Psychology 2a

frontal lobe

A region of the cerebral cortex at the front of the brain (lying just behind the forehead) that is necessary for motor control and more complex, high-end functioning like speech, decision making, and judgments.

Acetylcholine

Acetylcholine (ACh) is the most common type of neurotransmitter, and the most well understood. It's found in parts of the peripheral nervous system, spinal cord, and areas of the brain. In the peripheral nervous system, ACh activates muscles that help the body move. When Ach is released to the muscle cells, the muscle contracts. In the brain, ACh is involved in breathing, attention, arousal, motivation, etc. Obviously there are many problems that can occur if ACh is blocked (muscles can't contract). One example is the black widow spider uses venom that causes a flood of ACh into muscle cells and results in violent, uncontrollable muscle contractions, paralysis, and death for it's prey.

Central Nervous System

CNS is a term that describes the brain and the spinal cord. This is a term you are probably familiar with, since it is one of the most commonly used scientific terms around. Despite this, there is some small debate about the CNS - some claim that the retina is also part of the CNS. However, the most accepted view is that the CNS contains only the brain and spinal cord, and that the retina is part of peripheral nervous system.

dopamine

Dopamine is both a neurotransmitter and a neurohormone produced in multiple areas of the brain. As a hormone it is often associated with pleasant experiences. Receiving an unexpected reward may cause your heart to speed up and increase your alertness due to the sudden release of dopamine. As a neurotransmitter it transmits signals associated with concentration and motor skills. Conditions such Parkinson's Disease and schizophrenia are associated with an interruption in the brain's production of dopamine.

Plasticity

In psychology, when we talk about plasticity we're referring to "brain plasticity", which refers to the ability for nerve cells to change through new experiences. The process of changing nerve cells is learning, and it was once believed that the only kind of change that could take place after childhood was related to strength in nerve cell connection, not the ability for the cells to actually change. Most psychologists now believe that nerve cells actually can continue to change and function well into adulthood. What does this mean for you? Well, it seems that the old saying is wrong - you really can teach an old dog new tricks.

myelin sheath

Myelin is a fatty substance that covers neurons. Around your neurons is a myelin sheath (a layer of myelin) that helps increase the speed at which information can travel on the neurons. If you could look at a neuron you would see the sheath covering the axon of the neuron in a way that looks like a row of sausage links.

neurotransmitter

Neural transmission (information being sent from neuron to neuron) works at both the electrical and chemical levels. When the space between two neurons is small enough the electrical signal can simply jump the gap and continue on its way. However, when the gap is too large, the signal must be converted from electricity to chemicals. These chemicals are neurotransmitters, which can be defined as chemicals released by neurons which carry information from one neuron to another. These chemicals are then read or received by a neuron's synapses

Norepinephrine

Norepinephrine (noradrenaline) belongs to a family of biological compounds called catecholamines. These compounds are synthesized in sympathetic neurons and in the adrenal glands.

serotonin

Serotonin is a neurotransmitter with functions in various systems of the body. In the central nervous system serotonin works to regulate mood, appetite, sleep, memory and learning. When present, the neurotransmitter acts as something of a connector between cells, and is associated with a feeling of happiness or decreased anxiety. Serotonin is a major part of many popular drug treatments for depression and anxiety. SSRI's or Selective Serotonin Re-Uptake Inhibitors (like Prozac and Zoloft) help to maintain the serotonin connection between cells.

all or none principled

The all-or-none law is a principle that states that the strength of a response of a nerve cell or muscle fiber is not dependent upon the strength of the stimulus. If a stimulus is above a certain threshold, a nerve or muscle fiber will fire. Essentially, there will either be a full response or there will be no response

temporal lobe

The area in the brain involved with hearing. The temporal lobes are part of the cerebral cortex and are located above the ears. Interestingly, each lobe is responsible for hearing in the opposite ear -- so the lobe on the left side of your brain is responsible for hearing from the right ear

parietal lobe

The area in the brain which plays a major part in touch, pressure and temperature. The parietal lobe would inform you the temperature of a hard boiled egg and would allow you to pick up that egg with just enough pressure to hold it and not crush it.

occipital lobe

The brain can be divided into four main areas, one of which is the occipital lobe, which is the area of the brain located at the rear of the head. The occipital lobe is responsible for sight

flight or fight response

The fight-or-flight response, also known as the acute stress response, refers to a psychological reaction that occurs in the presence of something that is terrifying, either mentally or physically. The fight-or-flight response was first described in the 1920s by American physiologist Walter Cannon. Cannon realized that a chain of rapidly occurring reactions inside the body help mobilize the body's resources to deal with threatening circumstances.

Hippocampus

The hippocampus is a part of your brain, specifically a part of the limbic system that is vital for the formation of memories. Without the hippocampus, you would not be able to remember anything that you are reading hear or anywhere

Limbic system

The limbic system is a grouping of structures in the brain that sits between in the most primitive part of the forebrain called the rhinecephalon. This is a doughnut-shaped network of neurons that inlfuences many deep-rooted drives and emotions including pain, anger, hunger, sex, thirst, and pleasure. The thalamus, hypothalamus, amygdala, fornix, mammiliary bodies, and septal areas are all parts of the limbic system.

Parasympathetic nervous system

The parasympathetic nervous system is part of the autonomic nervous system. Its main function is to conserve/restore your body's energy. For example, the parasympathetic nervous system is responsible for sending signals to slow your heart rate and breathing, and speed up your digestive tract in order to digest calories and save energy.

Peripheral Nervous System

The peripheral nervous system controls all voluntary and involuntary muscles and glands. Essentially, the peripheral nervous system contains all your nerves and nerve bundles excluding the brain and spinal cord.

Synapse

The synapse is the entire junction between neurons, including the pre-synaptic neuron's axon terminal, the synaptic cleft, and the dendrite of the post-synaptic neuron, across which communications flow, usually in the form of neurotransmitter molecules secreted by the pre-synaptic neuron (on its axon terminal) that travel a short distance across the synaptic cleft (this is the actual space between the neurons - the space between the axon terminal of one neuron and the dendrite of the other) to the post-synaptic neuron. Once at the post-synaptic neuron, some of the neurotransmitters will attach themselves (bind) to some receptors. It is important to know that the neurotransmitters and receptors work like a lock and key; that is, they both have certain shapes and only specific neurotransmitters can fit into certain receptors

Thalamus

The thalamus is a structure deep within the brain stem that receives sensory information from the nervous system and passes the information to the cerebral cortex and other parts of the brain. It acts as a director of information related to bodily functions such as seeing, sleeping, hearing, waking, tasting, and touching.

Cerebral cortex

The thin outer layer of the brain's (approximately 2 mm) cerebral hemispheres that acts as the main control center and information processing center. The cerebral cortex is not required for performing many simple actions, but is crucial for creating new episodic memories, the fancier associations, and many new movement programs. The cerebral cortex is made up of two different sub-components: the motor cortex and the sensory cortex.

sympathetic nervous system

Think about a time you've been in a really dangerous or frightening situation. In that situation your body responded by, for example, increasing your heart rate, raising your respiration, moving blood from one place (e.g., your digestive system) to another (your muscles), etc. These responses are all "arousal" responses which get you ready to fight or flee in times of danger. It is the sympathetic nervous system that is responsible for these responses that get your body aroused to respond. This system works with the parasympathetic nervous system which is responsible for then calming your body after the arousal (to get you back to normal). Both of these are actually part (subparts) of the autonomic nervous

corpus callosum

This area contains the largest bundle of nerve fibers in the brain and connects the two sides (hemispheres) of the brain. The corpus callosum doesn't just sit there, it is responsible for allowing the two hemispheres to communicate with each other and share information. Thus, the corpus callosum carries massages between the left and right hemispheres of the brain.

Neurons

are nerve cells and the basic building blocks of our entire nervous systems. The neurons act as sensors for all types of stimuli and communicate the stimuli throughout the body. For example, neurons communicate to the brain that you should not leave your hand on a hot stove. In addition, the neurons are composed of 3 main components, the axon (the tail), the soma (the body), and the dendrites (the branch-like arms that stem from the soma).

Dendrite

are the branch-like structures of neurons that extend from the cell body (soma). The dendrites receive neural impulses (electrical and chemical signals) from the axons of other neurons. The signal always travels in the same direction - the signal comes into the neuron through the dendrites, through the cell body (soma), to the axon, and then out the terminal buttons to the dendrites of the next neuron. In this way information travels all around your body by going from neuron to neuron.

Axon

are the long, spider-thin, tail-like structures found on neurons (nerve cells). Each neuron has a nerve body, dendrites, and axons, all of which are used to send information throughout your body. The axon carries signals (electric voltages) between the dendrites (the neuron's input sites) and the terminal buttons (the neuron's output sites that are at the very end of the axon).

end bulb

or terminal bulbs, look like tiny bubbles that are located at the extreme ends of the axon's branches. Each end bulb is like a miniature container that stores chemicals called neurotransmitters which are used to communicate with neighboring cells.