BioPsych Exam 1

Modularity Theory

Mind and brain contain specialized regions or modules

Distributed Processing Theory

Cognition emerges from patterns of activity distributed across interacting brain regions rather than isolated modules

Neuroplasticity

The brain can change its structure, connectivity, and function in response to experience, learning, development, and injury

Global Workspace Theory

Conscious experience occurs when information becomes globally available across multiple brain systems

Nativism

The contents of the mind are influenced by its inborn structure

Dynamic Systems Theory

How complex behaviors and patterns emerge from the interaction of multiple smaller parts over time

The Neuron Theory

Neurons are discrete, autonomous cells that interact with each other through electrical and chemical signals

Afferent Nerve

Carries messages from the body parts/organs to the CNS

Efferent Nerve

Carries messages from the CNS to the body parts/organs

Dendrite

Branched extensions that receive incoming signals

Dendritic Spines

Tiny protrusions on dendrites where many excitatory synapses form

Soma

The metabolic and integrative center of the neuron

Axon hillock

Cone-shaped region where the axon begins and the action potentials are initiated

Axon initial segment

Trigger zone just beyond the hillock, crucial for spike generation

Axon

Long projection that carries action potentials away from the soma

Myelin sheath

Insulated wrapping around the axon that speeds conduction

Node of Ranvier

Gap between adjacent myelin segments where action potentials are regenerated

Terminal branches

Fine endings of the axon

Axon terminals/synaptic boutons

Endings that release neurotransmitters

Synaptic vesicles

Small sacs that store neurotransmitters

Synaptic cleft

Tiny gap between the pre-synaptic and post-synaptic cells

Postsynaptic membrane/receptor sites

Bind neurotransmitters and release electrical signals

Unipolar neuron

One process directly off the soma

Bipolar neuron

Two processes directly off the soma

Pseudounipolar neuron

One process leaves the soma and then divides into two branches

Multipolar neuron

Three or more processes, typically many dendrites and one axon

Anaxonic neuron

Many processes extend from the soma, but no clearly identifiable axon can be distinguished

Sensory neuron function

Carries information from body and world to brain and spinal cord

Motor neuron function

Conducts messages from brain and spinal cord to muscles and organs

Interneuron function

Conducts information between neurons in the same area

How are neurons classified?

Function, Structure, and Signaling Role

Excitatory neuron

Causes other neurons to fire

Inhibitory neuron

Still fires but tells others to not fire

Motor neuron form and location

Multipolar - CNS

Sensory neuron form and location

Unipolar - PNS and cranial nerves

Bipolar - PNS

Interneuron form and location

Multipolar in the CNS

Motor neuron description

Axon, dendrites extend in several directions from cell body

Sensory neuron description

Single short stalk from cell body divides into 2 branches

Axon and dendritic processes are on opposite sides of cell body

Interneuron description

Short or no axon, communicates locally

Resting potential (approx -70mV)

Voltage-gated Na and K channels closed

Leak channels and Na/K pump maintain resting potential

Depolarization (rising phase)

Voltage-gated Na channels open

Na influx causes rapid depolarization

Peak/Overshoot (approx 30mV)

Na influx continues but begins to slow

Repolarization (falling phase)

Na channels inactivate

Voltage-gated K channels open

K efflux causes membrane potential to fall

Hyperpolarization

K channels remain open briefly

Continued K efflux makes membrane potential more negative than resting

Return to resting potential

K channels slowly close

Na/K pump and leak channels restore and maintain resting potential

6 stages in the action potential

Resting potential, Depolarization, Peak/Overshoot, Repolarization, Hyperpolarization, Return to resting

Glial Cell

Specialized CNS and PNS cells that maintain the environment necessary for neuronal signaling and actively regulate development, synaptic communication, metabolism, immune responses, myelination, plasticity, and repair

Absolute Refractory Period

No new action potential can be generated

Relative Refractory Period

A phase following an action potential when a neuron or muscle cell can fire another impulse, but only if the incoming stimulus is stronger than normal

Monism

The idea that the mind and the body are the same

Dualism

The idea that the mind and the brain are separate

Localization

The idea that specific areas of the brain carry out specific functions

Overactive neurons

Can cause anxiety, panic attacks, insomnia, and other physical changes

Underactive neurons

Can cause depression due to a deficiency in serotonin, dopamine, and norepinephrine

Local Potential

Graded and Decremental

A small, short-lived change in a neuron's voltage membrane

Action Potential

All-or-none law and Propagates undecremented

A rapid, temporary change in electrical voltage across a neuron's cell membrane

What happens when a person has MS?

Loss of myelin sheath, which leads to holes

Ionic homeostasis

Maintain precise extracellular ion gradients

Neurotransmitter regulation

Remove, recycle, or metabolize transmitters

Myelin

Insulate axons and speed signal conduction

Astrocytes

Balance glutamate (excitatory nature of the brain)

Support blood-brain barrier

Myelinating Glia

Oligodendrocytes (CNS) and Schwann Cells (PNS)

Speeds up electrical signal transmission

Oligodendrocytes

One cell can myelinate segments of multiple axons

Schwann Cells

One cell typically myelinates one segment of one axon

Important for peripheral nerve repair and regeneration

Radial Glia

Developmental scaffolding for migration and neural progenitor cells

Microglia

Resident CNS immune cells. Survey tissue, respond to injury or infection, phagocytose debris, and participate in synaptic pruning

Why do Glia matter?

Glial dysfunction can affect axonal conduction and myelin, neuroinflammation, glutamate regulation and metabolism, blood-brain barrier function, and peripheral nerve signaling

Meningies

Three protective layers of membrane that cover and protect the brain and spinal cord

White Matter Tracks

Bundles of axons in the brain and spinal cord (CNS)

Cranial Nerves (12)

Brain to sensory organs

Spinal Nerves

Spine to extremities

Ganglions

Cluster of neuron cell bodies located in the PNS

Relative Lateralization of Function

Tendency for specific processes to be more dominant in one cerebral hemisphere than the other

Hierarchical organization

Less complex systems inward and more complex systems outward

Simple —> Complex thought processes

Magnetic Brain Imaging Techniques

MEG - maps brain activity by recording the tiny magnetic fields produced by electrical currents in neurons

MRI - uses a large magnet and radio waves to create detailed pictures of your brain and brainstem

Radioactivity Brain Imaging Techniques

PET - measure chemical activity and blood flow inside the brain

Optical Brain Imaging Techniques

Use light to measure blood flow in the brain

Electrical Activity Brain Imaging Techniques

EEG

Measures neurons firing

Corpus callosum

How the brain hemispheres talk

Gyrus

Bumps in the cerebrum

Sulcus

Divets in the cerebrum