Honors Psychology Test - The Brain

Nervous System

• directs thinking, feeling, and movement

Sympathetic: arouses the body (fight-or-flight)

Parasympathetic: calms the body (rest-and-digest)

Central Nervous System:

• brain + spinal cord

Peripheral Nervous System:

• nerves linking CNS with body

Somatic Nervous System:

• voluntary movements, sensory signals

Autonomic Nervous System:

• automatic functions (heart, breathing, digestion)

Sympathetic:

Parasympathetic:

• arouses the body (fight-or-flight)

• calms the body (rest-and-digest)

Endocrine System

• glands release hormones into blood to influence growth, mood, metabolism, stress, and sex drive

• Key Hormones: testosterone, estrogen, progesterone, adrenaline

How many neurons are there in the brain?

• 100 billion

  • they are supported by glial cells, which feed, protect, and insulate neurons

Parts of a Neuron

Cell Body: contains nucleus, keeps cell alive

Dendrites: receive incoming messages

Axon: sends messages away

Myelin Sheath: fatty insulation that speeds signals

Axon Terminals: release neurotransmitters into the synapse

Synapse: small gap between neurons where messages are passed

Action Potential: an electrical impulse that travels down the axon. “All-or-None” - it fires or it doesn’t

Myelination: fatty substance that covers neurons

Neurotransmitters

• chemicals that are stored in sacs in the axon terminals, used to send messages across the synapses

• Each kind of neurotransmitter acts on its own kind of receptor on the next neuron, crossing the synapse and binding receptors in the next neuron, fitting like a key into a lock

• Can excite (increase activity) or inhibit(decrease activity)

• Reuptake: neurotransmitters are reabsorbed after use.

• Many drugs change brain chemistry by blocking, mimicking, or boosting neurotransmitters

• everything you put in your body affects your neurochemistry

Major Neurotransmitters

Dopamine: reward, motivation, movement. Low: Parkinson’s, lack of drive. High: schizophrenia

Serotonin: mood, sleep, appetite, well-being. Low: depression, anxiety

Norepinephrine(Noradrenaline): alertness, arousal, fight or flight. Imbalances lead to anxiety, attention issues

Epinephrine(adrenaline): stress response, energy, metabolism

Glutamate: main excitatory transmitter, learning and memory. Excess: migraines, seizures.

GABA: main inhibitory transmitter, calms brain, reduces anxiety

Endorphins: natural painkillers, increase pleasure and mood

Histamine: wakefulness, immune response, and arousal

Stress Portrait of a Killer: In nature, what is the adaptive/evolutionary purpose of the stress response for animals?

• They stress about saving their lives from predators

  • Adrenaline, hyperventilate, heart pounds, muscles tense, stress + hierarchy in baboons; baboons are horrible to each other

• a baboon’s rank determines their stress levels

Stress Portrait of a Killer: How is the stress that modern day humans deal with so different than that of our ancestors?

• we stress about being in traffic, speaking in front of a crowd

• we are always stressed out

• ancestors were threatened by animals and other dangerous forces - stress response - best chance at survival

Stress Portrait of a Killer: How can stress be a positive force?

• surviving a crisis - adrenaline and glucocorticoids can save your life.

Stress Portrait of a Killer: How does one’s status in society tend to impact stress levels?

• rank determine stress levels

• people lower on the hierarchy were more prone to health issues due to stress

Stress Portrait of a Killer: How has modern research changed our understanding of ulcers

Stress - ulcers,

• researchers in the 80’s identified a bacterial infection was the major cause of ulcers.

• Stress did not cause ulcers

• 2/3 of the worlds population have this bacteria

• immune system is hurt by stress - it wipes out the ability to heal stomach from bacteria

Stress Portrait of a Killer: what parts of the body are damaged by chronic stress?

• artery walls

• stress can lead to a heart attack

• clog arteries, restricted blood flow

Stress Portrait of a Killer: what impact does stress have on the brain, specifically?

• kills some of your brain cells

• stressed brain cells are dramatically smaller

• Chronic Stress - change brain circuits - affects memory

• Acute Severe Stress - stress makes you “stupid” - affects learning

• stress makes us miserable

Stress Portrait of a Killer: How does chronic stress impact body weight and shape?

• distribution of weight - position in the hierarchy

• stress changes the way you deposit fat on your body

• fat brought on by stress is dangerous fat

• we need to value stress reduction

Stress Portrait of a Killer: How does stress impact our chromosomes?

• we have 46 chromosomes

• the length of the telomere directly relates to the amount of stress

• discovered enzyme that can repair damage

• stress may damaged us long before we are aware

• babies who were alive during the dutch hunger winter are more likely to have high cholesterol, stress levels, etc

Stress Portrait of a Killer: other important notes

• its not just your rank, its what your rank means in society

• control can be an ancedote to stressn- in your life

• give people more involvement in work, more say in work, more collaboration - healthiar and more productive work envior

Medulla

• Located at the base of the brainstem, governs basic autonomic life-support functions - brain and spinal cord connect

• A key conduit for nerve signals to and from your body

• Helps to control vital processes like your heartbeat, breathing, and blood pressure

• Severe trauma to this area compromises involuntary breathing, heart rate control, and vital reflexes, necessitating mechanical life support

Nucleus Accumbens

• Serves as a major hub in the brain’s reward pathway, utilizing dopamine to process pleasure and motivation.

• Damage to this center leads to anhedonia: the inability to experience pleasure or motivation from previously rewarding stimuli

Pons

• a major structure in the lower brainstem that acts as a vital communication bridge between the cerebrum, cerebellum, and spinal cord

• a key merging point for several of your cranial nerves, which are nerves with direct connections to your brain

• they help with several of the senses on or in your head, plus your ability to move various parts of your face and mouth

• if damaged, it can disrupt vital functions like movement, breathing, consciousness, and cranial nerve control

Cerebellum

• coordinates voluntary movements, posture, balance, and motor precision

• Damage results in ataxia: clumsy, slow, and uncoordinated physical movements

Reticular activating system

• runs through the brainstem and regulates arousal, alertness, and consciousness

• disruption to this network prevents wakefulness and sleep-wake regulation, frequently causing a deep coma

Thalamus

• acts as the central sensory relay station, routing tactile, visual, auditory, and gustatory data to the cortex.

• sensory input from the right side of the body passes through the left thalamus, smell is the only sense that bypasses this relay entirely

• damage will disrupt the brains main relay station. for sensory and motor signals, leading to wide-ranging physical, cognitive, and neurological effects

Hypothalamus

• the ventromedial region serves as the brains “satiety center,” signaling to the body when it is full

• damage to this structure disrupts fulness cues., leading to hyperphagia (uncontrolled, continuous eating)

Hippocampus

• is essential for consolidating short-term memory into long term declarative memories

• damage prevents the formation of new memories (anterograde + amnesia), causing patients to experience repeated encounters as completely new events

Amygdala

• processes emotional reactions, particularly fear, threat detection, and social evaluation of facial expressions

• damage to this region impairs fear conditioning, leaving individuals unable to feel fear or recognize fearful expressions in others

Corpus Callosum

• bridges communication between the left and right cerebral hemispheres

• disruption of interhemispheric transfer can cause alien hand syndrome, where one hand (often the non-dominant left hand controlled by the right hemisphere) performs autonomous actions outside the person’s conscious control

Occipital Lobe

• the primary visual cortex is required for conscious visual awareness

• damage here produces cortical blindness, but undamaged subcortical pathways allow patients to unconsciously navigate around obstacles

Temporal Lobe

• the primary auditory cortex processes sound and auditory signals

• internal damage or abnormal neural firing in this structure can generate auditory hallucinations without external sound or undamaged ear structure

Frontal lobe and prefrontal cortex

• manages executive functioning, including impulse control, emotional regulation,and social appropriateness

• damage impairs inhibition, leading to inappropriate outbursts, loss of social filters, and aggressive behaviors

Motor cortex

• receives information from various lobes of the brain and uses it to carry out body movements like playing the piano, blowing a kiss, and skipping

• damage can disrupt voluntary movement control, typically causing weakness or paralysis on the opposite side of the body

Paretial Lobe

• plays a major role in spatial awareness and orienting attention to the opposite side of space

• damage to this area causes hemispatial neglect, where patients fail to perceive, attend to, or acknowledge sensory input on the left side of their body and environment

Somatosensory cortex

• maps tactile and sensory sensations from specific regions across the body.

• -Following an amputation, cortical remapping in this sensory map can cause phantom limb sensations, making the patients perceive pain or touch in a missing limb

Broca’s Area

• coordinates the precise motor planning and articulation required for fluent speech production

• minor damage or altered motor pathways can affect speech timing, intonation, and rhythm, resulting in Foreign Accent Syndrome

Olfactory Bulb

• receives direct sensory input from nasal receptors to process smell

• damage to this pathway causes anosmia (loss of smell), which also dramatically reduces flavor perception because taste heavily relies on olfaction

Wernicke’s Area

• located in the left temporal lobe, is responsible for comprehending spoken and written language

• damage causes receptive aphasia where speech remains fluid in rhythm but loses meaning, making language sound garbled and uninterpretable

Pituitary Gland

• is the master endocrine gland that secretes essential hormones, including growth hormone

• tumors in this gland can cause excessive growth hormone secretion, resulting in physical overgrowth (gigantism/acromegaly) and endocrine imbalances

Pineal Gland

• responds to environmental light changes by secreting melatonin to regulate circadian rhythms.

• damage or surgical disruption prevents melatonin secretion, impairing sleep-ake cycles, and causing severe insomnia

Basal Ganglia

• it has six structures: the caudate nucleus, putamen, nucleus accumbens, globus pallidus, and substantia nigra

• processes movement-related information and information related to emotions, motivations, and cognitive functions

• damage can cause disorders that influence movement like parkinson disease, huntington disease, and dystonia

Left Vs. Right Brain Differences

• The left side of the brain controls the right side of the body

• The right side of the brain controls the left side of the body

• The left is specialized in language, logic, speech, and comprehension

• The right is specialized in visual tasks, holistic processing, face recognition, and emotional connection

Fun Facts About the Brain

2% of total body weight; burns 20% of your body’s glucose.

• Signals in your brain travel along neurons at up to 250 miles per hour; faster than a race car!

• Half of the 30,000 genes are dedicated to the nervous system.

• The brain produces about 12–25 watts of electricity when awake; enough to power a

lightbulb.

• A newborn’s brain is only about 25% of its adult size. By age 2, it’s about 80% grown.

• Neuroplasticity: People who lose one sense (like sight or hearing) often experience an

enhanced development of other senses because the brain “rewires” to adapt.

• The brain itself cannot feel pain: headaches come from surrounding tissues, blood vessels,

or nerves, not the brain tissue.

• About 100,000 miles of blood vessels run through your brain, enough to circle the Earth four

times.

• With 100 billion neurons and trillions of connections, the human brain is the most complex

object in the known universe

The case of Phineas Gage

Railroad worker injured when an iron rod blasted through his

skull.

• He survived, but his personality dramatically changed (became impulsive, irritable, irresponsible).

• This case provided the first evidence linking the frontal lobes to personality and decision-making.

Scientists relied on observing patients with brain damage and linking personality changes to injuries in specific areas of the brain.

Lesion studies and functional localization

Broca & Wernicke (1860s and 70s):

• Paul Broca (1860s): Studied patients with speech

problems and identified Broca’s area (speech

production).

• Carl Wernicke (1870s): Identified Wernicke’s area

(language comprehension).

• Showed that specific brain regions control specific

functions (localization of function).

• 1930s: Prefrontal lobotomies:

• Dr. Walter Freeman

• Eliminated severe behavioral problems; also took away

emotions, problem solving, thinking.

• Animal studies: scientists created lesions in animal brains to

study behavior changes or used electrical stimulation:

• 1954: James Olds and Peter Milner placed an electrode

in the hypothalamus of the brains of rats by mistake and

discovered the pleasure center of the brain.

Electroencephalogram (EEG)

A device that amplifies and records the electrical activity of the brain

through electrodes placed on the scalp.

•Noninvasive, painless, and inexpensive, but it doesn’t show where the

activity is happening.

•Used to study sleep, epilepsy/seizures.

Computerized Axial Tomography (CAT)

Uses X-rays to take many images from different angles; a

computer combines them into cross-sectional images of the

brain.

• Used to detect structural problems: tumors, brain injuries,

bleeding, skull fractures.

• Quick, widely available, relatively inexpensive, but does not show

brain activity or function.

• Uses radiation (not ideal for repeated use)

Magnetic Resonance Imaging (MRI)

Aligns hydrogen atoms with powerful magnetic fields and radio waves.

• Exceptional and detailed 3D images ofthe brain’s soft tissue without radiation.

• Used to study brain anatomy, locate damage, and identify abnormalities (tumors,

strokes)

Positron Emission Tomography (PET)

Patient is injected with a small dose of radioactive glucose;

active brain areas “light up” as they consume the glucose.

•Shows brain function and can detect diseases before structural changes

appear; excellent for cancer detection.

DTI: Diffusion Tensor Imaging

Maps the movement of water molecules in the brain, revealing the white

matter pathways between different brain regions.

• Used in research and medicine and to understand disorders like

multiple sclerosis, Alzheimer’s disease, and traumatic brain injury.

• Used to map brain networks before surgery to avoid damaging critical pathways.

fMRI: functional magnetic resonance imaging

Tracks blood flow in the brain (since active areas use more oxygen).

• Used to study brain activity while people perform tasks (i.e. language, memory, decision making).

• Shows both structure and function and pinpoints exactly where activity is happening; “brain mapping.”

• Will this technology be used to read minds and detect lies in the future?

• Recently, with 80% accuracy, a research team was able to identify one of eight different mental tasks.

Traumatic Brain Injury

• damage to the brain caused by an external physical force, such as a blow, bump, or jolt to the head.

• categorized based on severity (mild, moderate, or severe).

• They can occur in falls, car accidents, sports injuries, or assaults.

• Damage may be focal (in one area) or diffuse (spread throughout

  the brain).

• Symptoms range from headaches and confusion to loss of consciousness and long-term cognitive impairments.

• TBIs were the “signature injury” of the wars in Iraq and Afghanistan. More

  than 450,000 U.S. service members were diagnosed with a TBI from 2000 to 2021.

Concussion

• a mild traumatic brain injury caused by a sudden impact or jolt to the head that

  disrupts normal brain function.

• can have serious short and long-term effects, especially with repeated injury.

• they often cause temporary confusion, dizziness, memory loss, and headaches

• they disrupt brain metabolism and communication between neurons

• if repeated they can lead to Chronic Traumatic Encephalopathy (CTE), a serious and progressive neurodegenerative disease.

Contusion

• is a bruise on the brain tissue, typically caused by direct impact.

• often occur with more severe TBIs and involve bleeding and swelling in specific areas.

• They may lead to increased intracranial pressure and damage to nearby brain tissue. When there is a collection of clotted blood in one area, this is referred to as a hematoma.

Coup-Contrecoup Injury

• Brain damage occurring at both the site of impact (coup) and the opposite side of the brain (contrecoup) where the brain rebounds off the inside of the skull.

Diffuse Axonal Injury (DAI)

• is widespread damage to white matter axons caused by rotational forces or rapid

  acceleration/deceleration (common in car crashes and shaken baby syndrome).

• Microscopic shearing of axons interrupts communication pathways throughout the brain.

• Because it’s often microscopic, it may not show up on imaging, yet it can cause coma or persistent vegetative states in severe cases.

Stroke

• Occurs when blood flow to a brain region is interrupted.

• are a leading cause of death and serious long term disability in the US

Ischemic Stroke (87% of cases):

• Caused by a blockage (clot or plaque buildup from atherosclerosis) in a cerebral artery. Treatments may include clot-busting drugs given quickly after onset.

Hemorrhagic Stroke:

• Occurs when a blood vessel bursts, bleeding into or around the brain.

Often caused by high blood pressure or aneurysms. The bleeding compresses brain tissue and can increase pressure in the skull, causing severe damage.

Transient Ischemic Attack (TIA)

• is a brief interruption of blood flow to the brain. Symptoms are similar to a full

stroke but last only a few minutes to hours, then resolve. However, TIAs are serious warning signs of future strokes and indicate underlying vascular problems.

Anoxic/Hypoxic Brain Injury

• Occurs when the brain is completely deprived of oxygen (anoxia) or receives reduced oxygen (hypoxia) due to near-drowning, cardiac arrest, or carbon monoxide poisoning

Alzheimer’s Disease

The most common cause of progressive dementia. Driven by two key protein abnormalities:

• Amyloid Plaques: Beta-amyloid protein clumps accumulating between neurons, blocking signaling.

• Neurofibrillary Tangles: Tau protein tangles inside neurons, collapsing the cell's internal transport

system. Damage typically originates in the hippocampus before spreading across the cortex.

Huntington’s Disease (HD)

A rare, inherited genetic disorder caused by a mutation in the HTT gene. The resulting abnormal protein destroys neurons in the striatum (caudate and putamen), leading to uncontrolled dance-like movements (chorea), severe emotional dysregulation, and cognitive decline.

Multiple Sclerosis (MS)

• An autoimmune disorder in which the immune system mistakenly attacks the myelin sheath

  surrounding axons in the central nervous system. The resulting scar tissue (sclerosis) slows or blocks

  nerve impulses, affecting motor control, vision, and cognition.

Prion Diseases (Transmissible Spongiform Encephalopathies)

• Rare, fatal conditions (e.g., Creutzfeldt-Jakob Disease) caused by misfolded prion proteins. These misfolded proteins cause neighboring normal proteins to misfold as well, creating a destructive domino effect that leaves microscopic "spongy" holes in brain tissue.

Neurotoxin Exposure

• are substances that damage or destroy neurons. The heavy metals lead and mercury are particularly harmful to developing brains. Lead exposure is linked to lowered IQ, attention problems, and behavioral dysregulation in children.

• A tragic recent example of mass lead contamination occurred in Flint, Michigan, where the city’s water supply became contaminated with lead in 2014 due to corroding pipes. Thousands of children and adults were exposed before the problem was widely recognized, making it one of the most serious public health crises in recent U.S. history.

• Other toxins include solvents, pesticides, or drugs (such as methamphetamine) that can result in cognitive impairments, memory loss, and motor dysfunction.

Alcohol-Related Brain Damage

• Chronic alcohol abuse can lead to structural and functional brain changes. Prolonged heavy drinking reduces brain volume and can lead to Wernicke-Korsakoff syndrome, a condition involving memory problems due to vitamin B1 (thiamine) deficiency. Alcohol-related damage is especially evident in the frontal lobes, affecting judgment and decision-making.

Encephalitis

• Encephalitis is inflammation of brain tissue, usually caused by a viral infection. Viruses like herpes simplex, West Nile, or measles can infect brain tissue, leading to swelling, fever, seizures, and confusion. Rapid treatment is essential to prevent long-term neurological deficits

Bacterial meningitis

• Infection of the meninges (the membranes that protect the outside of the brain). Rapid onset of fever, neck stiffness, and altered mental status is typical.

Parasitic & Amoebic Infections

• Rare organisms like Naegleria fowleri ("brain-eating amoeba") directly destroy brain tissue. Parasites like Taenia solium (pork tapeworm) cause neurocysticercosis, forming cysts in brain tissue that provoke seizures.

Primary Brain Tumors:

• Originate within brain tissue. Gliomas (such as astrocytomas and the

more aggressive type, glioblastomas) arise from glial support cells and infiltrate surrounding tissue. Meningiomas arise from the outer meninges and compress adjacent brain regions.

Secondary (Metastatic) Tumors:

• Cancer cells that spread to the brain from other parts of the

  body (e.g., lung, breast, melanoma)’

• Symptoms vary widely depending on the tumor’s location, but can include headaches, seizures, sensory or motor impairments, and personality changes.

Circuitry Changes:

• Chronic stress shrinks dendrites in the prefrontal cortex and hippocampus

  while hyperactivating the amygdala, impairing memory and emotional control

Cellular Stress:

• Accelerates telomere shortening, increases oxidative stress, damages

  mitochondria, and suppresses neurogenesis in the hippocampus

Christopher Nowinski

• defensive tackle in college (football)

• professional wrestler outside of college

• he got hit during a match - forgot everything that was supposed to happen in the match

• got constant headaches, sleepwalking, memory loss, nausea

• was not aware of the amount of concussions he had

• went on to be a neuroscientist

• co-founded Boston University’s CTE center

• CEO of cuncussion legacy foundation

Isaiah Kavinsky

• former NFL Player

• suffered a horrible concussion during a game - went back to play in the game only a few minutes after symptoms wore down - injured further

• Fun Fact: 50% of football players feel symptoms and still continue to play

Andre Waters

• died at 44 - suicide

• stopped counting his concussions at 15

• damage in his brain linked to football

• brain microscope sample:

• - should be all cream color - healthy brain

• Water’s brain had a lot of dark brown spots - damaged brain

Gene Atkins

• former NFL Player

• diagnosed with a few concussions

• said he had many more

• memory loss, impulsive thoughts

• was not able to remember something after someone said it

• blurry vision so bad he could barely see

Keith Premeau

• hockey player - NHL

• still suffers from symptom

• headaches, head pressure, fatigue, irritability

• six full weeks of major concussion symptoms

• after fourth concussion his trainer told him he was done

• went on to coach his sons youth hockey program, and teach young hockey players about the risks, and precautions to take when getting injured

Ben Smith

• hockey player NHL

• took a blow to the head - went unconscious

• he only had one diagnosed concussion

Cindy Parlow Cone

• soccer player

• retired b/c of post concussion syndrome

• often when playing she used her head to punt the ball

• Fun Fact: girls soccer/basketball players are more likely to get concussions

• also takes longer to recover

Mary Pounce

• 15 yr old soccer player

• lots of concussions already at such a young age

Owen Thomas

• college football player

• died by suicide

• damage to his frontal lobe - controls impulse control

Facts about CTE

• Chronic traumatic encephalopathy - is a progressive, degenerative brain disease caused by cumulative, repeated head impacts and concussions

• during a test - 4/4 foo players tested with it

• no cure for CTE

• CTE could make you crazy and do terrible things but it also could allow someone to live a normal life

Head Games: other important facts

• Study of retired NFL players - UMICH

  • Ages 30-49 are 1.9% or 19x more likely to get dementia

  • Ages 50+ are 6.1% or 61x more likely to get dementia

  • NFL donated $1 million to BU for research

• 1600 kids — 14 diagnosed with a concussion during the school year

• sub concussive hits - impacts to the head that shift the brain inside the skull but do not cause immediate, noticeable symptoms like dizziness, confusion, or headaches

What the professional sports have done since head games

• restricting dangerous plays

• Almost every major league has expanded centralized video review and digital tracking (such as Hawk-Eye or puck/ball tracking) to minimize officiating errors.

• Driven by growing awareness of long-term head trauma, contact sports have drastically tightened baseline concussion testing, spotters, and returning-to-play guidelines