endogenous chemicals that transmit signals from a neuron to a target cell across a synapse

• stored in vesicles
• Released neurotransmitter molecules bind with autoreceptors and inhibit subsequent neurotransmitter release
• bind to postsynaptic receptors
• deactivated either by reuptake or enzymatic degradation

• cholinergic neurons located in CNS and PNS
• most common neurotransmitter in PNS
• usually excitatory

  agonist = nicotine

  antagonist = curare

used on poison arrows

Glutamatergic neurons located throughout CNS

•   most common excitatory neurotransmitter

postsynaptic receptors

• agonist = AMPA

    ionotropic receptor opens Na+ channel  (i.e., causes EPSP)

agonist = NMDA

  antagonists = alcohol, PCP (hallucinogen)

•   ionotropic receptor opens Na+/Ca++ channel (i.e., causes EPSP)
• Ca++ = 2nd messenger
• important for learning

• GABAergic neurons located throughout CNS
•   most common inhibitory neurotransmitter in CNS

• ionotropic receptor opens Cl- channel
•    (i.e., causes IPSP)

•  calming effect
  
•  benzodiazepines (e.g., valium, rohypnol)
•   barbiturates (e.g., sleeping pills)
•  alcohol
• steriods
  

• picrotoxin
•   inhibits GABAA, can cause seizures

• Glycinergic neurons
• most common inhibitory neurotransmitter in PNS 
• lower brain and spinal cord

inhibits synaptic release of glycine

• muscles become rigid -- i.e., lockjaw   
• also inhibits GABA release

• antagonist of glycine
• causes convulsions, death

catecholamines:

• dopamine
• norepinephrine
•   epinephrine

indolamines

• serotonin

Dopaminergic neurons located in brain stem, and send axons to:

  • the limbic system (reinforcement/reward)

  • the prefrontal cortex (memory/cognition)

  • the basal ganglia, from the substantianigra (motor control)

  pathway damaged in Parkinson’s disease; symptoms relieved with L-DOPA

reuptake blocked by

  cocaine, amphetamine (stimulants, such as methamphetamine), and

  methylphenidate (Ritalin)

Noradrenergic neurons

•   located in brain stem, with axons projecting throughout brain
• regulate vigilance & attention

• chlorpromazine, clozapine
•   alleviate symptoms of schizophrenia
•   hallucinations, delusions, illogical thought

• hormone from adrenal glands on the kidneys
• serves minor role as NT in brain

• found in terminal buttons
• regulates production of catecholamines (DA and NE)

destroys MAO-B found in DA neurons

• serotonergic neurons

  located in brain stem

  -axons project widely throughout brain

  -involved in regulation of mood, eating,   sleep, dreaming, pain

• reuptake inhibited by SSRIs

   (serotonin-specific reuptake inhibitors)

    fluoxetine (Prozac, for depression)

    fenfluramine (appetite suppressant)

• MDMA (Ecstasy)  

• discovery of acetylcholine
• identified adrenaline as a nervous system transmitters, and noradrenaline as the most important neurotransmitter

• major cholinergic output of the central nervous system (CNS)
• important in the production of acetylcholine

a string of nuclei in the midline of the midbrain and brainstem that contain most of the serotonergic neurons of the brain

produces serotonin

short-term effects of ecstacy on serotonin

  • inhibiting serotonin reuptake

  • increasing release of serotonin (reverses the serotonin reuptake transporter)

•   causes a depletion of serotonin that can take weeks to restore
• often experience a period of depression and memory disruption after use

• long-term damage to serotonergic neuron
• axonal withering
• followed by abnormal regrowth (or none at all)

• Made of two or more linked amino acids
• Endogenous opioids (“like opium produced within”) involved in pain regulation, reinforcement (reward)

• opium (derived from poppies), morphine, heroin, OxyContin 

• naloxone
• blocks opiate receptors
• used to treat a heroin overdose

• Released from postsynaptic cell & regulate
• release of neurotransmitter from presynaptic cell
• Endogenous cannabinoids increase dopamine release

    • agonist = THC (marijuana)

• diffuses across cell membrane w/o vesicle or active transport

• learning, blood vessel dilation, control of involuntary muscle

• Process by which information (energy) in the environment is converted to information (energy) in the nervous system

caused by sudden release of inhibition from neighboring cells

• the cell overcompensates for release of surrounding inhibition

• wavelength = hue/color
• Amplitude = brightness

for their work in understanding how neurons in primary visual cortex represent the world

sparks = scientists that favored the idea that electrical signals crossed synapses

soups = scientists that though neurons released a chemical that flowed across synapses

central portion of retina, pakced with highest density of photoreceptors, center of our gaze

smaller cones

a photoreceptor cell in the retina that is most active at low levels of light (night)

located outside fovea, high sensitivity, stimulated by weak light intensity, slow reponse time

any of several classes of photoreceptor cells in the retina that are responsible for color vision

concentrated in and near fovea, low sensitivity, needs relatively strong stimulation

relatively rapid response time

the portion of the visual field from which light falls on the optic disc

because there are no receptors in this region, light striking the blind spot cannot be seen

a hypothesis of color perception stating that there are three different types of cones, each excited by a different region of the spectrum and each having a separate pathway to the brain

Helmholtz - blue, green, red

a hypothesis of color perception stating that different systems produce opposite responses to light of different wavelengths

Hering - blue, green, yellow, red and opposed pairs of colors

a hormone produced by male gonads, that controls a variety of bodily changes that become visible at puberty

changes in voice, hair growth, genital size

female gonads, produces eggs for reproduction

hormone secretion more complicated, produced in cycles, about 4 weeks

a duct system in the embryo that will develop into male reproductive structures if testes are present in embryo

a duct system in the embryo that will develop into female reproductive structures if testes are not present in embryo

inhibited by anti-mullerian hormone - protein hormone secreted by fetal testes

a gene on the Y chromosome that directs the developing gonads to become testes

sex determining region on the Y chromosome

a condition in which an apparent female has underdeveloped but recognizable ovaries

carrying a single X chromosome