module 5 bio psychology
Research Methods in Neuropsychology
Focus: Understanding the brain's function and structure through various research techniques.
Key Note: Content will be important for Test #2 but not for Test #1.
The Problem Solved by Korbinian Brodmann (1868-1918)
Historical Context:
Development of neurology and psychiatry in the late 19th - early 20th century created communication challenges among researchers from different nations.
Brodmann's Contribution:
Examined cellular and laminar structure of the human cortex.
Published a monograph on cytoarchitectonic structure in 1909.
Subdivided human cortex into 47 identifiable areas based on cellular similarity.
Brodmann Areas:
Numbering system established for identifying brain areas, widely used in clinical texts.
Example: BA 45, 46 are referenced as distinct areas of interest.
Learning About Brain Function
Key Question: How do researchers understand the brain's functions?
Methods for Investigation:
Effects of Brain Damage:
Studied to understand the role of specific brain regions.
Brain Stimulation:
Analyzing behavioral changes post-stimulation.
Correlating Anatomy with Behavior:
Linking specific brain structures with their functions.
Recording Brain Activity:
Monitoring electrical or metabolic activity during tasks.
Brain Damage Analysis
Case Study: Paul Pierre Broca's work.
Observed patient could only say "tan" after a stroke, leading to discovery of Broca's Area related to expressive aphasia.
Research on Animal Brains:
Mainly conducted with rats/mice through lesions or ablation to observe effects on behavior.
Modern Techniques in Neuropsychological Research
Transcranial Magnetic Stimulation (TMS)
A non-invasive method for brain stimulation.
Creates focused magnetic fields to either stimulate or inhibit brain activity temporarily.
Useful for observing behavioral changes without long-term damage.
Optogenetics
Technique using light to control neurons genetically modified to respond to light.
Enables researchers to activate or inhibit specific neurons and observe resulting behavior.
Imaging Techniques
Computerized Tomography (CT):
Uses x-rays to produce cross-sectional images of the body, including the brain.
Important for diagnosing strokes and injuries.
Magnetic Resonance Imaging (MRI):
Utilizes strong magnets and radio waves for imaging brain structure.
No radioactive material is involved.
Functional Magnetic Resonance Imaging (fMRI):
Measures blood flow & oxygenation levels in the brain to identify active regions during tasks.
BOLD signal indicates brain function during cognitive activities.
Electroencephalography (EEG):
Measures electrical activity across the scalp, often used to diagnose epilepsy or tumors.
Positron Emission Tomography (PET):
Uses radioactive glucose tracers to measure metabolic activity in the brain.
Functional Networks in the Brain
Brain networks can be categorized into structural and functional connections.
Structural Connectivity:
Anatomical links between neural elements; generally stable over short time frames but can change over longer periods.
Functional Connectivity:
Reflects real-time interactions between neurons during cognitive tasks.
Major Functional Networks Identified:
Sensorimotor Network (SMN):
Engaged in processing motor responses and sensory stimuli.
Visual System (VIS):
Processes visual information and aids in spatial awareness and recognition.
Limbic System (LMBS):
Regulates emotions and memory processing.
Central Executive Network (CEN):
Manages decision-making and task-oriented actions, functioning in collaboration with other networks.
Default Mode Network (DMN):
Active during rest and mind-wandering; involved in introspection and autobiographical memory.
Salience Network (SN):
Regulates attention and selects which network is active based on incoming stimuli.
Dorsal Attention Network (DAN):
Focuses on directing attention to important stimuli and is involved in task execution.