Unit 1 Brain and Nervous System Terms

Central Nervous System

the Nervous System comprised of the Brain and the spinal cord

Brain

a complex organ that controls thought, memory, emotion, touch, motor skills, vision, breathing, temperature, hunger and every process that regulates our body.

Spinal Cord

main pathway from nerve signals to and from the brain; controls reflexes

Peripheral Nervous System

the second main classification of NS that is comprised of the Autonomic NS and the Somatic NS

Autonomic Nervous System (ANS)

Automatic response system that controls the Fight or Flight Response (comprised of the Sympathetic NS (Alarm) and the Parasympathetic NS (Resistance)

Somatic Nervous System

Muscular control NS; Efferent Nerves exit the brain, and afferent nerves enter the brain (division of ANS)

Sympathetic Nervous System

"fight or flight" (division of ANS)

Parasympathetic Nervous System

rest and digest system (division of ANS)

Neuron

a nerve cell; the basic building block of the nervous system

Glial cells

cells in the nervous system that support, nourish, and protect neurons

Reflex Arc

a neural pathway that controls a reflex.

Sensory neurons

neurons that carry incoming information from the sense receptors to the central nervous system

Motor neurons

neurons that carry outgoing information from the central nervous system to the muscles and glands

Interneurons

central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs

All-or-Nothing Principle

the idea that a neuron will either fire or it will not

Depolarization

this occurs when positive ions enter the neuron, making it susceptible to fire an action potential.

Refractory period

the minimum length of time after an action potential during which another action potential cannot begin

Resting Potential

The stable, negative charge of a neuron when it is inactive. Prior to a neuron firing, the neuron is at resting potential, there are more potassium ions inside the cell and more sodium ions outside of the cell.

Reuptake

the reabsorption of the neurotransmitter after it has done its job in the synapse.

Threshold

the level of stimulation required to trigger a neural impulse

Multiple Sclerosis

the loss of muscle control resulting from a deterioration of myelin sheaths.

Myasthenia Gravis

A disease in which antibodies made by a person's immune system prevent certain nerve-muscle interactions. It causes weakness in the arms and legs, vision problems, and drooping eyelids or head.

Action potential

a neural impulse; a brief electrical charge that travels down an axon

Neurotransmitter

A specialized chemical messenger which sends signals between neurons.

Excitatory

a neurotransmitter that causes a postsynaptic neuron to propagate more action potentials.

Inhibitory

Describes a neurotransmitter that causes a postsynaptic neuron to propagate fewer action potentials.

Dopamine (loss of dopamine is associated with Parkinson's Disease),

A neurotransmitter involved in movement, mood, attention, and learning.

Serotonin

A neurotransmitter that regulates sleep, mood, appetite, and body temperature.

Norepinephrine

A neurotransmitter important in controlling alertness, wakefulness, mood, and attention.

Glutamate

The main excitatory neurotransmitter in the central nervous system; important for learning and memory.

GABA loss of GABA is associated with Anxiety disorders

the main inhibitory NT in the brain and spinal cord;

Endorphins

endogenous morphine; pleasure and pain reduction

Substance P

NT that plays a key role in the modulation of pain. It also has a role in sexual behavior and has been implicated in the regulation of mood.

Acetylcholine

NT associated with memory; loss of Acetylcholine is associated with Alzheimer's Disease.

Hormones

chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another

Adrenaline

Released during times of stress; synonym: Epinephrine

Leptin

a protein that is released when fat is present in the body; signals the hypothalamus that the body has enough fat stored to function normally.

Ghrelin

secreted by the stomach as a peptide secreted by endocrine cells in the stomach stimulating appetite and the release of growth hormone

Melatonin

released by the pineal gland that produces sleepiness

Oxytocin

a chemical that can induce anti-stress-like effects such as reduction of blood pressure and cortisol levels. It increases pain thresholds, exerts an anxiolytic-like effect and stimulates various types of positive social interaction

Agonist

a chemical that mimics the action of a neurotransmitter

Antagonist

a chemical that opposes the action of a neurotransmitter

Reuptake inhibitors

A particular type of drug that can prevent the absorption(re-uptake) of NT in the synapse thus increasing the longevity of the effect of the NT. (eg.- SSRI; selective serotonin reuptake inhibitors are drugs that help to treat depression by preventing the reuptake of Serotonin)

Stimulants

substances that excite functional activity in the central nervous system

Caffeine

a stimulant and vascular constrictor that increases heart rate, breathing, blood pressure, and decrease fatigue.

Cocaine

a powerful stimulant drug that increases levels of dopamine, a neurotransmitter associated with pleasure and movement, in the brain's reward circuit

Depressants

one classification of drugs that reduce or slow our neural activity and body functions.

Marijuana

A hallucinogen: something that causes changes in perceptions of reality; loss of identity and vivid fantasies

Opioids

drugs that effect the brain and Influences the limbic system in particular (pleasure and relaxation)

Heroin

a narcotic; derived from the opium plant that have a sedative effect

Tolerance

resulting from persistent use of a drug, characterized by a markedly diminished effect with regular use of the same dose of the drug or by a need to increase the dose markedly over time to achieve the same desired effect.

Addiction

compulsive drug craving and use, despite adverse consequences.

Withdrawal

the physical and mental symptoms that occur after stopping or reducing intake of a substance such as drugs or alcohol, which the body has become dependent on

Brain stem

The oldest part and central core of the brain. It connects the brain and spinal cord and is responsible for automatic functions.

Medulla

part of the brainstem; responsible for breathing, circulation, heart rate

Reticular formation

the nerve fibers in the brain stem that relays signals about sleep and arousal to/from the brain to the body.

Pons

The structure in the brain stem that is responsible for sleep and arousal.

Cerebellum

Known as the little brain; back of the brain stem; responsible for balance, coordination, fine motor movement, and procedural memory.

Cerebral cortex

The intricate fabric of interconnected neural cells that covers the cerebral hemispheres; it is the body's ultimate control and information processing center.

Limbic system

A doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres; associated with emotions such as fear and aggression and drives such as those for food and sex.

Thalamus

The relay center for all sensations but smell; the sensory switchboard.

Hypothalamus

The part of the limbic system that is responsible for biological motivation; also regulates the endocrine system.

Pituitary gland

The endocrine system's most influential gland; regulates growth and controls other endocrine glands.

Hippocampus

Part of the limbic system that is responsible for the formation of memory and processes explicit memories for storage.

Amygdala

Located at the end of the hippocampus, responsible for primary emotional processing (i.e., rage, aggression in the left amygdala; fear, anxiety in the right

Corpus callosum

The white matter that connects the left and the right hemispheres; this allows for the mind's comprehension of cerebral laterality.

Frontal Lobe

Part of the brain that is responsible for movement and detailed memory.

Parietal Lobe

Part of the brain that is responsible for body sensations (somatosensory cortex).

Occipital Lobe

Part of the brain that is responsible for visual processing (visual cortex).

Temporal Lobe

Part of the brain that is responsible for more personal/emotional memories (hippocampus is located here).

Prefrontal Cortex

Part of the frontal lobe that is responsible for emotional control/regulation, thought control, and decision making.

Motor Cortex

Part of the frontal lobe that is responsible for movement.

Split brain

A condition in which the two hemispheres of the brain are isolated by cutting connecting fibers between them.

Cerebral hemispheres

The right and left halves of the cerebrum.

Broca's area

Located in the left frontal lobe, it is responsible for language production.

Wernicke's area

Part of the left temporal lobe that is responsible for language comprehension.

Aphasia

Impairment of language, usually caused by left hemisphere damage either to Broca's area or to Wernicke's area.

Plasticity

The brain's capacity for modification, as evident in brain reorganization following damage and in experiments on the effects of experience on brain development.

Electroencephalogram (EEG)

An amplified recording of the waves of electrical activity that sweep across the brain's surface, measured by electrodes placed on the scalp.

Functional Magnetic Resonance Imaging (fMRI)

A form of active brain scan that monitors the consumption of oxygen as the brain is performing its functions.

Lesioning

The deliberate destruction of brain tissue; this allows for brain function to be ascertained by what functions are now lost due to the destruction of the brain area.

Blood-brain barrier

a semipermeable membrane-like mechanism that stops some chemicals from passing between the bloodstream and the brain

Cerebrospinal fluid (CSF)

a solution that fills the hollow cavities (ventricles) of the brain and circulates around the brain and spinal cord

Afferent nerve fibers

axons that carry information inward to the central nervous system from the periphery of the body

Efferent nerve fibers

axons that carry information outward from the central nervous system to the periphery of the body

Electrical stimulation of the brain (ESB)

sending a weak electric current into a brain structure to stimulate (activate) it

Forebrain

the largest and most complicated region of the brain, encompassing a variety of structures, including the thalamus, hypothalamus, limbic system, and cerebrum

Hindbrain

The part of the brain that includes the cerebellum and two structures found in the lower part of the brainstem: the medulla and the pons

Inhibitory PSP

An electric potential that decreases the likelihood that a postsynaptic neuron will fire action potentials

Midbrain

The segment of the brain stem that lies between the hindbrain and the forebrain

Neuromodulators

Chemicals that increase or decrease (modulate) the activity of specific neurotransmitters

Perceptual Asymmetries

Left-right imbalances between the cerebral hemispheres in the speed of visual or auditory processing

Postsynaptic Potential

A voltage change at the receptor site on a postsynaptic cell membrane

Soma

The cell body of a neuron; it contains the nucleus and much of the chemical machinery common to most cells

Stereotaxic Instrument

a device used to implant electrodes at precise locations of the brain

Synaptic cleft

a microscopic gap between the terminal button of a neuron and the cell membrane of another neuron

Terminal buttons

small knobs at the end of axons that secrete chemicals called neurotransmitters

MRI

a technique that uses magnetic fields and radio waves to produce computer generated images that distinguish among different types of soft tissue; allows us to see structure within the brain

Axon

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

Biological psychology

a branch of psychology concerned with the links between biology and behavior