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Neurological Basis of Behavior (PSY - 610)

Lesson16

RESEARCH METHODS AND TECHNIQUES OF ASSESSMENT OF BRAIN FUNCTION

Objectives:

To familiarize the students with

· The various techniques used to study the brain and its function and structures.

· Invasive vs. Non- Invasive methods, Stereotaxic surgery.

· Stereotaxic Atlas used for brain surgery and manipulation,

· Hislotogical and cytological methods for Cell staining, Radio labelling, Flourescence,

autoradiography, Lesioning and electrical stimulation, single cell recordings, push-pull

cannulae.

· The advanced techniques such as MRI, fMRI, CAT, PET, CT, EEG, EOG, EMG, X Ray etc

Histological, electrical chemical and pharmacological processes and techniques why so many?

· Advanced technologies and methodologies

Pharmacological paradigms: Drugs administered into the system in a wide range of procedures

varying from drugs entering the body (various procedures again) or directly into the brain. This is done

to identify the changes in behavior or electrical/chemical changes of the neurons, their transmission and

also to assay metabolites for chemical analysis. There are several methods for drug administration and

different routes:

a) Through oral ingestion: drugs fed to the subject (human, animal)

b) Administration/ Injection through various routes: When the drug is tubed directly into the

stomach bypassing the oral region this is known as the intra gastric (IG) procedure. When a drug is

injected into peritoneum (the stomach region) it is known as the intraperitoneal or IP procedure.

When drug is injected into the in large muscles such as the forearm or the thigh this is known as the

IM or intramuscular route. When drug is injected under into the space under skin this is known as the

Sub Cutaneous (SC) procedure. The IV (intravenous) is injecting directly into circulatory system for

a rapid action), and even more rapid is the IV (intraventricular) where substance is injected directly

into the brain, into the ventricles, using the stereotaxic apparatus. This procedure is quickest way of

reaching the brain, but needs skills of a neurosurgeon.

Behavioral paradigms: are used to control, simplify and objectify behaviour at molar level. Behavioral

paradigms are used to produce investigate measure behaviour under control conditions. They measure

higher order functioning through experiments in which behaviors are manipulated.

Psychological/ Experimental paradigms

Conditioning: One of the most commonly used paradigms in early research on brain-behavior

relationships. These experiments have provided information on sensory, motor, motivational and

cognitive state of the animal through its ability to learn task or unlearn it. The findings of some of

the experiments are a) self stimulation behaviors: animals were trained using the conditioning

paradigm of pressing the level for food, and it was discovered that animals preferred to electrically

stimulate themselves, b) animals learn to avoid certain foods which made them sick: Conditioned

Taste aversions c) T maze and homing behaviour: Using the T maze experiments were carried out,

where animals had to make a choice between food or drugs ( variation could be food or mother), or

young animals could learn to locate their nest

Neurological Basis of Behavior (PSY - 610)

Seminatural learning paradigm. These are paradigms which use a combination of laboratory

conditions+ naturalistic behavior which are measured and observed under control conditions. The

following examples are given:

a) Addiction: rats in the laboratory housing were given free access to choose between water or

morphine bottles. These were available and refilled whenever these bottles are empty. The amount

consumed gives a comparison.

b) Early experiences of Harlow's monkeys. These experiments were carried out by Harry Harlow

and his colleagues at the University of Wisconsin Primate Center. He studied the effects of

separation and lack of contact on the development of the young primates.

c) Water Mazes. These experiments are carried out to assess motor development of young animals,

their ability to learn using a different modality.

d) Other paradigms: the Sleep platforms where rats are set up to sleep, and when they go into REM

they fall off the platform. Hoarding behaviors: increasing temperature in the cage, or lowering food

available to see the effects on animals trying to hoard material in their cages.- crowded vs. solitary

those animals reared in crowded conditions, vs., normal conditions with mother and siblings, and

those without any of these. The difference in the three groups would show the importance of social

influence. External stimulation during early development, many experiments have shown that early

stimulation during early development affects brain development.

No one method is the right or the wrong one. These can be sued separately or in combinations. It

depends on the research area the question, and the expertise of the researcher.

Neuropsychological Testing: Neurologists assess damage to the Nervous System using simple,

sensory- motor functional tests. Psychologists ask the question, what about emotional, behavioral

and cognitive functioning? The specialized functions are assessed by the neurophysiologists who

aim to understand the extent of the damage and to identify areas which can be used for

rehabilitation. Neuropsychological testing requires several hours spread over 2-3 day. Why does it

take so long? Because we use the test results

A) To identify diagnose and support finding of other (PET, CAT, MRI),

B) Provide rehabilitation and counseling

C) To assess and evaluate if treatment or therapy ahs been effective

There are specialized tests for memory, language, intelligence, cognitive functions, attention,

perceptual and motor functions. There are also tests for hemispheric functioning

WAIS as a Neuropsychological test

The General Intelligence test Weschler Adult Intelligence Scale (WAIS) and Weschler Child

Intelligence Scale (WISC) are used as part of Halstead Reitan Battery.

If a patient scores low on verbal as compared to the performance tests we can suspect left

hemisphere deficit,

If the Picture completion performance is poor then we suspect memory and visual spatial

deficits, which are right hemisphere functions

Poor performance on the Block Design indicates Left/right Posterior parietal damage

For Language: the Sodium Amytal tests (where an anesthetic substance is injected in the

carotid artery whereby one side of the brain is anaesthetized and cannot function or respond.

The dichotic listening test simultaneously words or sounds are given to both ears- and the

preferred ear responds, Speech and Rhythm tests (Hallstead Reitan and Luria Nebraska

batteries)

Neurological Basis of Behavior (PSY - 610)

Harris Tests of lateral Dominance: these are 11 quick tests to assess dominance of eye, ear,

foot, and hand; Assessments also give scores on congruence of hand eye ear and foot

dominance. Difficulties such as reading and writing deficits arise if there is non congruence

between eye, hand and feet.

References

1. Kalat J.W (1998) Biological Psychology Brooks/ Cole Publishing

2. Carlson N.R. (2005) Foundations of Physiological Psychology Allyn and Bacon, Boston

3. Pinel, John P.J. (2003) Biopsychology (5th edition) Allyn and Bacon Singapore

4 Bloom F, Nelson and Lazerson (2001), Behavioral Neuroscience: Brain, Mind and Behaviors (3rd

edition) Worth Publishers New York

5. Bridgeman,B (1988)The Biology of Behaviour and Mind. John Wiley and Sons New York

6. Seigel,G.J. ( Ed. in chief) Agranoff, B.W, Albers W.R. and Molinoff, P.B. (Eds) Basic

Neurochemistry: Molecular, Cellular and Medical Aspects.

7. Brown,T.S. And Wallace. (1980) P.M Physiological Psychology

Academic Press New York

Note: References #2, 3, and 4 are followed most closely, as they have been used in teaching as well;

further individual references/pages are also given on the power points of each lesson

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