Understanding What Biopsychologists Do UNIT 3 The Research Methods of Biopsychology.

Understanding What Biopsychologists Do

UNIT 3The Research Methods of Biopsychology

Neuron and Its Parts

Neuron: Individual nerve cell Dendrites: Receive messages from other neurons Soma: Cell body; body of the neuron Axon: Fiber that carries information away from the cell body Axon Terminals: Branches that link the dendrites and somas of

other neurons

FIGURE: A neuron, or nerve cell. In the right foreground you can see a nerve cell fiber in cross section. The upper left photo gives a more realistic picture of the shape of neurons. Nerve impulses usually travel from the dendrites and soma to the branching ends of the axon. The nerve cell shown here is a motor neuron. The axons of motor neuron stretch from the brain and spinal cord to muscles or glands of the body.

FIGURE: A highly magnified view of a synapse. Neurotransmitters are stored in tiny sacs called synaptic vesicles (VES-ihkels). When a nerve impulse reaches the end of an axon, the vesicles move to the surface and release neurotransmitters. These molecules cross the synaptic gap to affect the next neuron. The size of the gap is exaggerated here; it is actually only about one millionth of an inch. Some transmitter molecules excite the next neuron, and some inhibit its activity.

FIGURE: (a) Central and peripheral nervous systems. (b) Spinal nerves, cranial nerves, and the autonomic nervous system.

Two Divisions of the Autonomic System

Sympathetic: Arouses body; emergency system Parasympathetic: Quiets body; most active after an emotional event

FIGURE: Sympathetic and parasympathetic branches of the autonomic nervous system. Both branches control involuntary actions. The sympathetic system generally activates the body. The parasympathetic system generally quiets it. The sympathetic branch relays its messages through clusters of nerve cells outside the spinal cord.

Cerebral Cortex

Definition: Outer layer of the cerebrum

Cerebrum: Two large hemispheres that cover upper part of the brain

Corticalization: Increase in size and wrinkling of the cortex

Cerebral Hemispheres: Right and left halves of the cortex

Corpus Callosum: Bundle of fibers connecting cerebral hemispheres

Split Brains

Corpus Callosum is cut; done to control severe epilepsy (seizure disorder).

Result: The person now has two brains in one body.

This operation is rare and is often used as a last resort.

When the Brain Fails to Function Properly

Association Cortex: Combine and process information from the five senses

Aphasia: Speech disturbance resulting from brain damage

Spatial neglect resulting from a right hemisphere stroke. Notice the neglect of the left side of the pictures which were being reproduced.

When the Brain Fails to Function Properly (cont'd)

Broca’s Area: Related to language and speech production If damaged, person knows what s/he wants to

say but can’t say the words Wernicke’s Area: Related to language

comprehension If damaged, person has problems with

meanings of words, NOT pronunciation

Subcortex

Hindbrain (Brainstem) Medulla: Connects brain with the spinal cord and

controls vital life functions such as heart rate and breathing

Pons (Bridge): Acts as a bridge between medulla and other structures Influences sleep and arousal

Cerebellum: Located at base of brain Regulates posture, muscle tone, and muscular

coordination

Subcortex: Reticular Formation (RF)

Lies inside medulla and brainstem Associated with alertness, attention and some

reflexes (breathing, coughing, sneezing, vomiting)

Reticular Activating System (RAS): Part of RF that keeps the cortex active and alert

Its alarm clock

FIGURE This simplified drawing shows the main structures of the human brain and describes some of their most important features. (You can use the color code in the foreground to identify which areas are part of the forebrain, midbrain, and hindbrain.)

Forebrain

Structures are part of the Limbic System: System within forebrain closely linked to emotional response Thalamus: Relays sensory information to the cortex;

switchboard Hypothalamus: Regulates emotional behaviors and

motives (e.g., sex, hunger, rage, hormone release) Amygdala: Associated with fear responses Hippocampus: Associated with storing memories;

helps us navigate through space

FIGURE Parts of the limbic system. Although only one side is shown here, the hippocampus and the amygdala extend out into the temporal lobes at each side of the brain. The limbic system is a sort of “primitive core” of the brain strongly associated with emotion.

Endocrine System

Glands that pour chemicals (hormones) directly into the bloodstream or lymph system Pituitary Gland: Regulates growth via growth

hormoneToo little means person will be smaller than

average Hypopituitary Dwarfs: As adults,

perfectly proportioned but tinyToo much leads to giantism

Excessive body growth

Endocrine System (cont'd)

Acromegaly: Enlargement of arms, hands, feet, and facial bones Too much growth hormone released late in

growth periodAndre the Giant

Endocrine System Concluded

Pineal Gland: Regulates body rhythms and sleep cycles. Releases hormone melatonin, which responds

to daily variations in light. Thyroid: In neck; regulates metabolism.

Hyperthyroidism: Overactive thyroid; person tends to be thin, tense, excitable, nervous.

Hypothyroidism: Underactive thyroid; person tends to be inactive, sleepy, slow, obese.

The Adrenal Glands

Adrenals: Arouse body, regulate salt balance, adjust body to stress, regulate sexual functioning; located on top of kidneys Releases epinephrine and norepinephrine

(also known as adrenaline and noradrenaline)Epinephrine arouses body; is associated with

fearNorepinephrine arouses body; is linked with

anger Remember – This has been a simplified view of

the brain and nervous system.

Neural Communication

The Brain

Lesion tissue destruction

a brain lesion is a

naturally or experimentally caused destruction of brain tissue

Researching the Brain

Cerebral Angiography (CA): Tool specifically looking at the vessels of the brain

Computed Tomographic Scanning (CT): Computer-enhanced X-ray image of the brain or body

Magnetic Resonance Imaging (MRI): Uses a strong magnetic field, not an X-ray, to produce an image

Functional MRI (fMRI): MRI that also records brain activity

Positron Emission Tomography (PET): Computer-generated color image of brain activity, based on glucose consumption in the brain

Researching the Brain

Cerebral Angiography (CA): Tool specifically looking at the vessels of the brain

Computed Tomographic Scanning (CT): Computer-enhanced X-ray image of the brain or body

Magnetic Resonance Imaging (MRI): Uses a strong magnetic field, not an X-ray, to produce an image

Functional MRI (fMRI): MRI that also records brain activity

Positron Emission Tomography (PET): Computer-generated color image of brain activity, based on glucose consumption in the brain

BIOPSYCHOLOGY 8eJohn P.J. Pinel

Copyright © Pearson Education 2011

Clinical Observation

Study effects of accidents/brain damage

(oldest way of studying) Strokes Traumatic Injury Tumor Lesion

Clinical Observation

Frontal lobotomyPhineas

Gage

Methods of Visualizing the Living Human Brain

Contrast X-rays – inject something that absorbs X-rays less or more than surrounding tissue cerebral angiography

About 1.5 to 5 percent of the general population has or will develop a cerebral aneurysm. 3 to 5 million people in the United States have cerebral

aneurysms, but most are not producing any symptoms. Between 0.5 and 3 percent of people with a brain aneurysm may

suffer from bleeding.


Angiography: study of blood vessels, by the use of contrast to make the vessels visible under fluoroscopic procedures.

Cerebral angiography: specifically looking at the vessels of the brain Done to detect abnormalities, blockages, or for

therapeutic reasons COST: $4,000

FIGURE A cerebral angiogram of a healthy subject.

Cerebral Angiography

Cerebral angiography may also help figure out the cause of certain symptoms, including:

severe headaches loss of memory slurred speech dizziness blurred or double vision weakness or numbness loss of balance or coordination

Computed Tomography

http://www.stabroeknews.com/images/2009/08/20090830ctscan.jpg

http://upload.wikimedia.org/wikipedia/commons/archive/d/da/20060904231838!Head_CT_scan.jpg

http://www.capitalhealth.org/subpage.cfm?ref=36

X-Ray Computed Tomography

Computed tomography (CT) scanning builds up a picture of the brain based on the differential absorption of X-rays.

During a CT scan the subject lies on a table that slides in and out of a hollow, cylindrical apparatus.

An x-ray source rides on a ring around the inside of the tube, with its beam aimed at the subjects head.

Methods of Visualizing and Stimulating the Living Human Brain

• Contrast X-rays – inject something that absorbs X-rays less or more than surrounding tissue

Cerebral Angiography

• X-Ray Computed Tomography Computer-assisted

X-ray procedure

Provides a 3-D representation

of the brain

FIGURE: Computed tomography (CT) uses X-rays to create a CT scan of the brain.

FIGURE: Computed tomography (CT) uses X-rays to create a CT scan of the brain.

X-Ray Computed Tomography

After passing through the head, the beam is sampled by one of the many detectors that line the machine’s circumference.

Images made using x-rays depend on the absorption of the beam by the tissue it passes through.

Bone and hard tissue absorb x-rays well, air and water absorb very little and soft tissue is somewhere in between. Thus, CT scans reveal the gross features of the brain

but do not resolve its structure well.

CT SCANS STROKE

Copyright © 2011 Pearson Education, Inc. All rights reserved.

Siemens Allegra 3TMagnetic Resonance Imaging (MRI)

Open MRI

Claustrophobic MRI


Magnetic resonance imaging (MRI) High resolution images Constructed from measurement of waves that

hydrogen atoms emit when activated within a magnetic field

Magnetic Resonance Imaging (MRI)

Magnetic Resonance Imaging (MRI) is a test that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures inside the body.

In many cases, MRI gives different information about structures in the body than can be seen with an X-Ray, Ultrasound, or Computed Tomography (CT). MRI also may show problems that cannot be seen

with other imaging methods

-49-

MRI vs CT in the Brain Skull gets in the way of X-ray imaging:

Bone scatters X-rays much more than soft tissue MRI radio waves pass unimpeded through bone

Same patient

FIGURE 5.3 A color-enhanced midsagittal MRI scan.

FIGURE 5.4 Structural MRI can be used to provide three-dimensional images of the entire brain. (Courtesy of Bruce Foster and Robert Hare, University of British Columbia.)

Fig. Post Contrast Axial MR Image of the brain

1

2

3

4

5

Answers

1. Cisterna Magna

2. Cervical Cord3. Nasopharynx4. Mandible5. Maxillary Sinus


7

6Answers

6. Medulla7. Sigmoid Sinus


15

8

9

10

11

12

13

14

16

178. Cerebellar Hemisphere9. Vermis10. IV Ventricle

11. Pons12. Basilar Artery

13. Internal Carotid Artery14. Cavernous Sinus15. Middle Cerebellar Peduncle16. Internal Auditory Canal

17. Temporal Lobe


18

19

20

21

22

Answers

18. Aqueduct of Sylvius

19. Midbrain20. Orbits21. Posterior Cerebral Artery22. Middle Cerebral Artery


23

24

25

26

27

Answers

23. Occipital Lobe24. III Ventricle

25. Frontal Lobe26. Temporal Lobe27. Sylvian Fissure


28

29

30

31

32

38

33

34

36

35

37

Answers

28. Superior Sagittal Sinus

29. Occipital Lobe30. Choroid Plexus within the occipital horn31. Internal Cerebral Vein32. Frontal Horn

33. Thalamus34. Temporal Lobe35. Internal Capsule36. Putamen37. Caudate Nucleus

38. Frontal Lobe


45

46

Answers

45. Parietal Lobe46. Frontal Lobe

Magnetic Resonance Imaging

According to this study released by Medicare, the average cost of an MRI is $2,611

Underwood Memorial Hospital in New Jersey reported an average of $13,259 for an MRI

Northbay Medical Center in California reported the average cost at $9,766

Positron Emission Tomography (PET) Inject a radioactive

substance in an individual.

Usually some radioactive sugar that produces gamma rays.

When the brain metabolizes (burns) the sugar, the PET machine will measure it.

Great diagnostic tool for showing abnormalities in brain activity.


Positron emission tomography (PET) Provides images of brain activity Scan is an image of levels of radioactivity in

various parts of one horizontal level of the brain A radiolabeled substance is administered prior to

the scan

FIGURE A series of PET scans. (From “Positron Tomography: Human Brain Function and Biochemistry” by Michael E. Phelps and John C. Mazziotta, Science, 228 [9701], May 17, 1985, p. 804. Copyright 1985 by the AAAS. Reprinted by permission. Courtesy of Drs. Michael E. Phelps and John Mazziotta, UCLA School of Medicine.)

PET (Positron Emission Tomography)

SPECT (Single Photon Emission Computed Tomography) Advantages

Allows functional and biochemical studies Provides visual image corresponding to anatomy Can identify specific receptors or transporters

associated with some neurotransmitters

Disadvantages Requires exposure to low levels of radioactivity Provides spatial resolution better than that of EEG,

but poorer than that of MRI Cannot follow rapid changes (faster than 30 seconds)

How it works

A short lived radioactive tracer isotope, is injected in to the living subject (usually in to blood circulation) . The tracer is chemically incorporated in to a biologically active molecule.

There is a waiting period while the active molecule becomes concentrated in tissues of interest.

As the radioisotope undergoes positron emission decay (also known as positive beta decay), it emits a positron, an antiparticle of the electron with opposite charge.

After traveling up to a few millimeters the positron encounter an electron.

The encounter annihilates them both, producing a pair of (gamma) photon moving in opposite directions.

These are detected when they reach scintillator in the scanning device creating a burst of light which is detected by photomultiplier tubes.

The technicians can then create an image of the parts of your brain, for example which are overactive.

PET SCAN

Uses

Detect cancer. Determine whether a cancer has spread in the body. Assess the effectiveness of a treatment plan, such as cancer therapy. Determine if a cancer has returned after treatment. Determine blood flow to the heart muscle. Determine the effects of a heart attack, or myocardial infarction, on areas of the

heart. Identify areas of the heart muscle that would benefit from a procedure such as

angioplasty or coronary artery bypass surgery (in combination with a myocardial perfusion scan).

Evaluate brain abnormalities, such as tumors, memory disorders and seizures and other central nervous system disorders.

To map normal human brain and heart function.

Patients with Brain Disorders

PET scans of the brain are used to evaluate patients who have memory disorders of an undetermined cause, suspected or proven brain tumors or seizure disorders that are not responsive to medical therapy and are therefore candidates for surgery.

http://www.radiologyinfo.org/content/petomography.htm

Normal brain Image of the brain of a 9 year old female with a history of seizures poorly controlled by medication. PET imaging identifies the area (indicated by the arrow) of the brain responsible for the seizures. Through surgical removal of this area of the brain, the patient is rendered "seizure-free".

Htt://www.nucmed.buffalo.edu/petdef.htm

Alzheimer’s disease

With Alzheimer’s disease there is no gross structural abnormality, but PET is able to show a biochemical change.

ADHD



Functional MRI (fMRI) Provides images of brain structure and activity As with MRI uses strong magnetic field Structure is imaged using waves emitted by

hydrogen ions Function is imaged using signal created from

interaction between oxygen and iron in the blood BOLD signal

1. What is fMRI ?

1. What is fMRI ?

isn’t

fMRI is not Bumpology

Phrenology claimed that bumps on the skull reflected exaggerated functions/traits

It lacked any mechanism underlying its claims.

It used anecdotal, rather than scientific, evidence.

Nevertheless, its central idea persisted:

Localization of FunctionFranz Joseph Gall (1758-1828)

Johann Spurzheim (1776-1832)

from Gall (c. 1810)

fMRI is not Mind-Reading

This is not an anti-thought.This is not a thought.

This is not a thought.

FMRI – Week 1 – Introduction

Scott Huettel, Duke University

fMRI is not a Window on the Brain

“Mirror neuron activity in the right posterior inferior frontal gyrus – indicating identification and empathy - while watching the Disney/NFL ad.”

rIFG

“Ventral striatum activity – indicating reward processing - while watching the Disney/NFL ad.”

ventStr

[Citations omitted to protect the offenders.]

fMRI is not invasive

Positron Emission Tomography (PET)

Intracranial Stimulation / Recording

FMRI is… a technique for measuring metabolic correlates of neuronal activity

Uses a standard MRI scanner Acquires a series of images (numbers) Measures changes in blood oxygenation Use non-invasive, non-ionizing radiation Can be repeated many times; can be used for a wide

range of subjects Combines good spatial and reasonable temporal

resolution

fMRI is a Measurement Technique…

BRAINBRAIN BEHAVIORBEHAVIOR

Measurement Techniques

fMRI, PET, EEG

Manipulation Techniques

Lesions, TMS, Stimulation

… that provides information about a wide range of topics.

Berns et al. (2006) Science

From what we see… (ocular dominance columns)

… to what we feel. (the dread of an upcoming shock)



Contrast: Conceptual Overview

Contrast: Anatomical

Contrast: 1) An intensity difference between quantities: “How much?” 2) The quantity being measured: “What?”

Contrast-to-noise: The magnitude of the intensity difference between quantities divided by the variability in their measurements.

Contrast: Functional

Contrast-to-noise is critical for fMRI: How effectively can we decide whether a given brain region has property X or property Y?



Spatial Resolution: Examples

~8mm~8mm22 ~4mm~4mm22 ~2mm~2mm22

~1.5mm~1.5mm22 ~1mm~1mm22



Functional ResolutionThe ability of a measurement technique to identify the

relation between underlying neuronal activity and a cognitive or behavioral phenomenon.

Functional resolution is limited both by the intrinsic properties of our brain measure and by our ability to

manipulate the experimental design to allow variation in the phenomenon of interest.

ADHD

Healthy Older Adult

Mr. Sarver



Schizophrenia

Magnetoencephalography (MEG)


Magnetoencephalography (MEG) A measure of neural activity Measures changes in magnetic fields on the

surface of the scalp Created by underlying patterns of neural activity

Fast temporal resolution

MEG

MEG has advantages over both fMRI and EEG.

The technologies complement each other, but only MEG provides timing as well as spatial information about brain activity.

fMRI signals reflect brain activity indirectly, by measuring the oxygenation of blood flowing near active neurons



Transcranial magnetic stimulation (TMS) NOT a measure of neural activity But provides an experimental probe to alter neural

activity TMS applies a brief, strong magnetic field that

alters neural activity Can either activate or “deactivate” brain structures Observe changes in behavior

• Scalp electroencephalography (EEG)

Measure of gross electrical activity of the brain

Uses electrodes attached to scalp

• Many techniques of EEG Wave form assessment (e.g.,

alpha waves) Event-related potentials

(ERPs) Combination of EEG with MRI

Recording Human Psychophysiological Activity

Electrical Stimulation

Note effect of weak electrical currents on behavior

Can be used on humans or animals

Electroencephalograph (EEG)Electrodes measure electrical waves sweeping across

surface of the brain

EEG (Electroencephalography)

Technique: Multiple electrodes are pasted to outside of head

What it shows: A single line that charts the summated electrical fields resulting from the activity of billions of neurons

Electroencephalogram (EEG)

Most widely used in sleep research.

It can measure what stage of sleep you are in.

1st, 2nd, 3rd, 4th

REM (Rapid Eye Movement)

Not that accurate in research showing us localization of function.

EEG (Electroencephalogram)

Advantages Detects very rapid changes in electrical activity,

allowing analysis of stages of cognitive activity

Disadvantages Provides poor spatial resolution of source of

electrical activity

Behavioral Research Methods of Biopsychology

Neuropsychological Testing: Time-consuming – only conducted on a

small portion of those with brain damage Assists in diagnosing neural disorders Serves as a basis for counseling/caring Provides information on effectiveness and

side effects of treatment

Tests of Specific Neuropsychological Function

Memory – exploring nature of deficits Short-term, long-term, or both? Anterograde or retrograde? Semantic or episodic? Explicit or implicit? (repetition priming tests)

Language – problems of phonology, syntax, or semantics

Frontal-Lobe Function Wisconsin Card Sorting Task

FIGURE The Wisconsin Card Sorting Test.

Behavioral Methods of Cognitive Neuroscience

Goal is to identify the parts of the brain that mediate various constituent cognitive processes

Paired-image subtraction technique: compare PET or fMRI images during several different cognitive tasks

Biopsychological Paradigms of Animal Behavior

Procedures developed for the investigation of a particular behavioral phenomenon

Assessment of Species-Common Behaviors: Open-field Test

anxiety, activity Tests of Aggressive and Defensive Behavior Tests of Sexual Behavior

Biopsychological Paradigms of Animal Behavior Continued

Seminatural Animal Learning Paradigms continued: Morris Water Maze

Spatial learning Rat must find hidden platform in an opaque pool

Conditioned Defensive Burying Following a single aversive stimulus delivered from an object,

rats will spray bedding at the object Anti-anxiety drugs decrease the amount of burying behavior

FIGURE A radial arm maze.

Understanding What Biopsychologists Do UNIT 3 The Research Methods of Biopsychology.

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