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?