baseline

Neurons

cells that are specialized for the reception, conduction, and transmission of electrochemical signals

Multipolar neuron

more than two processes extending from its cell body, most neurons are multipolar.

Unipolar neuron

with one process extending from its cell body.

Bipolar neuron

two processes extending from its cell body.

Interneurons

with a short axon or no axon at all, the ones in between their function is to integrate neural activity within a single brain structure, not to conduct signals from one structure to another

neuron cell membrane

is composed of a lipid bilayer (two layers of fat molecules)

Some membrane proteins are:

**Channel proteins**

**Signal proteins**

**Channel proteins**

certain molecules can pass.

Signal proteins

transfer a signal to the inside of the neuron

Gray matter

neurons

**white matter**

glial cells

__Oligodendrocytes and Schwann cells:__

Myelin

CNS and PNS.

__Microglia:__

Immune system responsibilities

Role in cell death, synapse formation, and synapse elimination.

__Astroglia:__

Support and provide nourishment

Form blood-brain barrier

Send signals

Establish and maintain connections.

Action potential

an electrical charge that travels along the membrane of a neuron

**the all-or-none response**

either occur to their full extent or do not occur at all.

**Synapses**

contact between neurons where information is passed from one neuron to the next.form between axons and dendrites

Synapses consist of

consist of a presynaptic neuron, a synaptic cleft, and a postsynaptic neuron.

**axodendritic synapse**s

synapses of axon terminal buttons on dendrites.

**axosomatic synapses**

synapses of axon terminal buttons on somas (cell bodies).

**axoaxonic synapses**

can mediate presynaptic facilitation and inhibition. 

**Dendrodendritic**

connections between the dendrites of two different neurons.

**Dendroaxonic**

a dendrite communicates with axon (rare).

**Presynaptic Inhibition**

inhibitory neuron provides synaptic input to the axon of another neuron (axo-axonal synapse).

**Postsynaptic Inhibition**

postsynaptic receptors are attached to neurons. As a result, the postsynaptic neuronal membrane’s sensitivity to certain ions will be altered.

**directed synapses**

synapses at which the site of neurotransmitter release and the site of neurotransmitter reception are in close proximity.

**Nondirected synapses**

synapses at which the site of release is at some distance from the site of reception

**The vertebrate nervous system** includes

the **brain, brainstem, spinal cord, cranial and peripheral nerves, and ganglia.**

**The central nervous system** is composed of

two divisions: the brain and the spinal cord.

**Peripheral nervous system (PNS)**

is the division located outside the skull and spine. The peripheral nervous system is located outside the skull and spine.

**The somatic nervous system (SNS)**

is the part of the PNS that interacts with the external environment.

**SNS** is composed of

It is composed of afferent nerves that carry sensory signals from the skin, skeletal muscles, joints, eyes, ears, and so on, to the central nervous system and efferent nerves that carry motor signals from the central nervous system to the skeletal muscles. 

**The autonomic nervous system (ANS)**

is the part of the peripheral nervous system that regulates the body’s internal environment.

**ANS** is composed of

It is composed of afferent nerves that carry sensory signals from internal organs to the CNS and efferent nerves that carry motor signals from the CNS to internal organs. 

**The sympathetic nerves**

are autonomic motor nerves that project from the CNS in the lumbar (small of the back) and thoracic (chest area) regions of the spinal cord.

**The parasympathetic nerves**

are those autonomic motor nerves that project from the brain and sacral(lower back) region of the spinal cord.

**The cranial nerves**

include purely sensory nerves such as the olfactory nerves (I) and the optic nerves (II), but most contain both sensory and motor fibers. The longest cranial nerves are the vagus nerves (X), which contain motor and sensory fibers traveling to and from the gut. 

**Ganglia**

clusters of cell bodies in the peripheral nervous system.

**EEG**

signal reflects the sum of electrical events throughout the head. These events include action potentials and postsynaptic potentials as well as electrical signals from the skin, muscles, blood, and eyes.

**Magnetic resonance imaging (MRI)**

is a structural brain-imaging procedure in which high-resolution images are constructed from the measurement of radio-frequency waves that hydrogen atoms emit as they align with a powerful magnetic field.

**Functional MRI (fMRI)**

produces images representing the increase in oxygen flow in the blood to active areas of the brain. 

**Intracranial Recording**

used for decades in patients with epilepsy to localize the seizure onset zone, prior to brain tissue resection

**Antagonist**

drug that blocks a neurotransmitter (inhibits), decreases activity at a synapse (low affinity, low efficacy).

**Agonist**

drug that increases effects (facilitates), increases activity at a synapse (high affinity, high efficacy).

**Mixed agonist-antagonist**

agonist for some effects or doses and antagonist for others.

**Affinity**

tendency of a drug to bind to a receptor (varies from strong to weak).

**Efficacy**

drug’s tendency to activate/ stimulate the receptor.

**Parental alcohol use correlates**

with that of biological (stronger) and adopted children.

**Unstable environment**

increased if having a gene affecting serotonin synapses.

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**Prenatal environment**

Pregnant drinking alcohol = child likely to develop alcoholism, same in rats.

**People with early-onset alcoholism**

usually family history of alcoholism, genetic predisposition, rapid onset of the problem.

**Late-onset**

life difficulties, usually no history of alcoholism in family, respond better to treatment.

**Drugs affect synapses differently at diff. stages**

when its in the brain, during withdrawal and effects responsible for cravings

**Cocaine, amphetamine, sexual excitement**

increase or prolong the release of dopamine in nucleus accumbens 

**Alcohol, marijuana, nicotine**

non-stimulants increase dopamine release but not much. The amount of **produced dopamine doesn’t correlate with pleasure or probability of addiction**. 

**Cravings**

insistent search for the activity/ substance. Even after a long period of abstinence cues can trigger a craving.

**Tolerance**

decrease in effect of the drug; its learned and can be weakened through extinction procedures

**Withdrawal**

body’s reaction to the absence of drugs. Addictive behavior might be a way to avoid withdrawal symptoms or to cope with stress.

**Medications to combat alcohol use**

**Antabuse**

**Naloxone and naltrexone**

**Methadone**

**Buprenorphine and levomethadyl acetate (LAAM)**

**Antabuse** (disulfiram)

antagonizes the enzyme that metabolizes acetaldehyde = sickness after drinking; nausea-inducing drug to associate the two-learned aversion. 

**Naloxone and naltrexone**

block opiate receptors and decrease pleasure from alcohol

**Methadone**

similar to heroin and morphine, activates the same brain receptors and produces the same effects; it can be taken orally and it gradually enters the blood and brain avoiding the ‘rush’ which disrupts behavior 

**Buprenorphine and levomethadyl acetate (LAAM)**

long-lasting effects so people don’t have to go to the clinic daily but 3 times a week. People using them live longer and healthier that heroin/morphine users and can hold a job.

Major Depressive Disorder

extremely low mood for weeks, .

nucleus accumbens less responsive to reward

Feelings of worthlessness, sadness, suicidal thoughts, trouble sleeping. Low motivation, problems with attention, memory and impaired sense of smell

Report less number of pleasant experiences, reacted normally to sad/ frightening images but rarely smiled at comedies/ pleasant pictures

Depression more common in women during

during reproductive era

**moderate heritability**

for depression

Depression could be an

**evolutionary adaptation**

Early onset depression (before 30 yo):

likely to have relatives with depression, anxiety disorders and etc.More severe, long-lasting and more associated with suicidal tendencies

Late onset depression (especially after 45-50)

likely to have relatives with circulatory problems.

**Serotonin transporter gene**

a protein that regulates the ability of axons to reabsorb serotonin after its release.

**People without depression**

increased activity in the left prefrontal cortex.

**Depressed people** – higher activity in

the right prefrontal cortex

**Iproniazid**

first antidepressant drug, it was firstly used to treat tuberculosis then they found out it works for depression.

**Chlorpromazine**

used to treat schizophrenia.

**Tricyclics**

__block the transporter protein__ that reabsorb **serotonin**, **dopamine** and **norepinephrine** into the presynaptic neuron. 

**Tricyclics** also block

block **histamine** and **acetylcholine** receptors, and certain sodium channels.

**Serotonin reuptake into presynaptic neuron**

serotonin transporter protein open to the outside of the neuron. Then it picks the molecule and flips position to the inside (tricyclics and SSRI lock the protein in position on the left):

**SSRI**  

selective serotonin reuptake inhibitors; similar to tricyclics but specific to neurotransmitter serotonin.

**SSRI**  meds

Fluoxetine (Prozac)

Sertraline (Zoloft)

Fluvoxamine (Luvox)

Citalopram (Celexa)

Paroxetine (Paxil/ Seroxat)

**SNRI**

serotonin norepinephrine reuptake inhibitors; block serotonin and norepinephrine reuptake. Improve memory, many patients take two or more drugs with different mode of action.

**SNRI** meds

Duloxetine (Cymbalta)

Venlafaxine (Effexor)

**MAOIs**

monoamine oxidase inhibitors; they **block** the enzyme **monoamine oxidase.**

MAO:

presynaptic enzyme that metabolizes catecholamines (dopamine, norepinephrine) and serotonin into __inactive chemicals__

**Atypical antidepressants**

other types f. ex. Bupropion which reuptake of dopamine and norepinephrine but not serotonin. 

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**Possible antidepressants:**

**Ketamine**,**St. John’s wort herb**

**Ketamine**

antagonizes NMDA type glutamate receptors; forms new synapses, rapid effects in patients who don’t respond to other medications.

People with depression have lower

have lower **brain-derived neurotrophic factor (BDNF)**

**brain-derived neurotrophic factor (BDNF)** - important for

important for __**synaptic plasticity**__,

**Positive symptoms**

behaviors that are present that should be absent

**Negative symptoms**

behaviors that are absent that should be present

**Causes of schizophrenia**:

Genetics, Prenatal and Neonatal Environment, Mild Brain Abnormalities

**Genetics-**schizophrenia

schizophrenia does not depend on any single gene.

Microdeletion

deletion of a small part of a chromosome, more common among ppl with schizophrenia

prenatal influence – women with schizophrenia often

often abuse drugs, alcohol, eat a poor diet and have complications during pregnancy and delivery.

environmental influences – higher probability for schizophrenia if

if a mother has the disease **and** the child is in a dysfunctional adopting family.

schizophrenia treatment

Chlorpromazine

Phenothiazines

Butyrophenones

**Temporal lobe**

learning, advanced visual processing

**Occipital lobe**

vision

**Postcentral gyrus**

primary somatosensory cortex 

**Parietal lobe**

body sensation