Biopsych Exam 1

Resting State

The baseline electrical state of a neuron membrane at give or take $-70\,\text{mV}$, during which both sodium and potassium channels are closed.

Threshold

The membrane potential level, typically around $-55\,\text{mV}$, required to open electrically gated sodium channels and trigger an action potential.

Local Potential (Graded Potential)

A slight depolarization on the cell membrane that varies in intensity according to stimulus strength and dies out without reaching threshold.

Ungraded

A characteristic of action potentials indicating that once threshold is hit, the neuron fires at the exact same intensity regardless of stimulus size.

Nondecremental

A characteristic of action potentials meaning that the intensity remains constant all the way down the length of the axon.

Decremental

A characteristic of local potentials meaning that the electrical disturbance gradually dies out over distance and time.

All-or-None Law

The principle stating that once the neuron hits threshold, an action potential will fire completely and at full intensity every time.

Axon Hillock

The region of the neuron where the action potential is first generated.

Hyperpolarization

A brief period following repolarization where open potassium channels overshoot, making the inside of the cell temporarily more negative than its resting state.

Absolute Refractory Period

The period during depolarization and repolarization when sodium channels close and channels are insensitive to electrical stimulation, preventing the neuron from firing another action potential.

Relative Refractory Period

The period following hyperpolarization (around $-80\,\text{mV}$) when a neuron can fire another action potential, but requires a greater voltage change (about $25\,\text{mV}$) to hit threshold compared to resting state (about $15\,\text{mV}$).

Nodes of Ranvier

Teeny tiny gaps between approximately $1\,\text{mm}$ stretches of myelin sheath where the action potential jumps to ensure signal intensity remains constant down the axon.

Biopsychology

The study of the relationship between the body (including the brain and other biological systems) and behavior.

Behavior

All observable actions and internal states of an organism, encompassing what we do, say, think, and feel.

Dualism

The philosophical viewpoint that the mind and body/brain are separate and distinct entities.

Monism

The philosophical position that the mind and body are part of a single unified entity or substance.

Idealistic Monism

A form of monism asserting that everything, including the body and brain, consists solely of non-physical mind or spirit.

Materialistic Monism

A form of monism asserting that everything in existence is physical matter, and that the mind is a product of physical brain activity.

Trephining

An ancient surgical practice documented around $5000\text{ BCE}$ that involved drilling holes into the skull.

Ebers and Edwin Smith Papyrus

Ancient Egyptian medical documents dating to $1550\text{ BCE}$ (with potential original sources $1500$ years older) containing early records of brain knowledge and medicine.

Hydraulic Theory

Rene Descartes' early 1600s CE model proposing that human movement and behavior are driven by fluids moving through nerves.

Luigi Galvani

The late 18th-century scientist who demonstrated that nerves conduct electricity, contributing to the concept of the electrical brain.

Localization of Function

The principle that specific behaviors, cognitive abilities, or mental processes are controlled by distinct regions of the brain.

Phrenology

An 1800s theory developed by Franz Gall and J.G. Spurzheim claiming that mental faculties and personality traits are reflected in skull bumps.

Broca's Area

A region of the brain identified in 1861 by Paul Broca that is critical for speech production.

Equipotentiality

Karl Lashley's early 1900s theory proposing that all parts of the cerebral cortex contribute equally to complex functions such as learning and memory.

Distributed Function

The modern model of brain organization showing that functions like memory rely on integrated networks across multiple brain regions, evidenced by Patient H.M., Brenda Milner, and Mortimer Mishkin.

Tabula Rasa

John Locke's 17th-century concept describing the mind as a blank slate shaped entirely by experience and environment.

Sir Francis Galton

The 19th-century scientist who popularized the phrase "Nature vs Nurture".

Natural Selection

Charles Darwin's theory of evolution explaining how traits that enhance survival and reproduction under environmental pressures are preferentially passed on.

Strategic Pluralism

An evolutionary concept associated with adaptation, natural selection, and trade-offs in behavioral strategies.

Darker Skin Tone Adaptation

An evolutionary trait selected in equatorial climates with high UV exposure, acting as natural sunblock to prevent folate deficiency.

Lighter Skin Tone Adaptation

An evolutionary trait selected in high-latitude climates with low UV exposure, permitting greater UV absorption needed for Vitamin D synthesis.

Adaptive Emotion

The perspective that emotions evolved because emotion-driven behaviors serve functional, survival-enhancing adaptations.

Watson & Crick

The researchers who proposed the double-helix structural model of DNA in 1953.

Nucleotides

The building blocks of DNA containing base pairs Adenine paired with Thymine, and Cytosine paired with Guanine.

Alleles

Different molecular versions or variations of a single gene.

Homozygous

Having two identical alleles for a given gene.

Heterozygous

Having two different alleles for a given gene.

Genotype

The underlying genetic makeup or specific allele combination of an organism.

Phenotype

The observable physical, physiological, or behavioral characteristics of an organism.

Monogenic Effect

A genetic inheritance pattern where a single gene determines a specific phenotypic trait.

Polygenic Effect

A genetic inheritance pattern where a trait is influenced by the cumulative action of multiple genes.

X-Linked Recessive Traits

Conditions caused by recessive genes on unpaired X-chromosomes, such as Red/Green color weakness, Haemophelia A, and male-pattern baldness.

X-Linked Dominant Traits

Conditions caused by dominant genes on unpaired X-chromosomes, such as Rett Syndrome and Vitamin D Resistant Rickets.

Identical Twins

Monozygotic twins who share $100\%$ of their genes, utilized in twin studies to examine genetic concordance.

Fraternal Twins

Dizygotic twins who share approximately $50\%$ of their genes, serving as a genetic baseline in twin studies.