W3 L6 211 Flashcards
Approaches to Neuropsychological Testing
Single Test
§ To detect presence of brain damage.
§ Discriminate patients with psychological problems resulting from structural rather than functional changes to the brain.
Standardised-Test Battery
Single Test
§ Unsuccessful: one test fails to detect the multitude of psychological symptoms that occur in a single brain-damaged patient.
Standardised-Test Battery
§ To detect presence of brain damage; §
§ Involved using a ‘set’ of tests.
§ E.g. California verbal learning test,
Iowa gambling task, lexical decision task, memory assessment scales, and several more.
§ Score in each test are added together to form an aggregate.
§ If the aggregate score falls below the designated cutoff, the patient is diagnosed with brain damage.
Unsuccessful: discriminate between neurological patients and healthy patients, but not very good at discriminating between neurological patients and psychiatric patients.
Customised-Test Battery
§ Highly successful; used routinely in hospitals for clinical diagnosis and in the laboratory for scientific investigation.
§ To characterise the nature of the psychological deficits of each brain- damaged patient.
§ Starts with a handful of selected tests to provide an indication of the general neuropsychological impairment.
§ On the basis of the common battery, the patient is subjected to a customised series of tests to provide more detail of the specific symptoms.
Customised-Test Battery
§ Successful: Measure aspects of psychological function.
§ The interpretation of the test does not rely on how well the patients performs on the test. The focus is on the cognitive strategy the patient employs (brain damage often changes that strategy without lowering the score). Need strategies, to be specific and focus on areas to test,
Neuropsychological Testing
§ Neuropsychological tests are specifically designed tasks used to measure a psychological function known to be linked to a particular brain structure or pathway.
§ Memory
§ Intelligence
§ Language
§ Visuoperception
§ Executive function
§ Several advantages to neurospychological assessments:
§ Clinical diagnosis
§ Scientific investigation
§ Provide a basis for caring and counseling for patients
§ Provide a means of evaluating the effectiveness of treatment and
seriousness of its side effects
Can be long.
Also people with brain damage often are non selective areas.
Isolating region difficukt for these tests.
Matching sample due to all of this is almost impossible,
The Wechsler Adult Intelligence Scale (WAIS)
Basic functions everyone is tested on.
Note intelligence and IQ seperate.
Iq can help mak inference, as it has different areas.
WAIS weakness:
Not good at detecting Emory weakness.
Intelligence quotient (IQ) - Poor indicator of brain damage but can be used to make inferences about general neuropsychological dysfunction
§ Memory - Not sensitive enough to detect memory problems per se. Only has digit span, least likely to be affected by brain damage. nothing about episodic or others,
§ Language - Token test (Touch the red square: patient must follow instructions) lately see function: located in one hemisphere! Left,
Language Lateralisation: Tests
The Sodium Amytal Test (Wada and Rasmussen, 1960)
Dichotic Listening Task (Broadbent, 1954; Kimura,1961
Left carotid artery, invasive injection. Ipsilateral hemisphere anesthetized.
§ The left hemisphere participates more in language than the right hemisphere
§ Language lateralisation is important to detect before surgery, in case there is a difference.
No matter if left or right handed apparently.
Also dichotic test
Person wear stereo headphones.
§ Three digits are presented to both ears simultaneously.
§ Patients must report as many of the six digits as they can.
§ Typically, subjects correctly report more digits heard by the
ear contralateral to the dominant hemisphere.
Neuropsychological Tests - Memory
What is the nature of the memory deficit?
§ Does it involve short-term, long-term memory, or both?
§ Is it anterograde (can no longer retain new info) or retrograde, or both?
§ Is the deficit one of semantic memory or episodic memory?
§ Is the deficit one of explicit memory (e.g. remembering an appointment) or implicit memory (e.g. riding a bike; tying a shoe lace), or both?
Neuropsychological Tests - Language
What is the nature of the language deficit?
§ It is a phonological problem?
§ Is it a problem of syntax?
§ Is it a semantic problem?
§ Is it a reading problem (e.g. dyslexia)?.
Wisconsin Card Sort Task (WCST) (Milner 1964) A Test of Frontal Lobe Function
Really a test of cognitive flexibility
Good for frontal lobe injury, unlike others for temporal I think.
§ Subject is presented with four stimulus cards which differ in several dimensions (e.g. colour, shape, number)
§ The cards have to be sorted according to one dimension (e.g. number)
§ The only feedback the subject receives is “correct” or “incorrect.”
§ When the subject has established the correct category, the rule is changed without warning.
§ Now, the cards must be sorted according to a new dimension (e.g. colour)
§ Patients with frontal damage continue to sort on the basis of one sorting strategy: perseveration.
Behavioural Methods of Research in Animals
Behavioural Paradigms of Animal Behaviour
A behavioural paradigm is a single set of procedures used to
investigate a particular behavioural phenomona, e. g.
§ Paradigms for the assessment of species common behaviour
- Displayed by virtually all members of that species (e.g. nesting)
§ Traditional conditioning paradigms
- Play a major role in learning. Animals have to be trained to
behave in a fashion consistent with the goals of the experiment.
§ Seminatural animal learning paradigms
- Animal exposed to a learning environment that mimics their
natural environment.
Tests assessing species common behaviours
Open-Field Test - a test of general activity
§ Animal placed in a large, open arena and general activity is recorded.
§ It is also normal to count the number of boluses (pieces of excrement)
§ Low activity and high bolus counts indicate fearfulness.
§ Fearful rats tend to be “thigmotaxic”; they rarely venture away from thewalls
Screening method for drugs,
Note: rats laugh. Actually have frequenxy ranges.
Colony-Intruder task - a test of aggressive and defensive behaviour
§ Usually measured during combative encounters between a dominate male rat in an established colony and a smaller male intruder. Biting rear. Piloerection, makes look bigger, like cat attack lol. Or pinning down.
§ Dominant male is typically aggressive whereas the hapless intruder is defensive.
Elevated Plus Maze - a test of anxiety and defensive behaviours
Open and closed ended arms. Anxious rate stay in closed arms.
Tests of sexual behaviour
§ Typically the male mounts the female from behind by clasping her hindquarters. Uses ear wiggle first.
§ If she is receptive, she assumes a position of “lordosis;” sticks her hindquarters in the air and bends her back into a U.
§ During some mounts, the male will penetrate the female (intromission).
§ He may then dismount, jump back and return a few seconds later.
§ He may only ejaculate after about 10 cycles of mounting, dismounting and intromitting.
Intervals, and lordosis quotients many possible measures.
Conditioning paradigms
Contemporary animal learning theory aside.
§ Conditioning paradigms involve a learned relationship called associations.
§ Two major classes of relations between events:
1) Predictive relations between stimuli and outcomes
(Pavlovian or classical conditioning)
2) Causal relations between actions/responses and outcomes
(Operant or instrumental conditioning)
§ Determining which relationship controls behaviour is no easy task
Pavlovian Conditioning (Ivan Pavlov 1927)
Phases
1
2
3
4
§ A learning process in which two stimuli are paired
§ The stimuli are under the control of the experimenter
§ The subjects own behaviour has no role in the presentation
of food
§ The animals behaviour is elicited by the conditioned
stimulus
Are automatic/ reflexive like getting hungry (for food and sex) also drug addiction. See-do
Instrumental behaviour and the Puzzle box (Thorndike,1938)
Thorndike’s Puzzle Box
Learning curve for solving the puzzle box
§ The reward is contingent on the cat performing an action/ response (i.e. unlatch the door)
§ A gradual decrease in escape latencies provides an index of learning
Hmm, but this is also just a chance association paired positive stim leading to action. But cc above can do similar thing, interesting,
But unlike Pavlovian cond. the animal must ACT on his enviro. It is contingent on it!
Now to operant conditioning by Skinner
A rat pressing a lever for reward in a Skinner
Box (Operant Chamber)
Operant Conditioning (Skinner, 1938)
§ The animals behaviour is instrumental in determining its outcome (e.g. reward)
§ The animals behaviour is emitted (and voluntary)
§ Instrumental responses are operants
§ Operant behaviour can be strengthened and weakened by
its consequences
Discrimination learning using touchscreen operant chambers video
The 5 Choice Reaction Time Task (5CRTT): A Test of Visuospatial Attention (Carli et al., 1983)
§ light is presented in one of 5 spatial locations, randomly
§ Duration of light is 0.5 sec
§ Rat must detect the light by making a nosepoke in the hole in which the light appeared measure impulsivity and compulsively and like past two AUTOMOTATED, saves time, and more precise. Sample prinicples as Skinner box.
Seminatural Animal Learning Paradigms
§ The animal is exposed to an environment that mimics their natural environment
§ Learning is likely to be highly developed and more directly related to innate neural mechanisms
§ Four common seminatural learning environments:
1) Conditioned taste aversion
The platform located in same position but the start position varies from trial to trial
§ An avoidance response that develops as a consequence of consuming something that lead to illness
Injected with a nausea-inducing drug (emetic) such as Lithium Chloride (LiCl)
Consume food and get sick.
§ Rats are neophobic (afraid of new things). Eat a little get sick, avoid food thereafter. Cancer patients too, nausea inducing. Drinking to excess…
2) Radial arm maze: 16-1-8 arms through history,
Four arms are baited.
§ Rats learn to enter the arms
baited with food and rarely enter a nonbaited arm.
§ In training, four arms are baited. Four arms are blocked. Rat must enter baited arms for food.
§ After a delay, the rat is put back into the central arena. This time all arms are open.
§ Now, only the ‘previously blocked arms’ are baited.
§ The rat must enter the arms he did not enter in the training phase to get food. Show animals have a gps navigation system. Shift behaviour to blocked arms. Turn maze around. Or curtain.
3) Morris water maze
4) Conditioned defensive burying
A test of anxiety.
§ Rats receive a single aversive stimulus.
§ The aversive stimulus comes from an object mounted in the wall of chamber just above the floor.
§ The rat learns that the mounted object is a threat.
§ The rat responds by spraying the object with bedding and burying it.
§ Anxiolytic drugs reduce the amount of conditioned burying.
