Neuroanatomy and Neurogenesis

  • Vocabulary:

    • Glial cells: Structure and support, electrical insulation, neuromodulation. Fairly unknown

    • Astrocytes: Make the blood brain barrier, regulate reuptake, a role in plasticity, release neurotransmitters and modulate synaptic strength

    • Reuptake: Regulated by astrocytes, when a neurotransmitter is absorbed and recycled

    • Oligodendrocytes: Squeeze out cytoplast, form myelin, electrical insulators

    • Microglial cells: Remove damaged cells (phagocytes), able to divide

    • Schwann cells: Oligodendrocytes in the PNS

    • Soma: Neuron cell body, has ions like Na, K, Ca, and Cl. Also has protiens

    • Synapse: Space between 2 neurons where signals are transferred

    • Postsynaptic density: On the receiving end of a synaptic cleft

    • Dendrites: Arborized, have many receptors and take input, open and close channels to let in charge, have specialized spines

    • Resting potential: -70, charge of a resting ion

    • Action potential: A signal, sent when summation is at least -55

    • Axon hillock: Start of the axon

    • Axon terminal: Has vesicles with nts on the axon

    • Nodes of Ranvier: Gaps in the myelin sheath

    • Axon collateral: A branch of an axon

    • Connexons: Connect axons together in regions like the heart, a ‘synapse’ for electrical signal, basically fused

    • Sodium/Calcium pump: Na and Ca, make the cell less negative by letting in Ca and Na out

    • Voltage gated channel: A Na channel, opens when channel detects electrical membrane change

    • Ligand channel: Channels activated by things like neurotransmitters, ionotropic or metabotropic

    • EPSP: Positive signal

    • IPSP: Negative signal

    • Tonic signaling: Neurons fire and are active at some basal level, detected by EEGs or slices, spontaneous

    • Voltage gated Ca++ channels: At terminal ends of axons, voltage causes these to open which makes vesicles fuse with the membrane and expel nts into the synaptic cleft (exocytosis)

    • Thalamus: Directs sensory information around the brain

    • Prefrontal cortex (PFC): Responsible for executive functions

    • Cerebellum: Responsible for balance and motor coordination

    • Hippocampus: Responsible for memory

    • Ventricle: Make CSF, pools in the brain

    • Meninges: Protective membranes for the brain, dura, arachnoid, and pia matter. Arachnoid and pia have CSF

    • Nucleus: A collection of soma

    • White matter: Axons

    • Grey matter: Cell bodies

    • Tract: A group of many axons, can be cross hemispheric

    • Corpus callosum: ‘Information highway”, crosses hemispheres, an axon tract

    • Neurogenesis: The process by which neurons are generated in the brain

    • Developmental neurogenesis: Neurogenesis prenatally, in first 2 trimesters primarily, bursts in the first 3 months after birth

    • Adult neurogenesis: Neurogenesis later in life, hotly debated

    • Neural plate: Forms the neural tube, which elongates to form ventricles and a brain during development

    • Neural progenitor cells: In the neural tube, differentiate into neurons

    • Radial glial cells: Serve as both progenitor cells and scaffolding for migrating neurons, undergo asymmetric division

    • Proliferation: First stage of neurogenesis, NSC divide to make NPCs

    • Neurogenic hypothesis of forgetting: Things are forgotten because connections are broken between the neurons that form the memories

  • People:

    • Joseph Altman (1960s): Observed neurogenesis in adult rats

    • Elizabeth Gould (1990s): Saw adult neurogenesis in primates

    • Fred Gage (1998): Saw adult neurogenesis in the human hippocampus

  • Neuron types (can be multiple)

    • Multipolar, most CNS

    • Bipolar, olfactory and retinal

    • Unipolar

    • Pyramidal

    • Subplate

    • Granule

    • Principal (projection)

    • Inhibitory, mostly GABAergic

    • Purkinje

    • Medium spiny neurons

    • Golgi cells

    • Amacrine cells

    • Projection, on a pathway

    • Tonic-firing

    • Pacemaker

    • Fast spiking

    • Regular spiking

  • Glial cells

    • Astrocytes

    • Microglial cells

    • Oligodendrocytes