The Brain and Nervous System

Central Nervous System

Made up of the brain and spinal cord. Primarily responsible for processing sensory information. Communicates largely by sending electrical signals through individual nerve cells.

Spinal Cord

CNS’s information highway that connects the peripheral nervous system to the brain.

spinal reflexes

An automatic response controlled solely by neural circuits in the spinal cord, often relating to posture of locomotion.

peripheral nervous system

Complex network of nerves that travels to every part of the body, carrying the signals necessary for the body to survive.

sensory nerves

Nerves responsible for sensing a stimulus.

motor nerves

Nerves responsible for carrying signals away from the central nervous system in order to initiate an action.

somatic nervous system

The division of the peripheral nervous system that processes incoming sensory information and controls our voluntary movements.

autonomic nervous system

The portion of the nervous system innervating smooth muscle and glands, including the circulatory, digestive, respiratory, adn reproductive organs.

sympathetic nervous system

Prepares the body for action and mobilizes energy resources (fight or flight).

parasympathetic nervous system

Network of nerves that relaxes your body after periods of stress or danger. Helps run life-sustaining processes like digestion, when you feel safe and relaxed.

neurons

Individual brain cells

glial cells

Cells that support the neurons in many different ways

dendrites

Part of a neuron that extends away from the cell body and is the main input to the neuron.

cell body

The spherical part of the neuron that contains the nucleus.

axon

Part of the neuron that extends off the soma, splitting several times to connect with other neurons. Main output of the neuron.

axon terminals

The very end of the axon that contains neurotransmitters and makes synaptic contact with the next neuron in the chain.

myelin sheath

Fatty tissues that insulates the axons of the neurons. Necessary for normal conduction of electrical impulses among neurons.

nodes

A point in a graph, tree diagram, or the like at which lines intersect or branch. A single point or unit in an associative model of memory.

nerve

Smallest cells in the body that are responsible for carrying information around your body.

neurogenesis

The process by which new neurons are formed in the brain.

stem cells

A cell that its itself undifferentiated but can divide to produce one or more types of specialized tissue cells.

synaptic cleft/gap

The small space between the presynaptic terminal button and the postsynaptic dendritic spine, axon, or soma

synapse

Junction between the presynaptic terminal button of one neuron and the dendrite, axon, or soma of another postsynaptic neuron.

plasticity

The brain’s ability to change and adapt as a result of experience.

action potential

A transient all-or-nothing electrical current that is conducted down the axon when the membrane potential reaches the threshold of excitation.

synaptic vesicles

Any of numerous small spherical sacs in the cytoplasm of the knoblike ending of the axon of a presynaptic neuron that contain molecules of neurotransmitter.

neurotransmitter

Chemical substance released by the presynaptic terminal button that acts on the postsynaptic cell

receptor sites

The spaces on the neural cells that house the molecules considered to be the receptors.

endorphins

Neurotransmitters linked to reduced pain and increased pleasure.

hormones

Chemical substances produced in your body that control and regulate the activity of certain cells or organs

endocrine glands

A system of glands that secretes hormones into the circulatory system.

melatonin

A hormone known to regulate sleep and wake cycles

adrenal hormones

Responsible for releasing epinephrine and norepinephrine-hormones that are present in the “fight or flight” response.

cortisol

Aids the body during stress by increasing glucose levels and suppressing immune system function, stress hormone.

epinephrine and norepinephrine

Two neurotransmitters that also serve as hormones behind your “flight or fight” response.

sex hormones (androgen, estrogen, progesterone)

Hormones that stimulate various reproductive functions.

Androgen- male sex hormone that is produced in the testes and responsible for typical male sexual characteristics

Estrogen- Female sex hormones that are primarily produced in the ovaries.

Progesterone- A hormone secreted mainly by the corpus luteum in the ovary that stimulates the proliferation of the endometrium (lining) of the uterus required for implantation of an embryo.

lesion method

1. Method where patients with brain damage are examined to determine which brain structures are damaged and how this influences the patient’s behavior. 

electrode

Small devices that are implanted in the brain to record the activity of individual neurons or groups of neurons. Used for Electrode Stimulation of the Brain (ESB)

electroencephalogram (EEG)

A neuroimaging technique that measures electrical brain activity via multiple electrodes on the scalp

transcranial magnetic stimulation (TMS)

Non-invasive procedure that uses magnetic fields to stimulate nerve cells in specific areas of the brain. 

PET scan (positron-emission tomography)

A neuroimaging technique that measures brain activity by detecting the presence of a radioactive substance in the brain that is initially injected into the bloodstream and then pulled in by active brain tissue.

MRI (magnetic resonance imaging)

A technique that uses magnetic fields and radio waves to produce computer generated images of soft tissue.

localization of function

Idea that different areas of the brain are responsible for specific functions or behaviors. 

brain stem

The “trunk” of the brain comprised of the medulla, pons, midbrain, and diencephalon.

pons

Part of the brainstem that regulates several functions (hearing, equilibrium, taste, facial sensations, movements)

medulla

Controls automatic functions of the body (breathing, heart rate, blood pressure).

reticular activating system

Responsible for sensation, consciousness, attention, and sleep-wake cycle. Transmits the sensory message to different areas of the cerebral cortex through the thalamus.

cerebellum

The distinctive structure at the back of the brain

thalamus

Brain’s sensory switchboard, directs messages to the sensory areas in the cortex and transmits replies to the cerebellum and medulla.

olfactory bulb

A pair of swellings above the olfactory epithelium and underneath the frontal lobes of the brain that transmit odor information from the nose to the brain.

hypothalamus

Regulates autonomic nervous system by producing and releasing hormones

pituitary gland

“master gland” of the endocrine system. Hormones from PG help regulate growth, metabolism... Controlled by the hypothalamus.

limbic system

Includes the subcortical structures of the amygdala and hippocampal formation as well as cortical structures, responsible for aversion and gratification

amygdala

Center of emotion and motivations. Responsible for fear responses and learning out of fearful situations. Also involved in regulation of memory consolidation or turning memory into long-term memory.

hippocampus

Part of the limbic system and in the temporal lobe, responsible for the formation of memory and processes explicit memories for storage. Memories are reconstructed.

cerebrum

Usually refers to the cerebral cortex and associated white matter, but in some texts includes the subcortical structures

cerebral hemispheres

Cerebral cortex divided into two hemispheres. Left gets sensory messages and controls motor functions of the right half of the body, right does the same for the left half of the body.

corpus callosum

The thick bundle of nerve cells that connect the two hemispheres of the brain and allow them to communicate

lateralization

Concept that different functions and processes are primarily located in one hemisphere of the brain, left or right.

cerebral cortex

Intricate fabric of interconnected neural cells that covers the cerebral hemispheres.

occipital lobes

The back mose part of the cerebrum. involved in vision

visual cortex

The area of the cerebral cortex that processes visual information. Located in the occipital lobe.

parietal lobes

The part of the cerebrum between the frontal and occipital lobes. Involved in bodily sensations, visual attention, and integrating the senses.

somatosensory cortex

The site that registers touch, pressure, temperature, and pain in the cerebral cortex.

temporal lobes

The part of the cerebrum in front of (anterior to) the occipital lobe and below the lateral fissure. Involved in vision, auditory processing, memory, and integrating vision and audition.

auditory cortex

Responsible for analyzing and categorizing different sound frequencies and patterns. Located in the left temporal lobe.

wernicke’s area

Involved in understanding written and spoken language, located in the back of the temporal lobe near the occipital lobe of the left cerebral hemisphere.

frontal lobes

The most anterior part of the cerebrum, anterior to the central sulcus and responsible for motor output and planning, language, judgment, and decision-making.

motor cortex

Crucial part of the brain that controls the voluntary movement of the human body. 

Broca’s area

An area in the frontal lobe of the left hemisphere, implicated in language production

association cortex

Areas of the cerebral cortex that are not involved in primary motor or sensory functions.

prefrontal cortex

Controls executive functions or a set of abilities that are needed to control cognitive behaviors.

split-brain surgery

The corpus callosum, the huge bundle of fibers that connects the two hemispheres, is cut for people who have had their hemispheres surgically separated as a treatment for epilepsy.

hemispheric dominance

Proposes that each hemisphere of the brain controls certain cognitive processes. Left is considered to be adept at logical, rational, calculating tasks; right is artistic, creative, and spontaneous tasks.

Mirror Neurons

class of neuron that enables empathy and imitation (chameleon effect). Modulate their activity both when an individual executes a specific motor act and when they observe the same or similar act performed by another individual.

Primary motor cortex

Provides most important signal for production of skilled movements

brainstem

Controls essential function (breathing, consciousness, blood pressure, sleep, heart rate)

Reticular formation

Keeps the brain awake, regulates arousal and sleep-wake transitions.

Left hemisphere

In charge of language, logic, symbolic, sequential tasks. Talky one!!

Right Hemisphere

In charge of spatial visual ability, art and music appreciation, non-verbal sounds. Language comprehension one!!!

Lesioning

Destroying parts of your brain when they are damaged

Dual processing

Conscious perception and out of sight processing (priming, insight, implicit learning)