Cogs107A First Exam

Central Nervous System (CNS)

The brain and spinal cord

Peripheral Nervous System (PNS)

Nervous tissue outside the brain and spinal cord

Neuroscience Across Scales

Studying the nervous system at different levels of size and organization

Systems

Multiple connected brain regions working together to perform a function

Maps

Spatial organization of neural activity within a brain region

Circuits or Networks

Groups of connected neurons that process information together

Neuron

Specialized cell that processes and communicates electrical and chemical signals

Synapse

Site where neurons communicate with other cells

Molecule

Smallest scale of investigation discussed in the course

Connectome

Map of connections within a nervous system

Cortical Homunculus

Map of body parts represented in the cerebral cortex

Tonotopic Map

Spatial organization of neurons according to sound frequency

Orientation Map

Organization of visual cortical neurons by preferred stimulus orientation

Histology

Microscopic study of tissue structure

Nissl Stain

Stains neuronal cell bodies and helps measure cell density or loss

Golgi Stain

Stains a random subset of entire neurons to reveal dendrites and axons

Cresyl Violet

Dye used for Nissl staining

Reticular Theory

Theory proposing that the nervous system forms one continuous interconnected network

Neuron Doctrine

Theory that neurons are separate cells that communicate at points of contact

Santiago Ramón y Cajal

Scientist who helped establish the neuron doctrine using Golgi staining

Camillo Golgi

Scientist associated with Golgi staining and the reticular theory

Contiguous

Structures that touch or are close together without being continuous

Continuous

Physically connected without separation

Law of Dynamic Polarization

Original theory that impulses travel toward the soma in dendrites and away through axons

Gap Junction

Connection that permits ions and electrical signals to pass directly between cells

Soma

Cell body of a neuron containing the nucleus and many organelles

Dendrite

Branching neuronal structure that usually receives signals

Dendritic Arbor

Complete branching structure of a neuron's dendrites

Dendritic Spine

Small dendritic protrusion that can influence synaptic strength

Axon

Neuronal extension specialized for conducting electrical impulses

Axon Hillock

Region near the soma where the axon begins

Axon Collateral

Branch extending from an axon

Axon Terminal

Ending of an axon where neurotransmitters can be released

Presynaptic Neuron

Neuron that sends a chemical signal across a synapse

Postsynaptic Neuron

Neuron that receives a synaptic signal through receptors

Synaptic Cleft

Small extracellular gap between communicating cells at a chemical synapse

Synaptic Vesicle

Membrane-bound structure that stores neurotransmitters

Neurotransmitter

Chemical messenger released by neurons to communicate

Neurotransmitter Receptor

Protein that recognizes a neurotransmitter and triggers a cellular response

Nucleus

Cell structure containing DNA

DNA

Genetic material containing instructions used in gene expression

Gene

Segment of DNA containing instructions for a functional product

Exon

Gene segment retained in mature messenger RNA

Intron

Gene segment removed during RNA splicing

Promoter

DNA region where RNA polymerase binds to initiate transcription

Transcription

Process of producing RNA from a DNA template

RNA Polymerase

Enzyme that synthesizes RNA from DNA

Precursor mRNA

Initial RNA transcript that undergoes processing before becoming mature mRNA

RNA Splicing

Process that removes introns and joins exons

Mature mRNA

Processed messenger RNA that can be translated into protein

Translation

Process of constructing a protein using mRNA instructions

Ribosome

Cellular machinery that assembles amino acids into proteins

Transfer RNA (tRNA)

RNA that brings specific amino acids to ribosomes during translation

Free Ribosome

Ribosome in the cytoplasm that often produces proteins remaining in the cytosol

Rough Endoplasmic Reticulum

Organelle with attached ribosomes that often produce membrane-destined proteins

Smooth Endoplasmic Reticulum

Organelle involved in functions including protein folding and calcium regulation

Golgi Apparatus

Organelle that modifies and sorts proteins for delivery

Post-Translational Modification

Chemical change made to a protein after translation

Mitochondrion

Organelle that produces ATP through cellular respiration

ATP

Adenosine triphosphate which supplies energy for cellular processes

ADP

Adenosine diphosphate formed when ATP loses a phosphate group

Phosphorylation

Addition of a phosphate group to a molecule

Cytoskeleton

Internal framework that supports neuronal shape and intracellular transport

Microtubule

Cytoskeletal structure that acts as a track for intracellular transport

Axoplasmic Transport

Movement of materials through the axon

Anterograde Transport

Movement of materials from the soma toward the axon terminal

Retrograde Transport

Movement of materials from the axon terminal toward the soma

Kinesin

Motor protein typically responsible for anterograde transport

Dynein

Motor protein typically responsible for retrograde transport

Principal or Projection Neuron

Neuron whose axon extends to distant brain regions

Interneuron

Neuron whose axons and dendrites remain within one brain region in the lecture definition

Morphology

Physical shape and structural organization of a neuron

Cholinergic Neuron

Neuron that releases acetylcholine

Acetylcholine (ACh)

Neurotransmitter released by cholinergic neurons

GABAergic Neuron

Neuron that releases GABA

GABA

Neurotransmitter commonly associated with inhibitory signaling

Physiological Classification

Classifying neurons by characteristic electrical response patterns

Fast-Spiking Neuron

Neuron capable of producing rapidly repeated electrical spikes

Low-Threshold Spiking Neuron

Neuron characterized by firing responses at relatively low stimulation thresholds

Gene Expression

Use of genetic information to produce functional products such as proteins

ChAT Stain

Staining method used to identify cholinergic neurons

MAP2

Microtubule-associated protein used to identify neuronal cell bodies and dendrites

MAP Tau

Microtubule-associated protein found in neuronal somas and processes including axons

Glial Cell

Nervous system cell that provides support and also participates in signaling and regulation

Ependymal Cell

CNS glial cell involved in cerebrospinal fluid circulation

Choroid Plexus

Specialized ventricular tissue that produces cerebrospinal fluid and forms the blood-CSF barrier

Cerebrospinal Fluid (CSF)

Fluid that cushions the CNS and circulates nutrients and waste products

Ventricle

Fluid-filled cavity within the brain containing cerebrospinal fluid

Blood-CSF Barrier

Barrier formed by choroid plexus epithelial tight junctions that regulates entry into CSF

Microglia

Resident CNS immune cells involved in phagocytosis and synaptic pruning

Phagocytosis

Process by which cells engulf other cells or particles

Synaptic Pruning

Removal of synapses to refine neural connections

Microglial Activation

Response of microglia to injury or other signals

Necessary Condition

Factor that must be present for an effect to occur

Sufficient Condition

Factor that can produce an effect on its own

ATP as an Injury Signal

Extracellular ATP from damaged neurons can trigger microglial responses

Oligodendrocyte

CNS glial cell that forms myelin around portions of multiple axons

Schwann Cell

PNS glial cell that forms myelin around a segment of one axon

Myelin Sheath

Insulating layers of glial membrane wrapped around an axon

Myelination

Formation of the myelin sheath around an axon