Bio Bases exam

1.2 Dualism vs. Monism

• Dualism: The belief that the mind and body are separate entities. Two entities (Descartes' view).

• Monism: The belief that the mind and body are one, and mental processes arise from physical brain activity. the belief that the mind is the result of activity in the brain and can be studied scientifically

• Modern Neuroscience: Follows monism, as research shows mental states are rooted in neural activity.

Galvani (frogs & bioelectricity)

Gall (phrenology)

Müeller (specific nerve energies: localization)

Darwin (evolution: comparative; genetic studies)

Wundt (physiology of the senses)

1.3 Applied vs. Basic Neuroscience

• Basic neuroscience: Studies fundamental mechanisms of brain function (e.g., neurophysiology, cognitive neuroscience).

• Applied neuroscience: Uses findings to solve real-world problems (e.g., clinical neuropsychology, neuropharmacology).

• Subfields in psychology departments:

  • Cognitive Neuroscience (studies perception, memory, attention)

  • Behavioral Neuroscience (examines neural mechanisms of behavior)

  • Clinical Neuropsychology (assesses brain injuries/disorders)

Neuroanatomy

2.1 Neuron Structure & Function

• Neuron Diagram & Labels:

  • Dendrites: Receive signals from other neurons.

  • Soma (Cell Body): Processes incoming signals.

  • Axon: Transmits electrical impulses away from the soma.

  • Myelin Sheath: Speeds up signal transmission.

  • Nodes of Ranvier: Gaps in myelin that facilitate saltatory conduction.

  • Axon Terminals: Release neurotransmitters into synapses.

• Types of Neurons:

  • Sensory Neurons: Carry information from sensory organs to the CNS.

  • Motor Neurons: Send commands from CNS to muscles.

  • Interneurons: Connect sensory and motor neurons within the CNS.

• Reflex Arc:

  • Receptor → Sensory Neuron → Interneuron → Motor Neuron → Effector (muscle/gland)

  • Example: Touching a hot stove → sensory neuron detects heat → interneuron processes → motor neuron moves hand away.

• Glial Cells & Functions:

  • Microglia: Immune defense, remove debris.

  • Astrocytes: Blood-brain barrier, nutrient support.

  • Oligodendrocytes: Myelinate CNS axons.

  • Schwann Cells: Myelinate PNS axons.

2.2 Brain Orientation & Directional Terms

• Directional Terms:

  • Dorsal (top) vs. Ventral (bottom)

  • Anterior (front) vs. Posterior (back)

  • Medial (middle) vs. Lateral (side)

• Brain Planes (Cuts):

  • Coronal: Vertical slice, front & back halves.

  • Sagittal: Vertical slice, left & right halves.

  • Horizontal (Axial): Divides into top & bottom halves.

2.3 Nervous System & Meninges

• Divisions of Nervous System:

  • Central Nervous System (CNS): Brain & spinal cord.

  • Peripheral Nervous System (PNS):

    • Somatic (voluntary movements, sensory info)

    • Autonomic (involuntary control: sympathetic = fight/flight, parasympathetic = rest/digest)

• Spinal Cord Anatomy:

  • Gray matter (inner processing), white matter (outer communication pathways).

• Meninges (Protective Brain Layers):

  • Dura Mater (tough outer layer)

  • Arachnoid Mater (web-like middle layer)

  • Pia Mater (delicate inner layer, directly on the brain)

• Ventricles & CSF Function:

  • Lateral, third, and fourth ventricles contain cerebrospinal fluid (CSF), which cushions the brain, removes waste, and maintains pressure.

2.4 Brain Structures & Functions

• Five Major Embryological Divisions:

  • Telencephalon (Cerebral cortex, basal ganglia, limbic system)

  • Diencephalon (Thalamus, hypothalamus)

  • Mesencephalon (Midbrain structures: tectum, tegmentum)

  • Metencephalon (Pons, cerebellum)

  • Myelencephalon (Medulla)

• Four Lobes of the Cerebral Cortex:

  • Frontal: Decision-making, planning, motor control (contains prefrontal cortex & motor cortex).

  • Parietal: Sensory processing, spatial awareness (somatosensory cortex).

  • Temporal: Hearing, language (Wernicke’s area), memory (hippocampus).

  • Occipital: Vision processing.

• Basal Ganglia Functions & Structures:

  • Involved in movement control, habit formation.

  • Major parts: Caudate nucleus, putamen, globus pallidus, substantia nigra.

• Limbic System Functions & Structures:

  • Emotion regulation, memory, motivation.

  • Major parts: Hippocampus (memory), amygdala (fear/emotion), cingulate cortex (decision-making).

• Midbrain & Brainstem Structures:

  • Thalamus: Sensory relay station.

  • Hypothalamus: Regulates hunger, thirst, body temperature, hormones.

  • Tectum: Controls visual & auditory reflexes.

  • Pons: Motor control, sleep regulation.

  • Medulla: Regulates vital functions (breathing, heart rate).

Neuron Communication

• Key Ions in Neuron Communication:

  • Sodium (Na⁺), Potassium (K⁺), Chloride (Cl⁻), Calcium (Ca²⁺)

• Ion Concentration Differences Across Membranes:

  • More Na⁺ and Cl⁻ outside, more K⁺ inside the neuron.

• Neuron Membranes & Membrane Potential:

  • The phospholipid bilayer with embedded proteins creates a selective barrier.

  • Resting membrane potential is ~-70mV due to unequal ion distribution.

• Resting vs. Threshold Potential:

  • Resting Potential: The neuron is at ~-70mV, ready to fire but stable.

  • Threshold Potential: Around -55mV, which is needed to trigger an action potential.

• Types of Ion Channels:

  • Voltage-gated: Open in response to voltage changes (e.g., Na⁺ and K⁺ during action potential).

  • Ligand-gated: Open when neurotransmitters bind.

  • Leak channels: Always open, helping maintain resting potential.

• Action Potential Stages:

  • Depolarization: Voltage-gated Na⁺ channels open, Na⁺ rushes in, neuron becomes positive (+30mV).

  • Repolarization: Voltage-gated K⁺ channels open, K⁺ exits, neuron becomes negative again.

  • Hyperpolarization: Too much K⁺ exits, neuron becomes extra negative (~-80mV) before stabilizing.

  • Return to Resting State: Na⁺/K⁺ pump restores original ion balance.

• All-or-None Principle:

  • An action potential either happens or doesn’t—if the threshold is reached, the full response occurs; if not, nothing happens.

Myelin & Action Potential Speed

• Myelin insulates the axon and speeds up action potential conduction through saltatory conduction.

• Instead of traveling continuously, the action potential jumps between Nodes of Ranvier, where voltage-gated ion channels are concentrated.

• This reduces ion leakage and decreases the time needed for depolarization.

Na⁺/K⁺ Transport After an Action Potential

• The sodium-potassium pump (Na⁺/K⁺ ATPase) restores resting potential by:

  • Pumping 3 Na⁺ ions out and 2 K⁺ ions in using ATP.

  • This maintains the negative resting potential (~-70mV) inside the neuron.

Types of Synaptic Connections

• Axodendritic: Axon connects to a dendrite (most common).

• Axosomatic: Axon connects directly to the soma (cell body).

• Axoaxonic: An 1Axon connects to another axon, often modulating neurotransmitter release.

Exocytosis & Voltage-Gated Ion Channels

• Exocytosis: The release of neurotransmitters from the presynaptic neuron into the synaptic cleft.

• Process:

  1. Action potential reaches the axon terminal.

  2. Voltage-gated Ca²⁺ channels open, allowing Ca²⁺ to enter.

  3. Synaptic vesicles fuse with the membrane, releasing neurotransmitters.

Postsynaptic Receptors

1. Ionotropic Receptors (Fast, Direct)

   • Ligand-gated ion channels that open when a neurotransmitter binds.

   • Example: AMPA receptor (glutamate) → Na⁺ influx → depolarization.

2. Metabotropic Receptors (Slow, Indirect)

   • Activate second messenger systems, affecting ion channels indirectly.

   • Example: Dopamine receptors activate G-proteins, which influence other cellular processes.

Excitatory vs. Inhibitory Neurotransmitter Effects

• Excitation (EPSP - Excitatory Postsynaptic Potential):

  • Depolarizes the neuron, increasing likelihood of an action potential.

  • Example: Glutamate binding to AMPA receptors → Na⁺ enters.

• Inhibition (IPSP - Inhibitory Postsynaptic Potential):

  • Hyperpolarizes the neuron, decreasing action potential likelihood.

  • Example: GABA binding to GABA-A receptors → Cl⁻ enters.

Major Neurotransmitters & Their Roles

Neurotransmitter Regulation & Reuptake

• Reuptake: Transporters (e.g., serotonin transporter, SERT) reabsorb neurotransmitters into the presynaptic neuron.

• Enzymatic Degradation: Enzymes (e.g., acetylcholinesterase) break down neurotransmitters.

• Autoreceptors: Receptors on the presynaptic neuron regulate neurotransmitter release.

Methods in Neuroscience Research

Scientific Method Stages

1. Observation (Identify a phenomenon)

2. Hypothesis (Make a testable prediction)

3. Experimentation (Collect data via controlled studies)

4. Analysis (Interpret data)

5. Conclusion & Replication (Confirm findings through repeated studies)

• Hypothesis vs. Theory:

  • Hypothesis: A testable, specific prediction.

  • Theory: A well-supported explanation based on multiple studies.

Why Use Animals in Neuroscience?

• Similar biological processes.

• Ethical limitations prevent certain human studies.

• Shorter lifespans allow for longitudinal studies.

Physiological Research Devices

• Heart Rate Monitor: Measures autonomic nervous system activity.

• Electromyography (EMG): Measures muscle activity.

• Skin Conductance Response (SCR): Measures sweat gland activity (arousal).

Brain Imaging Techniques

• 
  ERP (Event-Related Potential) vs. Continuous EEG:

  • ERP extracts signals linked to specific stimuli.

  • Continuous EEG tracks general brain activity over time.

• PET vs. MRI:

  • PET: Uses radioactive glucose to show metabolic activity.

  • MRI: Uses magnetic fields to show brain structures.

tDCS vs. TMS

• tDCS (Transcranial Direct Current Stimulation): Applies a weak electrical current to enhance/inhibit activity.

• TMS (Transcranial Magnetic Stimulation): Uses magnetic pulses to temporarily disrupt brain activity.

Hemispheric Lateralization

Definition

• Hemispheric lateralization: The tendency for some functions to be specialized to one hemisphere of the brain.

Left vs. Right Hemisphere Functions

Neuroanatomical Features

• Longitudinal Fissure: Separates the two hemispheres.

• Corpus Callosum: Connects hemispheres, allowing communication.

• Broca’s Area (Left Frontal Lobe): Language production.

• Wernicke’s Area (Left Temporal Lobe): Language comprehension.

Right-Brain/Left-Brain Myth

• The idea that people are strictly "right-brained" (creative) or "left-brained" (logical) is a misconception.

• Both hemispheres work together for most cognitive tasks.

BLANK SLATE 

According to your text, what was trepanation believed to treat? Mental illness

Which Renaissance artist studied neuroanatomy? Leonardo da Vinci

What philosophy suggests the mind and body are separate? Dualism

What is an example of holism in psychology? Gestalt theory

What is reductionism? Breaking systems into parts

What is an emergent property? Complexity from simpler parts

Which subfield focuses on brain activity linked to genes? Behavioral genetics

What does ethology study? Animals in natural environments

A researcher in this ______ might examine how hormones influence social bonding. 

Behavioral neuroendocrinology

Which subfield uses fMRI to study brain activity? Cognitive neuroscience

Which subfield studies brain injuries to understand behavior? Neuropsychology

Who would study the bumps on your head to assess mental strengths in the late 1800s? Phrenologist

A psychopharmacologist is most interested in how drugs affect the brain and behavior.

Which of the following subfields of neuroscience are most related in terms of their shared interests?

behavioral genetics and evolutionary psychology

Who introduced the concept of specific nerve energies? Mueller

2.Neuroanatomy

What part of a neuron receives signals? Dendrites

What organelle produces energy in a neuron? Mitochondria

Which type of neuron has no axon? Anaxonic

Which cell forms the myelin sheath in the PNS? Schwann cells

What does dorsal mean in brain orientation? Toward the back

Which plane cuts the brain into left and right? Sagittal

How many layers are in the meninges? Three

What is the function of cerebrospinal fluid? Protects the brain

Which lobe processes visual information? Occipital

What structure controls basic life functions? Medulla

What is the function of the basal ganglia? Motor control

Which structure is part of the limbic system? Hippocampus

What structure contains a neuron's genetic material? Nucleus

Which cell type acts as the immune defense in the CNS? Microglia

What term describes a structure toward the belly? Ventral

What plane cuts the brain into front and back? Coronal

What is the outermost layer of the meninges? Dura mater

What part of the brain coordinates voluntary movement? Cerebellum

What lobe is involved in decision-making and planning? Frontal

Which structure relays sensory information to the cortex? Thalamus

What structure connects the two hemispheres of the brain? Corpus callosum

Which division of the brain forms the pons and cerebellum? Metencephalon

The nucleus, endoplasmic reticulum, mitochondria, and ribosomes are all types of organelles.

The fatty insulation that surrounds axons is called myelin.

When standing straight up, the top of your brain (the highest point) is referred to as dorsal.

Sensory information enters the spinal cord through the ____ root. dorsal

The meningeal layer that is thin and lies directly against the cortex of the brain is called the pia mater

What are the large spaces within the brain filled with cerebral spinal fluid? Ventricles

What role do gyri play in brain function? Expand the brain's cortical area

Which action is controlled by the parasympathetic nervous system? Slowing the heart rate

Which ion is most important for action potentials? Sodium (Na⁺)

3.Neuro Communication

Which ion is more concentrated inside the neuron? Potassium (K⁺)

What makes up the neuron’s membrane? Lipid bilayer

What maintains the resting membrane potential?

Na⁺/K⁺ pump

What is the typical resting membrane potential? -70 mV

What is the threshold potential for an action potential? -55 mV

Which ion channels open first in an action potential? Sodium (Na⁺) channels

Where is an action potential first generated? Axon hillock

• What happens during depolarization? Na⁺ enters the neuron

• What happens during repolarization? K⁺ exits the neuron

Why is an action potential all-or-none? It always reaches the same size

How does myelin affect action potential speed? Increases conduction

Where does an action potential jump in myelinated axons? Nodes of Ranvier

What ion is pumped into the neuron after firing? Potassium (K⁺)

What restores the resting potential after an action potential? Na⁺/K⁺ pump

What connects neurons in an electrical synapse? Gap junction

How do chemical synapses transmit signals? Neurotransmitters

Which ion triggers neurotransmitter release? Calcium (Ca 2+)

What process releases neurotransmitters into the synapse? Exocytosis

Which receptor type opens ion channels directly? Ionotropic

Which receptor type uses second messengers? Metabotropic

What does an excitatory neurotransmitter do? Depolarizes the neuron

What does an inhibitory neurotransmitter do? Hyperpolarizes the neuron

What is a characteristic of a graded potential? Varies in strength

Where does an action potential occur? Axon

Which neurotransmitter is primarily excitatory? Glutamate

Which neurotransmitter is primarily inhibitory? GABA

Which neurotransmitter binds to nicotinic receptors? Acetylcholine

How are neurotransmitters removed from the synapse? Reuptake

What repackages neurotransmitters in the presynaptic neuron? Vesicles

4.Research

What is the first step of the scientific method? Observation

What step comes after forming a hypothesis? Experiment

What device measures heart rate in research? ECG

What measures skin conductance? EDA

What scan provides the best structural brain image? MRI

Which technique tracks brain activity using glucose? PET scan

Which method measures electrical brain activity? EEG

What EEG method examines responses to specific stimuli? ERP

Which scan uses magnetic fields to create images? MRI

What does DTI track in the brain? White matter pathways

Which method uses weak electrical currents? tDCS

Which technique uses magnetic pulses to stimulate neurons? TMS

In an experiment, the __________ is what is manipulated. independent variable

Which of the following brain imaging devices is not good at recording or imaging structures deep in the brain?

EEG

What does the “O” stand for in BOLD-contrast imaging? oxygen