Psych Unit 3

A nerve cell/neuron

A nerve cell/neuron

the basic building blocks of the nervous system. We have tens of billions of neurons in the human brain. Neurons transmit messages when stimulated by signals from our senses or when triggered by a chemical signal from a neighboring neuron

How a neuron works

• Dendrites receive neurotransmitters

• They send the info to the cell body

• The cell body sends it to the axon, which has a myelin sheath (insulating fatty layer that speeds transmission)

• The info travels to axon terminals

• The terminals release the info to other neurons

• The process is repeated

Types of neurons

Sensory Neurons Motor Neurons Interneurons

Sensory Neurons (afferent)

Take information from the senses to the brain. Ex: pencil poke game with the arm

Interneurons

Shortcut/reflex. They make it to the brain eventually but the spinal cord processes them first. Ex: when the doctor hits your knee with a hammer and it moves.

Motor Neurons(Efferent Neurons)

Take information from brain to the rest of the body. Ex: you stub your toe, so your brain sends pain signals to your toe

How a Neuron Fires

It is an electrochemical process. A neuron fires an impulse when it receives a signal from a sense receptor (pressure, heat) or when stimulated by chemical messages from neighboring neuron This impulse is called the action potential, and is a brief electrical charge that travels down the axon

The All-or-None Response

• The idea that either the neuron fires or it does not

• There is no part-way firing.

• Like a gun

• A tap is differentiated from a punch bc more neurons will fire or fire more quickly

refractory period

a period of inactivity after a neuron has fired. Just like how you can't flush a toilet twice in a row

Steps of Action Potential

• Dendrites receive neurotransmitter from another neuron across the synapse (the small gap between two neurons, where nerve impulses are relayed)

• Reached its threshold(is there enough there to fire)- then fires based on the all-or-none response.

• Opens up a portal in axon, and lets in positive ions (Sodium) which mix with negative ions (Potassium) that is already inside the axon (thus Axon is negative at rest). Because potassium is inside and sodium is outside. The mixing of + and - ions (called depolarization) causes an electrical charge that opens up the next portal (letting in more Na) while closing the original portal. The time it takes for the negative ions to recharge is the refractory period.

• Process continues down the axon to the axon terminals.

• Terminal buttons turn electrical charge into chemical (neurotransmitter) and shoot the message to the next neuron across the synapse.

how neurons communicate

axon terminals release neurotransmitter from sacs called vesicles, neurotransmitter enters synapse, neurotransmitter binds to receptors that it fits then reuptake: where the sending neuron absorbs excess neurotransmitters molecules (they make more neurotransmitters than they need)

Acetylcholine (ACh)

MUSCLE ACTION, LEARNING

Enables muscle action, learning, and memory. With Alzheimer's disease, ACh-producing neurons deteriorate.

Dopamine

PLEASURE

influences movement (more involuntary like tremors), learning, attention, and emotion. Oversupply linked to schizophrenia. Undersupply linked to tremors and decreased mobility in Parkinson's disease

Serotonin

DEPRESSION

Affects mood, hunger, sleep, and arousal. Undersupply linked to depression. Some antidepressant drugs raise serotonin levels.

Norepinephrine

helps control alertness and arousal; undersupply can slow you down and decrease your alertness

GABA (gamma-aminobutyric acid)

CALMING

A major inhibitory neurotransmitter. Undersupply linked to seizures, tremors, and insomnia.

Glutamate

MEMORY

A major excitatory neurotransmitter; involved in memory. Oversupply can overstimulate the brain, producing migraines or seizures (which is why some people avoid MSG in food)

Agonists

drugs that increase the action of a neurotransmitter, acts like a neurotransmitter

Antagonists

drugs that block the function of a neurotransmitter

Central Nervous System (CNS)

brain and spinal cord

peripheral nervous system

the sensory and motor neurons that connect the central nervous system to the rest of the body

Somatic nervous system (part of the peripheral)

controls voluntary movements of skeletal muscles

autonomic nervous system (part of the peripheral)

Automatic actions of your organs and glands

sympathetic (part of the peripheral)

arousing Ex: fight or flight

Parasympathetic (part of the peripheral)

calming

Neural network

fire together, wire together

refers to interconnected neuron cells that work together as a team. The brain learns by modifying certain connections in response to feedback

endocrine system

Secretes hormones

Slower than neurotransmitters, but last longer. They are transmitted through blood.

Ex: your friend steps on your foot, your neurotransmitters give you immediate pain, but you feel anger towards your friend slightly after and it lasts for a few minutes

Thalamus

sensory switchboard, processes every sense other than smell

Medulla

controls heartbeat and breathing

Brainstem

oldest part of the brain, newer parts are built on top of this, automatic survival functions

Reticular formation

controls arousal

Cerebellum

Processes coordinates voluntary movement and balance

Amygdala

FEAR AND AGRESSION

linked to emotion

Hippocampus

learning and memory

Hypothalamus

brain region controlling the pituitary gland reward center, hunger, thirst, sexual arousal

pituitary gland

Master gland, works with hypothalamus

cerebral cortex

Outside of the brain, control an information-processing center of the brain

Cerebrum

beefy portion of the brain

frontal lobe

higher order thinking (what makes us human)

parietal lobe

receives sensory input for touch/body position

occipital lobe

receives visual information

temporal lobe

receives auditory information

motor cortex

left hemisphere section controls movement of the right side of the body and right hemisphere section controls movement of left side of the body

sensory cortex

area at front of parietal lobe that registers and processes the senses

association areas

not included in primary motor or sensory function, but involved in higher mental functions

Wernicke's Area

language comprehension. Carl Wernicke established it

Broca's area

controls speech. Paul broca established it

Plasticity

brain's ability to reorganize itself, higher in younger people to overcompensate for damage

corpus callosum

connects the left and right brain hemispheres half way down

might be severed because of frequent seizures (epilepsy)

Opposite hemispheres

• control opposite sides of the body- Right side/Right visual field → left hemisphere- Left Side/Left Visual Field → Right hemisphere

Left hemisphere

Analytical thoughts Math/ScienceLanguage/Speech Controls more important functions than right hemisphere controls speech brocas area

Right hemisphere

Emotion Artsy facial recognition

biological psychology

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

neuron

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

limbic system

EMOTIONS

neural system composed of the hippocampus, amygdala, and hypothalamus

endorphins

pain control and pleasure. Ex: will help soothe a runner's achy muscles

nerves

bundled axons that form neural "cables" connecting the central nervous system with muscles, glands, and sense organs

Reflex

an automatic response to a sensory stimulus

Hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

adrenal glands

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

Lesion

tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue

Electroencephalogram (EEG)

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

Ex: may help identify the cause of certain symptoms - such as seizures or memory problems

CT

a series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body

Ex: to assess brain tumors

PET scan

a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task. Basically shows pathway

Ex: looks for disease or injury in the brain

MRI

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

Ex: look for bleeding and swelling in the brain

fMRI (functional MRI)

A technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function.

glial cells (glia)

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

may play a role in learning and thinking

somatosensory cortex

area at the front of the parietal lobes that registers and processes body touch and movement sensations

neurogenesis

the formation of new neurons

split brain

a condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them

cognitive neuroscience

study of the brain activity linked with cognition (including perception, thinking, memory, and language)

behavior genetics

the study of the relative power and limits of genetic and environmental influences on behavior

environment

every external influence

genome

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

identical twins

twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms. monozygotic, same-sex only

fraternal twins

twins who develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment. same or opposite sex. dizygotic

molecular genetics

the subfield of biology that studies the molecular structure and function of genes

Heritability

The proportion of variation among individuals that we can attribute to genes. ex: height has a 90% heritability score

interaction

the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity)

Epigenetics

the study of environmental influences on gene expression that occur without a DNA change

evolutionary psychology

the study of the evolution of behavior and the mind, using principles of natural selection

who we share dna with

share 96% of dna with gorillas share 99.9% with other humans

1959 Russian Fox story

30 males, 100 females mated, then kept only tamest of bunch. mated the tame bunch. 40 years later, new breed of fox

Why is casual sex more accepted by men? (when avg women and men asked strangers for sex tn, 75% of men agreed, almost no women)

sperm is cheap, eggs are not

What do men want?

healthy, young, waist 1/3 narrower than hips

what do women want?

wealth, power, security

twin studies

dr. bouchard, whether or not they are raised in same environment, they are very alike in many ways

placental arrangement

can determine how similar twins are

• most of the time they share a placenta

• 1/3 of the time, two separate placentas, can create differences, one can get more nutrients than the other

Roger Sperry

In the early 1960s, Sperry and colleagues, including Michael Gazzaniga, conducted extensive experiments on an epileptic patient who had had his corpus collosum, the "bridge" between the left and right hemispheres of the brain, split so that the connection was severed

Michael Gazzaniga

worked w sperry studied split brain patients; showed that left/right hemispheres have different functions

superchiasmatic nucleus

group of neurons in hypothalamus that makes us drowsy at different times of the day/night

William James

thoery of emotion. emotion arises in response to external events

Ernest Hilgard

believed hypnosis invovles not only social influences but also a special state of dissociation

Types of environmental influence

• parents

• prenatal

• experience

• peer influence

• culture

• gender

PPEPCG

as we age

IQ becomes more aligned w bio influence, less w the environment