Cognitive Neurobiology: Nervous System Anatomy, Cellular Physiology, and Neurodevelopment

Comprehensive vocabulary flashcards covering neuroanatomy, structural and functional cellular neurobiology, synaptic transmission, and embryonic neural development based on COGS 17 lectures.

Dualism

The philosophical view proposed by René Descartes in the 1600s stating that the physical brain is not identical to the immaterial mind or soul.

Monism

The contemporary neurobiological stance that the mind equals the brain, meaning the mind is the activity of the physical brain.

The Hard Problem

The philosophical question asking why consciousness exists and what the physical nature of consciousness is.

Dura Mater

The thick, tough outer layer of the meninges situated immediately under the protective bone of the skull and spinal column.

Arachnoid Mater

The spider-web-like spongy middle layer of the meninges beneath which the subarachnoid space is filled with cerebrospinal fluid.

Pia Mater

The pliant, inner layer of the meninges that closely conforms to the surface of the brain and spinal cord and contains blood vessels.

Hydrocephalus

A pathological buildup of cerebrospinal fluid ("water on the brain") occurring when the outflow from the ventricles is blocked, which may require surgical drainage.

Blood-Brain Barrier

A semi-permeable protective barrier composed of tightly joined capillary cells and astrocyte glia that strictly regulates chemical passage into the central nervous system.

Medulla Oblongata

The ancient hindbrain structure that controls vital reflexes such as breathing, heart rate, vomiting, and coughing, featuring a weaker blood-brain barrier.

Pons

The hindbrain structure ("Bridge") that relays information between cortex and cerebellum and between brain and spinal cord, housing cranial nerves V through XII, the reticular formation, and raphe system.

Cerebellum

The hindbrain structure ("Little Brain") responsible for motor programs, coordinating online sensory input to guide movement, timing graceful actions, and shifting attention.

Tectum

The sensory "roof" of the midbrain comprising the superior colliculus for visual processing (including blindsight) and the inferior colliculus for auditory processing.

Tegmentum

The motor pathway region below the tectum in the midbrain that includes the red nucleus, cranial nerves III and IV, and the dopaminergic substantia nigra.

Thalamus

The paired diencephalon structures atop the midbrain serving as the primary relay station of sensory and motor inputs (except olfaction) projecting to the cerebral cortex.

Hypothalamus

The small diencephalic structure situated ventral to the thalamus that regulates the "4 Fs" (feeding, fighting, fleeing, sex), temperature, and circadian rhythms via autonomic and pituitary connections.

Hippocampus

A seahorse-shaped telencephalic limbic structure located posterior and inferior to the thalamus/hypothalamus, critical for spatial mapping and forming new memories.

Amygdala

An almond-shaped limbic structure situated at the anterior end of the hippocampus in the temporal lobe, important in emotional expression (especially anger and fear) and interpreting emotions.

Cingulate Gyrus

A re-entrant limbic cortex layer immediately inferior to the cerebral cortex that collaborates with cortical and limbic structures to evaluate positive and negative outcomes.

Basal Ganglia

A subcortical complex consisting of the caudate nucleus, putamen, and globus pallidus that interfaces with the frontal cortex to regulate planned sequential movements and task-setting.

Basal Forebrain

A subcortical area located anterior to the hypothalamus that serves as the brain's main source of acetylcholine (ACh) and GABA, regulating attention and cortical arousal.

Central Sulcus

The prominent cortical groove that physically separates the frontal lobe from the parietal lobe.

Lateral Sulcus

The deep cortical groove separating the temporal lobe from the overlying frontal lobe.

Wernicke's Area

A language comprehension area located in the higher auditory projection region of the left temporal lobe.

Inferior Temporal (IT) Cortex

A higher visual cortical region along the ventral "Who/What" pathway containing specialized face-selective cells.

Medial Temporal (MT) Cortex

A cortical visual area along the dorsal "Where/How" pathway containing motion-sensitive neurons and optic flow detectors.

Canonical Cells

Parietal lobe neurons belonging to the "Where/How" visual pathway that fire in response to the affordances of an object (how it can be grasped or used).

Postcentral Gyrus

The parietal cortical ridge immediately posterior to the central sulcus that houses primary somatosensory cortex ($S1$) and the Penfield body surface map.

Broca's Area

A specialized motor planning region in the frontal lobe anterior to the ventral motor cortex responsible for language production.

Corpus Callosum

A large bundle of myelinated axons beneath the cerebral cortex communicating between the left and right cerebral hemispheres.

Bell-Magendie Law

The physiological principle dictating that sensory information enters the spinal cord through dorsal roots, while motor information exits through ventral roots.

Sympathetic Nervous System

The autonomic "fight or flight" division featuring an interconnected chain of ganglia near the spinal cord that releases norepinephrine and prepares the body for vigorous action.

Parasympathetic Nervous System

The craniosacral "rest and digest" autonomic division that exclusively releases acetylcholine ($ACh$) to promote vegetative functions such as digestion and sexual arousal.

Parasympathetic Rebound

An exaggerated, compensatory parasympathetic response following extreme sympathetic activation that can result in fainting or gastric ulcers.

Exocytosis

The release of neurotransmitter packets from vesicles into the synaptic cleft triggered by the opening of voltage-dependent $Ca^{2+}$ channels at the presynaptic terminal.

EPSP (Excitatory Post-Synaptic Potential)

A hypo-polarizing graded potential that moves a postsynaptic neuron closer to its firing threshold, typically mediated by $Na^+$ influx.

IPSP (Inhibitory Post-Synaptic Potential)

A hyper-polarizing graded potential that moves a postsynaptic neuron farther from its firing threshold, typically mediated by $K^+$ efflux or $Cl^-$ influx.

Temporal Summation

The cumulative postsynaptic effect produced when a single presynaptic cell repeatedly stimulates a postsynaptic neuron in rapid succession.

Spatial Summation

The cumulative postsynaptic effect produced when multiple presynaptic inputs converge simultaneously upon a single postsynaptic neuron.

Ionotropic Mechanism

A rapid, short-lived synaptic process in which the binding of a neurotransmitter directly opens or closes an ion channel gate.

Metabotropic Mechanism

A slower, long-lasting synaptic transmission process where neurotransmitter binding alters a receptor, activating a G-protein and second messenger system to open ion channels.

Agonist

A chemical agent that increases or mimics the functional effects of a specific neurotransmitter.

Antagonist

A chemical agent that decreases or blocks the functional effects of a specific neurotransmitter.

Auto-Receptors

Receptor sites on a presynaptic axon terminal that detect the neuron's own neurotransmitter, mediating a negative feedback loop to halt further release.

Astrocytes

Glial cells that provide structural and metabolic support, help constitute the blood-brain barrier, recycle neurotransmitters, and clear neuronal waste.

Microglia

Small glia that proliferate in areas of brain damage to remove toxic materials, acting as the brain's internal immune-like defense system.

Ependymal Cells

Glial cells lining the brain's ventricles that synthesize cerebrospinal fluid and use beating cilia to circulate it.

Resting Potential

The steady-state electrochemical difference of approximately $-70\,mV$ across an unstimulated neuron's membrane, polarized so the inside is more negative than the outside.

Sodium/Potassium Pump

An active, energy-consuming transport mechanism that pumps $3\,Na^+$ ions out of the neuron for every $2\,K^+$ ions moved in.

All-or-None Law

The principle stating that an action potential in a given neuron always occurs at a constant amplitude and velocity regardless of the triggering stimulus intensity.

Saltatory Conduction

The rapid propagation of an action potential along a myelinated axon, jumping from one Node of Ranvier to the next to accelerate velocity up to $100\text{--}120\,m/s$.

Neural Tube

A dorsal ectodermal cylinder formed by week 4 of embryonic development whose rostral end develops into the brain and caudal end forms the spinal cord.

Spina Bifida

A severe congenital defect of the spinal cord and brain that occurs when the embryonic neural folds fail to fuse properly.

Asymmetrical Division

The process beginning around embryonic week 7 in which a stem cell divides to generate one identical stem cell and one migrating neuron.

Radial Glia

Embryonic glial cells that extend spoke-like fibers outward from the ventricular zone, providing physical paths for migrating neurons.

Neurotrophins

Chemical signals, such as Nerve Growth Factor ($NGF$) and Brain-Derived Neurotrophic Factor ($BDNF$), that direct axon growth and promote neuronal survival.

Apoptosis

Programmed cell death mediated by the activation of internal suicide genes when developing neurons fail to receive sufficient neurotrophic support.

Dualism

The philosophical position, articulated by Descartes in the 1600s, stating that the brain does not equal the mind or soul; the brain is physical, whereas the mind is immaterial.

Monism

The prevalent contemporary scientific position stating that the brain equals the mind, meaning that the mind is the activity of the physical brain.

"The Hard Problem"

The fundamental philosophical and scientific question addressing why consciousness should exist at all and what the physical nature of consciousness is.

Dura Mater

The outermost layer of the meninges (translating to "Tough mother"); a thick layer located immediately under the bone of the skull and spinal column.

Arachnoid Mater

The spider-web-like spongy middle layer of the meninges ("Spider mother"); contains the subarachnoid space filled with cerebrospinal fluid ($\text{CSF}$).

Pia Mater

The pliant, delicate inner layer of the meninges ("Pious mother") that conforms directly to the surface contours of the brain and spine and carries blood vessels.

Ventricles

Hollow, interconnected cavities in the brain that produce cerebrospinal fluid ($\text{CSF}$); consists of two lateral ventricles and a third ventricle in the forebrain, the cerebral aqueduct in the midbrain, and a fourth ventricle in the hindbrain.

Blood-Brain Barrier

A semi-permeable physiological barrier composed of tightly joined capillary walls lacking intercellular gaps and astrocyte glia, preventing toxins and pathogens from entering brain tissue while requiring active transport for nutrients like glucose.

Medulla

An ancient hindbrain structure (Medulla Oblongata) responsible for controlling vital autonomic reflexes, including breathing, heart rate, coughing, and vomiting.

Pons

A hindbrain structure (Latin for "Bridge") that relays information between the cortex and cerebellum and between the brain and spinal cord; contains Cranial Nerves V through XII, the reticular formation, and the raphe system.

Cerebellum

A hindbrain structure ("Little Brain") that organizes real-time sensory input to guide motor programs, critical for timing coordinated actions and shifting attention.

Tectum

The sensory pathway structure forming the "roof" of the midbrain; composed of the superior colliculus for visual processing and blindsight, and the inferior colliculus for auditory processing.

Tegmentum

Major motor pathway structures situated below the tectum in the midbrain; contains the red nucleus, substantia nigra with dopaminergic neurons, Cranial Nerves III and IV, and part of the reticular formation.

Thalamus

A paired diencephalic structure atop the midbrain that serves as the primary relay station and source of input to the cerebral cortex for all sensory systems except olfaction.

Hypothalamus

A small diencephalic structure situated ventral to the thalamus that oversees critical survival functions ("the 4 Fs": Feeding, Fighting, Fleeing, and Sex), internal temperature, and circadian rhythms, regulating the endocrine system via the pituitary gland.

Basal Ganglia

A complex subcortical telencephalic system—including the caudate nucleus, putamen, and globus pallidus—that interfaces with the frontal cortex to regulate planned sequential movements and task-setting.

Basal Forebrain

A cortical region located anterior to the hypothalamus that acts as the brain's main source of acetylcholine ($\text{ACh}$) and inhibitory $\text{GABA}$, regulating attention and cortical arousal.

Cerebral Cortex

The outermost, evolutionarily recent structure of the brain consisting of $6$ lamina/layers; it is approximately $3\,\text{mm}$ thick with an unfolded surface area of roughly $2.5\,\text{ft}^2$, two-thirds of which is hidden in folds (sulci).

Occipital Lobe

The ventral posterior lobe of the cerebral cortex dedicated to visual processing; houses primary visual cortex ($\text{V1}$ or striate cortex) and distinct visual processing pathways for color, detail, motion, and depth.

Temporal Lobe

The lateral cortical lobe involved in auditory processing ($\text{A1}$), language comprehension (Wernicke's Area in the left hemisphere), "Who/What" higher visual processing (including face cells in $\text{IT}$), and emotional processing.

Parietal Lobe

The dorsal posterior cortical lobe containing the primary somatosensory cortex ($\text{S1}$ / Penfield Map along the postcentral gyrus), spatial mapping circuits, canonical cells, and the mirror cell system.

Frontal Lobe

The anterior cortical lobe encompassing primary motor cortex (precentral gyrus), premotor planning areas, Broca's area for speech production, and the prefrontal cortex for impulse control, planning, and self-control.

Corpus Callosum

A dense bundle of myelinated axons situated beneath the cortex and inferior to the cingulate gyrus that facilitates communication between the left and right cerebral hemispheres.

Bell-Magendie Law

The neurological principle establishing that sensory information enters the spinal cord through dorsal roots, while motor commands exit through ventral roots.

Somatic Nervous System

The subdivision of the peripheral nervous system consisting of $31$ pairs of spinal nerves and $12$ pairs of cranial nerves that manages interactions with the external environment via sensory input and skeletal muscle control.

Sympathetic Nervous System

The autonomic division responsible for "Fight or Flight" responses; its ganglia form a tight paravertebral chain near the spinal cord and predominantly release norepinephrine ($\text{NE}$) to prepare the body for action.

Parasympathetic Nervous System

The autonomic "Rest & Digest" or craniosacral system comprising cranial nerves (especially Cranial Nerve X: the Vagus Nerve) and sacral nerves; all its postganglionic fibers release acetylcholine ($\text{ACh}$) to promote restorative functions.

Parasympathetic Rebound

An exaggerated, compensatory parasympathetic surge occurring immediately after an extreme sympathetic response, capable of inducing fainting or gastrointestinal ulcers if repeatedly experienced.

Astrocytes

Star-shaped glial cells that supply nutrients to neurons, maintain the blood-brain barrier, recycle neurotransmitters, and clear cellular waste products.

Microglia

Small glial cells that proliferate in damaged areas of the central nervous system to engulf and remove toxic materials and cellular debris, functioning like the body's immune system.

Oligodendrocytes

Glial cells in the central nervous system (brain and spinal cord) that extend cellular arms to insulate multiple axon segments with myelin sheaths.

Schwann Cells

Glial cells in the peripheral nervous system where each individual, intact cell wraps entirely around an axon to create a segment of the myelin sheath.

Sodium-Potassium Pump

An energy-dependent membrane protein complex that actively expels $3\,\text{Na}^+$ ions out of the cell for every $2\,\text{K}^+$ ions it transports in, establishing the neuronal resting membrane potential.

Resting Potential

The electrical polarization across a non-stimulated neuronal membrane, typically measured at $-70\,\text{mV}$, resulting from unequal concentrations of ions across the semipermeable membrane.

Action Potential

A rapid, transient depolarization and repolarization of an axon membrane originating at the axon hillock, reaching approximately $+50\,\text{mV}$ through sequential opening of voltage-activated $\text{Na}^+$ and $\text{K}^+$ channels.

All-or-None Law

The rule that an action potential in a given neuron always maintains the same amplitude and conduction velocity regardless of the strength or duration of the initiating stimulus.

Saltatory Conduction

The rapid jumping propagation of an electrical nerve impulse from one Node of Ranvier to the next along a myelinated axon, elevating conduction speed from $1\text{--}10\,\text{m/s}$ up to $100\text{--}120\,\text{m/s}$.

Graded Potential

A local, non-propagated membrane potential change whose amplitude varies directly in proportion to the intensity of the input stimulus, allowing variable neurotransmitter release without producing an action potential.

Synaptic Cleft

The narrow extracellular gap, typically $20\text{--}50\,\text{nm}$ wide, separating the presynaptic terminal from the postsynaptic cell membrane across which neurotransmitters diffuse.

Exocytosis

The calcium-dependent process by which synaptic vesicles fuse with the presynaptic terminal membrane to release neurotransmitters into the synaptic cleft following depolarization.

Excitatory Post-Synaptic Potential (EPSP)

A graded hypopolarization of the postsynaptic membrane, usually triggered by the influx of $\text{Na}^+$, that moves the membrane potential closer to the firing threshold.

Inhibitory Post-Synaptic Potential (IPSP)

A graded hyperpolarization of the postsynaptic membrane, typically driven by the efflux of $\text{K}^+$ or influx of $\text{Cl}^-$, that drives the membrane potential farther away from the firing threshold.

Temporal Summation

The integration of postsynaptic potentials generated when one or more presynaptic terminals fire in rapid, repeated succession upon a single postsynaptic neuron.

Spatial Summation

The additive integration of simultaneous postsynaptic potentials originating from multiple distinct presynaptic terminals converging on different locations of a single postsynaptic cell.