Transcript Animal Models of Addiction

MSc Addiction Studies:
CNS Structure and Function I
Gross Anatomy
DR. ALANNA EASTON
1 9 TH N O V E M B E R 2 0 1 3
[email protected]
Lecture Overview
1). What is the CNS and how it is protected
2). Terminology and brain dimensions
3). Deconstruction of the brain:
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Hemisphere, lobular categorisation, region and system
4). What happens when things go wrong?
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A look at neurodegenerative diseases and related alterations in
structure and function
5). Brain imaging techniques and how they can be used to
visualise disease
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Brief look at MRI and PET imaging
Learning Objectives
1.
To understand the relationship between structure
and function of the CNS
2. To be able to name and describe the structures of
the brain and their key functions
3. To have a knowledge of the various ways to
visualise the CNS/brain systems and structures
What is the CNS
Central Nervous System
PNS
CNS
Nerves and Ganglia
outside of the brain
and spinal cord
Brain and
Spinal Cord
Terminology and Brain Dimensions
Right
Hemisphere
Lateral
Dorsal / Superior
Medial
Rostral/ Anterior
Caudal/ Posterior
Left
Hemisphere
Ventral / Inferior
Terminology and Brain Planes
 The CNS is traditionally examined in
3 perpendicular planes
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Coronal
Horizontal / Transverse
Sagittal
Protection of the Brain
1). Skull/Spinal column
2). Meninges
Series of tough membranes surrounding
the brain and spinal cord
(dura mater, arachnoid mater & pia mater)
Both are intended to provide mechanical protection for the brain
3). Cerebrospinal Fluid (CSF)
Produced in the Choroid Plexus and acts as a shock absorber
Protection of the Brain
4). Ventricular System
 Cavities in the brain containing CSF
 Act like big cushions in the brain
Brain Blood Supply
 A highly specialised system by which each artery is
the only means to supply blood to a CNS region.
 Circle of Willis
 Blood Brain Barrier
Deconstructing the Brain
Cerebral Hemispheres
Left
Right
Personality
Logic
Language
Mechanistic
Intuitive
Music
Detail
Science
Artistic
Design
Creativity
Reason
Math
Strategy
Imagination
Emotional
Expression
Developmental Categorisation
 Forebrain (Prosencephalon)
 Midbrain (Mesencephalon )
 Hindbrain (Rhombencephalon)
 Spinal cord
Development of the CNS
4wk old
human
Neural tube
development
Telencephalon
Prosencephalon
Diencephalon
CNS
Brain
Mesencephalon
Brain stem
Rhinencephalon, Amygdala, Hippocampus, Neocortex,
Basal ganglia, Lateral ventricles
Epithalamus, Thalamus, Hypothalamus, Subthalamus,
Pituitary gland, Pineal gland, Third ventricle
Tectum, Cerebral peduncle, Pretectum, Mesencephalic
duct
Metencephalon
Rhombencephalon
Myelencephalon
Spinal Cord
Pons,
Cerebellum
Medulla
oblongata
Lobular Organisation
Frontal Lobe
Central Fissure
Lateral Fissure
Parietal Lobe
Temporal Lobe
Occipital Lobe
Cerebellum
Regions of Interest
Thalamus
Cerebral
Cortex
Substantia
Nigra
Corpus Callosum
Hypothalamus
Nucleus
Accumbens
Cerebellum
Hippocampus
Mid Brain
Amygdala
Pituitary
Gland
Pons
Medulla
Oblongata
Brain Stem
Functional Systems: The Limbic System
 Limbus = ‘Border’ or ‘Margin’
 Collection of structures that lie in the cortical border
where the cortex meets the sub cortex, in the region
between the cerebral cortex and the hypothalamus
 Includes structures
which are concerned
with emotion, learning,
memory and motivation
Functional Systems: The Motor System
 Three level hierarchy
 Spinal Cord
 Brain Stem
 Cerebral Cortex / Motor Cortex
 Three major areas in the frontal lobe
 Primary Motor Cortex
 Premotor Cortex
 Supplementary Motor Cortex
Functional Systems: The Sensory System
 A means to get information from the outside world
into the CNS. Once there:
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Integration with other sensory information
Integration with limbic/regulatory influences
Calculation and execution of appropriate response
 Components of a
sensory system
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Higher centres
Spinal reflex
When things go wrong
Neuroscience as a basis for understanding neuronal
dysfunction.
Neurodegeneration
Toxins
Vascular Disorders
Tumours
Trauma
Neuropsychiatric Disorders
Infections
Normal Aging
Neurodegeneration: Alzheimer’s Disease
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AD is the most common form of dementia
First described by Alois Alzheimer in 1906
Most cases occurring age 65 yrs +
Alzheimer's is predicted to affect
1 in 85 people globally by 2050
Symptoms: confusion, irritability,
aggression, trouble with language,
long-term memory loss
Cause and progression of the disease
Gyri and Sulci
more pronounced
is not well understood.
Current treatment only helps the
symptoms of the disease
Neurodegeneration: Parkinson’s Disease
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First recognised by
James Parkinson in 1817
death of dopamine-generating cells
in the substantia nigra
Most cases occurring age 50 yrs +
Symptoms: shaking, rigidity,
bradykinesia, akinesia, tremor
Modern treatments: L-Dopa,
DA agonists, stem cell treatment,
deep brain stimulation
Surgery
30 yrs old
42 yrs old
Neurodegeneration: Huntington’s Disease
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Genetic disorder
(autosomal dominant mutation)
More common in people of Western
European descent than in those of
Asian or African ancestry
Affects both men and women
Usually manifests age 35-44 yrs
Mood and cognitive problems
followed by lack of coordination and a
decrease in mental ability
Neurodegeneration: Motor Neuron Disease
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A group of neurological disorders affecting the body’s motor
neurons
Damage to the nervous system
What causes motor neurones to
stop working properly is unclear
Not thought to be a link with factors
such as race, diet and lifestyle
Affects muscles controlling; speech,
gripping, walking, swallowing and
general bodily movements
Stephen Hawking
Currently there is no cure
Diagnosed aged 21
Brain Imaging Techniques
 Computerised Tomography (CT Scan)
 Uses x-rays to image internal organs, blood vessels, bones and
tumours
 Mangentic Resonance Imaging (MRI)
 Brain function based on local metabolism
 Positron Emission Tomography (PET)
 Activity dependent changes in blood flow, tissue metabolism
or biochemical activity
Magnetic Resonance Imaging
 Makes use of the fact that body tissue contains lots of water, and
therefore protons, which align under the application of a strong
magnetic field and then relax at different rates in different
tissues of the body
 fMRI and BOLD contrast:
measures brain activity by
detecting associated changes in
blood flow. When an area of the
brain is in use, blood flow to
T2 weighted image: Stroke vs. Control
that region also increases.
Positron Emission Tomography
 Involves the injection of precursor molecules or specific
neurotransmitters or radio-labelled glucose
Red = highest level of glucose utilisation
Yellow = less utilisation
Blue = least glucose utilisation
 Allows us to see how the brain uses glucose
 Glucose provides energy to each neuron so it can perform work
 The reduction in a neurons ability to use glucose (energy) results
in disruption of many brain functions
MRI & PET in Alzheimer’s Disease
PET
MRI
References and Reading
Key Texts:
• “Principals of Neural Science”. Kandel and Schwartz
•
“Neuroscience at a glance”. Barker and Barasai
How to find out more:
• Wikipedia
• Brain facts. www.brainfacts.org
• Text Book: “Pharmacology”. Rang and Dales
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