hand, alexia is a disorder in which the reading ability is absent and it’s permanent. It is a neurological injury in the temporal and parietal lobe. The patient is unable to read anything because the reading ability is not with him. In short it is an acquired disorder

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Our Two Hemispheres

Lateralization (“going to one side”)

The two hemispheres serve some different functions.

How do we know about these differences?

• Brain damage studies revealed many functions of the left hemisphere.
• Brain scans and split brain studies show more about the functions of the two hemispheres, and how they coordinate with each other.

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The intact but lateralized brain�Right-Left Hemisphere Differences

Thoughts and logic

Details such as “trees”

Language: words and definitions

Linear and literal

Calculation

Pieces and details

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Feelings and intuition

Big picture such as “forest”

Language: tone, inflection, context

Inferences and associations

Perception

Facial Recognition

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Left Hemisphere

Right Hemisphere

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Wernicke Area

Carl Wernicke (1848-1905)

Discovered an aphasia - impairment of comprehension rather than execution (receptive rather than expressive).

Patient could speak but not understand language.

Lesions in posterior temporal lobe.

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RESOURCES

NOVA - How does the brain work?

Right Hemisphere Contribution to Language

• Since Broca, the left hemisphere’s role in language has been viewed as primary and the right hemisphere has viewed as non-language hemisphere
• In split-brain patients language can emerge from the right hemisphere
• The right hemisphere can not produce speech but can extract basic meaning

28/02/2006