Comprehensive Neuroscience & Philosophy of Mind: Key Concepts and Brain Structures

Mind-body problem

The question of how the **mind and mental experiences relate to the physical body/brain**. |

| **Dualism**

The view that the mind and body are fundamentally different. |

| **Physicalism**

The view that mental processes ultimately arise from **physical processes**. |

| **Substance dualism**

The view that the mind and body are **two different substances**: the mind is nonphysical and the body is physical. |

| **Property dualism**

The view that there is one physical substance, but it has both **physical and mental properties**. |

| **Identity theory**

The view that mental states **are physical brain states**. |

| **Functionalism**

The view that mental states are defined by **what they do/how they function**, rather than what they are physically made of. |

| **Hippocrates**

Ancient Greek physician who argued that the **brain is the organ responsible for thought and sensation**. |

| **Aristotle**

Believed the **heart** was the center of thought and emotion and that the brain helped cool the blood. |

| **Galen**

Supported the idea that the **brain controls sensation and movement**, based partly on observations of injuries and anatomy. |

| **Golgi**

Developed a staining technique that allowed individual neurons to be visualized. He believed neurons formed a continuous network. |

| **Cajal**

Used Golgi's staining method and argued that neurons are **separate cells**, supporting the neuron doctrine. |

| **Neuron doctrine**

The idea that the nervous system is made of **individual neurons** that communicate with one another rather than forming one continuous network.

| **1906 Nobel Prize**

Golgi and Cajal shared the Nobel Prize for their work on the structure of the nervous system. |

| **Chalmers**

Philosopher who described the **hard problem of consciousness**. |

| **Hard problem of consciousness**

The question of **why physical brain activity produces subjective conscious experience**. |

| **Qualia**

The subjective, personal qualities of conscious experiences, such as what pain or the color red feels/looks like. |

| **Seductive allure**

The tendency for people to find an explanation more convincing simply because it contains **neuroscience/scientific terminology**, even if that terminology doesn't actually add useful evidence. |

| **Methodological physicalism**

The scientific approach of investigating mental processes through **physical mechanisms** of the brain and body.

| **Central nervous system (CNS)**

The **brain and spinal cord**. |

| **Peripheral nervous system (PNS)**

All nervous system structures **outside the brain and spinal cord**. |

| **Somatic nervous system**

PNS division involved in **voluntary movement** and sensory information from the body. |

| **Autonomic nervous system**

PNS division controlling mostly **involuntary functions**, such as organs and internal processes. |

| **Sympathetic nervous system**

Autonomic division generally associated with **arousal and action/fight-or-flight responses**. |

| **Parasympathetic nervous system**

Autonomic division generally associated with **rest, digestion, and recovery**. |

| **Enteric nervous system**

Nervous system division that controls much of the **digestive system**. |

| **Gyrus**

A raised ridge/fold on the surface of the brain. |

| **Sulcus**

A groove between gyri. |

| **Fissure**

A deeper groove separating major brain regions. |

| **Gray matter**

Brain tissue containing many **neuron cell bodies** and structures involved in processing information. |

| **White matter**

Tissue containing many **myelinated axons** that connect different brain regions. |

| **Corpus callosum**

Large bundle of axons connecting the **left and right cerebral hemispheres**. |

| **Frontal lobe**

Involved in functions including **planning, decision-making, behavior, impulse control, and movement**. |

| **Parietal lobe**

Involved in **somatosensory processing and spatial/body information**. |

| **Temporal lobe**

Involved in **auditory processing, memory, and language-related processing**. |

| **Occipital lobe**

Major region for **visual processing**. |

| **Cerebellum**

Important for **movement coordination, balance, and motor learning**. |

| **Brainstem**

Includes the midbrain, pons, and medulla; involved in **basic functions and communication between brain and spinal cord**. |

| **Central sulcus**

Groove separating the **frontal and parietal lobes**. |

| **Sylvian/lateral fissure**

Groove separating the **temporal lobe** from regions above it. |

| **Phrenology**

Historical idea that different mental abilities could be identified from **bumps on the skull**; it was not scientifically reliable. |

| **Broca**

Scientist associated with a left frontal region important for **speech production**. |

| **Broca's aphasia**

Difficulty producing fluent speech, often with relatively better comprehension. |

| **Wernicke**

Scientist associated with a brain region important for **language comprehension**. |

| **Wernicke's aphasia**

Speech can be fluent but difficult to understand, with impaired language comprehension. |

| **Phineas Gage**

Famous case showing that damage to frontal brain regions can affect **personality and behavior**. |

| **Penfield**

Neuroscientist who electrically stimulated the cortex to map **functional brain regions**. |

| **Cortical homunculus**

Map showing how different body parts are represented in the brain; representation reflects **amount of neural processing**, not physical body size. |

| **Dendrites**

Neuron structures that primarily **receive information** from other cells. |

| **Soma**

Cell body containing the nucleus and cellular machinery that maintains the neuron. |

| **Axon hillock/initial segment

Region where incoming signals are integrated and where an **action potential can begin**. |

| **Axon**

Long neuronal structure that carries action potentials away from the cell body. |

| **Axon terminals*

Ends of the axon where neurotransmitters are released to communicate with another cell. |

| **Multipolar neuron**

Neuron with **many dendrites and one axon**. |

| **Bipolar neuron**

Neuron with **one dendrite and one axon**. |

| **Unipolar neuron**

Neuron with one main extension that branches into different directions. |

| **Microglia**

CNS immune/cleanup cells that remove debris and respond to injury/inflammation. |

| **Ependymal cells**

| Cells lining the brain's ventricles that help produce/secrete and circulate **cerebrospinal fluid (CSF)**. |

| **Astrocytes**

| CNS glia that support neurons, interact with blood vessels, provide energy, regulate the environment, and help stabilize synapses. |

| **Oligodendrocytes**

| CNS glia that produce **myelin** around axons. |

| **Schwann cells**

| PNS glia that produce **myelin** and can help damaged peripheral axons regenerate. |

| **Myelin**

| Insulating material surrounding many axons that allows **faster signal transmission**. |

| **Electrical signal**

| A signal involving changes in **voltage and ion movement** within a neuron, such as an action potential. |

| **Chemical signal**

| A signal involving **neurotransmitters** released by one cell and detected by another. |

| **Ion**

| An atom or molecule with a net electrical charge. |

| **Cation**

| Positively charged ion, such as Na⁺, K⁺, or Ca²⁺. |

| **Anion**

| Negatively charged ion, such as Cl⁻. |

| **Voltage**

| The **difference in electrical charge/potential** between two locations. |

| **Current**

| The **flow/movement of charged particles**, such as ions. |

| **Resting membrane potential**

| The membrane voltage of a neuron when it is not producing an action potential; approximately **−65 mV**. |

| **Polarized**

| Having a difference in electrical charge across the membrane. |

| **Concentration gradient**

| Difference in concentration of an ion between two areas that causes the ion to tend to move from **high concentration → low concentration**.

| **Electrical force**

| Force caused by electrical charges; opposite charges attract and like charges repel. |

| **Electrochemical gradient**

| The combined effect of an ion's **concentration gradient and electrical force**. |

| **K⁺ leak channel**

| Channel that allows K⁺ to move across the membrane, especially important in establishing the resting membrane potential. |

| **Na⁺/K⁺ pump**

| ATP-powered pump that moves **3 Na⁺ out and 2 K⁺ into** the neuron. |

| **ATP**

| Energy-carrying molecule used by the Na⁺/K⁺ pump to move ions against their concentration gradients. |

| **Equilibrium potential**

| The membrane voltage where the **electrical and concentration forces on a particular ion balance**, producing no net movement of that ion. |

| **Important equilibrium point**

| At equilibrium, ions are **still moving in both directions**; the important point is that the movements balance, producing zero net movement. |

| **Selective permeability**

| The membrane allows some ions to cross more easily than others because of which channels are open. |

| **Why the neuron is negative at rest**

K⁺ tends to leave through leak channels, leaving the inside relatively more negative, while the membrane's selective permeability and ion gradients maintain this state. |

| **Action potential**

| A brief, all-or-nothing electrical signal that travels down an axon. |

| **Threshold**

| The membrane potential that must be reached to trigger an action potential. |

| **All-or-nothing**

| Once threshold is reached, a full action potential occurs; a stronger stimulus does **not produce a larger action potential**. |

| **Depolarization**

| Membrane potential becomes **more positive/less negative**. |

| **Hyperpolarization**

| Membrane potential becomes **more negative** than its resting level. |

| **Voltage-gated channel**

| Ion channel that opens or closes in response to changes in membrane voltage. |

| **Voltage-gated Na⁺ channel**

| Channel that opens during the rising phase of an action potential, allowing **Na⁺ to enter**. |

| **Voltage-gated K⁺ channel**

| Channel that opens during the later part of the action potential, allowing **K⁺ to leave**. |

| **Resting state**

| Membrane is around −65 mV; voltage-gated Na⁺ and K⁺ channels are closed. |

| **Rising phase**

| Voltage-gated Na⁺ channels open → **Na⁺ enters** → membrane rapidly depolarizes. |

| **Na⁺ channel inactivation**

| Voltage-gated Na⁺ channels become temporarily unable to open, helping stop the rising phase. |

| **Falling/repolarization phase**

Na⁺ channels become inactivated while K⁺ channels open → **K⁺ leaves** → membrane becomes more negative. |

| **Undershoot**

| K⁺ channels remain open briefly, causing the membrane to become **more negative than resting potential**. |

| **Refractory period**

| Period after/during an action potential when another action potential is difficult or impossible to initiate. |

| **TTX**

| Tetrodotoxin; blocks voltage-gated Na⁺ channels and therefore prevents normal action potentials. |

| **Myelination**

| Insulation of an axon by myelin that increases the speed of action-potential conduction. |

| **Node of Ranvier**

| Gap between sections of myelin where voltage-gated channels are concentrated and the action potential is regenerated. |

| **Saltatory conduction**

| Fast conduction in myelinated axons where the action potential effectively moves from **node to node**. |

| **Chemical synapse**

| Connection where one neuron releases a **neurotransmitter** that binds receptors on another cell. |