BIO467 ASU Neurobiology Module 1

Central Nervous System (CNS)

brain and spinal cord

Peripheral Nervous System (PNS)

cranial and spinal nerves

Peripheral Nervous System Somatic Motor System

motor nerves

Peripheral Nervous System Visceral Motor System

sympathetic, parasympathetic, and enteric divisions.

Autonomic Ganglia and Nerves

Peripheral Nervous System Sensory Components

sensory ganglia and nerves

sensory receptors and surface and within body

Visceral Motor System Effectors

smooth muscle, cardiac muscle, and glands

Somatic Motor System Effectors

skeletal (striated) muscles

ventral/anterior

on the front (belly side)

dorsal/posterior

on the back side

superior/cranial

on the top (skull side)

inferior

below

caudal

in the lowermost position (at the tail end)

Rostral

on the forward side (at nose end)

medial

close to or toward the middle

median

in the middle, the midplane (midsagittal)

lateral

away from the midline; toward the side

ipsilateral

same side

contralateral

opposite side

bilateral

both sides

Grey Matter

neuronal cell bodies

White matter

axons that are often myelinated

myelin forms basis of white matter. Myelin is a fatty substance that wraps around axons

Bundles of axons derived from _______________ neurons.

projection

PNS uses pathways, tracts, or nerves?

nerves

CNS uses pathways, tracts, or nerves?

tracts

Afferent

bring stimuli to brain where the signal is integrated and processed

INPUT

Efferent

send information from brain

OUTPUT

Converging circuit

sends info to one output

Diverging circuit

sends info to multiple outputs

Human Cerebral Cortex is subdivided into ____ major lobes.

5

What are the valleys of the brain called?

sulci

What are the ridges of the brain called?

gyri

What neuroanatomist categorized over 50 brain areas in 1909 that are still used to this day?

Korbinian Brodmann

Thalamus

Process sensory signals to and from the spinal cord and the cerebrum

Relay in multiple brain systems (e.g., basal ganglia, limbic system)

Hypothalamus & Pituitary

Regulation of motivated behaviors

Controls release of endocrine hormones

Forebrain

telencephalon and diencephalon

Midbrain

mesencephalon

Hindbrain

metencephalon and myelencephalon

Mesencephalon

Tectum & Colliculi

Metencephalon

pons and cerebellum

Pons

sensory motor relay point

Cerebellum

motor learning, coordination,balance

Myelen-cephalon

Medulla

Medulla

respiration, heart rate, basic life support

Tectum & Colliculi

Auditory, sensory, and visual processing

Limbic system

Emotion, learning, memory

Basal ganglia

Motor function, reward learning

Gene expression is controlled in the cell at multiple levels including:

Transcription

mRNA processing Translation

Differential Gene Expression

crucial for generating cellular diversity and maintaining cell-specific functions.

What tissue type are serotonin receptors most prominently expressed in?

brain

The neuron is very specialized to be able to.....

transmit electrical signals

Which of the following are ways that we can categorize neurons?

Anatomical Location

Morphology

Electrophysiological properties

Connectivity

Gene Expression

What two anatomical structure exhibit the highest expression of NeuroD6?

HPF

Isocortex

Studying Gene Expression via mRNA

In situ hybridization (ISH)

1. Must fix and permeabilize cells

2. Apply antisense mRNA complementary to specific mRNA(aka riboprobe)

3. Add antibody that recognizes digoxigenin conjugated to enzyme

4. Enzyme turns substrate blue/purple(often amplifies signal)

Transcriptomics

Studying genome-wide gene expression patterns can beachieved with high-throughput sequencing approaches

What does Transcriptomics require?

Requires extraction of RNA from a tissue or, more recently, single cells. You will be able to see every gene that's expressed in the sample.

Transcriptomics

Technologies continue to evolve to quantify the levels of all mRNAs in tissues/cells

Microarrays

Next-generation sequencing (NGS)

Single-cell RNA-seq

Heat Map

shows expression of genes

Western Blotting

Quantitative technique to analyse protein levels in homogenized lysates of tissues. tissues probed with antibodies

Immunohistochemistry (IHC)

Uses antibodies to detect a protein of interest in a preserved tissue sample.•

A wide range of detection/amplification chemistries are available.

Labels often multiplexed to allow co-localization or detection of multiple targets.

The cell is a

fundamental unit of structure, function, andorganization in all living organisms.

Neurons

Highly polarized and compartmentalized

Transmit electrical signals

Post-mitotic (don't divide any more, what you get is what you get)

How many neurons in human nervous system?

~100 billion

Neurons

1. Highly polarized and compartmentalized

Cell Body (aka Soma or Perikaryon)•

Axon

Dendrite

Neurons

2. Transmit electrical signals

Propagates action potentials• Specialized machinery for synaptic communication

Reticular theory

nervous system continuous

Neuron Theory

nervous system posses individual units

Who concluded the nervous system is continuous (reticular theory)?

Camillo Golgi

What did Camillo Golgi do?

In 1873, Golgi stained brain tissue (in a converted kitchen) with silver nitrate and potassium dichromate to yield silver dichromate (silver impregnation).

Surprisingly, he found that only a few random cells were stained black, providing an unprecedented technique to study neuronal morphology with impressive detail(used by Brodmann and still utilized to this day).

What did Santiago Ramon y Cajal conclude?

neurons were individual separate cells (neuron theory)

What did Santiago Ramon y Cajal do?

Customized the Golgi stain and meticulously traced and studied a variety of neurons.

Cajal & Golgi were awarded the Nobel prize in 1906 for?

defining the cellularanatomy of the nervous system.

Neural Diversity

anatomical location

connectivity

gene expression

shape or morphology

neurochemical properties

electrophysical parameters

and many other criteria...

Anatomical Location examples

Cortical, Spinal, Cerebellar

Connectivity examples

Long range vs. Local

gene expression examples

Transcription factor, Ca binding proteins, etc

Shape or Morphology examples

Excitatory vs Inhibitory vs Modulatory• Glutamatergic, GABAergic, Dopaminergic, etc.

Electrophysiological parameter examples

Fast spiking, adapting, tonic, etc

About how many protein coding genes are there?

~20,000

What do GAP junctions allow?

direct cytoplasmic exchange of small molecules such as K+, Ca++, and ATP between two cells/neurons.

Pores made of proteins called

connexins

Connexins are proteins that make _______ junctions which are pores that allow small molecules (typically ions) to pass between the cytoplasm of two cells.

Gap

Synapses in the CNS and junctions in the PNS are usually ______ synapses, meaning there's actually a small gap between the cells forming the synapse where neurotransmission occurs.

chemical

Vesicles that hold neurotransmitters are found......

in the pre-synaptic neuron

In the CNS each cell typically receives input via about _________ synapses.

many thousands

Astrocyte end-feet are part of the tripartite synapse and contribute to neural circuit homeostasis by modulating....

Synaptic Transmission

A neuronal membrane that is electrically active is potentially permeable to which of the following ions?

Sodium

Potassium

Chloride

Calcium

An electrochemical equilibrium is a balance between which of the following forces?

Diffusive and electromotive forces

How do ions typically cross the neuronal membrane?

Active transport by ATP hydrolyzing proteins.

Ion channels

If you inserted a microelectrode into a living neuron, what is the first type of electrical potential that you would most likely observe upon entering the cell?

Resting membrane potential

What is the membrane potential (Vm) of a cell that is NOT permeable to potassium, sodium, calcium, or chloride ions?

0mV

*Remember that if two compartments contain channels for all charged ions, movement of positive ions will be followed and balanced by movement of negative ions. Therefore, no separation of charge forms across this membrane and each solute simply diffuses down its own concentration gradient until its the same on both sides. Since no voltage difference is generated, across this membrane, Vm = 0 mV. A membrane must be selectively permeable to a charged ion to build a membrane potential.*

Contacts in the CNS

synapses

Contacts in the PNS

junction

*****Site of Chemical Neurotransmission******

** don't have answer **

A single cortical excitatory neuron can have _______ synapses!!

>10,000

Neurotransmission triggers the generation of?

action potentials

Different properties of postsynaptic neurons lead to diverse _______ characteristics

firing

Most regions of the human cerebral cortex contain ______.

layers

cerebral cortex

Layer 1 is at the

pial surface

cerebral cortex

Layer 6 is

close to the ventricular surface

What do Cortical Layers do?

Provide anatomical substrate for multiple inputs and outputs