Biological Bases of Behavior Flashcards
Heritability
The amount of variation among individuals that we can attribute to genetics
Charles Darwin Theory of Evolution by Natural Selection
Proposed that species evolve through a process of variation and selection, with those most adapted to their environment having a higher probability of surviving and reproducing.
Evolutionary Psychology
Explores how a change in environment over generations influences the development of certain characteristics.
Behavior Genetics
Examines the interplay between our genetics and the environment that shapes who we are.
Adaptation
Involves changing in response to our surrounding environment.
Epigenetics
Studies the molecular mechanisms through which the environment influences gene expression.
Nervous System
A complex/organized communication network that responds to internal and external stimuli with information received, interpreted, and responded.
Central Nervous System
Made up of the brain and spinal cord and controls our thoughts, feelings, and actions.
Ascending (Nervous System)
Sensory messages travelling to the brain.
Descending (Nervous System)
Travelling from the brain.
Reflexes
Are simple automatic behaviors that occur without any brain involvement.
Spinal Reflex
Sensory neurons send info to the spinal cord, and interneurons relay the info to motor neurons, who then signal the reflex. The brain receives info last.
Peripheral Nervous System
Comprises the sensory and motor nerves connecting the CNS to the body.
Comprises of Somatic and Autonomic.
Somatic
Controls skeletal muscles like raising your hand.
Autonomic
Controls the function of glands and internal organ muscles.
Ex - Heart rate, glandular secretion.
Comprises of Sympathetic and Parasympathetic.
Sympathetic
Activates Flight or Fight responses.
Ex - Increased heart rate, slows digestion,
and pupil dilation.
Parasympathetic
Calms you down after an emergency.
Ex - Settles heart rate, pupils constrict, and digestion resumes.
Sensory Neurons (Afferent)
Transmit messages from body tissues and sensors to the brain and spinal cord for processing. Sends signals about the external world or internal conditions.
Motor Neurons (Efferent)
Carry instructions from the central nervous system to muscles and glands. Allows the brain and spinal cord to communicate with the rest of the body, enabling voluntary movements and other bodily functions.
Interneurons
Relay and interpret signals received from sensory neurons before sending appropriate responses through motor neurons.
Neurons
Building block of the nervous system, responsible for transmitting information through electrical and chemical signals.
Nucleus
Contains genetic material in the form of chromosomes.
Dendrites
Receive messages from other cells. Traverse synaptic gaps between neurons.
Cell Body
The cell’s life support center.
Myelin Sheath
Covers the axon of some neurons and helps speed neural impulses.
Schwann Cell
Glial cells that form the myelin sheath
Glial Cells
Hold nerve cells in place and help them work properly
Node of Ranvier
Myelin sheath gaps formed between myelin sheaths generated by different cells.
Axon Terminal
Form junctions with other cells.
Presynaptic Neuron
Sends the message in neural transmission.
Postsynaptic Neuron
Receives the message in neural transmission.
Action Potential
The level of stimulation required to trigger a neural impulse.
Threshold
A neural impulse. A brief electrical charge that travels down an axon.
Synapse
The bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body.
Neurotransmitters
chemical messengers that transmit signals between neurons, muscles, and glands in the nervous system.
- Movement
- Heartbeat
- Responding to information from the body and environment
- Thoughts
- Emotions
- Memories
- Sleep patterns
Axon
The layer of fatty tissue segmentally encasing the fibers of many neurons.
Reuptake
The process by which excess neurotransmitter molecules left in the synaptic gap detaches from a postsynaptic neuron and is reabsorbed by the presynaptic neuron.
Repolarize
Reestablish
Depolarization
The initial phase of the action potential, this change creates an electrical impulse that continues down the length of the axon.
Refractory Period
After the action potential has taken place, the neurons enter a period in which they cannot fire, and works itself to its negative inside/positive outside.
Acetylcholine (NT)
Role includes learning, memory, and motor movement. Lack of it is linked to Alzheimer’s disease. Too much can cause muscle spasms.
Dopamine
Function includes movement, reward sensations, and alertness. Lack of it is associated with Parkinson’s disease. Too much is linked with Schizophrenia.
Endorphins (NT)
Function includes pain perception and emotions. It is linked to addictions (opiate).
Serotonin (NT)
Role includes sleep and emotional states. A lack of it is linked to depression.
GABA (Gamma-aminobutyric acid) (NT)
Holds back brain activity. Linked with anxiety disorders. Anti-anxiety Medication increase Gaba activity.
Norepinephrine (NT)
Assists in regulating alertness and arousal. A lack of it can lead to a depressed mood.
Glutamate (NT)
A key excitatory (causing excitation) neurotransmitter that plays a role in memory. Excess amounts can over-stimulate the brain, leading to migraines and seizures.
Substance P (NT)
Play a role in pain perception and the immune response. An excess can lead to chronic pain.
Endocrine System
The second communication system in your body, working in tandem with the nervous system to transmit info.
- Uses hormones as its messengers.
- Slower communication than nervous system since they travel through blood.
Pituitary Gland
Located at the base of the brain and regulated by the hypothalamus, it acts as a conductor, directing other endocrine glands to release their specific hormone into the bloodstream.
Pineal Gland
At the center of the brain and is responsible for producing melatonin, which is involved in feelings of sleep and wakefulness.
Thyroid Gland
Controls how quickly the body burns energy, makes protein, and is sensitive to other hormones.
Parathyroid
Consists of 4 small thyroid glands, which are responsible for adjusting calcium in the blood.
Thymus
Produces thymosin, which aids in the development of the immune system.
Adrenal Gland
Arouses the body in times of stress. Located just above the kidneys and they trigger flight or fight responses. Gland consists of the adrenal cortex.
Adrenal Cortex
Outer region of the adrenal gland that interacts with the immune system, and the adrenal medulla (inner region), which releases epinephrine and norepinephrine.
Pancreatic Gland
Regulates blood sugar levels. It releases insulin and glucagon, two opposing hormones that control sugar levels.
Gonads (Sex Organs Male)
Influences both emotional and physical development. For men the sex organ consists of the testes. The male testes secrete sex hormones called androgens, the most important testosterone.
Gonads (Sex Organs Female)
Influences both emotional and physical development. For women the sex organ consists of the ovaries. Females also secrete testosterone along with the hormones estrogen and progesterone.
Adrenaline (Epinephrine)
This hormone is released in response to stress or danger, triggering the body’s “fight or flight” response. Adrenaline increases heart rate, boosts energy levels, and enhances the ability to react quickly in threating situations.
Ghrelin (hunger hormone)
Stimulates appetite and promotes food intake, playing a role in regulating meal initiation and influencing food preferences.
Leptin (Satiety hormone)
Regulates appetite and energy balance. It signals to the brain when the body has had enough food, helping to control food intake and maintain a healthy weight.
Melatonin
Responsible for regulating the sleep-wake cycle, with levels rising in the evening to promote sleep and declining in the morning to awake the body. Melatonin helps in synchronization.
Oxytocin (Love hormone) (Bonding Hormone)
Associated with social bonding, trust, and emotional attachment. it is released in response to positive social interactions such as hugging, kissing, or bonding with loved ones.
Psychoactive Drugs
Chemical substances that can significantly impact a person’s moods and perceptions. Can modify arousal levels, thought processes, sensations, and overall perception.
Dependence
Both an individuals body and brain adjust to the substance.
Tolerance
Over time, too much intake of a drug can result in a reduced impact from the same amount.
Withdrawal Symptoms
When a drug is no longer present, symptoms such as physical discomfort and strong cravings can occur.
Depressants
Includes alcohol, tranquilizers, and opioids, are substances that reduce neural activity and slow down bodily functions.
Stimulants
Enhance neural activity and accelerate bodily functions.
Ex - Caffeine, nicotine, cocaine, amphetamines, meth, and ecstasy.
Hallucinogens
Alter perception and produce sensory images without any external input.
Ex - LSD and MDMA (synthetic)
Psilocybin and marijuana (natural)
Agonists
Drugs or chemicals that enhance or mimic the activity of a neurotransmitter, increasing the overall effect of the NT. They bind to receptors on the postsynaptic neuron which triggers the same response as intended.
This can lead to increased stimulation of the nervous system, resulting in effects like improved mood, increased alertness, or pain relief.
Antagonist
Drugs or chemicals that constrains or blocks the activity of a neurotransmitter by binding to the receptor without triggering a response. This prevents natural NT from binding to it, reducing its effects.
This can lead to less anxiety, decreasing pain, or slowing down certain bodily functions.
Right Cerebral Hemisphere
(Right side)
Responsible for perception, decision-making, language, and consciousness. It contains 16 billion neurons and 60 billion glial cells in 6 layers, forming neural circuits and containing grey matter.
Left Cerebral Hemisphere
(Left Side)
Responsible for language, number skills, reasoning, scientific skills, spoken language, and right-hand control.
Frontal Lobe
(Front)
Responsible for unique human behavioral traits like personality, decision making, and motor controls. It makes sense of environment, memories, and emotions, focusing on relevant info for attentions span. It maintains connections to other brain parts for efficiency.
Cerebral Cortex
Divided into 2 symmetric hemispheres connected by the corpus callosum, each with 4 lobes with specific functions.
Premotor Cortex
(Frontal lobe, anterior to primary motor cortex)
Responsible for controlling complex movements and posture, combining signals from the primary cortex in the spinal cords to create intentional motions. Role in decision-making as well.
Prefrontal Cortex
(Infront of the frontal lobe)
Responsible for executive functions, enabling complex and socially mindful decision-making. It filters out unimportant sensations, concentrates attention, and contextualizes decisions with memories
Motor Cortex
(Rear of the frontal lobe)
The primary motor cortex controls movement by controlling muscle contraction, also communicating with other area to ensure intentional, precise movements.
Broca’s Area
(Left frontal lobe)
It is crucial for speech production and coordination.
Broca’s aphasia - cannot respond, only understand speech.
Occipital Lobe
(Back of the brain)
Decodes visual signals from the retina, assisting in recognition and determining reactions.
Primary Visual Cortex
(Occipital Lobe)
Receives visual info from both eyes, processing it on both sides. Forms visual map alongside with other lobes.
Parietal Lobe
(Upper Middle of the brain)
Responsible for integrating sensory info. focusing attention, and interpreting touch signals. Monitors body position and occipital lobe signals, creating our sense of awareness.
Somatosensory Cortex
(Parietal lobe, behind Motor cortex)
Receives info from touch receptors in the skin, and organized according to a distorted mapping of the human body (homunculus).
Temporal Lobe
(Side of the brain near temples)
Comprises hippocampus, primary auditory cortex, and Wernicke’s area. It is responsible for memory, emotions, and language understanding. A key area for epilepsy recognition, facilitating info flow throughout the brain.
Primary Auditory Cortex
(Temporal lobe)
Interprets sound, detects high and low frequency sounds. Aids in Identifying unique sounds and comparing timing in both ears.
Damage to this can cause loss of sound awareness but maintains reflexive hearing due to brainstem.
Wernicke’s Area
(Left Temporal Lobe)
Enables language comprehension.
Wernicke’s aphasia - a speech problem that robs speech of meaning but leaves fluency.
Brainstem
(Base of the brain)
Controls heart rate, breathing, sleep, attention, temp regulation, vision, hearing, and motor control.
3 parts:
Midbrain, Pons, Medulla Oblongata
Midbrain
(Upper part of brainstem)
The substantia nigra, cluster of dopamine-producing cells in the midbrain, regulates movement.
These cells die in Parkinson’s Disease, causing motor disturbances.
Pons
(Middle of the brainstem)
Contains the locus coeruleus which is responsible for attention.
Medulla Oblongata
(Lower part of the brainstem)
It houses breathing control centers, including the pre-Botzinger complex, which generates breathing rhythm.
Limbic System
(Deep Within the Brain)
Comprises the olfactory bulb, hippocampus, amygdala, hypothalamus, basal ganglia, and cingulate gyrus, responsible for motivation, emotion, learning, and memory.
Amygdala
(Temporal lobe, limbic system)
Creates long-term memories of emotional events, such as fear, aggression, and anxiety.
Damage will cause reduced aggression but makes it difficult to avoid painful situations. It hardwires memories to recognize and avoid threats.
Hippocampus
(Temporal Lobe)
Responsible for long-term memory and spatial memory. It produces new neurons in adults and refines them through long-term potentiation. Creates mental maps of places which is crucial for navigation.
Hypothalamus
(Below the Thalamus)
Links the central nervous system and endocrine system, controlling the pituitary glands hormone release. Regulates body temp, thirst, hunger, circadian rhythms, and family bonding. Bridges subconscious brainstem signals with cerebral cortex signals.
Thalamus
(Center of the brain)
Relays sensory info to the cerebral cortex, directing signals to processing areas. Like vision, hearing, taste, touch, and proprioception. It coordinates signals between cortex regions, especially attention-related ones.
Basal Ganglia
(Deep within the Cerebral hemisphere)
Group of brain structures, regulates voluntary movements, habits, and emotions. They consist of 6 structures and act as intermediaries between thoughts, sensations, and reflexes. Issues with this region can cause neurological disorders
Cerebellum
(Back of the brain below the occipital lobe)
A small brain with 70 million neurons, hones motor skills by detecting errors and adjusting/ strengthening neural circuits.
Corpus Callosum
(Above thalamus, connects the hemispheres)
A thick, wide bundle of neural connections. It contains white matter, a thick layer of fatty myelin, providing insulation for electrical signals. Gray matter, containing neuron cell bodies, is where computations occur, while white matter stores info.
Olfactory Bulb
(Under frontal lobe, at the front of the brain)
A cortex area responsible for processing smell. Sensory neurons detect odors and send signals to the bulb, which are sorted by glomeruli. Neural circuits relay signals back to the brain to identify smells.
Brain Plasticity (Neuroplasticity)
Refers to the brain’s ability to reorganize itself by forming new neural connections throughout life. This ability allows the brain to adapt and compensate for injuries, such as when a specific brain region is damaged.
Neurogenesis
Involves the generation of new neurons, contributing to its plasticity and adaptability.
Left Hemisphere
Controls body’s right side, involves logic and sequential tasks.
Right Hemisphere
Controls left side, involves spatial and creative tasks.
Electroencephalogram (EEG)
- A machine that detects brain waves
- Alpha waves - awake
- Delta waves - asleep
- Commonly used in sleep research
Computerized Axial Tomography (CAT Scan)
- 3-D x-ray of the brain
- Helps locate tumors
- Does not show brain activity or brain function
Magnetic Resonance Imaging (MRI)
- Provides a detailed picture of the brain
- Uses magnetic fields to know electrons out of orbit
- Safe procedure; uses no radiation
Functional MRI (FMRI)
- Combination of PET and MRI
- Tracks oxygen rick blood flow
Positron Emission Tomography (PET Scan)
- Best way to measure brain activity
- Measures how much of a chemical substance the brain is using
- Greatest brain activity is usually yellow/red and lowest is blue
- Shows how active tissues are
Consciousness
It encompasses varying levels of awareness of our thoughts, feelings, behaviors, and the events in our internal and external worlds. It includes the different states of awareness, such as sleep and awareness.
Dual Processing
Suggests that conscious and unconscious mental activities co-occur. The brain operates on two levels:
The conscious, deliberate high road.
The unconscious, automatic low road.
Influences cognition, emotions, and behaviors.
Parallel Processing
A phenomenon where multiple aspects of a stimulus or problem are processed simultaneously. For example, when we perceive a visual scene, our brain processes color, shape, and movement concurrently.
Sequential Processing
involves focusing on one task at a time, ideal for solving complex problems that require sustained attention.
Conscious High Road: Cognition
(System 2)
When we engage in critical thinking, problem-solving, and logical reasoning, we are utilizing the conscious high road. This aspect of cognition allows us to exert control over our thoughts and actions consciously.
Unconscious Low Road: Cognition
(System 1)
Handles automatic processes, such as habitual behaviors, quick judgements, and implicit biases.
Fast, efficient, and often influences our decisions.
Conscious High Road: Emotion
(System 2)
When we are aware of our feelings like joy, sadness, or anger, we are engaging with our emotions on the high road level. This allows us to reflect on and regulate our emotional responses consciously.
Unconscious Low Road: Emotion
(System 1)
Processes emotional stimuli rapidly, triggering instinctual responses and emotional associations that guide our behavior from time to time as they happened with great labor and pain.
Circadian Rhythms
Ex - Sleep/wake cycle, lasting around 24 hours in humans. Disruptions to this rhythm can occur with jetlag or shift work, throwing off our internal biological clock.
Suprachiasmatic Nucleus (SCN)
(Hypothalamus)
Helps govern our body’s production of melatonin, a hormone that induces sleep.
It highlights the complicated interaction between external stimuli, our internal clock, and our sleep patterns.
Non-Rapid Eye Movement (NREM)
This sleep occurs in stages 1-3. Hypnagogic sensations mark initial stage 1 sleep as one transitions into sleep.
Rapid Eye Movement (REM)
(Literal Definition)
Considered paradoxical because it exhibits brain waves resembling wakefulness, yet the body is in its most relaxed state. Dreaming commonly occurs during REM sleep.
In cases where REM sleep is deprived, individuals may experience REM rebound.
REM Rebound
A phenomenon in which a person deprived of REM sleep increases the amount of REM sleep at the first opportunity to sleep uninterrupted.
Stage 1 NREM
- Sounds fade into the distance
- You are still able to quickly regain consciousness
- Less vivid imagery
- Hypnogogic Hallucinations
- Pulse slows, muscle relax, breathing more uneven
- Theta and alpha waves
Stage 2 NREM
- Brain activity continues to slow down
- Breathing becomes rhythmical, muscles begin to twitch
- Theta and delta waves are slower and longer
- Sleep spindles - Brief bursts of brain activity
- K-complexes - Single high voltage spikes of brain activity
Stage 3 and 4 NREM
- Physiologically very similar
- Defined by the amount of delta wave brain activity
- Stage 3 - delta waves make up 20%
- Stage 4 - delta waves make up 50%
- Deepest stage of sleep and also most restorative
- At the end of stage 4 you move backwards from 3rd stage to 2,1.
REM Sleep
(Effects)
- The brain becomes more active
- Smaller, faster, brain waves
- Visual and motor neurons act as if you are awake
- Voluntary muscle activity is suppressed
- 1st episode lasts approximately 5-15 minutes, but later periods can last up to 40 minutes.
Benefits of Sleep
(Why we Sleep)
- Sleep helps repair and rejuvenate the body and mind
- Sleep helps process and consolidate new info
- Sleep enhances problem-solving skills and creativity
- Sleep releases growth hormones essential for development
- Sleep reduces metabolic rate and energy consumption.
Effects of Poor Sleep
Body produces more ghrelin, a hormone that increases hunger and decreases leptin, suppressing appetite
- Poor sleep can lead to increased cortisol, a stress hormone that prompts the body to store fat, lowers metabolic rate, and raises blood pressure
- Other effects include disruption of gene expression, risk of heart attack, heightens the brain’s response to food in the limbic system, making it harder to resist unhealthy cravings.
Sleep Disorder
A severe disturbance in our ability to regularly have regular sleep patterns that interfere with daytime functioning and cause distress.
Primary Sleep Disorder
Not associated with any other health condition.
Secondary Sleep Disorder
Associated with medication, alcohol or drug use, and other health issues.
Insomnia
Difficulty falling asleep or staying awake, resulting in insufficient rest.
10-30% in adults, 10% in chronic insomnia
Narcolepsy
A chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden attacks of sleep.
Affects 0.002-0.006% of the population.
REM Sleep Behavior Disorder
A disorder where individuals act out vivid dreams during REM sleep, often resulting in physical activity.
Affects <1.00% of the population
Sleep Apnea
A potentially serious sleep disorder where breathing repeatedly stops and starts during sleep.
2-9% in adults
Somnambulism (Sleep Walking)
Involves getting up and walking around while in a state of sleep.
4% adults, 17% in children
Freud’s Wish Fulfillment
Sigmund Freud believed that dreams are “disguised” fulfillments of repressed “wishes”.
According to his theory aggressive human instincts that motivate, and drive behavior is pushed into our unconscious to align with societal standards. Through dream, these unacceptable wishes, and desires surface in a safe manner.
Activation-Synthesis Theory
This theory describes dreaming as a way of the brain continuing to try and make sense of activity during sleep. During REM sleep the cerebral cortex continues to try and interpret random electrical activity. To do this the brain synthesizes memory fragments, emotions, and sensations into dreams.
Information Processing/Consolidation Theory
According to this theory, dreams help us make sense of our daily experiences and assist in organizing our thoughts and memories. This process of sorting through our daily events while we sleep is believed to contribute to our overall cognitive functioning and emotional well-being.
Sensation
(bottom-up processing)
Through sensation, we receive and represent stimuli from the environment. We organize and interpret sensory information through perception into meaningful objects and ideas.
Sensory Interaction
It is the sensory systems working together constantly.
Perception (Top-Down Processing)
It is how the information is interpreted from the brain down.
Synesthesia
It is a condition where one sense is experienced through another.
Ex - A person might see colors when viewing letters or numbers or taste flavors when haring sounds.
Transduction (Sensation)
The process of converting sensory stimuli (light, sound, touch, etc) into neural impulses for the brain. Specialized receptor cells detect input, convert it to neural signals, and transmit it to the brain.
Threshold
A stimulus must reach a certain intensity for us to sense - enough flavor to taste, enough volume to hear.
Absolute Thresholds
The smallest amount of stimulus needed to be detected by the senses 50% of the time.
Difference Thresholds
“Just Noticeable Difference” (JND)
Refers to the smallest of differences between two stimuli that a person can detect at least half the time.
Weber’s Law
Explains that the difference threshold (JND) is proportional to the intensity of the original stimulus.
The stronger the stimulus, the larger the difference needed to notice a change.
Ex - A small change in a dim light is noticeable, but a bigger change is needed for a bright light.
Subliminal Stimulation
Refers to the sensory input that is below a person’s absolute threshold, meaning it’s too faint or quick to consciously detect, like faint sounds of brief images.
- Can influence behavior subconsciously
Prime a Response
It means to subtly influence or prepare someone to respond in a certain way, without directly forcing them to act.
Sensory Adaptation
Our response to a constant stimulus decreases with continuous exposure, so we stop noticing it. Allows us to detect changes in stimuli.
Ex - Not feeling a watch on your wrist later on after wearing it.
Hue
Colors that vary with the wavelength of light from violet to red.
Saturation
The intensity or purity of a color, and how vivid it appears to the viewer
Wavelength
The distance from the peak of one light wave to the peak of the next.
Retina
Thin light sensitive membrane that covers most of the inner surface of the eye.
Sclera
White portion covering the eye.
Cornea
Where light enters the eye (transparent part that covers the iris).
Lens
Transparent structure that bend or thickens to focus incoming light.
Pupil
Black opening in the center of the eye that allows light to pass through.
Iris
Surrounds the pupil; a colored muscle that expands or contracts.
Fovea
The central pit in the retina responsible for sharp vision
Optic Nerve
A bundle of nerve fibers that transmits visual information from the retina to the brain.
Extraocular Muscles (Eye Muscles)
Helps your eyes move around and include 6 muscles: superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, and inferior oblique.
Rods
Long, thin with blunt ends and outnumber about 20 to 1 cones. They are more sensitive to light and provide us with night vision. They adapt slowly to changes in light.
Cones
Are short and flat in shape with tapered ends. They are sensitive to color wavelengths and adapt quickly to changes. Cones are in the fovea (focal point of the retina).
Transduction (Eye)
Light first activates rods and cones. Rods, more numerous and sensitive to light, provide night vision, while cones, located in the fovea, detect color and adapt quickly to changes in light. After activation, the information passes to bipolar cells, then to ganglion cells, whose axons form the optic nerve. The optic nerve transmits signals to the thalamus, which relays them to the occipital lobe, where the visual cortex processes images through feature detectors and parallel processing.
Myopia (Nearsightedness)
A condition in which the light from rays from distant objects is focused in front of the retina. This causes objects that appear up close to be clear, but those far away to be fuzzy.
Hyperopia (Farsightedness)
A condition when light rays reach the retina before they have produced a focused well up close and often overstrain our eyes.
Young-Helmholtz Trichromatic Theory
States that we have three different types of cones, red for long wavelengths, green for medium, and blue for short, each sensitive to one wavelength.
People who have colorblindness lack cone receptor cells for one or more of these primary colors.
Afterimage Effect
A visual experience that occurs after the original source of stimulation is no longer present.
Opponent Process Theory
States there are 4 base color combinations divided into two pairs of color-sensitive neurons. Red/green, yellow/blue, and then black/white which absorb and reflect all light. If one of the colors in the pairing is stimulated, the other becomes dormant. However due to sensory adaptation, if the color that is being stimulated is removed, we will se its opposite.
Dichromatism
A specific type of colorblindness where individuals have trouble distinguishing between two specific colors.
Monochromatism
A rare condition where individuals see the world mostly in shades of gray.
Feature Detectors
Specialized nerve cells in the occipital lobe’s visual cortex. These neurons respond to specific visual features like edges, lines, and movements.
They receive input from ganglion cells in the retina and pass it to other brain areas for complex pattern processing, helping us interpret the world.
Prosopagnosia (Face blindness)
A condition where people can’t recognize faces. it can be caused by brain damage or be present from birth, while other aspects of vision remain normal.
Blindsight
Is when a person with damage to their primary visual cortex can’t consciously see objects in part of their visual field but can still correctly point to or avoid them when asked, even when they insist they can’t see anything.
Hearing (audition)
The ability to perceive subtle differences in sound (air in motion).
Frequency
The number of wavelengths that pass through a point at a given time. It is usually measured in hertz and determines a tone’s pitch or experienced highness/lowness.
Amplitude
Is how loud the sound is. The higher the wave, the louder the sound. This is measured in decibels. Absolute threshold for hearing is 0 decibels.
Transduction (Ear)
Sound waves are collected in the outer ear by the pinna.
Sound waves are amplified in the middle ear once they bounce into the eardrum. The vibrations from the eardrum are amplified by three tiny bones: the hammer, the anvil, and the stirrup.
Its vibrations are relayed to the cochlea - a fluid filled tube that ripples creating a vibration that is transmitted to the basilar membrane.
Inside the basilar membrane there are sensory receptors for sound called hair cells or cilia. When they vibrate they create a neural impulse called organ of Corti. These neural impulses leave the ear travelling to the thalamus and then the auditory nerve.
Cochlea
A fluid filled tube that ripples creating a vibration that is transmitted to the basilar membrane.
Oval Window
The oval window is a membrane that separates the middle ear from the inner ear.
Basilar Membrane
Inside there are sensory receptors for sound called hair cells or cilia. When they vibrate they create a neural impulse called organ of Corti. These neural impulses leave the ear travelling to the thalamus and then the auditory nerve.
Place Theory
States that we hear different pitches because sound waves trigger different hairs to vibrate at various places along the basilar membrane. High-frequency sounds have a maximum vibration near the stirrup end of the basilar membrane, while low-frequency sounds have the opposite effect.
Valley Theory
Suggests that our brains interpret pitch based on the firing rate of groups of auditory neurons, rather than the individual firing rate of a single neuron.
Frequency Theory
States that the basilar membrane vibrates the incoming sound waves by triggering neural impulses at the same rate as the sound wave. A sound wave of 100 hertz causes vibrations 100 times per second. One problem with this theory is that neurons cannot fire more than 1000x per second, but some wave frequencies are above 1000 waves per second.
Conduction Deafness or Conduction Hearing Loss
It is when the eardrum is punctured, or something goes wrong causing the tiny bones in the middle to lose the ability to vibrate. Hearing aids can be then used to amplify sounds.
Nerve Deafness or Sensorineural Hearing Loss
It is caused by disease, age, or over exposure to loud sounds ( 80< decibels). The hair cells in the cochlea become damaged or destroyed. Once damaged they remain dead. Cochlear implant can be surgically placed to directly stimulate the auditory nerve.
Primary Touch Sensations
Pain
Pressure
Cold
Warmth
Pressure
Identified by Pacinian corpuscles receptors, which are triggered by pressure and send neural messages to the brain.
Pain
- Nociceptors is the body’s pain receptor
- Distinguishes between fast pain, felt as sharp sensations via A-delta fibers, and slow pain, experienced as lingering throbs through C-fibers.
Gate Control Theory
Suggests that the spinal cords acts as a gate, amplifying or reducing pain signals to the brain. Intense stimuli open the gate, increasing pain, while it closes to reduce it.
Vestibular Sense
Enables balance and spatial orientation through signals from the inner ear. it detects changes in head position, direction, and speed and coordinates eye movements with head movements for clear vision during motion.
- Dysfunction can cause dizziness, vertigo, and balance issues.
Kinesthesis
Is the body’s ability to sense the position and movement of muscles, joints, and limbs, crucial for coordinated movements and balance.
Oleogustus (6th Primary Taste)
A 2015 study in chemical sense suggested fat as the 6th primary taste, alongside sweet, sour, bitter, salty, and umami.
Smell (Olfaction)
Airborne molecules activate the sense of smell, reaching the brain without the thalamus. Molecules pass through the palate to 5 million receptors in the nose. Signals travel to the olfactory bulb, then to the smell cortex and limbic system.
Lesion
The destruction or removal of part of the brain.
Association Areas
Regions of the cerebral cortex that integrate and interpret info from various sources to enable higher cognitive process.
