Introduction to Neuroscience

Introduction to Neuroscience Lecture 1 ~ Sept 5th

What is Psychology?

Expanding Understanding of the Brain

  • Prehistoric Brain Surgery: Trephining

    • History: About 7000 years of neurosurgery.

Ancient Views of the Nervous System

  • Stone Age Practices

    • Trephining: An ancient surgical practice.

    • Edwin Smith Papyrus:

    • Date: 1500 B.C.E

    • Describes the treatment of diseases and behavioral disorders.

    • The brain is described.

Evolution of Brain Understanding

  • Early Egyptians and Greeks:

    • Believed the heart was the seat of mental capacities (Aristotle).

  • Hippocrates:

    • Proposed the brain as the seat of thoughts and emotions.

  • Galen (circa AD 129-199):

    • Proposed behavior results from connections between the brain and nerves based on his experiences with treating brain-injured gladiators.

  • Leonardo da Vinci (1452-1519):

    • Pioneer in anatomical drawings, including cross-sections of the brain.

  • Rene Descartes (1596-1650):

    • Explained animal behavior mechanically, proposed the concept of spinal reflexes and their neural pathways.

Brain Utilization

How Much of Our Brain Do We Use?

  • 10% of the Brain Myth:

    • Popularized by William James: "Compared to what we ought to be, we’re only half awake."

    • Wilder Penfield's discoveries in the 1920s contributed to this myth.

    • Silent Cortex: Identified brain areas without visible reactions to electrical stimulation.

    • Albert Einstein: Attributed some intelligence to the 'silent cortex'.

    • Resting State fMRI: Shows constant active motion of the brain.

Music and Intelligence

  • Study by Raucher et al. (1993):

    • Participants: University students.

    • Method: 10 minutes of Mozart listening.

    • Results: Temporary improvement in spatial reasoning and IQ.

    • Governor of Georgia: Provided classical music to children.

    • The “Mozart Effect” Requiem: Challenges the notion that specific music effects were unique to Mozart; enjoyment may increase cognitive capacity.

Historical Neuroanatomy Concepts

Prehistoric Brain Surgery & Ancient Treatments

  • Trephining: Evidence of early surgical interventions to treat physical ailments believed to originate in the brain.

  • Edwin Smith Papyrus: Ancient medical text detailing treatments, including references to the brain.

Ancient Conceptualizations of the Nervous System

  • Aristotelian Perspective: Heart as the center of feelings and thought.

  • Hippocratic Foundations: Shift towards viewing the brain as essential for cognitive functions.

  • Galen's Findings: Established connections between physical brain structures and behavioral responses.

Neuroscience Development Throughout History

Milestones in Brain Research

  • Renaissance Advances: Da Vinci's anatomical explorations.Gave rise to better understanding of neuroanatomy.

  • Descarte's Mechanism: Patterns of behavior attributed to the workings of the nervous system rather than mystical explanations.

  • Localization of Function: The early 19th-century theories built on the concept that specific bodily functions and personality traits could be associated with specific brain areas.

    • Broca and Wernicke: Demonstrated through lesions that specific brain areas are connected to language and speech functions.

The Microscope and the Formation of Neuroscience

Reticular Theory vs. Neuron Doctrine

  • Santiago Ramón y Cajal: Demonstrated that the nervous system consists of distinct, independent cells, introducing concepts vital in understanding synaptic connections.

Connecting Behavior to Neurons

  • Hebb's Hypothesis: Psychological phenomena being products of brain activity. Introduced the idea that behaviors are linked to synaptic connections.

    • Hebbian Synapses: Characterized by plasticity and ability to strengthen with experience.

Neuroscience as an Interdisciplinary Approach

Exploring the Connections of Behavior

  • Biological Psychology: Positions human behavior in relation to the workings of the nervous system.

  • Influence of Various Disciplines: Integrates concepts from biology, psychology, and other fields to form a holistic understanding of brain and behavior.

Lecture 2 ~ Sept. 12th - Anatomy and Structure

Comparative Anatomy

  • General Observations: Greater mass correlating to more nerves and complex connections.

  • Statistical Relationships: Understanding variables to make predictions (line of best fit and residuals).

Complexity and Evolution of Brain Structure

  • Cortical Complexity: More folds equates to an increased area for neurons without size enlargement of the skull.

  • Gyrification: Refers to the process of folding in the brain, leading to enhanced surface area.

Brain Size and Intelligence

  • Human Cerebrum: Development tied to enhancing cognitive abilities.

    • More developed cerebrum compared to the brainstem.

Orientation & Terminology of Brain Anatomy

Anatomical Directions

  • Anterior: Front

  • Posterior: Back

  • Ventral: Inferior

  • Dorsal: Superior

  • Caudal: Towards the tail

  • Rostral: Towards the nose

  • Ipsilateral: Same side

  • Contralateral: Opposite side

Sections of the Brain

Organization of Brain Areas Based on Skull Structure

  • Cortical Areas: Named based on skull parts

Cellular Differences

  • Brodmann Areas: 52 distinct cortical areas based on cytoarchitecture.

  • Layered Insights: Input layer (layer 4) & output layer (layer 6).

Major Brain Divisions in Embryonic Development

Telencephalon

  • Most recently evolved, involved in cognition and forethought.

Structures and Functions of the Cortex

Lateralization of Brain Functions

  • Left Hemisphere: Language, logic, reasoning.

  • Right Hemisphere: Spatial abilities, emotional processing.

  • Broca's and Wernicke's Areas: Language processing centered in the left hemisphere.

Diencephalon

  • Includes Hypothalamus: Regulates four fundamental behaviors – fleeing, fighting, feeding, and reproduction.

  • Thalamus's Role: Main hub for sensory information relay.

  • Limbic System: Involved in emotion regulation, includes structures like the hippocampus (memory & learning) and amygdala (emotional regulation).

Neuroscientific Methods in Understanding Brain & Behavior

Causal Methods

  • Lesion Studies: Investigate the necessity of brain areas for specific functions through damage.

  • Electrical Stimulation: Mapping brain functions by direct cortical stimulation during surgeries.

Imaging Techniques

CT and MRI Scanning

  • CT Scans: Based on X-ray absorption for anatomical brain mapping.

  • MRI: Uses magnets for aligning atoms to visualize brain structure, useful for high resolution imaging.

Functional Imaging Techniques

  • fMRI (Functional MRI): Measures brain activity through blood oxygenation levels (BOLD effect).

    • Pulse Sequence: Relates to changes in neural activity, images based on brain function.

  • PET Scans: Measures metabolic processes, useful for investigating specific neurotransmitter activity.

Neuroplasticity and the Role of Neurons

Neuron Hypothesis

  • States individual neurons generate behaviors.

Neural Units

  • Four Functional Zones of Neurons:

    • Input Zone: Information collection and integration.

    • Integration Zone: Decision-making location, where action potentials begin.

    • Conducting Zone: Transmits information over distances (axon).

    • Output Zone: Transfers information to other neurons.

Neuron Types

  • Multipolar Neuron: Most common type with multiple dendrites; 75-80% of neurons.

  • Bipolar Neurons: Found primarily in sensory systems (e.g., retina).

  • Unipolar Neurons: As seen in sensory ganglia, have a single branch that splits into two.

Cellular and Molecular Aspects of Neurons

Structure of Neurons

  • Neuron Components: Neural membrane, nucleus, and organelles like mitochondria for energy.

Axonal and Dendritic Function

  • Dendrites receive signals; axons conduct signals away from the cell body.

Action Potentials and Neural Transmission

Ionic Basis of Membrane Potential

  • Resting Membrane Potential: Typically -60 mV; designed by sodium and potassium dynamics and pumps.

Generation of Action Potentials

  • Triggered by depolarization past a specific threshold; involves voltage-gated Na+ and K+ channels.

Speed of Propagation

Myelinated vs. Unmyelinated Axons

  • Continuous Conduction: Slower along unmyelinated axons (10 m/s)

  • Saltatory Conduction: Rapid in myelinated axons (150 m/s).

Neurotransmission and Synaptic Interaction

Chemical Synapses

  • Mechanisms of neurotransmitter release and receptor interactions at synapses, involving both ionotropic and metabotropic receptors.

Signal Termination Processes

  • Includes reuptake and enzymatic breakdown of neurotransmitters.

Influence of Drugs on Neurotransmission

Drug Classes

  • Presynaptic Influence: Alterations in transmitter production and release.

  • Postsynaptic Effects: Modulate receptor activity, affecting memory and mood.

Memory and Learning

Types of Memory

  • Declarative Memory: Facts and events linked to the hippocampus.

  • Non-declarative Memory: Skills and procedures, relying on systems including the basal ganglia and cerebellum.

Patient Studies

  • Analysis of cases such as HM and K.C. to understand distinct memory systems and functional neuroanatomy.
    \n# Conclusion

  • Recap of major topics related to the brain's structure and function, highlighting the interconnectivity of neuroanatomical studies with psychological perspectives and real-life applications of neuroscience.

Important Terms Defined

Key Definitions

  • Neuron Doctrine: Concept that the nervous system consists of distinct, individual cells.

  • Hebbian Learning: Principle that synaptic strength increases when pre- and postsynaptic neurons are activated simultaneously.

  • Neuroplasticity: Brain's ability to reorganize, forming new neural connections throughout life, taking experiences into account.

This exhaustive note covers the comprehensive range of topics discussed in the introductory neuroscience lecture and sets the foundation for understanding brain function and behavior. It hosts terminologies with relevant detail and connections, making it ideal for further study in related fields.