PSY 212: Biopsychology Final Review 1 (Biopsych Overview and Cells of the Nervous System)

What is monism?

the view that the "mind" is the of the physical brain and thus, part of the physical brain

What is dualism?

the view that the mind is a metaphysical entity, distinct from our physical form

What is consciousness?

a concept framed by the mind-body problem

What is wakefulness?

Either conscious or unconscious

What is self-awareness?

the ability to describe one's own internal mental state

What is free-will?

the notion that you are the author of your own actions

What is split brains?

Cut a certain pathway (sever two parts of the brain - Restricts seizure to one hemisphere

What is unilateral neglect?

Part of their reality is erased on one side

What is generalization?

identifying similar behaviors and understanding them with respect to their "pro-survival" utility

What is reduction?

"reducing" behaviors to the neurobiological mechanisms subserving the behavior mechanisms subserving behavior

Who authored a theory/model of natural selection giving rise to evolution?

Charles Darwin

What is Natural Selection?

Survival of the fittest - the best genes suited to the environment they are in

What is speciation?

recognizing species from a cohort perspective

Who discovered plasticity and was Charles Darwin's competitor?

Jean Baptiste Lemark

What does the Darwinism model suggest about genes?

genes are inherited

What is phrenology?

complete nonsense; the antiquated discipline of partitioning the brain into areas that control certain behaviors

What is a Molecular/Histochemical approach?

Studying tissue - tissues of the nervous system and the nerve cells; understanding of neurochemistry, molecular neuroscience and protomics; study or organ tissue

What is a Structural/Functional approach?

Includes neuroimaging studies meant to determine the structure and function of specific brain regions (primarily in humans); how it functions collectively/form and function

What is a behavioral approach?

Techniques designed to study and manipulate behavior; may occur in conjunction with other techniques; attention, memory

What is an ablation?

the earliest neuroscience techniques relies on damage induced either naturally or experimentally to determine the role of certain brain areas in behavior

• modern day ablation can be reversible or irreversible and may include chemical, radio or electrical lesions

What is stereotaxic surgery?

is a surgical stand with a probe that can move in three dimensions used for neurosurgery

What are microscopy techniques?

used to visual nerve cells

What are tracer studies?

Allows you to inject a molecule into an area of the brain and then it is carried to a receptor’ ;see neural pathway

• tracing efferent neurons; anterograde labeling methods

• inject a chemical into the neuron that moves forward, down the axon to the end of the neuron

• tracing afferent neurons; we use retrograde labeling methods

• inject a chemical into neuron that moves backwards, away from the terminal button, back to the cell body

What labeling methods do you use for tracing efferent neurons?

anterograde labeling methods

What labeling methods do you use for tracing afferent neurons?

retrograde labeling methods

What is autoradiography?

Used to radio label certain proteins in the brain to monitor their expression

What are two techniques used for imaging the human brain?

Structural and Functional Techniques

What are the structural techniques of imaging the human brain?

-Computerized Tomography (CT)

-Magnetic Resonance Imaging (MRI)

-Diffusion Tensor Imaging (DTI)

What are the functional techniques of imaging the human brain?

-Single Unit Recordings

-Positron Emission Tomography (PET)

-Functional Magnetic Resonance Imaging (fMRI)

-Electroencephelograms (EEG) or Event-Related Potentials (ERP)

What do CT scans do?

Good for looking for a tumor or brain but limited in what you can see for research

• areas grey are grey matter

• areas white are white matter (myelinated)

• black is empty space (typically fluid-containing ventricles)

What does diffusion tensor imaging do?

Allows you to reconstruct fiber pathways by measuring fluid changes within the brain (via diffusion)

What does postrion emission tomography do?

(PET scan )

Scale depicts regional level of activity (red is high,activity blue/purple is low)

What does an FMRI do?

Uses Blood- Oxygenation-Level-Dependent (BOLD) signal to determine regions of activity

• typically, red denotes heightened glucose metabolism in that area

• good for spatial viewing

What does EEG or ERP do?

Traces show neural activity after exposure to certain stimuli or during certain mental states using electrodes that each record a small sub population of neurons

What does single/multiple unit recordings do?

Allows for surface recordings without the skull buffering

• can record from a single neuron or multiple neurons

• recordings can be transfuced to produce movement of a mechanical arm (brain machine interfaces- BMIs)

cons

• highly invasive

• bmi technology is expensive

• can have poor spatial resolution

What does a brain machine interface do? (BMI)

A machine that directly interacts with the brain for the purpose of controlling that machine; electrode arrays placed on certain areas of the cortex allow for control of robotic limbs or manipulation of a computer

• several studies conducted with animals and humans

What does autopsy research do?

Brains are typically sliced to identify structural abnormalities

What controls excitatory channels?

Channel Rhodopsin; responsive to blue light

What controls inhibitory channels?

Halphrodopsin- responsive to yellow light

What is the soma of a neuron?

the cell body, containing the nucleus and other cellular machinery

What are the dendrites of a neuron?

branches that serve as the primary input to the neuron

What is the axon of a neuron?

the cable-like structure through which action potentials (impules) are conducted

• responsible for intracellular communication

• may be myelinated for faster (insulated) impulse conduction

• composed of microtubule-based (thick protein) cytoskeleton

• serves two roles

  • conduction of action potentials

  • axoplasmic transport of cellular materials (anterograde or retrograde)

What are terminal buttons of a neuron?

portions of the neuron containing neurotransmitter release machinery necessary for communication (axon ending)

What is the synapse of a neuron?

the space in which two neurons communicate via chemical/electrical signals (extracellular space)- synaptic transmission

What is a bipolar neuron (interneuron)?

a neuron that relays a signal from one neuron to another

What is a unipolar neuron?

A neuron common in sensory systems, detects stimuli, and relays messages to the CNS

What are multipolar neurons?

Commonly motor neurons and are responsible for executing movment

What are pyramidal neurons?

Neurons only found in the CNS, contain dendritic spines, and are found in areas involved in learning, memory, and synaptic plasticity

What is the cell membrane?

the lipid bilayer protecting the cell from the external environment

What is cytosol?

water-based fluid that fills the cell

What is the nucleus?

contains genetic information (chromosomes containing genes) site of DNA replication and DNA→mRNA transcription

What is the Endoplasmic Reticulum?

site of mRNA --> protein translation (at the ribosomes) and is involved in protein folding (tertiary structure)

What does the mitochondria do?

extracts nutrients from the environment to produce ATP (cellular energy)

What does the Golgi-apparatus do?

packages cellular products and waste; usually neurotransmitters, enzymes, lysosomes

What is the myelin sheath of a neuron?

Insulated portions of the axon to increase conduction efficacy

What are the unmyleinated portions of an axon

the nodes of ranvier- at equal intervals

What do Oligodendrocyctes do?

myleinate CNS neurons

What do Schwann cells do

myleinate PNS neurons; also helps neurons repair themselves (usually doesn’t happen in the CNS due to production of scar tissue) ; role in neurodevelopment and axiogenesis.

How do neurotransmitters leave to neuron?

Via exocytosis from terminal portion of axon called terminal buttons

What are synaptic vessicles?

Little parcels containing fixed about of neurotransmitter; contain neurotransmitters- leave via exocytosis

What are Glial Cells function?

To support neurons - "nerve glue"; support roles

What are the different types of Glial Cells?

1. Microglia

2. Astrocytes

3. Oligodendrocytes

4. Schwann Cells

What do microglia do?

provides an immune response, cell maintenance, spatial buffering, and may even release neurotransmitters! (Basically immune cells)

What do astrocytes?

star-shaped cells that wrap around neurons and supply them with nutrients (usually lactate for ATP synthesis); also immue function and phagocytosis

What is the blood-brain-barrier?

Selectively permeable barrier occurring between CNS blood vessels and neurons

• large ptoteins must be actively transported through the membrane or they do not enter the brain

• other molecules (glucose, waste, etc.) are moved in and out via active transport (atp-dependent transport)

Where is the blood-brain-barrier weakest?

the area postrema (near the brainstem) as it detects the presence of toxins in the blood and induces vomiting response

What increases the probability of an action potential?

excitation; activation

What decreases the probability of an action potential?

Inhibition; deactivation

What are examples of excitatory drugs?

caffine, molly, cocaine

What are examples of inhibitory drugs?

THC (cannabis), antihistamines (nyquil), alcohol, opioids

What is an action potential?

An electrochemical impulse that "flows" down the axon, just as electricity flows through a wire

• measured in vitro with correct type of neuron

What is the resting potential of most neurons?

-70mV

What is the potential outside of the cell

+70mV

What is inside a cell?

Potassium (K+) and Amino Acid Proteins (A-)

What is outside a cell?

Sodium (Na+) and Chloride (Cl-)

Who first studied the chemical properties of the action potential?

Hodgkin and Huxley in the mid 20th century

• used whole cell recording methods to record changes in membrane potential over time

What is hyperpolarization?

the cells become more negative relevant to the outside environment (moving farther from zero - inhibitory)

What is depolarization?

The cell becomes more positive relative to the outside environment (moving closer to zero- excitatory)

What is diffusion?

a movement of molecules down a concentration gradient; move until both sides are balanced

What is electrostatic pressure?

ions (charged particles) move away from similarly charged areas for example positive away from positive charged environments

What is threshold?

the minimum amount of voltage change needed to start the biochemical process of the action potential (-55)

What happens if an input is excitatory?

the postsynaptic (receiving) cell will fire an action potential once it reaches threshold

What two forces allow the action potential to take place?

Diffusion and Electrostatic pressure

What is the goal of an action potential?

To stimulate a neurons in such a way that now it is able to communicate with another neuron

What is in extracellular fluid?

Rich with Cl- and Na+ ions and a low concentration of K+ ions

What is in intracellular fluid?

Rick in K+ ions with negatively charged molecules; a low concentration of Na+ and Cl- ions

• net difference allows for cells to be negatively charged at rest

What mechanisms are responsible for keeping the concentration of Na+ higher in extracellular fluid?

• The semi-permeable axonal membrane- Na+ can only enter through open pore ion channel

• the sodium potassium pump- uses atp to actively remove Na+ from the intracellular environment and bring in K+ in a 3:2 ratio

When do voltage-gates ion channels open?

once threshold excitation is reached

What pushes the membrane potential closer to zero

An increase in Na+ conductance

What happens at peak response

Na+channels become refractory (they close)

What is the all-or-none law?

Action potentials either occur or they do not occur and frequency of action potentials can change, but the amplitude does not; don’t change in magnitude

What is the rate law?

This can happens at different rates: Rate of firing conveys the signal

-Low rate firing = weaker signal

-High rate firing = stronger signal

Where does communication between neurons occur?

at the synapse (synaptic transmission)

What can postsynaptic potentials be?

EPSPs or IPSPs (excitatory or inhibitory)

What does Presynaptic activity produce?

Presynaptic (output neuron) produces postsynaptic (input neuron) activity

What do presynaptic cells have?

Contains all of the materials necessary to transmit a chemical signal (Mitochondria and Synaptic Vesicle)

What do post-synaptic cells have?

Proteins embedded in the membrane that make the neuron responsive to chemical signals to chemical signals

AND

Ligands bind to these receptors at their binding sites

Where are chemicals involved in transmission stored?

synaptic vesicles via transport proteins

What is the process of transmitters leaving the cell known as?

exocytosis

What helps in the releasing of chemical contents of the cell?

the vesicle must fuse with the presynaptic membrane at the release zone and scaffolding proteins aid in this process