Brain Behavior

Neurons

A neuron is a single cell in the nervous system that transmits information through the nervous system.

2 main branches of nervous system

Central Nervous System (CNS) & Peripheral Nervous System (PNS)

Central Nervous System

Consists of the brain, spinal cord and majority of neurons.

Peripheral Nervous System

Spinal cord transmits information to the brain and PNS.

Includes all parts of nervous system beyond CNS.

2 Parts: Autonomous Nervous System (ANS) & Somatic Nervous System (SNS).

Autonomous Nervous System

Collection of neurons transmitting info to and from internal organs

Consists of 2 parts: Parasympathetic (to converse energy), Sympathetic (to arouse)

Somatic Nervous System

Network linking the spinal cord with the upper body and sense organs.

Controls voluntary behavior.

Parts of a neuron

4 parts:

• Dendrite: 1000s of branches/roots receiving incoming information.

• Cell body (Soma): Receives information from the dendrites, stores genetic information

• Axon: Carries Information away from the Soma

• Axon terminals: Bulb shaped terminal at the end of axon, forms synapses with other dendrites & releases chemicals.

Ions

The charged molecules found inside and outside neurons.

Both positive and negatively charged.

Ion channels: Tiny tunnels in the axon membrane function as doors.

Resting Potential

Neurons at rest when more positive ions accumulate outside as more negative charges exist within.

As messages are received, the resting potential becomes slightly raised while electric charges rise.

When threshold breaks → Action potential.

Myelin Sheath

An insulating material, made of fatty substances coating the axon, to allow electrical impulses transmit more quickly and effectively.

Action Potential

Change in the neuron’s overall charge.

Ion channels are blocked by molecules that prevent sodium (Na+) ions from entering the axon.

During an action potential, the gates open and Na+ ions rush into the axon.

In the end, a negative after potential occurs where it dips slightly below a resting potential.

Synaptic Transmissions

Occur when an action potential reaches the tips of an axon terminal and releases a neurotransmitter.

Neurotransmitter: Chemical that moves information from one neuron to another

Transmissions: Dendrites → Soma → Axons → Axon terminals

Brain structure

2 parts: Corpus Callosum & Cerebral Hemispheres,

Hemispheric lateralisation: Specialization of abilities of the left vs right hemisphere.

Left brain: Language, speech, time sense, writing, rhythm, calculation, complex movements.

Right brain: nonverbal, perceptual skills, visualization, recognition, expression of emotions.

Lobes of Central Cortex

Frontal: Sense of self, motor control and higher mental abilities; reasoning.

Occipital: Vision.

Parietal: Sensations such as touch, temperature and pressure.

Temporal: Hearing and language.

Cerebellum: Posture, coordination, muscle tone and memory.

Exploring Brain Structure

2 Types:

Computed Tomography (CT) scans:

Multiple X-ray scans of a single location taken from different angles and forms an image.

Magnetic Resonance Imaging (MRI) scan:

Placing body into strong magnetic fields, as computers processing creates a 3D model of the brain or body, more detailed than CT scans.

Exploring Brain Function

Electroencephalography (EEG):

Measures electrical activity near the surface of the brain through small electrodes.

Functional Magnetic Resonance Imaging (fMRI) scan:

Uses MRI technology to record activity level in various areas of the brain.

Positron Emission Tomography (PET) scan:

High resolution imaging technique that captures brain activity by attaching radioactive brain particles to glucose molecules.