Transcript Nervous System Overview

Welcome to the APPL601,
Biological Bases of Behavior!
Your Host for the Semester
• Jim McConkey
– MS/PMAC Biomedical Engineering from
Johns Hopkins
• Specialties in neuroscience, medical imaging and
computer-guided surgery
– [email protected]
Tonight
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Details about the course
What are we studying?
Organization of the nervous system
Anatomy of the nervous system
Development of Psychology
• Ideopathic model
– Spirits, demons, etc. cause pathologies.
• Mental model
– Cognitive defects or faulty thinking cause
psychopathologies.
• Medical (biological) model
– Psychopathologies are biologically driven.
– They can be treated with drugs.
• Integrated model
– The real world is somewhere in between.
Biological Bases of Behavior
aka Biopsychology
aka Physiological Psychology
• The study of behavior and other
psychological phenomena in terms of the
development, functioning, and pathologies
of the nervous system.
Biological Psychology
• How are behaviors controlled by the brain?
• What parts of the brain control which
behaviors?
• How much control do humans have?
• How do psychoactive drugs work?
Neuroscience
Neuroanatomy
(structure)
Neurophysiology
(function)
Biopsychology
(behaviors)
Neuropathology
(disease)
Neuropharmacology
(drugs)
Neurochemistry
Methods of Biopsychology
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Historical techniques: dissection, staining
Surgical methods
Electrical stimulation and measurement
Pharmacological methods
Genetic engineering
Neuropsychological tests
Non-invasive imaging techniques
Introduction to the Nervous System
Introduction to the Nervous System
• Nervous System
– A system of nerves.
• Cells specialized for the translation and processing
of information.
• Produce electrical and chemical activity.
• Connects and coordinates all parts of the body.
– A collection of specialized subsystems.
Divisions of the Nervous System
• Central Nervous System
– Brain
– Spinal Cord
• Peripheral Nervous System
– Everything else
Divisions of the Peripheral NS
• Somatic
– Receives sensory input from periphery
– Conscious control of peripheral muscles
• Autonomic
– Receives unconscious sensory input from organs
– Unconscious control of movement and organs
Divisions of the Autonomic NS
• Parasympathetic
– Mostly inhibitory
– Controls “housekeeping” functions
• Sympathetic
– Mostly excitatory
– Controls “fight or flight” responses
Anatomy of the PNS
• Autonomic nerves
– Parasympathetic nerves leave
the spinal cord at the cervical
and sacral levels.
– Sympathetic nerves leave the
thoracic and lumbar vertebrae.
• Somatic nerves
– Enter and leave the spinal cord
at every vertebra.
– Sensory nerves have bodies in
the dorsal root ganglia and
ascend in the dorsal horns.
– Motor nerves descend in the
ventral horns.
Recap of NS Organization
Nervous System
Central NS
Peripheral NS
Somatic NS
Autonomic NS
Parasympathetic
Sympathetic
Organization of Nerves
• Nerves are organized in a tree-like fashion
– Solitary neurons in the outermost periphery,
protected by an endoneurium.
– Solitary neurons gather in small bundles called
fascicles, bound by a perineurium.
– Fascicles gather with blood vessels in larger
bundles, bound by an epineurium.
Organization of Nerves
• Endoneurium wraps
each neuron w/myelin.
• Perineurium wraps
several neurons into a
fascicle.
• Epineurium wraps a
bundle of fascicles
plus blood vessels.
Organization of Nerves
• Collections of neurons, grouped by function
– CNS: tracts
– PNS: nerves
• Neuron cell bodies tend to clump together:
– CNS: nuclei (nucleus)
– PNS: ganglia (ganglion)
Protection of the CNS
• The CNS is very important and very sensitive
and is therefore well protected by:
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Thick bones
3 layers of meninges
Cerebrospinal Fluid (CSF)
Blood-Brain Barrier
Circle of Willis – redundant blood supply
Protection of the CNS
• Skull
– Thick, hard
bone
– Over 1 cm
thick in places
– Totally
surrounds and
protects the
brain
Protection of the CNS
• Meninges
– Thick, fibrous
layers
• Dura mater
– Periosteal
– Meningeal
• Arachnoid mater
• Pia mater
Protection of the CNS
• Cerebrospinal Fluid
(CSF)
– Mostly water
– Shock absorber
– Produced in choroid
plexus
Protection of the CNS
• Blood-Brain Barrier
– Tight junctions
• pass O2, CO2, OH
– Carrier-mediated
transport of
• glucose, AAs, ions
– Blocks
• large molecules
• many drugs and
toxins
Organization of the CNS
• The lower the brain level, the more primitive
the more instinctive, and the less brain
control.
• Pure reflexes occur in the spinal cord with no
intervention from the brain.
• The older/lower parts of the brain have 2
layers of neurons. The newer parts of the
brain (neocortex) have 6 layers.
Organization of the CNS
• Myelencephalon
– Medulla oblongata (or just medulla)
• Contains nuclei which are part of the
reticular formation and control:
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Arousal and attention
Heart rate
Respiration rate
Cardiovascular smooth muscle tone
Skeletal muscle tone
Organization of the CNS
• Metencephalon
– Pons (=“bridge”)
• Part of reticular formation responsible for
sleep and arousal
• Relay nuclei between cortex and
cerebellum
– Cerebellum
• Primarily responsible for coordinated
movements
• Receives all sensory input except olfactory
• Connected to pons via cerebellar peduncles
Organization of the CNS
• Mesencephalon
– Tectum (=“roof”)
• Inferior (auditory) and Superior (visual) colliculi
• Responsible for audiovisual reactions
– Tegmentum (=“covering”)
• Contains nuclei of the reticular formation
• Controls eye movements
• Red Nucleus – sends motor info from cortex and
cerebelum to spinal cord
• Substantia Nigra – communicates with caudate
and basal ganglia
Organization of the CNS
• Diencephalon (“2 brains”)
– Surrounds the 3rd ventricle
– Thalamus
• Two lobes
• Major sensory transfer station
• Many sensory nuclei
– Hypothalamus (=“beneath thalamus”)
• Autonomic control center, four F’s
• Hormonal control, direct and thru pituitary
Organization of the CNS
• Telencephalon
– Cerebral cortex
• Two cerebral hemispheres
• Lateral ventricles (two)
• Corpus callosum/
anterior commisure
• Limbic cortex
– Involved in motivation and emotion
• Basal ganglia
– Caudate nucleus, globus pallidus, putamen
– Involved in planned movement
Organization of the CNS
• Cerebral hemispheres
– Lateralization, specialization per side
– Left
• Verbal abilities
• Analysis and serial behaviors
– Right
• Spatial abilities
• Synthesis
• Music, arts, emotions
Anatomical Directions
Superior (top)
Dorsal = back
Ventral = front
Posterior
Anterior
Caudal = tail
(rear)
(front)
Rostral = head
Lateral = side
Medial = center
Inferior (bottom)
Anatomical Terminology
• Brain topography terminology
– A gyrus (gyri) is a bump
– A sulcus (sulci) is a shallow groove
– A fissure (fissures) is a deep groove
Gyrus
Sulcus
Fissure
Gyrus
Sulcus
Anatomy of the Cortex
• Major anatomical landmarks
– Longitudinal Fissure separates
hemispheres
– Central Sulcus
– Lateral (Sylvian) Fissure
– Parieto-Occipital Sulcus
(internal)
Anatomy of the Cortex
• Major lobes of the cortex
• Demarcated by fissures and sulci
– Frontal lobe - anterior to central sulcus
• Thinking, planning, executive function
– Parietal lobe - posterior to the central sulcus
• Association area
– Temporal lobe - inferior to the lateral fissure
• Auditory function
– Occipital lobe - posterior of cortex
• Vision
Anatomy of the Cortex
Anatomy
of the
Cortex
White Matter –
has myelin
sheath.
Gray Matter –
no myelin. Cell
bodies are here.
Cranial Nerves - 12 pairs
Spinal Pathways
• Spinal cord has two gray matter horns which
contain cell bodies. The two sides are connected
by the gray commissure, and are surrounded by
white matter, which carries tracts.
• Dorsal horns receive sensory afferents.
– Afferent somas external in dorsal root ganglia
• Ventral horns carries somatic motor efferents.
– Efferent somas in ventral horns
Sensory Pathway
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