Neural Components, Communication, and Brain Structure: Study Notes for Psychology

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Neural Components and Communication

Neurons

Neurons are the basic building blocks of the nervous system, responsible for transmitting information via electrical and chemical signals.

Cell body (soma): Contains the nucleus and maintains cell health.
Dendrites: Branch-like extensions that receive information from other neurons.
Axon: Long fiber that transmits information away from the cell body.
Axon Terminal: End of the axon where neurotransmitters are released.
Synapse: Junction between neurons where neurotransmitters are exchanged.

Glial Cells and Myelin

Glial cells support and protect neurons, while myelin (produced by glia) insulates axons to speed up neural transmission.

Glia: Provide structural support, nutrition, and insulation for neurons.
Myelin Sheath: Fatty insulation surrounding axons, increases speed of electrical transmission.
Multiple Sclerosis: Disease caused by loss of myelin, resulting in erratic signals.

How Does a Neuron Fire?

Neurons communicate through electrical impulses known as action potentials, which follow a specific sequence:

Resting Potential: Neuron is polarized, with more positive ions outside than inside.
Action Potential: Sudden reversal of charge when the neuron fires, positive ions rush in, transmitting the signal.
Repolarization: Potassium flows out, restoring the resting state.
Refractory Period: Short period during which the neuron cannot fire again.

Formula:

Electrochemical Communication

Neurons communicate by releasing neurotransmitters into the synapse, which bind to receptors on the receiving neuron to transmit signals.

Release: Action potential triggers neurotransmitter release.
Reuptake: Excess neurotransmitters are reabsorbed by the presynaptic neuron.
Agonists: Mimic or enhance neurotransmitter effects.
Antagonists: Block or impede neurotransmitter activity.

Major Neurotransmitters and Their Functions

Glutamate and GABA

Glutamate and GABA are the primary excitatory and inhibitory neurotransmitters in the brain, respectively.

Glutamate: Increases likelihood of neuron firing; involved in learning and memory.
GABA: Decreases likelihood of neuron firing; regulates sleep and alertness.

Acetylcholine

Acetylcholine is involved in movement, attention, and memory.

Functions: Arousal, selective attention, memory, sleep.
Alzheimer's Disease: Linked to loss of acetylcholine-producing neurons.
Aricept: Medication that boosts acetylcholine levels.

Dopamine

Dopamine regulates pleasure, reward, and voluntary movement.

Pleasure and Reward: Central to motivation and reinforcement.
Parkinson's Disease: Caused by loss of dopamine-producing neurons.
Schizophrenia: Associated with excess dopamine activity.

Serotonin

Serotonin affects mood, emotion, and sleep.

Source: Synthesized from tryptophan (found in diet, blood, platelets).
Functions: Regulates sleep, mood, emotional responses, and sensitivity to pain.
Influences: Diet, exercise, sunlight, sleep.

Brain Structure and Function

Hindbrain

The hindbrain controls basic life functions such as heartbeat, breathing, and sleep.

Medulla: Controls heartbeat, breathing, swallowing.
Cerebellum: Coordinates movement and balance.
Reticular Activating System: Regulates arousal, sleep, and attention.

Midbrain

The midbrain is involved in movement, sensory processing, and motor activities.

Functions: Controls movement, transmits sensory information.

Forebrain and Cerebral Cortex

The forebrain includes the cerebral cortex, which is responsible for higher mental processes such as reasoning, perception, and decision making.

Cerebral Cortex: Divided into four lobes, connected by the corpus callosum.

Lobes of the Cerebral Cortex

Lobe	Main Functions
Frontal	Planning, decision making, movement
Parietal	Sensation, pressure, pain, temperature
Temporal	Hearing, language, memory
Occipital	Vision processing

Lateralization

Lateralization refers to the specialization of certain cognitive functions in one hemisphere of the brain.

Left Hemisphere: Language, logic, writing.
Right Hemisphere: Spatial abilities, simple language skills.

Split Brain Surgery

Split brain surgery involves severing the corpus callosum to reduce seizures, affecting communication between hemispheres.

Effects: Can impact information processing and decision making.

Brain Mapping and Imaging Techniques

CT Scan

CT scans use X-rays to create images of the brain, showing structural changes and densities.

PET Scan

PET scans measure brain activity by tracking radioactive substances injected into the bloodstream.

EEG

EEG records electrical activity from the scalp, useful for studying timing of brain activity.

Brain Mapping

Magnetic Field Measurement: Locates seizures and brain activity.
Deep Brain Stimulation: Modifies brain function through electrodes.
Transcranial Magnetic Stimulation: Uses magnetic fields to enhance or interrupt brain functioning.

Additional Brain Structures and Functions

Limbic System

The limbic system regulates emotion, motivation, and memory.

Amygdala: Involved in fear and aggression.
Hippocampus: Essential for memory formation.
Thalamus: Relays sensory information.

Summary Table: Brain Imaging Methods

Method	Main Purpose
CT Scan	Structural imaging, detects brain damage
PET Scan	Functional imaging, measures activity
EEG	Measures electrical activity, timing of events
Brain Mapping	Locates activity, guides treatment

Additional info: Some explanations and examples have been expanded for clarity and completeness based on standard introductory psychology textbooks.