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BCMB 415 (Section 002) Foundations in Neurobiology

Instructor Information

  • Instructor: Dr. Billy Lau

  • Departments: Psychology; BCMB

  • Semester: Fall 2025

  • Date: 10/15/2025

  • PointSolution ID: 191465

Developmental Principles Underlying Body Plan

  • Body Regions:

    • Anterior

    • Head

    • Thorax

    • Abdomen

    • Posterior

  • Gene Homologs in Development:

    • lab (labial)

    • pb (pregnancy)

    • Dfd (deformed)

    • Scr (sex-combs reduced)

    • Antp (anthropod)

    • Ubx (Ultrabithorax)

    • abd-A (abdominal-A)

    • Abd-B (Abdominal-B)

    • Genes corresponding to Drosophila:

    • Ant-C (Anterior Complex)

  • Ancestral HOM-C Genes:

    • Hox Genes:

    • HoxA (mouse homolog)

      • Configured in clusters: a-1, a-2, …, a-13

    • HoxB

      • Configured in clusters: b-1, b-2,… b-13

    • HoxC

      • Configured in clusters: c-8, c-9, …, c-13

    • HoxD

      • Configured in clusters: d-1, d-3, …, d-13

    • Homology Group: Defines evolutionary relations among genes.

    • Transcription Orientation:

    • 3' - 5' orientation from anterior (front) to posterior (back).

Neural Tube Patterning

  • Morphogen Gradients:

    • Neural tubes are patterned by gradients of morphogens.

    • Function of Brain Regions:

    • F/M – Frontal/Motor cortex

    • S1 – Primary somatosensory cortex

    • V1 – Primary visual cortex

    • A1 – Primary auditory cortex

Neuron Generation from Progenitor Cells

  • Cajal’s drawing of neurons:

    • Illustrates neural development via Golgi-stained preparation.

    • Allen Brain Institute: Reference atlas for neuronal structure.

Building a Brain

  • Key Processes:

    • Patterning

    • Neuronal differentiation

    • Cell division (birth of progenitor cells)

    • Neuronal migration

    • Axon and dendrite growth

    • Pathfinding of neural connections

    • Embryonic morphogenesis

    • Early postnatal synapse formation

    • Modifications of synaptic connections throughout life.

Orderly Neurogenesis and Migration

  • Roles in Brain Development:

    • Different types of neurons are formed at specific embryonic stages:

    • Neurons born at: E13, E15, E17 (E = embryonic)

    • Cell Types Involved:

    • Radial glia

    • Intermediate progenitors

    • Regions/Abbreviations:

    • CP – Cortical Plate

    • IZ – Intermediate Zone

    • VZ – Ventricular Zone

Modes of Neural Progenitor Divisions

  • Two Modes:

    • Symmetric Division: Progenitors divide into two identical daughters, maintaining pool size.

    • Asymmetric Division: Progenitors divide into one identical daughter and one differentiated neuron, decreasing progenitor pool.

Radial Migration of Neurons to Cortex

  • Neurons Utilizing Radial Migration:

    • Inhibitory neurons

    • GABAergic neurons

    • Pyramidal neurons

Types of Radial Migration

  1. Somal Translocation: Neuron's cell body moves toward its target position, pulling the axon and dendrite along.

  2. Glia-Guided Migration: Neurons utilize radial glial cells as a scaffold to migrate to their appropriate locations.

Reelin Protein and Its Role

  • Function: Acts as a STOP signal in neuronal development.

  • Genetic Background of Reeler Mouse:

    • Mutation: Spontaneous loss of expression of Reelin protein (400 kDa).

    • Phenotype: Severe Ataxia observed in Reeler mice.

    • Cellular Source: Secreted and expressed by Cajal-Retzius cells in the marginal zone.

  • References for Reelin Studies:

    • Curran and D’Arcangelo, 1998

    • Tissir and Goffinet, 2003

    • D’Arcangelo, 1997

    • D’Arcangelo et al., 1995, 1997

    • Caviness and Rakic, 1978