michael putman macro-neuroscience. brief overview: topics for today general anatomy mechanics and...
TRANSCRIPT
MICHAEL PUTMAN
Macro-Neuroscience
Brief Overview: Topics for Today
General Anatomy Mechanics and maters
Sensation Pathways and parallel
Cortex Localization and specificity
Movement Networks and coordination
Limbic System Regulation and drive
Brainstem Homeostasis and regulation
Brief real-world applications / Q&A after each section
General Anatomy: Lobes of the Brain
Broad purposesFrontal
Personality Parietal
Touch, body awarenessOccipital
Vision Temporal
Recognition Cerebellum
Balance, refined motion
General Anatomy: Lobes of the Brain
Reality check: things aren’t that easy
The brain has highly specialized areas
Many areas run together
We don’t know everything yet
Purves 46.5
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General Anatomy: Two Halves
There are brain has two halves
“corpus callosum” connects them and is responsible for coordinating their function
The majority of processes split sides, so left controls right and vice versa
General Anatomy: Many Maters
Dura mater “Strong” mother
Arachnoid Membrane Little less “Cerebral fluid” in the
space betweenPia matter
Not so strong mother Coats brain
General Anatomy: Ventricles
Four ventricles Remnants of neural
developmentContain essential fluids
Produced in choriod plexus
Why are spinal taps useful? Fluid drains down spinal
cord Easy(ish) access to brain
molecules
NEXT TOPIC: SENSATION
Questions?
Sensation: Parallel Pathways
Sensory organs Peripheral nervous
system (PNS)Spinal CordThalamusCortex
Sensation: Similar Paradigms
We’re focusing on touch
Other senses (sight, audition, olfaction, gustation) rely on very similar paradigms
Sensory organs thalamus Cortex (Except olfaction)
Sensation: (PNS) Sensory Organs
Variety of different receptors
Physical deformation opens ion channels
Influx of ions forms basis of an action potential
Sensation: (PNS) Axons and Afferents
All nervous signals travel through nerve fibers
Nerve fibers are composed of individual axons
Speed of axons varies Afferent axons take
information from sensory organs to spinal cord
Sensation: Spinal Cord
Sensory axons enter dorsally
Synapse and head up toward the brain
Motor efferents exit spinal cord ventrally
Organized by dermatomes
Sensation: Thalamus
Often called the routing station of the brain
Thalamus receives inputs and sends them on to higher level structures
All sensory (except olfaction) goes through thalamus
Sensation: Cortex
Final(ish) destination of sensation is the cortex
Higher level processing occurs here
Why do elephants hate stubbing their toes? Different pathways
NEXT TOPIC: CEREBRAL CORTEX
Questions?
Cerebral Cortex: Summary
Organization Localization Plasticity Mapping Magnification
Cerebral Cortex: Across (mammalian) Species
“There’s a nickel of difference between you and a banana”
- Dr. Patton
Cerebral Cortex: Localization
Many highly specialized areas
Damage can be selective
Folds and sulci to increase surface area
Cerebral Cortex: Plasticity
Important study on plasticity
Amputation Reorganization Ethics people can
touch on this one later
Cerebral Cortex: Mapping
Parts of the body are topographically mapped on the cortex
Consistent across individuals
Frequently observed in other modalities
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Cerebral Cortex: Magnification
More useful organs have greater representation
Hands, lips, tongue get large portions of cortex
This allows for more refined perception of these areas
Why is this animal so ugly? Nose as sensory organ Huge magnification
NEXT TOPIC: MOVEMENT
Questions?
Movement: Cortex
Starting from motor cortex
Magnification, somatotopic mapping, localization, etc.
Opportunity for enhancement?
Movement: Interconnected Networks
Cortex crosstalk Systems of regulationParallel pathways Basal ganglia
Essential for motor control
Heavily involved in Parkinson’s, Huntington’s, etc.
Movement: Cerebellum
Highly foldedTwo halves Ancient “little brain” Regulation of movement,
posture, balance Why can’t people stand
after drinking too much ethanol? GABA receptors are
agonists High concentration of
GABA in cerebellum
NEXT TOPIC: LIMBIC SYSTEM
Questions
Limbic System: Summary
Includes thalamus, hypothalamus, amygdala, and hippocampus
Basic physiological drives, emotions, and instincts
HypothalamusAmygdalaHippocampus
Limbic System: Hippocampus
Major role in short term memory and spatial navigation
Damage linked to Alzheimer’s disease
Limbic System: Amygdala
Essential in processing of memory and emotional reactions
Linked to diseases like Bipolar and phobias
Important in social interactions
Strong role in fear, fear memory, and avoidance behavior
Limbic System: Hypothalamus
Essential connection between nervous system and endocrine (hormones)
Connections to anterior pituitary
Controls a number of physiological changes
Why is this guy so tall? 7’ 7” and 360 lbs Acromegaly
NEXT TOPIC: BRAINSTEM
Questions?
Brainstem
Medulla oblongata and pons
Motor pathways Basic physiological
processes Regulates cardiac and
respiratory function Controls sleep/wake
cycles and consciousness
Central to questions at end of life
(ANS) Sympathetic Nervous System
Part of autonomic nervous system (ANS)
“Flight or flight” system
Manages stressors Accelerates heartbeat,
opens airways, stimulates secretion of norepinephrine/epinephrine, inhibits digestion
(ANS) Parasympathetic Nervous System
Part of ANS“Rest and digest”
divisionShown in blue at
right Mostly beyond
conscious control Promotes digestion,
glycogen production, pupil constriction, etc.
THE END!
Questions?