Summary Brain & Cognition 1

Brain & Cognition

Lecture 1:
 Fluorescent algae, proteins
 Golgi: staining mechanism to visualize neurons, black absorb (responsive neurons)
o So many canals (axons), thoughts they were all connected not true!
 Cajal: observed different types of cells
o Cerebellum: large dendrites
o Discrete units, separated from each other, own cell membrane
 A function can’t be assigned to a single neuron!
o Neural networks do exist
 Neurons are plastic (brain changes!)
 Axon hillock: axon part closest to cell body, very sensitive
 Sensory neurons: info to CNS
o Bipolar neuron (retina): light sensitive
o Somatosensory neuron: skin, muscle
 Interneurons: associate sensory and motor activity in CNS (most!)
o Stellate cell (thalamus)
o Pyramid cell (cortex) (grey matter)
o Purkinje cell (cerebellum)
 Motor neurons: send signals from brain and spinal cord to muscles
o Large dendrites
 Excitation and Inhibition
 Glial cells:
o Ependymal cell: produce CSF (fluid)
o Astrocyte and Microglial cell: neuronal nutrition, support, defensive
 Blood-brain barrier
 Astrocytes: structural support blood vessels
 Microglial: protective against intrusion
 A red nucleus
 B toxin
 C a lot of microglial, scar tissue inside brain
o Oligodendroglial cell and Schwann cell: form myelin, repair
 Schwann cells divide
 Axon sprouts: in all directions
 We don’t have this for in the CNS: spinal cord

,Lecture 2
 Endoplasmic reticulum: polypeptide formed
 Golgi: packages proteins
 Tubule: support, transport
 Cell membrane:
o Phospholipid bilayer: extracellular and intracellular fluid
 Hydrophilic head and hydrophobic tails (lipids, fatty acid)
 Nucleus:
o Nucleotides: T and A, G and C
o Protein synthesis:
 1. DNA unwinds to expose a gene:
 2. One strand (mRNA) reads info and goes to ER
 3. Ribosomes in ER translates into specific amino acid chain -> protein
 DNA (GCCAAACCG) -> mRNA (CGGUUUGGC) -> translation (Arg – Phe)
 Amino acid:
o Amino group (NH3)
o Carboxyl group (COO-)
o R-group
 Primary -> secondary (pleated sheets or helices) -> tertiary -> quaternary
 Proteins enter Golgi bodies -> wrapped in membrane -> microtubule
o 1. Can be incorporated into membrane
o 2. Remain within cell to act as enzyme
o 3. Excreted from cell by exocytosis.
 Cell membrane:
o Channel
o Gates
o Pumps
 Recessive and dominant gene (allele, e.g., eye color)
 Epigenetics: expression of genes
o No alteration of DNA (phenotypic)
o Experience and environment -> expression yes or no
o Describe cell differentiation, phenotypic variation and how cell functions can
go astray producing diseases
o Environmental control:
 1. Histone modification: methyl group bind to tails of histones, blocking
them
 2. Gene (DNA) methylation: methyl group bind to CG base to block
transcription
 3. mRNA modification: ncRNA binds to mRNA, preventing translation
Chapter 4:
 Glial cells (glue)
 Membrane potentials
o Channels and pumps are specialized proteins
 Diffusion: more neg on inside than outside
 Generates membrane potential (-70mV)
 A (extracellular fluid) and B (neuron)
 Concentration equal
 With channels: high to low: move along the concentration
gradient
o Concentration equal
o Potassium (+) and neg ions (-) and potassium channels
o Kinetic force (diffusion) and opposites attract! (- and +)
o Voltage gradient: attracts and repel

, o Equilibrium
o Concentration gradient = voltage gradient
o K/Na pump: creating concentration gradient (3Na out of
cell for every 2K that goes inside)
 K and anion (neg. stay inside cell, for resting
potential) higher inside cell
 K leak channels: K goes outside of cell
 Cl and Na higher outside cell
 Cl: channels freely, also for
concentration gradient
o Recording electrodes inside cell body (-70mV)