Intro to Neuroscience Lecture 1

Intro to Neuroscience Lecture 1 ~ Sept 5th

What is Psychology? (In this context)

  • Expanding understanding of the brain
    • Prehistoric Brain Surgery: Trephining
    • Approximately 7000 years of neurosurgery.
    • Ancient Views of the Nervous System
    • Stone Age:
      • Trephining practiced as a form of surgery.
    • Edwin Smith Papyrus:
      • Dating back to 1500 B.C.E, it discusses the treatment of diseases and behavioral disorders.
      • The brain is explicitly described in historical texts.

The Science of Brain and Behaviour

  • Spans Past, Present, and Future:
    • Early Egyptians and Greeks, particularly Aristotle, believed the heart was the center of mental capacities.
    • Hippocrates (circa 460-370 B.C):
    • Proposed the brain as the seat of thoughts and emotions.
    • Galen (circa AD 129-199):
    • His experiences treating brain-injured gladiators led him to theorize that behavior results from connections between the brain and nerves.
    • Leonardo da Vinci (1452-1519):
    • Pioneer in anatomical drawings, notably using cross-sections for detailed illustrations.
    • Rene Descartes (1596-1650):
    • Explained animal behavior through mechanical principles and introduced the concept of spinal reflexes and their neural pathways.

How Much of Our Brain Do We Use?

  • The 10% Myth:
    • Attributed to William James suggesting humans are only “half awake.”
    • Wilder Penfield:
    • Discovered the “silent cortex,” areas of the brain that appeared inactive when stimulated electrically.
    • In the 1920s, he found parts of the brain that did not visibly react to electrical stimulation, suggesting these areas might have latent functions.
    • Albert Einstein:
    • Claimed his intellectual capacity was partly due to using ‘silent cortex.’
    • Resting State fMRI:
    • Shows constant activity in the brain, indicating that different areas may be active at different times, not simultaneously.

Music and Intelligence

  • Raucher et al. (1993):
    • Conducted a study with university students showing that 10 minutes of Mozart could temporarily improve spatial reasoning.
    • Included a brief enhancement in IQ scores following musical exposure.
    • In 1998, the Governor of Georgia mandated classical music exposure in schools.
    • Termed the “Requiem for the ‘Mozart Effect’,” underscoring that enjoyment and arousal play critical roles in cognitive enhancement—listening to engaging stimuli like a Stephen King passage can yield similar improvements.

The Science of Brain and Behaviour (Reiterate)

  • Historical Context:
    • Psychology has a long past; historically, psychology's scientific history is relatively short (Ebbinghaus, 1908).
  • Prehistoric Brain Surgery & Treatment of Disorders:
    • Reflects ancient methods such as trephining.
    • Ancient Egyptian and Greek conceptualizations positioned the heart as central, with reference to Aristotle’s belief system.
  • Mentalism (Aristotle, 350 B.C):
    • Thought functions originated from the heart. Blood circulation was believed to regulate emotional states through cooling effects on the brain.

Evolution of Understandings

  • Labeling emotions through physiological references (e.g., ‘kindhearted’ or ‘heartless’) reflects the historical paradigm linking emotions to bodily functions.
  • Hippocrates’ Contributions:
    • Promoted the notion that the brain is the seat of thoughts and emotions.
  • Galen’s Rejection of Heart Theory:
    • Proposed that an imbalance of cerebral fluids influenced emotional states, rather than the heart.
  • Renaissance to Early Modern Period:
    • Leonardo da Vinci's anatomical advancements and Descartes’ mechanistic explanations laid groundwork for modern neuroscience.

Early Neural Discoveries

  • Luigi Galvani (1737-1798):
    • Regarded electricity as a fundamental life source, demonstrated by his frog leg experiments.
  • Charles Darwin (1809-1892):
    • Advocated that rational behavior could be explained by the workings of the nervous system, negating the necessity of a non-material mind.

Phrenology and Localization of Function

  • Phrenology (19th century):
    • Linked physical bumps on the skull to variations in behaviors; a precursor to localization theories.
  • Modern research delineates regions of the brain responsible for specific behaviors, supported by studies from Broca and Wernicke, demonstrating predictable impairments from localized brain damage.
    • Broca’s Area:
    • Identified as critical for speech generation.

Under the Microscope: The Neural Framework

  • Reticular Theory (Golgi):
    • An obsolescent theory positing the nervous system as a single interconnected network.
    • Covered advancements in visualization techniques like Golgi stain aiding the identification of brain cells.
  • Santiago Ramon y Cajal:
    • An artist turned scientist, articulated the neuron doctrine, positing that the nervous system is made up of distinct and independent cells, interconnecting yet not forming a continuous network.

Psychological Phenomena and Neuronal Activity

  • Hebbian Theory:
    • Proposed by Donald Hebb, suggesting psychological phenomena as products of brain activity; introduced the idea of Hebbian synapses, which are synaptic connections that strengthen with activation co-occurrences.
    • Eric Kandel:
    • Connected neuroplasticity (changes in neurons) to observable behavior changes.

Neuroscience Relationship with Psychology

  • Psychology:
    • Defined as the study of behavior.
  • Biological Psychology and Neuroscience:
    • Explore the interplay between human behavior and brain function, intersecting various disciplines.

Brain Hypothesis and Neuron Hypothesis

Lecture 2 ~ Sept. 12th

Anatomy of the Brain

  • Comparative Anatomy:
    • Studies similarities and differences in anatomical structures and their functional significance.
  • Cortical Complexity and Intelligence:
    • Posits that increased brain mass correlates with more nerves and connections.

Size vs. Intelligence Correlation

  • On average, knowledge of one variable allows assumptions about another.
  • The concept of 'residuals' relates to the distance from the line of best fit in statistical modeling.

Cortical Complexity As a Factor of Intelligence

  • More cortical folds increase surface area, allowing more neurons without substantial cranial size changes.
    • Gyrification:
    • Refers to the increases in brain’s folds for greater surface area, crucial for survival.
    • Gyri:
    • The folds within the brain.

Executive Brain Structures

  • The brain structure associated with higher cognitive functions—particularly evident in humans with notable cerebrum size relative to brainstem.
  • Lizard Brain:
    • Represents instinct-driven parts of the brain, emphasizing the cerebrum’s role in executive functioning.

Anatomical Terminology

  • Anatomical directions (local vs. global) defined:
    • Anterior: Front
    • Posterior: Back
    • Superior: Above
    • Inferior: Below
    • Proximal: Close to reference point.
  • Fissure: Major separations within brain structure.
  • Ipsilateral: Refers to the same side; Contralateral: Opposite side; Decussate: Crossing midline.

Brain Organization

  • Three methods of brain organization used:
    • Cortical Areas:
    • Named after parts of the skull and neuroanatomical landmarks.
    • Broadmann's Areas:
    • Defined 52 distinct areas of the brain based on cytoarchitecture (cellular organization); how form relates to function across different regions.

Structural Brain Development

  • Telencephalon:
    • Most recently evolved; critical for cognition and higher-order functions.

Functions and Structures of the Cortex

  • Left Hemisphere:
    • Associated with logic, reasoning, and language capabilities.
  • Right Hemisphere:
    • Associated with spatial manipulation, musical ability, emotional processing, and facial recognition.

Key Brain Structures

  • Broca’s Area:
    • Critical for speech production, localized to the left hemisphere.
  • Wernicke’s Area:
    • Language comprehension, also primarily in the left hemisphere.
  • Temporal Lobe:
    • Critical for processing auditory information.
  • Fusiform Gyrus:
    • Right hemisphere area crucial for facial recognition.

Limbic System Functions

  • Hypothalamus and Thalamus (Diencephalon):
    • Thalamus: Acts as the main sensory information relay center.
    • Hypothalamus: Regulates basic motivated behaviors:
    • Fleeing
    • Fighting
    • Foraging
    • Sexual behaviors.
  • Hippocampus:
    • Vital for memory and learning processes.
  • Amygdala:
    • Involved in emotional regulation.
  • Cingulate Gyrus:
    • Facilitates emotional memory connections.

Basal Ganglia

  • Group of structures within the cerebral hemispheres that coordinate intentional actions:
    • Composed of:
    • Head of the caudate nucleus
    • Putamen
    • Globus pallidus

Midbrain and Hindbrain Functions

  • Midbrain:
    • Connects sensory inputs for coordinated responses; Tectum and Tegmentum roles in processing visual and auditory stimuli.
  • Hindbrain:
    • Pons: Facilitates arousal and attention;
    • Cerebellum: Coordinates voluntary movements and balance;
    • Medulla: Controls autonomic bodily functions (e.g., respiratory and cardiovascular processes).

Lecture 3 ~ Sept 19th

Brain & Behaviour

  • Key Concepts include:
    • Causal relationships: Between brain areas and functions.
    • Structural Examination: Understanding functions through physical brain alterations (lesions).

Phineas Gage Case Study

  • Gage suffered damage to his left prefrontal cortex; his personality underwent striking changes post-injury, demonstrating the pivotal role of this brain region in personality and social behavior.
  • Reference to historical context: "the equilibrium between his intellectual faculties and animal propensities seems to have been destroyed" (Harlow, 1868).

Electrical Stimulation

  • Utilized in the 1930s and 40s for brain mapping insights; stimulating cortical areas in awake patients provided early understandings of functional localization.
  • Transcranial Magnetic Stimulation (TMS):
    • A modern non-invasive method for controlling brain activity by delivering magnetic pulses, useful in functional mapping.

Causal Methods of Analysis

  • Lesions: Damage signifies essential functions.
  • Stimulation: Tests cause and effect relationships concerning brain and behavior.
  • These methods establish causal conclusions essential for understanding brain functionalities.

Imaging Techniques in Neuroscience

  • CT Scan:
    • Based on x-ray absorption; generates anatomical maps of tissues based on density; captures images of the brain structure non-invasively.
    • Advantages include painless procedures, while disadvantages comprise radiation exposure and restrictions for pregnant individuals.
  • MRI:
    • Uses strong magnetic fields to align atomic particles; explores structural attributes of the brain; ideal for revealing volumes and types of brain structures.
  • Functional MRI (fMRI):
    • Monitors changes over time using Blood Oxygen Level Dependent (BOLD) responses, where angiogenic activity provides insights into brain functionality.
    • Demonstrates poor temporal resolution but substantial spatial coverage and resolution at a macroscopic level.
  • PET Scans:
    • Positron Emission Tomography assesses metabolic processes; tracks neurotransmitter activities; includes disadvantages of requiring radioactive tracers and comparatively low temporal and spatial resolution.

Invasive vs. Non-Invasive Testing

  • Invasive Tests:
    • Involves surgical procedures (e.g., lesions, TMS).
  • Non-Invasive Tests:
    • Conducted without breaching the skin, e.g., MRI, fMRI.

Resolution Types in Imaging

  • Spatial Resolution:
    • Measures precision in determining the location of brain activity.
  • Temporal Resolution:
    • Measures precision in determining the timing of brain activity.