04research methods in biopsychology

[A] What are the three primary functional categories of methods used to study brain functions?

1. Visualize brain structure or activity in brain areas

2. Measure brain activity and investigate behavior/cognition

3. Stimulate brain areas and investigate behavior/cognition

[A-ExQ] What is Computed Tomography (CT / CAT), what is its imaging principle, and what structures does it show best?

• Terms: CT (Computed Tomography) and CAT (Computerized Axial Tomography) refer to the exact same technique.

• Imaging Principle: Uses X-rays (absorption of X-rays) to create 3D representations of the brain.

• Safety & Cost: Involves radiation exposure; shorter examination time (5–10 min) and lower cost than MRI.

• Resolution: High detail for bony structures; lower detail for soft tissue compared to MRI.

• Preferred areas: lung, abdomen, bone etc.

• Weren’t used for brain function

[A] How does Structural MRI differ from CT in terms of imaging principle, safety, and soft tissue detail?

• Imaging Principle: Uses strong magnetic fields and radio waves (no X-rays / no radiation exposure), to create images of inside the body

• Examination Time & Cost: Longer examination time (15–45 min) and higher cost than CT.

• Resolution: Provides higher detail in soft tissue (e.g., brain, spinal cord, junctions=preferred areas) compared to CT, lower detail in bony structures

Why does MRI work?

• Most of human body made up of water molecules, which consist of hydrogen and oxygen atoms

• each hydrogen atom contains a proton which acts like tiny magnet and is very sensitive to magnetic fields

[B] What are the 5 primary EEG frequency bands (oscillations) and which functional/mental states are they associated with?

• Delta (δ): Sleep.

• Theta (θ): Drowsiness, learning and memory processes.

• Alpha (α): Relaxed awake state (e.g., eyes closed).

• Beta (β): Mental, physical, and psychological activity.

• Gamma (γ): Representation and analysis of perceptual objects

[A] How do radio-ligands in PET imaging visualize neurotransmitter receptors, and what does the color scale indicate?

• Mechanism: Radio-ligands are radioactive molecules injected into the body that specifically bind to target structures (neurotransmitters, receptors, transporters, or amyloid plaques).

• Example: Radio-ligand ¹¹C-WAY-100635 used for imaging serotonin receptors.

• Color Scale:

  • Red / Warm colors: Highest radioactivity → The redder the color, the higher the receptor density / binding.

  • Blue / Cool colors: Low or no activity / binding.

[B] Compare EEG, fMRI, PET, and TMS in terms of their spatial and temporal resolution based on the Sejnowski neuroscience methods matrix

• EEG / MEG:

  • Temporal Resolution: Extremely HIGH (milliseconds range). Best for tracking fast real-time activity and ERPs.

  • Spatial Resolution: LOW (brain lobe level, 10–100 mm).

• fMRI:

  • Temporal Resolution: LOW / SLOW (seconds range, delayed by BOLD hemodynamic response).

  • Spatial Resolution: HIGH (millimeter range, 1–3 mm). Best for precise anatomical localization of active regions.

• PET Imaging:

  • Temporal Resolution: VERY LOW (minutes to hours).

  • Spatial Resolution: MODERATE to HIGH (5–10 mm). Best for mapping neurotransmitter receptor density.

• TMS:

  • Temporal Resolution: HIGH (milliseconds pulse application).

  • Spatial Resolution: MODERATE (cortical target region). Provides direct causal testing.

[A] What is Transcranial Magnetic Stimulation (TMS), how does it work, and what are its 3 main advantages?

• Definition: An electromagnetic coil is positioned next to the skull to temporarily turn off or on a specific area of the human cortex.

• Main Purpose: Allows researchers to assess direct consequences of brain (in)activity on cognition and behavior (establishes causality).

• 3 Key Advantages:

  1. Non-invasive method.

  2. Serves as a direct measure of causal relations between brain (in)activity and behavior/cognition.

  3. Can be used prior to surgery (e.g., tumor removal) to determine how much tissue can/should be safely removed

[A-keep in mind] What does Functional MRI (fMRI) measure, and how does the BOLD signal work?

• BOLD Signal: Stands for Blood Oxygenation Level Dependent signal.

• Mechanism:

  1. Active brain areas experience increased energy demand and higher oxygen consumption.

  2. Proportion of deoxyhemoglobin ( in blood) initially increases.

  3. Vascular response increases local blood supply, causing oxygen concentration to increase

• Hemodynamic Response Function: A mathematical model describing the temporal changes of the BOLD signal in a brain region following neural activity

• Different magnetic susceptibility of oxygenated and deoxygenated blood → MR signal

• (How magnetic changes depends on arounding tissue?- richtig verstanden?)

[A]What is Positron-Emission Tomography (PET), and how are radio-ligands used?

• Mechanism: Involves injecting radioactive chemicals (e.g., 18F-DOPA or radioactive 2-deoxyglucose).

• Chemical: 18F-DOPA = radioactive analog of L-DOPA → absorbed by cells that actively produce dopamine or serotonin

• Radio-ligands: Ions or molecules that bind to other molecules, allowing researchers to identify the distribution of specific neurotransmitters, receptors, transporters, or amyloid plaques.

• Example: 18F-DOPA is absorbed by cells actively producing dopamine or serotonin (used in studying Parkinson's disease)

Positron-emission tomography (PET) what is it similar to and by what is it taken up?

• Chemical: Radioactive fluorodeoxyglucose (FDG) = similar to glucose → rapidly taken up by active (energy-consuming) cells

[A] What is the principle of fNIRS, its depth limit, and its pros/cons?

• Principle: Photons scatter through the brain ("photon banana" path) within the Near-Infrared (NIR) window and are absorbed differently by oxygenated (HbO2) and deoxygenated (Hb) hemoglobin (absorbing structure)

• Mass movement of photons is predictable

• Concentration of HbO2 und Hb can be measured

• Depth Limit: Penetrates only 2–3 mm deep into the cortex.

• Pros: Transportable/flexible (usable in natural environments), relatively inexpensive, robust against external movement, artifacts

• Cons: Lower temporal and spatial resolution; restricted to cortex only

[A-ExQ] What is Transcranial Magnetic Stimulation (TMS), and why is it crucial for establishing causality?

• Definition: An electromagnetic coil positioned next to the skull turns off or on a specific area of the human cortex.

• Causality: While neuroimaging shows correlations, TMS serves as a direct non-invasive measure of causal relations between brain (in)activity and behavior/cognition.

• (Explicitly tested in sample exam question as a non-invasive method!)

[A] What does Electroencephalography (EEG) record, and what is the 10–20 System?

• Recording: Records the electrical activity of brain cells (neurons) through electrodes attached to the scalp.

• 10–20 System: Standardized international electrode placement system based on relative distances (10% and 20%) between anatomical landmarks (Nion, Inion, Preauricular points).

• Temporal Resolution: Provides extremely high temporal resolution (millisecond range)

[A] How is the output processed according to EEG and what distinction does it allow?

• Output Processing: The raw electrical signal/output is amplified and recorded.

• Distinction: Allows researchers to differentiate between spontaneous brain activity (e.g., ongoing brain waves/oscillations) and activity in response to a stimulus (Event-Related Potentials / ERPs)

[A-ExQ] What does Electromyography (EMG) measure, and which part of the nervous system does it assess?

• Measurement: Measures the level of muscle tension (electrical activity generated when muscles contract) using surface electrodes.

• Nervous System Division: Measures activity of the Somatic Nervous System.

• (Explicitly tested in sample exam question!)

[A-ExQ] What does Electrooculography (EOG) record, and how is it applied?

• Measurement: Records eye movements by placing electrodes above/below and left/right of the eye.

• Invasiveness: Completely non-invasive.

• Application: Serves as an indicator of attention, perception, arousal, and sleep stages, etc.

• (Explicitly tested in sample exam question!)

• (Eye has + and - side and at these points it got measured the movement - so I understand it)

[B] What are Event-Related Potentials (ERPs), and what cognitive processes do N1, P2, N2, and P3 reflect?

• ERP Definition: Averaged EEG waveforms locked to the presentation of specific sensory stimuli.

• Components:

  • N1 (N100, 90–200 ms): Orienting response, sensory encoding.

  • P2 (P200, 100–250 ms): Attentional processes, information storage.

  • N2 -different components: N2a or MMN (Mismatch negativity),N2b =changes physical stimulus properties, N2c = classification.

  • P3 (P300, 250–400 ms): cognitive processing, conscious processing

[B] How does tDCS work, and what is the difference between Anodal and Cathodal stimulation?

• Mechanism: Induction of a weak electrical field across the scalp via electrodes.

• Anodal Stimulation: can enhances activity of synapses (Increases neural excitability)

• Cathodal Stimulation: can suppresses activity of synapses (Decreases neural excitability)

[B] Which psychophysiological measures assess Autonomic Nervous System activity?

1. Skin Conductance (SCR/SCL): Sweat gland activity in emotional situations increases electrical conductivity of skin. Indicator of emotional thoughts and experiences

2. Cardiovascular Activity: Indicator of emotional thoughts and experiences

   • Heart Rate: Measured via Electrocardiogram (ECG)

   • Blood Pressure: Systolic and diastolic pressure

[B] Why do researchers move "From Visualization to Stimulation", and what is the difference between correlation and causality?

• Visualization (fMRI, PET, EEG): Shows only correlations (co-occurrence) between brain activity and behavior.

• Stimulation (TMS): Serves as a direct measure of causal relations by actively turning brain areas on/off to test their direct effect on cognition and behavior.

[B] Which psychophysiological recording techniques measure the Central, Somatic, and Autonomic Nervous Systems according to the layout slide?

• Central Nervous System (Brain): EEG & MEG.

• Somatic Nervous System: EMG (muscle tension) & EOG (eye movements).

• Autonomic Nervous System: Skin Conductance (sweat gland activity) & Cardiovascular activity (ECG / Heart rate & Blood pressure)

[C]EEG- Event related potentials (ERP) - Abbildung

[B] What are the 5 major types of lesion methods (+def) used in invasive animal research?

Def.: LM = part of brain is damaged, destroyed or inactivated

1. Aspiration lesions: Drawing/peeling off a layer of cortical tissue.

2. Radio-frequency lesions: Passing high-frequency current through target tissue to destroy it.

3. Knife cuts: Sectioning/cutting a nerve or tract.

4. Reversible lesions: Temporarily inactivating tissue via cooling or local anesthetics.

5. Selective chemical lesions: Injecting specific neurotoxins (neural poisons)(e.g., 6-OHDA) to destroy specific neurons

(Be careful with interpretation: lesion effects=very difficult to „apply“! You cannot destroy a structure without producing significant damage to neighbouring structures)

[B]Name 4 key standardized neuropsychological tests mentioned in the slides and what they assess.

1. WAIS (Wechsler Adult Intelligence Scale): General intellectual ability (verbal comprehension, working memory, perceptual organization, processing speed).

2. Tower of London (ToL): Executive functions & planning processes.

3. Beck Depression Inventory (BDI-II): Emotion / coping (21 items assessing depression severity).

4. Rey-Osterrieth Complex Figure Test: Visuospatial abilities & memory.
   
   

[B] What is the WAIS, who developed it, and what does it measure?

• Author: David Wechsler.

• Main Domain: General intellectual ability (IQ).

• Function & Task: Measures overall intelligence through standardized sub-tests across four main cognitive domains:

  1. Verbal comprehension: Language and verbal reasoning.

  2. Working memory: Short-term memory retention and manipulation (e.g., Digit span test – repeating number series forward and backward).

  3. Perceptual organization: Non-verbal visual reasoning (e.g., Matrix reasoning – completing visual patterns).

  4. Processing speed: Speed of performing simple cognitive tasks

[B] What is the Tower of London (ToL) test, who developed it, and what does it measure?

• Author: Tim Shallice.

• Main Domain: Executive processing & planning processes.

• Function & Task: Assesses problem-solving ability and executive function. The subject must move colored balls across pegs from an initial position to a goal position using a set number of moves

[B] What is the BDI-II, who developed it, how is it structured, and how is it scored?

• Author: Aaron Beck.

• Main Domain: Emotion, coping, and assessment of depression severity.

• Structure: A standardized questionnaire consisting of 21 groups of statements covering symptoms like sadness, pessimism, loss of pleasure, appetite changes, and sleep disturbances as such as concentration difficulty

• Scoring & Cut-offs: Each statement is rated from 0 to 3, yielding a sum score from 0 to 63:

  • 0–13: Minimal depression

  • 14–19: Mild depression

  • 20–28: Moderate depression

  • 29–63: Severe depression

[B] What is the Rey-Osterrieth Complex Figure Test, who developed it, and how is it conducted and scored?

• Authors: André Rey & Paul-Alexandre Osterrieth.

• Main Domain: Visuospatial abilities & visual memory.

• 3 Test Phases:

  1. Copy: Drawing the complex figure while viewing the template.

  2. Immediate recall: Drawing the figure from memory immediately after copying.

  3. Delayed recall: Drawing the figure from memory after a time delay.

• Scoring: Evaluates 18 figure units with a maximum score of 36 points (up to 2 points per accurately drawn and correctly located unit)

[B]How is raw EEG output processed, and how do brain waves change from an aroused state to deep sleep?

• Signal Processing: Raw electrical signals are amplified and recorded.

• Distinction: Differentiates between spontaneous activity and stimulus-induced activity (ERPs).

• Wave Changes across States:

  • Aroused: High frequency, low amplitude.

  • Relaxed: Alpha waves (relaxed awake state) (alpha most prominent one)

  • Asleep: Slower waves as sleep sets in

  • Deep sleep: Slow waves with high amplitude (Delta waves)