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:

  1. Effects of Brain Damage:

     • Studied to understand the role of specific brain regions.

  2. Brain Stimulation:

     • Analyzing behavioral changes post-stimulation.

  3. Correlating Anatomy with Behavior:

     • Linking specific brain structures with their functions.

  4. 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

1. Computerized Tomography (CT):

   • Uses x-rays to produce cross-sectional images of the body, including the brain.

   • Important for diagnosing strokes and injuries.

2. Magnetic Resonance Imaging (MRI):

   • Utilizes strong magnets and radio waves for imaging brain structure.

   • No radioactive material is involved.

3. 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.

4. Electroencephalography (EEG):

   • Measures electrical activity across the scalp, often used to diagnose epilepsy or tumors.

5. 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:

1. Sensorimotor Network (SMN):

   • Engaged in processing motor responses and sensory stimuli.

2. Visual System (VIS):

   • Processes visual information and aids in spatial awareness and recognition.

3. Limbic System (LMBS):

   • Regulates emotions and memory processing.

4. Central Executive Network (CEN):

   • Manages decision-making and task-oriented actions, functioning in collaboration with other networks.

5. Default Mode Network (DMN):

   • Active during rest and mind-wandering; involved in introspection and autobiographical memory.

6. Salience Network (SN):

   • Regulates attention and selects which network is active based on incoming stimuli.

7. Dorsal Attention Network (DAN):

   • Focuses on directing attention to important stimuli and is involved in task execution.