Transcript The Biology of Behavior

The Biology of
Behavior
Biology of Behavior
(8-10% of the AP Exam)
 Before we start. . .
 Lots of website to help you review.
 http://www.g2conline.org/
 http://thebrain.mcgill.ca/
The Neuron
Basic info
Structure
Trans parency
The Electrochemical Process
The neuron is adapted for sending
and receiving signals.
This is done within and between
neurons.
HOW?
Within the cell, the nature of the
neural impulse is electrical.
All-or-nothing Principle
Impulse along the axon is called
axonal transmission
The nature of the neural impulse
is electrical.
 The neuron at rest is more negative inside the cell
membrane relative to outside the membrane. The resting
neural potential is about -70 mV.
 The resting potential results from the selective
permeability of the membrane, the presence of electrically
charged particles called ions near the inside and outside
surfaces of the membrane and resulting concentration and
electrical gradients. The sodium potassium pump and
blocking of ionic channels by calcium ions help maintain
the resting potential.
The nature of the neural impulse
is electrical
 When sufficiently stimulated (to threshold) a net flow of
sodium ions into the cell occurs (along with the movement
of potassium ions out).
 The potential rapidly reverses its polarity to typically
+40mV very briefly.
 The brief change in potential is call the action potential.
This neural impulse travels down the length of the axon to
the axon terminals.
The nature of the neural impulse
is electrical
 The more intense a stimulus, the more frequent a neuron
fires.
 A brief period of time, called the refractory period, follows
the polarization changes during which the neuron is
resistant to a retriggering of an action potential.
The chemical process is via
neurotransmitters
Dozens of chemicals have been
identified that perform different
functions in the brain.
Basic Neurotransmitters
 Acetylcholine  Controls skeletal muscles
 Contributes to the
(ACh)
regulation of attention,
arousal and memory
 Some ACh receptors are
stimulated by nicotine
 Dopamine (DA)  Contributes to control of
voluntary movement,
pleasurable emotions
 Decreased levels associated with
Parkinson’s Disease
 Overactive at DA synapses
associated with schizophrenia
 Cocaine and amphetamines
elevate activity at DA synapses
 Norepinephrine
(NE)
 Contributes to
modulation of mood
and arousal
 Cocaine and
amphetamines
elevate the activity at
NE synapses
 Serotonin  Involved in regulation of sleep
and wakefulness, eating and
aggression
 Abnormal levels may contribute
to depression and OCD
 Prozac and similar
antidepressant drugs affect
serotonin circuits
 Gamma-
 Serves as widely
aminobutyic acid distributed inhibitory
transmitter
 (GABA)
 Valium and similar
antianxiety drugs
work at GABA
synapses
 Endorphins  Resemble opiate drugs in
structure and effect
 Contribute to pain relief
and perhaps to some
pleasurable emotions
The communication between cells
is chemical.
 More about that. . .
 Lock and Key
 http://www.biologyinmotion.com/minilec/lock.html
 Excitatory and Inhibitory
 Increases the likelihood that neuron will fire
 Decreases the likelihood that neuron will fire
 Agonist and Antagonist
 A chemical that mimics the neurotransmitter
 A chemical that opposes the action of a neurotransmitter
 Reuptake
 Process by which neurotransmitters are sponged up from synapse by
the presynaptic membrane
Making Synaptic Connections.
Birth
2 years
6
months
©2008 The Center for Effective Learning; Susan Kovalik & Associates, Inc.
www.theCenter4Learning.com
The Reflex Arc
 Types of sensory receptors (get information from the
environment). There are four types . . .
 The simplest form of a behavior is called a reflex.
 We need to know the basic types of neurons.
 Mnemonic is SAME (sensory-afferent, motor efferent).
 Take a look
Prune and Consolidate
©2008 The Center for Effective Learning; Susan Kovalik & Associates, Inc.
www.theCenter4Learning.com
HOW LONG DOES THIS TAKE?
ACTIVITY WITH REACTION TIME.
Fun with neurons
Fuzzy Neuron
Field Trip Preparation (look up terms)
Field Trip
AV The Mind #5 Endorphins
The Mind #5
Neuron 1:30
Fantastic Website!!!
 http://www.g2conline.org/2022
 3-D brain and neuron for explanation and study
The Brain
 Structure and Function
 Structure and Function
 Structure and Function
 Structure and Function
 Structure and Function
 Pinkie and the Brain
Organization of the Brain
How can we describe the brain?
Neural tissue description(the look)
Location description(the place)NAT
GEO photo gallery
General divisions of the nervous
system
 Peripheral Nervous System (PNS)
 Somatic Nervous System
 Autonomic Nervous System
 Sympathetic Nervous System
 Parasympathetic Nervous System
 Central Nervous System (CNS)
 Spinal Cord
 The Brain
 Reptilian Brain
 Old Mammalian Brain
 New Mammalian Brain (Neocortex)
Localization of function of the
human brain
 Structure and Function, Structure and
Function
 Subcortical areas
 Structure and Function
 Structure and Function
 Structure and Function
Neocortex
 The look
 The lobes
A review
 NAT GEO web site for review
 Brain Surgery
Let’s Look Into Your Brain!
How do the two hemispheres of
the brain communicate?
Lateralization of function of the
human brain
 Split Brain- although similarly located both cerebral
hemispheres generally have similar functions, but. . .
 There are some differences or lateralization of functions
shown to exist
 How did scientist figure this out???
Roger Sperry
 According to Dr.Sperry, the
brain has two hemispheres
with different but overlapping
functions. The right and left
hemispheres of the brain each
specialize in distinct types of
thinking processes.
Left and Right Brain
Specialization
 http://www.nobelprize.org/educational/medicine/split-
brain/index.html
How is this studied?
 Electrical stimulation
 PET scans
 Cerebral vascular accidents (strokes), injury or lesioning
 Left/Right Side neglect
 Split brain patients
 Drugs affecting half of brain
 Dichotic listening
Michael Gazzinga
 Over the course of several
decades, a major focus of his
research has been an extensive
study of patients that have
undergone split-brain surgery
that have revealed
lateralization of functions
across the cerebral
hemispheres.
 Split brain Paitent
Left Hemisphere Specialization
 Speech and Language Functions
 Wernicke’s Area
 Broca’s Area
 Angular gyrus
 Contralateral representation
Right Hemisphere Specialization
 Spatial Functions (patterns (gestalten),
visual configurations, color
discrimination)
 Musical Functions
 Contralateral Representation
 The Brain
 #6 Language and Speech
 #7 Plasticity
 #8 Visual Imaging Processing
Hemispheric Dysfunction
 Broca’s Aphasia
 Example (3 mins)
 Wernicke’s Aphasia
 example (4 mins)
 Anomic Aphasia
 Global Aphasia
 Developmental Dyslexia
Plasticity
 Chudler/plasticity
 See Hand out
 The Brain 7 mins
 QUICK THINK: Plasticity
Brain Reorganization
Plasticity
the brain’s capacity for
modification as evident in brain
reorganization following damage
(especially in children) and in
experiments on the effects of
experience on brain development
Windows to the Brain
 Brain Imaging Techniques
 See Hand Out
 Investigative Assignment
 Web search by Courtney Denton Plano ISD
Windows on the Brain
 The Greeks
 Franz Gall
 Brain Damage – Phineas Gage
 Lesion (ablation)
 Imaging Techniques
The Greeks
Hippocrates
Galen
 460-377 BCE
 130-200 CE
 Emotions,
 Fluids in the brain
thought and
mental health
arise from the
brain
ventricles were
responsible for
sensations,
reasoning, judgment
and memories
Gall’s Contribution
61
American Phrenology Journal
62
Phineas Gage
A railroad construction worker in
Vermont in 1848. Dynamite blew a
tamper rod through his eye and
out his skull. Remarkably, he
survived, but was never the same.
Once considerate and friendly, he
was now overbearing and
indecisive. Theory: executive
control system in prefrontal cortex
was damaged.
#25 Phineas Gage
Warren Museum Harvard Medical
School Boston MA
63
Lesions
 Cutting of brain tissue
 Ablation – destroy brain
tissue
 (Essentially these are
the same thing)
 Do we do this today?
Some cool guys
 Cajal
 Golgi
 Penfield
 Hess
Golgi’s Contribution (1872)
66
Cajal’s Contribution: Discrete cells
67
Wilder Penfield
 Electrode into brain to
map motor cortex
 1952
Walter Hess
 Electrode deeper in brain
to discover function of
hypothalamus and
“start-stop eating”
function
 1955
Brain Imaging Techniques
 The are now many, highly specific methods to see into
your brain.
 Assignment to follow will help you discover the techniques
used today.
 As an introduction. . .
More modern approaches
 EEG
 CAT
 MRI and fMRI
 PET
 MEG
 SPECT
 DTI
EEG
 Transmit electrical activity (brain waves)
CAT or CT scan
 Computerized axial tomography- computerized image of
x-rays
MRI
 Magnetic resonance imaging – magnetic field to develop
image of the brain
fMRI
 Functional MRI – detect the use of oxygen in the brain
PET
 Positron emission tomography- slightly radioactive
solution injected to see metabolic activity in imaged part
of the brain
MEG
 Magnetoencephalography- detect activity too brief to be
detected by PET or MRI
SPECT
 Single photon emission computerized tomography- tracks
cerebral blood flow as an indicator of neural activity in a
specific region of the brain
Diffusion Tensor Imaging
 An MRI technique that measures the diffusion of water
within a cell to yield an image of axons and neural tracts
Investigative Assignment
 Brain Imaging and web search
 Courtney Denton Plano ISD
Brain Dysfunction
 http://www.ted.com/talks/jill_bolte_taylor_s_powerful_str
oke_of_insight.html
 Ted talks and strokes
The Endocrine System!!!!
Chemical messengers telling the
body what to do
The Endocrine System
 We rarely think about the endocrine system
 However, it influences almost every cell, organ and
function of our bodies
 It is instrumental in regulating mood, growth and
development, tissue functions, metabolism, sexual
functions and reproductive processes
The Endocrine System
 Integration and control is achieved
through interaction of the nervous
system with the endocrine system of
glands that secrete chemical
messengers called hormones.
 Endocrine v. exocrine systems
 Endocrine glands secrete “within” the body
 See remaining lecture notes
 Exocrine glands secrete “outside” of the body
 Sweat glands
 Salivary glands
 Tear glands
A brief introduction
 The endocrine system 3 mins
Comparison of endocrine and
nervous system
 Endocrine Glands
 Secrete hormones
directly into the blood
stream
 Endocrine transport may
take minutes to hours
 Endocrine effects are
typically long lasting
 BOTH interact with
specific receptors on or in
the target cells
 Neurons (Nervous




System)
Neurons transmit signals
over neural networks
(generally speaking)
Nervous control may take
a fraction of a second to
minutes
Neural effects are short
lived
There is overlap between
systems!!
The foundations of the endocrine
system
 Glands
 Hormones
Glands
 A group of cells that
produce and secrete
chemicals
 A gland selects and
removes materials from
the blood, processes
them and secretes the
finished chemical product
for use somewhere in the
body
Hormones – the chemical
messengers of the body
 3 types
 Steroids
 Peptides or proteins
 Amino acid derivatives
 Small amounts
 Rapidly degraded
Specialized function of the
endocrine glands
 Pineal gland
 Pituitary gland- Hypothalamus
 Thyroid gland
 Parathyroid gland
 Adrenal gland
 Pancreas
 Ovaries and Testes
Discussion topics
How about synthetic
hormones?
Hormonal disorders?