Biological Psychology II: Nervous System Structure, Organization, and Brain Imaging

Lecture 4: Biological Psychology II

Overview

This study guide covers the structure and organization of the nervous system, key features of the cerebral cortex, and methods of brain imaging, as presented in an introductory psychology course.

Midterm Testing Tips

Strategies for Multiple Choice Exams

• Read each question slowly: Take your time to understand what is being asked before looking at the answer choices.

• Answer what you know first: Complete questions you are confident about before returning to more difficult ones.

• Return to skipped questions: After answering the easier questions, revisit the ones you left blank.

• Use process of elimination: Eliminate options that are definitely incorrect and focus on the most likely correct answers.

Nervous System Structure & Organization

Main Divisions of the Nervous System

The nervous system is the body's communication network, responsible for transmitting information throughout the body and coordinating actions.

• Central Nervous System (CNS): Consists of the brain and spinal cord. It interprets sensory information and issues instructions.

• Peripheral Nervous System (PNS): Connects the CNS to the rest of the body. It is divided into the somatic and autonomic nervous systems.

Subdivisions of the Peripheral Nervous System

System	Main Function
Somatic Nervous System	Transmits sensory information and controls voluntary movement of skeletal muscles.
Autonomic Nervous System	Regulates involuntary body functions (e.g., heart rate, digestion).
Sympathetic Division	Prepares the body for action (fight or flight response).
Parasympathetic Division	Conserves energy and restores the body to a resting state.

Spinal Cord

• Function: Acts as a pathway connecting the brain and the peripheral nervous system.

• Role: Transmits neural signals between the brain and the rest of the body; involved in reflex actions.

Features of the Cerebral Cortex

Major Structures

• Gyri (singular: gyrus): Raised ridges on the surface of the brain.

• Sulci (singular: sulcus): Grooves or furrows between the gyri.

• Gray Matter: Contains most of the brain's neuronal cell bodies; involved in muscle control, sensory perception, memory, emotions, and speech.

• White Matter: Made up of myelinated axons that connect different parts of gray matter to each other.

• Corpus Callosum: A large bundle of nerve fibers that connects the left and right cerebral hemispheres, allowing communication between them.

Functional Areas of the Cortex

• Frontal Lobe: Associated with reasoning, planning, movement, and problem-solving.

• Parietal Lobe: Processes sensory information such as touch, temperature, and pain.

• Temporal Lobe: Involved in perception and recognition of auditory stimuli, memory, and speech.

• Occipital Lobe: Responsible for visual processing.

Brain Imaging

Structural Imaging Techniques

Structural imaging provides detailed images of the brain's anatomy, allowing researchers and clinicians to examine the shape and size of brain structures.

• Computed Tomography (CT): Uses X-rays to create cross-sectional images of the brain.

• Magnetic Resonance Imaging (MRI): Uses strong magnetic fields and radio waves to produce detailed images of brain structures.

• Diffusion Tensor Imaging (DTI): A type of MRI that maps the diffusion of water molecules in brain tissue, useful for visualizing white matter tracts.

Functional Imaging Techniques

Functional imaging measures brain activity by detecting changes associated with blood flow, electrical activity, or metabolic processes.

• Electroencephalogram (EEG): Records electrical activity of the brain via electrodes placed on the scalp. Provides excellent temporal resolution but poor spatial resolution.

• Event-Related Potentials (ERPs): Measured using EEG, ERPs are brain responses that are the direct result of a specific sensory, cognitive, or motor event.

• Functional Magnetic Resonance Imaging (fMRI): Measures brain activity by detecting changes in blood oxygenation (BOLD signal). Offers good spatial resolution.

• Transcranial Magnetic Stimulation (TMS): A non-invasive method that uses magnetic fields to stimulate nerve cells in the brain, often used to study brain function.

Comparison of Imaging Techniques

Technique	Measures	Temporal Resolution	Spatial Resolution
EEG/ERP	Electrical activity	Excellent	Poor
fMRI	Blood oxygenation (BOLD)	Moderate	Excellent
CT/MRI	Brain structure	N/A (not functional)	Excellent

Key Terms and Concepts

• BOLD Signal: Blood Oxygen Level Dependent signal, used in fMRI to infer brain activity.

• Temporal Resolution: The ability to detect changes in brain activity over time.

• Spatial Resolution: The ability to distinguish between different areas of the brain.

Example Application

Researchers use fMRI to study which areas of the brain are activated during specific cognitive tasks, such as language processing or memory recall. EEG is often used to investigate the timing of neural processes, such as how quickly the brain responds to a visual stimulus.

Additional info: For more details on brain imaging, see resources such as "https://www.youtube.com/watch?v=ymKvSOXsMadw" for visual explanations of imaging techniques.