Neuroscience Exam Review

Final Examination Overview

The final will encompass a total of 45 questions distributed across various topics as follows:

1. Scientific Method - (2 questions)

2. Early Science - (4 questions)

3. Neuroanatomy - (6 questions)

4. Foundations (Neurons, Glia, Coding) - (4 questions)

5. Ion Channels - (1 question)

6. Neural Signaling (Action Potentials, Synapses, Transmitters) - (9 questions)

7. Neurochemistry - (2 questions)

8. Sensory Systems - (4 questions)

9. Learning/Memory - (9 questions)

10. Goals & Habits - (2 questions)

11. Neurodegeneration (Last Semester) - (2 questions)

1. Introduction to the Scientific Method (2 Questions)

Main Concepts:

• Objectivity: Refers to unbiased and impartial observation in scientific research.

• Reproducibility: Indicates that experimental results can be consistently reproduced by different researchers.

• Skepticism: Encourages questioning and critical analysis of scientific claims and methodologies.

• Falsifiability: A principle that hypotheses must be testable and potentially disprovable.

• Internal Validity: The accuracy of a study in terms of the causal relationships it claims.

• External Validity: The extent to which findings from a study can be generalized to other contexts.

Key Terms:

• Objective / Subjective

• Internal Validity / External Validity

• Falsifiability

• Empirical

• Reproducibility

• Skepticism

1.1 Scientific Ethics (1 Question)

Belmont Report: Outlines core ethical principles guiding research involving human subjects:

• Respect for Persons: Acknowledges autonomy and provides protection for those with diminished autonomy.

• Beneficence: Obligation to minimize harm and maximize benefits.

• Justice: Fair distribution of research benefits and burdens.

3Rs in Animal Research:

• Replacement: Use alternatives to animal research when possible.

• Reduction: Minimize the number of animals used in research.

• Refinement: Enhance animal welfare by minimizing suffering and improving living conditions.

Key Terms Related to Ethics:

• IRB (Institutional Review Board)

• IACUC (Institutional Animal Care and Use Committee)

2. Early Science (4 Questions)

2.1 Pre-Science

Common Arguments for Bodily Location of the Mind:

• Heart vs. Brain: The historic debate on whether the heart or brain is central to the mind's existence.

• Cogito Ergo Sum: "I think, therefore I am" - a declaration by René Descartes affirming consciousness as a fundamental aspect of existence.

Two Main Avenues to Understanding the Brain:

1. Psychological Studies

2. Physiological Studies

2.2 Electricity

Progress in Understanding Nerves and Electricity (18th and 19th Century):

• Electric Storage in the 18th Century: Use of the Leyden jar as one of the earliest capacitors.

• Debate Over Galvani vs. Volta: Galvani's experiments with frog legs vs. Volta's interpretation leading to the development of the battery.

Major Technology Resulting from Debate: The invention of the electrochemical cell, leading to significant advances in electrical science.

Key Terms:

• Leyden Jar

• Capacitor

• Galvani

• Volta

2.3 Localization

First Behavior Localized in the Cortex: Proof of language faculties localized in specific areas of the brain (Broca’s area).

• Causal Experiments Focus: Lesions in brain areas to study their effects on behavior, specifically language processing.

Key Figures:

• Broca

• Wernicke

2.4 Psychology and Inhibition

Behaviorism: A theory pushed to the forefront, promoting a focus on observable behaviors over internal mental states.

Key Figures in Behaviorism:

• Pavlov: Classical conditioning experiments (e.g., dog experiments).

• Freud: Psychoanalytic theory, often contrasting with behaviorism.

• Watson & Skinner: Pioneering figures in behaviorist research.

3. Neuroanatomy (6 Questions)

3.1 Neuroanatomy of the PNS:

Nervous System Subdivisions:

• Major Divisions: Brain, Spinal Cord, Peripheral Nervous Systems (PNS).

• Three Components of the PNS:

  1. Peripheral

  2. Somatic

  3. Autonomic (divided into Sympathetic & Parasympathetic)

Functions Associated with Subsystems:

• Sympathetic Nervous System: Prepares the body for 'fight or flight' responses.

• Parasympathetic Nervous System: Manages 'rest and digest' functions.

• Enteric Nervous System: Regulates gastrointestinal functions.

Key Terms:

• Peripheral / Somatic / Autonomic / Sympathetic / Parasympathetic / Enteric Nervous Systems

• Fight or Flight / Rest and Digest

• Vertebral / Carotid Artery

• Blood-brain Barrier

• Ischemic / Hemorrhagic Stroke

3.2 Neuroanatomy of the Brain

Anatomical Location Terms:

• Anterior / Posterior, Dorsal / Ventral, Superior / Inferior, Medial / Lateral, Proximal / Distal, Ipsilateral / Contralateral, Coronal, Horizontal, Parasagittal

Lobes of the Cortex:

• Frontal, Parietal, Temporal, Occipital Lobes

• Locations of primary sensory and motor cortices (e.g., V1 for vision, A1 for audition).

Subdivisions of the Brain by Embryonic Development:

1. Forebrain

2. Midbrain

3. Hindbrain

Cortex Relationship with Limbic Areas:

• Neocortex and isocortex vs limbic system importance for emotional regulation.

Commonly Studied Brain Areas:

• Premotor and motor areas, sensory areas with presumed functions in sensory processing and motor execution.

Key Terms:

• White Matter / Grey Matter / Myelin / Corpus Callosum

• Primary Visual (V1), Auditory (A1), Somatosensory (S1), Motor (M1) Cortices

4. Foundations (4 Questions)

4.1 Neurons and Glia

Debate between Golgi and Cajal:

• Cajal's Neuron Doctrine: Neurons are distinct cells, not part of a continuous network as proposed by Golgi's Reticular Theory.

Basic Parts of a Neuron:

• Dendrites: Receive signals.

• Soma (Cell Body): Contains the nucleus and integrates signals.

• Axon: Transmits impulses away from the cell body.

Types of Glial Cells:

1. Astrocytes: Support and nourish neurons.

2. Schwann Cells: Myelin sheath in the peripheral nervous system.

3. Oligodendrocytes: Myelination in the central nervous system.

4. Microglia: Act as immune defense in the nervous system.

Key Terms:

• Neuron Doctrine / Reticular Theory / Dendrite / Soma / Axon / Law of Dynamic Polarization / Axon Hillock / Interneuron / Glia

4.2 The Dominant Paradigm

Components of the Integrate-and-Fire Model:

• Describes how neurons respond to synaptic inputs through temporal and spatial summation until a threshold is crossed.

Findings of Adrian on Action Potential:

• Demonstrated that action potentials are generated by the influx of Na+ ions through voltage-gated channels.

Key Terms:

• Adrian / Resting Potential / Spike Threshold / Integrate-and-Fire Model / Rate Coding

5. Ion Channels (1 Question)

5.1 Basics of Ion Channels

Fundamental Concepts:

• Charge, Current, Voltage, Resistance, Conductance:

• These terms relate to electrical measurements in analogies like water flow.

Ohm's Law:

• Expresses the relationship between these variables: $V = IR$ where $V$ is voltage, $I$ is current, and $R$ is resistance.

5.2 Movement of Ions

Driving Forces for Ion Movement:

• Electrostatic Gradient: Affects the movement of ions towards opposite charge.

• Concentration Gradient: Results in ions moving from high to low concentration.

Reversal Potential:

• The membrane potential at which there is no net movement of ions across the membrane, derived from the Nernst Equation: $E<em>X = rac{RT}{zF} imes ext{ln}( rac{[X]</em>{outside}}{[X]_{inside}})$

Driving Force Equation:
$I<em>X = g</em>X(V - E_X)$
Where:

• $I_X$ = current through the ion channel,

• $g_X$ = conductance,

• $V$ = membrane potential,

• $E_X$ = reversal potential.

6. Ion Channels & Action Potentials (3 Questions)

6.1 Action Potentials Summary

Mechanisms of Generation:

• Action potentials are generated when depolarization reaches a spike threshold triggering the opening of voltage-gated Na+ channels.

Functional Properties of Action Potentials:

• After-Hyperpolarization (AHP): A phase after the action potential where the membrane potential becomes more negative than resting potential.

• Refractory Periods: Periods during which a neuron is unresponsive to another stimulus following an action potential, divided into absolute and relative refractory phases.

6.2 Synaptic Transmission (2 Questions)

Transmission Across Synapses

Process of Neurotransmitter Release:

• Presynaptic Action Potential: Triggers Ca2+ influx leading to neurotransmitter vesicle fusion and release.

Types of Synapses:

• Chemical Synapse: Utilizes neurotransmitter release.

• Ionotropic vs. Metabotropic Receptors:

  • Ionotropic: Ligand-gated, fast acting.

  • Metabotropic: G-proteins mediated, slower acting.

6.3 Receptors and Transmitters (5 Questions)

Neurotransmitters

Classification of Receptors in the Brain:

• Ionotropic Receptors: Fast response times; examples include AMPA and NMDA receptors for glutamate.

• Metabotropic Receptors: Slow, longer-lasting effects; often involved in modulatory functions.

Main Neurotransmitters:

• Glutamate: Most abundant excitatory neurotransmitter; important for learning and memory.

• GABA: Main inhibitory neurotransmitter.

Functional Roles and Patterns of Release:

• Fast Response Systems: Typically involves ionotropic receptors leading to immediate effects in neurotransmission; key neurotransmitters include glutamate (excitatory) and GABA (inhibitory).

• Neuromodulation: Involves slower, longer-lasting effects mediated through metabotropic receptors.

• Key Terms:

• Glutamate, AMPA, NMDA, mGluR, GABA

SLOWER, Metabotropic Neuromodulators

Functional Characteristics:

• Associated with learning, memory, attention, reward, and emotional regulation.

• Examples include norepinephrine and dopamine pathways that modulate mood and motivational states, as well as associated mental health conditions.

Brain Structures Associated with Functions:

• VTA (Ventral Tegmental Area): Associated with reward pathways, addiction, and motivation.

• Locus Coeruleus: Involved in arousal and the stress response.

7. Neurochemistry (2 Questions)

7.1 Drugs and Their Actions

Factors Affecting Drug Accessibility to the Brain:

• Bioavailability: The extent and rate at which the active ingredient or active moiety is absorbed and becomes available.

• Blood-Brain Barrier: Fundamental to whether substances can penetrate the brain tissue.

Mechanisms of Drug Action:

• Drugs act as agonists or antagonists at neurotransmitter receptors, altering synaptic transmission and thereby influencing behavior and physiology.

Key Terms:

• Bioavailability, Metabolism, Blood-Brain Barrier, Ligand, Agonist, Antagonist, Partial Agonist, Allosteric Modulator, Dose-Response Curve, Affinity, Efficacy

7.2 Addiction

Animal Experimentation Methods:

• Methods such as the self-administration paradigm provide insights into brain mechanisms underlying addiction by studying patterns of drug-seeking behavior.

Main Brain Areas/Circuits Involved in Addiction:

• Mesolimbic Pathway: Plays a critical role in the brain's reward system.

• Nigrostriatal Pathway: Associated with motor control, affected in substance use disorders.

Key Terms:

• Abstinence, Craving, Withdrawal, Relapse, Self-Administration, Reinstatement, Mesolimbic, Mesocortical, Nigrostriatal Pathways

8. Sensory Systems (4 Questions)

8.1 Maps and Receptive Fields

Sensory Information Organization:

• Brain Mapping: Sensory modalities such as vision, audition, and touch are processed through hierarchical representations.

Receptive Fields Explained:

• Center-Surround Mechanism: Marvels in how sensory systems emphasize changes in stimulus intensity resulting in enhanced perception via lateral inhibition.

• Neural Adaptation: Refers to the brain's ability to adjust its responses to constant or unchanging stimuli.

Key Terms:

• Brain Map, Phantom Limb, Receptive Field, Center-Surround, Lateral Inhibition, Adaptation

8.2 Feature Extraction

Hubel and Wiesel Experiments:

• Their studies highlighted how specific neurons in V1 respond to certain visual stimuli, cementing the hierarchical processing of visual input.

Hierarchical View of Feature Extraction:

• The flow of information starts from simple features to complex representations in higher cortical areas.

Ocular Dominance Plasticity:

• Significant for visual system adaptability and relevant in conditions such as amblyopia, where vision changes due to lack of stimulation during critical periods.

What and Where/How Pathways: Acts as two streams in visual processing, with the ventral pathway related to object recognition and the dorsal pathway related to spatial awareness and action.

Key Terms:

• Retina, Optic Chiasm, Lateral Geniculate Nucleus (LGN), Primary Visual Cortex (V1), Simple Cells, Complex Cells, Hierarchical Processing, Monocular Deprivation, Critical Period, Amblyopia

9. Learning and Memory (9 Questions)

9.1 Memory Definitions

Definitions of Memory:

• Memory is defined as the mental faculty of retaining and recalling past experiences. It relates to learning in that it enables the retention and usage of knowledge acquired through practice or experience.

• Various types of memory include:

  • Short-Term / Long-Term Memory:

  1. Short-term: Temporary storage of information.

  2. Long-term: More durable and lasting storage of information.

  • Working Memory: A form of short-term memory that is involved in the active manipulation of information.

  • Declarative (explicit) vs. Non-declarative (implicit):

  • Declarative: Involves memories that can be consciously recalled.

  • Non-declarative: Memory that does not require conscious thought.

Patient HM:

• Famous case study of a patient who underwent a lobotomy affecting the medial temporal lobe leading to profound anterograde amnesia; critical in understanding the role of the hippocampus in memory formation.

Key Terms:

• HM, Lobotomy, Medial Temporal Lobe, Hippocampus, Entorhinal Cortex, Retrograde, Anterograde Amnesia, Encoding, Retrieval, Memory Trace, Engram, Types of Memory

9.2 Memory Circuits

Cognitive Map Concept:

• Hippocampus: Functions as a cognitive map critical for episodic memories and spatial navigation.

• Place Cells: Neurons that become active when an animal is in a particular location, particularly within the hippocampal formation.

Circuits for Habit Formation and Motor Skill Learning:

• Habit formation primarily engages the basal ganglia, while motor skills also involve cerebellar circuits.

Working Memory Study Methods:

• Often utilizes delayed-response tasks to study intrinsic memory circuits in the prefrontal cortex.

Conditioned Fear Learning:

• Typically involves pairing an aversive stimulus with a neutral one, leading the neutral stimulus to elicit fear responses; involves structures such as the amygdala.

Key Terms:

• Place Cells, Habits, Basal Ganglia, Cerebellum, Working Memory, Prefrontal Cortex, Amygdala, Freezing, Classical Conditioning, Extinction

9.3 Cell and Molecular Aspects of Learning

Hebbian Learning:

• A theory stating that “cells that fire together wire together,” emphasizing the importance of synaptic activity patterns in strengthening synaptic connections.

Mechanisms Underlying Long-Term Potentiation (LTP) and Long-Term Depression (LTD):

• Involves NR2A and NR2B subunits of NMDA receptors mediating calcium signaling for long-lasting changes in synaptic strength, crucial for learning and memory.

Key Terms:

• Hebbian Learning, Fire-together-wire-together, Expression vs. Induction, NMDAR, Magnesium, AMPAR, LTP, LTD

9.4 Consolidation & Reconsolidation

Standard Model of Memory Consolidation:

• Involves transfer of information from short-term to long-term memory storage through processes such as rehearsal, integration, and reactivation.

Fire-Together Wire-Together Principle in Systems Consolidation: Suggests that memories are consolidated through the repetitive activation of interconnected neural circuits.

Evidence for Reconsolidation:

• Each time a memory is retrieved, it may be updated or altered before being reconsolidated for long-term storage, showcasing the malleability of memory.

Key Terms:

• Consolidation, Synaptic/System Consolidation, Memory Replay, Reconsolidation

10. Goals & Habits (2 Questions)

Functional Differences Between Goal and Habit Systems:

• The goal system involves deliberate decision-making while the habit system is automatic and often unconscious, enabling efficient behavior patterns.

Experimental Determination of Goal vs. Habit Use:

• Researchers use tasks that distinguish between learning strategies, behavioral flexibility, and outcome tracking mechanisms.

Theoretical Concepts in Reinforcement Learning:

• Includes explorations of how organisms learn and adapt based on rewards and punishments.

Temporal Difference Learning:

• Utilizes predictions about future rewards and adapts decisions accordingly to maximize outcomes.

Reward Prediction Error:

• The difference between expected and received rewards, crucial for learning adjustments in behavior.

Dopamine Depletion Studies: Help illuminate the relationship between wanting (motivation) and liking (hedonic response) leading to insights in understanding drug addiction and reward mechanisms.

Key Terms:

• Goal vs. Habit System, Exploration/Exploitation, Credit Assignment, Discounting, Reward vs. Value, Temporal Difference Learning, Rigidity, Tremor, Liking vs. Wanting, VTA, SNc

11. Neurodegeneration (2 Questions)

Mechanisms in Alzheimer’s Disease:

• Neuronal loss associated with amyloid plaques (Extracellular) and neurofibrillary tangles (Intracellular/associated with tau protein).

• Often starts within the hippocampus leading to cognitive decline.

Mechanisms in Parkinson’s Disease:

• Characterized by the loss of dopaminergic neurons in the substantia nigra (SNc), with interventions such as L-Dopa and deep brain stimulation (DBS) available for treatment.

Brain Organoids:

• Miniaturized organs generated from stem cells to study neurodevelopmental processes and potential disease mechanisms in vitro.

Key Terms:

• Neurodegeneration, Alzheimer’s Disease, Parkinson’s Disease, Beta Amyloid, Plaques, Tau, Neurofibrillary Tangles, Alpha-Synuclein, Lewy Bodies, Levodopa, DBS, Organoids