Psych midterm 2

Neurons

They all have same structure but vary in function and by location in the nervous system

Gilal Cells

digest dead neurons, physical and nutritional support and form more myelin

Purkinje Cells

Interneuron that carries information from the cerebellum to the rest of the brain and spinal cord

Pyramidal cells

In the cerebral cortex and have a triangular cell body and a single long dendrite with little smaller dendrites. Ex: hippocampas pyramidal

Bipolar cells

in the visual pathway. Type of sensory neuron in the retina of the eye and have a single axon and a single dendrite

Mirror neurons

Found in the frontal and parietal lobes of animals. Makes you want to copy actions and involved in empathy. Important for understanding brains role in complex social behavior

Lacoboni

conducted an fMRI study to show that mirror neuron response and intention behind actions.

ASD

disorder where you struggle with interpretation of others’ behaviour, not the recognition of it.

Resting potential

There's a lot of Na+ and Cl- outside. There are also negatively charged protein ions inside cell membrane compared to outside. K+ channels are open to allow them to leave to keep the electrochemical difference negative. (sodium channels are closed)

Action potential

An electrical signal that is always of the same magnitude and same characteristics. When threshold is reached, K+ closes and Na+ opens. Allowing them to flow in to raise the charge difference. When max value of +40mv, K+ gates open to let it exit the cell. There is now excess Na+ inside and K+ outside, and protein pump starts.

Refractory period

period of time where action potential cannot be initiated. ‘Pump” moves sodium outside and potassium inside to rebalance

How does action potential move down the ion

Spreads a short distance and generates an action potential at a nearby location. Regardless of distance travelled, it achieves its full intensity.

Autoreceptors

detect how much of a neurotransmitter has been released into synapse and signal the neuron to stop releasing neurotransmitters when an excess is present

Reuptake

neurotransmitters are reabsorbed by the terminal buttons of the presynaptic neurons axon

enzyme deactivation

neurotransmitters are destroyed by enzymes in the synapse

Acetycholine

(ACh) is involved in voluntary motor control, attention, learning and memory(cognitive processes). Alzheimers is when neurons front produce this

Glutamate

Major excitatory neurotransmitter involved in information transmittion. Too much of this causes seizures.

GABA

inhibitory neurotransmitter. Calms the system down and reduces anxiety, promiting sleep.

Dopamine

(DA) regulates motor behavior, motivation, pleasure and emotional arousal. Involved with addicton and schizophrenia if you have too much of it. Parkinson’s is when you dont have enough.

Norepinephine

(NE) influences mood and arousal and is responsible for the fight or flight mechanism.

Serotonin

(5-HT) involved in regulation of sleep and wakefulness. Eating and aggressive behavior as well.

Endorphins

Prevents pain and emotion centers of the brain. Involved with Runner’s high. Morphine works on endorphins

Drug types

Agonists which increase action of neurotransmitters and antagonist drugs that block the function of neurotransmitters. By binding

L dopa

developed to treat parkinson’s. Dopamine is created in neurons by modification of L dopa.

Ingesting this causes neurons to produce more dopamine(agonist). effectiveness decreases over time.

Amphetamine and cocaine

stimulate release and prevents reuptake of norepinephrine and dopamine. Taking this can cause you to make new receptors

CNS vs PNS

1. Brain and spinal cord. 2.Connects CNS to bodys organs and muscles

somatic

conveys information in and out of CNS. Voluntary muscle

autonomic

involuntary and unconscious processes.

Sympathetic and parasympathetic

branches of autonomic. Fight or flight and resting state

Sympathetic processes

Dilates pupils, relaxes bronchi, accelerates heartbeat, inhibits digestion, stimulates glucose release, stimulates secretion of epinephrine, relaxes bladder, stimulates ejaculation in male

Parasympathetic processes

contract pupil, constricts bronchi, slows heartbeat, stimulates digestive activity, stimulates gallbladder, contracts bladder, allows blood to flow to sex organs

Spinal reflex

simple pathway in the nervous system that rapidly generates muscle contractions. Reflexes goes to interneurons in the spinal cord and doesnt pass through the brain

Spine damage

damage higher up impacts the pathway earlier on so it usually causes greater damage.

Hind brain

Is continuous with the spinal cord. Coordinates information coming in and out of the spinal cord.

-Cerebellum: fine motor skills and balance.

-Pons: relays information from cerebellum to rest of brain(bridge).

-Medulla: heart rate, circulation and respiration.

-Reticular formation: sleep, wakefulness and arousal. anaesthetics work on this

Midbrain

-Tectum: orients an organism in the environment. Receives information from eyes ears and skin.

-Tegmentum: involved in movement and arousal also involved in orientation.

The forebrain

highest level of brain

1. cerebral cortex

2.subcortical structures(thalamus, hippocampus, hypothalamus, amygdala and pituitary gland)

Thalamus

relays and filters info from all senses(expect smell) and transmits to cerebral cortex

-filting includes paying attention to select things

-closes pathway during sleep

-thalamic syndrome= painful touch

Hypothalamus

regulates body temp, hunger and other drives

-lesioning leads to over or undereating

-electrical stimulation causes aggressive behavior or intense pleasure(cat example)

Hippocampus

creates NEW memories and integrates them into rest of cortext. Damage can lead to amnesia, can still ride a bike if they learnt but doesnt remember learning if it was after injury.

Aymugdala

Related to PTSD. attaches significance to previously neutral events. Implicated in anxiety and formation of memories through emotion—> works with hippocampus

Limbic system

Includes hypothalamus, hippocampus, amygdala. where stuctures meet in cerebral cortex

Basal Ganglia

Set of subcortical structures that directs intentional behaviour. Receives input from cerebral cortex and sends output to motor centers.

Striatum

involves in posture and movement. Also concentrated dopamine there so parkinsons is depletion of dopamine in the striatum.

Endocrine system

Works with limbic to regulate thoughts emotions and behaviours

-Pituitary gland: releases hormones

-Thyroid: regulates bodily functions(heart rate ex)

-Adrenals:stress

-pancreas:digestion

-Pineal gland:secretes melatonin

Texture of brain

Gyri: Raises smooth parts(aka folds)

Sulci: Indentation or fissures(aka wrinkles)

Corpus callosum

this and commissures(bundle of axons) connects areas of the cerebral cortex and help communicate between eachother

occipital lobe

sensory receptors send info to thalamus then to occipital in a map format. Damage causes blindness because it wont process info(it will still enter ur eye and thalamus)

Parietal Lobe

contains somatosensory cortex: a strip of brain tissue running from top to the sides. Larger=more sensitive part

In front of it is motor cortex(initiates voluntary movement)

Temporal lobe

hearing and language.

-Primary auditory cortex: sensory information from ears based on frequencies of sounds

-Visual Association Areas: interpret the meaning of visual stimuli (recognize objects)

Frontal Lobe

For executive function. Specialized for movement, thinking and planning. Contains most dopamine sensitive neurons.

Brain Plasticity

Brain can adapt to changes in sensory input. Higher levels on input in your fingers result in more space on motor or sematosensory cortex. Phantom limb syndrome: body compensates.(mirror box treatment)

Phineas Gage

Big metal rod went through his head and personality changed post accident.(affected connections between frontal and subcortical structures)

Split brain procedure

In these patients info presented to left hemisphere can be describes verbally (language is in one side, and both sides to not communicate)

Wada Test

AKA intracarotid sodium amobarbital procedure(ISAP)

-used to determine which hemisphere language is located in before surgery to not affect it.

Hemispatial Neglect

stoke in the right hemisphere is followed by ignorance of left side of the body(only shave half of your face)

Structural Brain Imaging

-CT scan: series of x-ray photos shows density of tissue, located humors(shows up dark)

--MRI: magnetic pulses absorbed by brain. Better resolution of soft tissue than CT

-Diffusion Tensor Imaging: type of mri used to map connectivity

EEG

-records electrical activity in synapse and action potential

-Neurofeedback=real time display of brain activity

Functional Brain Imaging

PET: radioactive substance injected in blood

fMRI: detects oxygenated hemoglobin(more sensitive than PET)

TMS

Magnetic pulse passes through skull to investigate brain and briefly deactivates neurons in cerebral cortex.

-Established causality in brain

Monozygotic twins

share 100% of their genes rather than dizygotic share 50%

Epigenetics

Epigenetic Marks

chemical modifications to dna

-DNA methylation: turns off expression (you can have the gene but not expressed

-Histone modification: turn gene on or off

Heritability

if its 0 then genes to not contribute to that behaviour, if its 100, gene is the only reason for that behaviour or difference in an individual

Transduction

many sensors convert that stimuli into neural signals and sends to CNS (sensation to perception)

Synesthesia

when one sense envokes more than one perceptual experience. ex: tasting colours when u see them. proved my fMRI(cross-activation in the brain)

Sensory adpatation

if there is unchanging constant stimulation, sensitivity declines

Psychophysics

methods that measure the strength of stimulus and the observers sensitivity to it.

Developed my Gustav Fechner. ex: did u see that flash of light

(was the stimulus strong enough to reach your treshhold)

Absolute threshold

minimal intensity needed to just barely detect a stimulus. Defines as loudness when stimulus is perceived 50% of the time

Weber’s Law

the JND of a stimulus is a constant proportion regardless of the intensity of stimulus. (just noticeable difference of weight is 2-3% regardless of the initial weight)

Signal detection theory

response to stimulus depends on persons’ sensitivity and presence of noise

Snellen chart

means of assessing visual acuity(ability to see fine detail)

Wavelengths

Length is distance between crest and crest of trough and trough(hue or colour).

Amplitude is height(brightness).

Purity is the level of saturation

Accomodation

muscles move to move cornea. Nearsighted see nearby and farsighted see from far and image is beyond the retina

3 major cone types

s-cones: respond best to short wavelengths(blue)

M-cones: best to medium(green)

L-cones: best to long(red)

trichromatic colour representation

how each cone responds provides a unique code for each colour.

One cone not working leads to colour deficiency

Colour opponent system***

pairs of visual neurons work in opposition(red against green sensitive)