j. lauwereyns, ph.d. professor graduate school of systems life sciences kyushu university...
TRANSCRIPT
J. Lauwereyns, Ph.D.ProfessorGraduate School of Systems Life SciencesKyushu University
Basic neuroscience
Anatomy
The neuron
DNA
Detection Chemical release
Transport
Insulation
Glia
In mammals: Axons are myelinated
Neuron communication
Neurons: 1. detect external environment 2. convert this sensory
information into cellular ‘language’
Simple reflex
Simple reflex
Touching a hot iron;muscles of the arm contract,withdraw the arm
Simple reflex
Dendrites ofa sensory neuronsignal the painfulstimulus
Simple reflex
This triggersan action potentialin the axon
Simple reflex
This activatesan inter-neuronin the spinal cord
Simple reflex
This activatesan inter-neuronin the spinal cord,which, in turn,activates a motor neuron
Simple reflex
Now the motor neuron sends aseries of action potentialsto the muscle, which contracts
Simple reflex
Note: for simplicity, only 3 neurons and 1 muscle are shown. In reality, even this simple reflex involves many hundreds of neurons, and groups of muscles…
How does this work??
• Action potentials (or nerve impulses) form the language of the brain, like computer bits or Morse code
• Cells that can generate and conduct action potentials have an excitable membrane
• When such cells are not generating impulses, the membrane is at its resting potential
Flash forward!
Action potentials: The brain’s information code
Data from a neuron in visual cortex
Visual stimulus
Neu
ron
’s r
esp
on
se
Visualstimulus
Neuron’sresponse(actionpotentials)
Back to the present…
The neuron
DNA
Detection Chemical release
Transport
Insulation
Glia
In mammals: Axons are myelinated
DNA
mRNA
Protein
Transcription
Translation
‘Central dogma’ of molecular biology
The axon and its terminal
Close up of terminal button
Following anaction potential:Neurotransmitterswill be released in the synaptic cleftand influence thepost-synapticneuron…
To be continued
Neuron communication
Two components:
• Within the neuron (action potentials)
• Between neurons (neurochemical release)
The logic of + and – in the brain
Inhibitory
Excitatory
“-”
“+”
Simple reflex
Touching a hot iron;muscles of the arm contract,withdraw the arm
The advantage of inhibitory control…
Returning to the example of the simple reflex,and a desire not to let go of the hot casserole
1 human2 monkey3 cat4 pigeon5 possum6 dog
rostral caudal
dorsal
ventral
neuraxis
lateralmedial
anterior
posterior
rostral
caudal
ventral dorsal
mediallateral
neuraxis
dorsal
ventral
rostral caudal
coronal
transversal
sagittal
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Cranial nerves
Meninges
Spinal cord
Ribs
Spinal nerves Kidney
Lung
(Cauda equina)
Dorsal
Ventral
Spinal nerve
VertebraFattissue
Dura materArachnoid membrane
Pia mater
Sub-arach-noid space
Dorsal
Ventral
Afferent axon
Efferentaxon
Dorsal rootganglion
Dorsal root
Ventral root
To brain
Motorneuron
Spinal nerve
VertebraFattissue
Dura materArachnoid membrane
Pia mater
Sub-arach-noid space
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Cranial nerves
Meninges
Spinal cord
Ribs
Spinal nerves Kidney
Lung
(Cauda equina)
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Let’s take a look
The meninges
Dura mater
Arachnoidmembrane
Subarachnoid space
Pia mater
Surface of the brain
(Arachnoid trabeculae)
Subdural space
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Lateral ventricle
FourthventricleCerebral
aqueduct
Massaintermedia
Third ventricle
Ventricular system: flotation, shock absorption
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Nervous system1 Central Nervous System2 Peripheral Nervous System3 The cranial nerves4 The meninges5 The ventricular system
Forebrain
Midbrain
Hindbrain
(Telencephalon)
(Diencephalon)Thalamus
Hypothalamus
(Mesencephalon) Tectum (Substantia nigra, Superior colliculus,…)
(Metencephalon)
(Myelencephalon) Medulla
Pons
Cerebellum
Limbic structures
Cerebral cortex
Basal ganglia
Forebrain
Midbrain
Hindbrain
(Telencephalon)
(Diencephalon)Thalamus
Hypothalamus
(Mesencephalon) Tectum (Substantia nigra, Superior colliculus,…)
(Metencephalon)
(Myelencephalon) Medulla
Pons
Cerebellum
Limbic structures
Cerebral cortex
Basal ganglia
Cerebral cortex
PrimaryVisual cortex
PrimaryAuditorycortex
PrimaryMotor cortex
PrimarySomatosensorycortex
Cerebral cortex
Frontal lobeParietal lobe
Occipitallobe
CerebellumSpinal cord
MedullaTemporal lobe
PrimaryVisual cortex
PrimaryAuditorycortex
PrimaryMotor cortex
PrimarySomatosensorycortex
Right hemisphere
Left hemisphere
PrimaryMotorcortex
PrimarySomatosensory cortex
PrimaryAuditory cortex
PrimaryVisual cortex
Right hemisphere
Left hemisphere
PrimaryMotorcortex
PrimarySomatosensory cortex
PrimaryAuditory cortex
Central sulcusCalcarine fissure
Lateral fissure
PrimaryVisual cortex
Fissure, sulcus: groove (major, minor)Gyrus: a convolution of the cortex (separated by sulci or fissures)
Forebrain
Midbrain
Hindbrain
(Telencephalon)
(Diencephalon)Thalamus
Hypothalamus
(Mesencephalon) Tectum (Substantia nigra, Superior colliculus,…)
(Metencephalon)
(Myelencephalon) Medulla
Pons
Cerebellum
Limbic structures
Cerebral cortex
Basal ganglia
Corpuscallosum
Cerebellum
Spinal cordMedulla
Pons
(largestcommissure,
connecting the two
hemispheres)
Pituitary gland
Hippocampus
Limbic cortex
Amygdala
Limbic structures
Forebrain
Midbrain
Hindbrain
(Telencephalon)
(Diencephalon)Thalamus
Hypothalamus
(Mesencephalon) Tectum (Substantia nigra, Superior colliculus,…)
(Metencephalon)
(Myelencephalon) Medulla
Pons
Cerebellum
Limbic structures
Cerebral cortex
Basal ganglia
Caudate nucleusand putamen
Tail of caudate nucleusGlobuspallidus
(can’t see:
Substantia nigra)
Basal ganglia
Thalamus
Hypothalamus
+ (Diencephalon)
Forebrain
Midbrain
Hindbrain
(Telencephalon)
(Diencephalon)Thalamus
Hypothalamus
(Mesencephalon) Tectum (Substantia nigra, Superior colliculus,…)
(Metencephalon)
(Myelencephalon) Medulla
Pons
Cerebellum
Limbic structures
Cerebral cortex
Basal ganglia