U2: Neuroscience

Biological psychology

The scientific study of the links between biological (genetic, neural, hormonal) and psychological processes. Also called **neuroscience**.

Nervous system

The body’s system of communication that controls everything we do (breathing, walking, thinking, feeling, etc.) Includes the brain, spinal cord, and nerves.

Neuron

A nerve cell. The cells within the nervous system that transmit information *within* the brain and *between* the brain and the rest of the nervous system. They use electrical impulses and chemical signals to send this information

Nerves

Bundles of axons (from neurons) that form “cables” connecting the central nervous system with muscles, glands, and sense organs

Central Nervous System (CNS)

Made up of two parts - the brain and spinal cord. Includes all of the nerves encased in bone in the skull and vertebrae.

Peripheral Nervous System (PNS)

Made up of all of the body’s nerves *outside of* the brain and spinal cord.

Sensory/Afferent Division (PNS)

The portion of the nervous system responsible for processing input from the environment. Takes in information from the senses (sight, sound, smell, taste, touch) and sends this information to the CNS.

Motor/Efferent Division

The portion of the nervous system responsible for sending information from the brain to the rest of the body to direct a response in the muscles or glands.

Sensory/Afferent neurons

The type of neurons that carry incoming information from the sensory receptors (in the eyes, ears, nose, mouth, skin) to the brain and spinal cord.

Motor/Efferent neurons

The type of neurons that carry outgoing information from the brain and spinal cord to the rest of the body.

Interneurons

The type of neurons that exist only within the brain and spinal cord, and are responsible for relaying messages between the sensory and motor neurons.Somatic Nervous System

Somatic Nervous System (SNS)

The part of the peripheral nervous system (PNS) that controls voluntary muscle movements. The nerves in this system deliver information from your senses to your brain, and from your brain to your muscles (directing them to move).

Autonomic Nervous System (ANS)

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The part of the peripheral nervous system (PNS) that controls the __automatic__ functions of your body that you need to survive (lungs, heart, glands, etc.) These are the processes you don’t need to think about, and that your brain manages while you’re awake or asleep. It is divided into the sympathetic and the parasympathetic division.

Sympathetic Division (ANS)

The part of the autonomic nervous system that is activated in response to stress - controlling the “fight, flight, or freeze” responses. (ex. dilated pupils, increase in heartbeat)

Parasympathetic Division (ANS)

The part of the autonomic nervous system that is activated during calm times or to calm a stress response. The “rest and digest” system. (ex. constricted pupils, slow heartbeat, uterus relaxation)

Reflexes / Reflex Arc

An important exception!! A neural circuit that controls reflexive responses *without passing a signal through the brain*. Sensory neurons route signals to interneurons in the *spinal column*, which immediately activate motor neurons to send a reflexive response (without sending a signal to the brain!).

Dendrites

Covered in receptor sites, this is the first piece of the neuron that receives the message (passed by neurotransmitters) from the previous neuron and passes it (impulse) toward the soma.

**Soma (cell body)**

Receives the message from the dendrites and calculates whether the message should be passed down the axon (the soma will only pass the message if it reaches *absolute threshold*).

Axon

The one-way path that sends the message to the terminal branches. In many neurons, this piece is covered in a myelin sheath.

Myelin sheath

A fatty tissue layer that encases an axon in segments; this casing helps to speed up the electric signals sent down the axon.

**Multiple Sclerosis (MS)**

A disabling disease of the brain and spinal cord caused by the immune system attacking the myelin sheath. This causes communication problems between the brain and the rest of the body, and permanent damage to the nerves.

Axon Terminals/**Terminal Buttons/Synaptic Buttons**

At the end of the axon, the last stop of the electrical neural impulse. These hold vesicles that contain neurotransmitters, which will travel across the synapse to stimulate the dendrites of the next neuron.

Vesicles

In the axon of a neuron; hold the neurotransmitters that will travel across the synapse to stimulate the dendrites of the next neuron. After reuptake, the neurotransmitters reform new vesicles and wait for the next impulse.

Synapse/Synaptic (gap/cleft)

The minuscule space between the terminal branches of the sending neuron and the dendrites of the receiving neuron. Neurotransmitters cross this gap to pass on their chemical message.

**Neurotransmitters**

Chemical messengers that cross the synaptic gap between neurons.

Receptors

The areas on the dendrites that receive the neurotransmitters sent across the synapse. Each receptor can receive a specific type of neurotransmitter.

**Presynaptic** *(sending)* neurons

The __pre__synaptic neuron is the neuron *sending* the message across the synapse, where it is *received by* the __post__synaptic neuron. 

**Postsynaptic** *(receiving)* **neurons**

The postsynaptic neuron then becomes the presynaptic sender when it sends its signal across the synapse to the next neuron.

**Electro-Chemical process**

The process of sending a neural message is electrical *within* the neuron (action potential) and chemical *between* neurons (neurotransmitters)

Conduction

The *electrical part* of the electrochemical process of neural transmission, in which an electrical charge is sent down the length of a neuron.

**Action potential**

A **neural impulse** - a brief electrical charge sent by the soma travels down the axon into the terminal branches.

Refractory period

A period of inactivity after a neuron has fired. Another action potential cannot send until this period of recovery is over and the axon has repolarized and returned to resting potential.

Resting potential

A polarized neuron that is at rest, with a slightly negative charge inside the axon and a slightly positive charge on the outside. When the soma signals the axon’s membrane to let in positive charges, an action potential will begin.

**(Absolute) Threshold**

The level of stimulation required for the cell body (soma) to trigger a neural impulse.

**All-or-nothing principle**

A neuron either fires (if threshold reached) or it does not. It is always the same intensity - it can’t fire just a little or a lot.

**Neuro-transmission**

The *chemical part* of the electrochemical process of neural transmission, in which neurotransmitters are released from the vesicles in the axon terminals, crossing the synapse to trigger receptors on the dendrites receiving neuron.

Reuptake

After neurotransmitters are released into the synapse, they are reabsorbed into the sending neuron and new vesicles are formed in the terminal branches.

**Excitatory neuro-transmitters**

Neurotransmitters that increase the likelihood that the receiving neuron will fire an action potential. They have an *excitatory effect* on the neuron.

**Inhibitory neurotransmitters**

Neurotransmitters that decrease the likelihood that the receiving neuron will fire an action potential. They have an *inhibiting effect* on the neuron.

Long-term potentiation

The process by which synaptic connections between neurons become stronger with frequent activation. *“The neurons that fire together wire together.”*

Acetylcholine (ACH)- type:__ + function: __

Excitatory; Muscle function, Attention, Learning/memory

Acetylcholine (ACH) surplus:_ + deficit:_

Muscle spasms; Alzheimer’s disease

Dopamine- type:__ + function:__

Inhibitory; Motor movement, mood and emotion, arousal/alertness

Dopamine- surplus:_ + deficit:_

Schizophrenia/Drug addiction; Parkinson’s Disease

Serotonin- type:_ + function:_

Inhibitory; Mood regulation, hunger, sleep

Serotonin surplus:_ + deficit:_

Hallucinations; Depression and mood disorders

Endorphins type: + function:

Inhibatory; Pain control, pleasure, reduction of stress

Endorphins surplus:_ + deficit:_

Artificial highs, body may not give adequate pain warnings;

Pain in body

Norepinephrine type: + function:

Excitatory; Fight-or-Flight arousal, Alertness/arousal

Norepinephrine surplus:_ + deficit:_

Anxiety; Depression

GABA type: + function:

Inhibitory; Regulates sleep-wake cycle

GABA surplus:_ + deficit:_

Sleep and eating disorders; seizures, tremors, Huntington’s disease, insomnia

Oxytocin type: + function:

Excitatory; Sexual arousal, Romantic attachment, Parent-infant bonding, Labor contractions in childbirth, Breast milk production

Oxytocin surplus:_ + deficit:_

Emotional oversensitivity; Autism spectrum disorder

Glutamate type: + function:

Excitatory; Learning and long-term memory

Glutamate surplus:_ + deficit:_

Migraines, seizures (overstimulation of the brain); N/A

Psychoactive Drugs

Chemical substances that change the way the nervous system functions, causing changes in mood, awareness, thoughts, feelings, or behavior.

Therapeutic drugs

Psychoactive drugs prescribed by a doctor to address a medical condition.

Misused / Abused drugs

Psychoactive drugs taken without medical supervision

Stimulants

Psychoactive drugs that heighten alertness, increase energy, and increase heart rate. *Ex: Caffeine, nicotine, cocaine, amphetamines*

Depressants

Psychoactive drugs that reduce feelings of tension, relax muscles, and slow breathing. *Ex: alcohol, benzodiazepines (‘benzos’)*

Hallucinogens

Psychoactive drugs that bring on hallucinations, a sense of not being real, or paranoia. *Ex: mushrooms, acid (LSD), PCP, peyote*

Opioids

Psychoactive drugs that relieve pain, cause drowsiness, confusion, and slow breathing *Ex: morphine, oxycodone, codeine, heroin*

**Marijuana**

Psychoactive drug that changes sensory perception, impairs memory, and increases relaxation *Ex: Cannabis*

Agonists

A chemical (drug) that is the same shape as a neurotransmitter, so it binds in the receptor sites, mimicking and therefore stimulating a response that would naturally occur by the neurotransmitter. This can trick your brain into thinking there is more of the neurotransmitter.

Antagonists

A chemical (drug) that can fit in the receptor site, but is not quite the same shape as a natural neuro- transmitter. Thus the antagonist is *blocking* the site (NOT mimicking). By blocking the receptor site, this drug keeps the usual neurotransmitter from getting in and affecting the neuron.

Reuptake Inhibitors

A chemical (drug) that blocks the reuptake of a neurotransmitter in the sending neuron, thereby increasing the amount of the chemical in the synapse.

Endocrine system (ES)

The body’s “slow” system of chemical communication (compared to the fast nervous system); a set of glands that secrete hormones into the bloodstream.

Hormones (ES)

Chemical messengers that are manufactured by the endocrine glands that travel through the bloodstream and affect other tissues.

Adrenal glands (ES)

A pair of endocrine glands that sit just above the kidneys and secrete hormones (adrenaline/epinephrine and noradrenaline/norepinephrine) that help arouse the body in times of stress.

Pancreas (ES)

A long, flat gland tucked behind the stomach that produces enzymes that aid digestion, as well as hormones that regulate the way the body processes glucose (sugar).

Gonads (Ovaries / Testes) (ES)

The glands (ovaries in females; testes in males) that produce sex hormones (estrogen for women; testosterone for men).

**Pituitary Gland -** *“Master P” (ES)*

The endocrine system’s most influential gland (master gland). Situated in the brain. Under the influence of the hypothalamus, it regulates growth and controls other endocrine glands.

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**Localization of brain function**

Simply means that different areas of the brain (i.e., locations) are associated with different behaviors and mental processes (functions)

Brainstem

The oldest part and central core of the brain, it is an extension of the spine as it enters the skull, linking the brain and spinal cord. It is responsible for automatic survival functions. Includes the hindbrain and midbrain

Medulla Oblongata (Hindbrain)

Involved in the control of heart rate, breathing, and blood pressure.

Pons (Hindbrain)

Manages sleep-wake cycle, setting level of alertness when you wake up. Also involved in the control of facial expressions.

Cerebellum (Hindbrain)

Literally means “little brain.” Coordinates balance as well as habitual voluntary muscle movements such as walking, posture, and eye movements.

Reticular Formation

A netlike connection of cells that controls general body arousal and the ability to focus attention. If it does not function; the result is falling into a deep coma.

Limbic System (LS)

The part of the neural system that wraps around the thalamus - it is associated with memory, emotions and motivations.

Thalamus (LS)

Receives incoming sensory signals coming up the spinal cord (from eyes, ears, mouth, skin- but not nose!) and routes them to the appropriate areas in the rest of the brain.

**Hippocampus (LS)**

Memories are processed here, then sent to other locations in the brain for permanent storage. People with damage to this part of the brain are unable to create new memories and retain new information.

Amygdala (LS)

Processing area for emotions, particularly fear and aggression.

**Hypothalamus (LS)**

Controls biological rhythms (“day person” or “night person”), body temperature, hunger and thirst, sexual arousal, and communicates with the pituitary gland to control the endocrine system.

**Cerebrum**

The largest part of the brain. It is divided into two hemispheres, or halves. Areas within the _______ control muscle functions and also control speech, thought, emotions, reading, writing, and learning.

Cerebral Cortex

The outermost layer of your brain. Its surface has many folds, giving it a wrinkled appearance. The folds consist of many deep grooves.

Cortex

Literally, “bark” in Latin - the outermost layer of the brain, made up of gray matter (somas).

Cerebral hemispheres

Two halves of the brain. Each side has similar parts.

**Contralateral Control**

Each hemisphere manages the opposite side of the body - receiving sensory input messages and sending muscle control messages.

Fissures

Grooves between hemispheres and lobes of the cerebrum

Corpus Callosum

A bundle of nerves at the bottom of the longitudinal fissure, connecting the two hemispheres of the brain.

Lobes

Eight sections of the cerebrum - 4 in each hemisphere (same four on both sides): frontal, parietal, occipital, temporal.

**Frontal lobes**

Lie just behind the forehead. Contain **motor cortex** and **Broca’s Area**. Important for controlling voluntary movement, expressive language, and managing higher level cognitive skills.

Prefrontal Cortex

The brain’s “executive control system” that is critical managing the planning functions of the brain such as pursuing goals, predicting consequences, making plans, making judgements, self-monitoring, and abstract thought. Primarily develops during adolescence and continues until about age 25.

Motor Cortex

Area at the rear of the frontal lobes that controls voluntary muscle movements.

Parietal lobes

Lie at the top of the head (crown) and toward the rear. Contain the **sensory cortex**. Vital for managing incoming sensory information.

Sensory Cortex

Area at the front of the parietal lobes that registers information from the senses - including touch, pain, temperature, and a sense of where the body’s limbs (arms & legs) are.

Occipital lobes

Lie at the back of the head, furthest from eyes; contains the **visual cortex**. Processes visual signals from the eyes.

Temporal lobes

Lie roughly above the ears; contains the **auditory cortex**. Left side (usually) contains **Wernicke’s Area**. Processes sound signals from the ears.

Association Areas

Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking.