HUMAN BRAINThe Most Complex Living Structure On The Universe

CONTENTS

1. Facts about Brain2. Brain Cells3. Lobes of the brain4. Synaptic Transmission5. Right & Left Brain 6. BCI7.Types of BCI8. How brain-computer interfaces work9.EEG10.Electrode placement11.Brain waves12.BCI applications

• About 3 pounds (1,300 grams)• 78% water, 10% fat, 8% protein • Less than 2.5% of body’s weight• Uses 20% of body’s energy• People only use 10% of their brain• 100 billion neurons (Greek word meaning

bowstring) • 1 trillion glial cells (Greek word meaning glue)

• 1,000 trillion synaptic connection points• 280 quintillion memories

Facts about Brain

• Brain is modified by environment •Brain is adaptable Plasticity ‘Use it or Lose it’• Left and Right Hemispheres• Left hemisphere for most people is the dominant hemisphere- responsible for production of language, mathematical ability, problem solving, logic•Right hemisphere thought to be responsible for creativity and spatial ability•Everything people have ever experienced is stored somewhere in their brain•At birth people have all the neurons that they will ever have

Facts about Brain

Two Kinds of Brain Cells

• Glia - (Greek word meaning glue) – 90% of the brain cells – Less known about glia cells – No cell body – Remove dead brain cells and give structural

support • Neurons (Greek word meaning bowstring)

– 100 billion neurons in human brain – Neurons essential to performing the brain's

work – Consist of a compact cell body, dendrites, and

axons

Neurons

• Neurons (brain cells) make connections between different parts of the brain.

• Information is carried inside a neuron by electrical pulses and transmitted across the synaptic gap from one neuron to another by chemicals called neurotransmitters.

• Learning is a critical function of neurons.

Dendrites and Axons

• Dendritic branching helps make connections between cells.

• As cells connect with other cells, synapses occurs.

• New synapses appear after learning. • Repeating earlier learning makes neural pathways

more efficient through myelination (fatty substances formed around axons, Myelination enables nerve cells to transmit information faster and allows for more complex brain processes)

The nerve cell, or neuron

Synaptic Density

2 year old

6 year old

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Lobes of the Brain

• Frontal

• Parietal

• Occipital

• Temporal

Lobes of the Brain - Frontal• The Frontal Lobe of the brain is located deep to the

Frontal Bone of the skull.

• It plays an integral role in the following functions/actions:

- Memory Formation

- Emotions- Decision Making/Reasoning

- Personality

Lobes of the Brain - Parietal Lobe

• The Parietal Lobe of the brain is located deep to the Parietal Bone of the skull.

• It plays a major role in the following functions/actions:

- Senses and integrates sensation(s)

- Spatial awareness and perception

Lobes of the Brain – Occipital Lobe

• The Occipital Lobe of the Brain is located deep to the Occipital Bone of the Skull.

• Its primary function is the processing, integration, interpretation, etc. of VISION and visual stimuli.

Lobes of the Brain – Temporal Lobe

• The Temporal Lobes are located on the sides of the brain, deep to the Temporal Bones of the skull.

• They play an integral role in the following functions:

- Hearing

- Organization/Comprehension of language

- Information Retrieval (Memory and Memory Formation)

• Two sides or hemispheres of the brain: LEFT and RIGHT

• We have two cerebral hemispheres connected by the corpus callosum. This is a bundle of nerves that allows each side of the brain to communicate with each other.

• Each side of the brain processes things differently.

Right & Left Brain

how the two sides process information that is!

Left Brain

• Logical• Sequential• Rational• Analytical• Objective• Looks at parts

Right Brain

• Random• Intuitive• Holistic• Synthesizing• Subjective• Looks at wholes

Left Hemisphere• processes things more in parts and

sequentially • recognizes positive emotions• Identified with practicality and rationality• Understands symbols and representations• Processes rapid auditory information faster

than the right (crucial for separating the sounds of speech into distinct units for comprehension)

• is responsible for language development. It develops slower in boys, that is why males usually develop more language problems than females.

Right Hemisphere• Recognizes negative emotions• High level mathematicians, problem

solvers, and chess players use • Responds to touch and music (sensory)• Intuitive• Responsive to color and shape• Emotional and originative

what information the two sides recognize!

Left Brain

• Letters

• Numbers

• Words

Right Brain

• Faces

• Places

• Objects

Sensory and motor strips

Auditory ActivityVisual ActivityThinking Activity

Memory Activity Motor Activity Seeing, ………

Electrode Placement

• Standard “10-20 System”• Spaced apart 10-20%• Letter for region

– F - Frontal Lobe– T - Temporal Lobe– C - Center– O - Occipital Lobe

• Number for exact position– Odd numbers - left– Even numbers - right

Electrode Placement

• A more detailed view:

Continuous Brain Waves

• Generally grouped by frequency: (amplitudes are about 100µV max)

Type Frequency Location Use

Delta <4 Hz everywhere occur during sleep, coma

Theta 4-7 Hz temporal and parietal correlated with emotional stress(frustration & disappointment)

Alpha 8-12 Hz occipital and parietal reduce amplitude with sensory stimulation or mental imagery

Beta 12-36 Hz parietal and frontal can increase amplitude during intense mental activity

Mu 9-11 Hz frontal (motor cortex)

diminishes with movement or intention of movement

Lambda sharp, jagged

occipital correlated with visual attention

Vertex higher incidence in patients with epilepsy or encephalopathy

Thank You!