Sem 2 Weeks 1-3 Flashcards
Test 1
Automaticity Theory
The word interferes with the colour naming when the word and colour do not match because reading is an automatic process and recognising colours is a more controlled process
Selective Attention process
Reading requires less attention compared to identifying a colour, that’s why it takes us longer to identify the colour of words in incongruent trials
Aphasia
Language disorder that affects a person’s ability to communicate, often
a result of a stroke or brain injury
What tasks might people with aphasia find difficult?
Talking , Comprehending spoken or written language, Writing, Using numbers, for example calculating answers to problems.
Broca’s Area
Involved in speech production.
Wernicke’s area
Involved in language comprehension
how does fMRI work
It is a safe and non invasive imaging method which detects changes in blood flow. An increase in blood flow correlates with neuronal activity
Transcranial Magnetic Stimulation
Non-invasive technique that disrupts specific brain activity for a fraction of a second. Allows us to investigate the role of certain areas in human functioning
Central Nervous System
brain and spinal cord
Peripheral Nervous system
Comprised of the autonomic and somatic systems
What is special about neuronal cells
Can transmit information by receiving and sending electrical and chemical signals.
Function of dendrites
Detect signals and receive information from branch points and sends it into the soma
What is the cell body (soma)
contains nucleus and organelles, life support system
Function of the axon
transmits signal away from the cell body and down the neuron
What are axon terminals
terminal end of axon where the neuron synapses
What are dendritic spines
The extra surface area along dendrites where axon terminals from other neurons can make connections - More surface area for connections to form
Axon Hillock
point of neuron at the base of the axon where it “fires”
What does “all or nothing” mean
Once the signal reaches a certain threshold, the neuron will fire
What is myelin
a fatty, lipid-rich substance that insulates most axons
Function of myelin
Allows the signal to “hop” along nodes of ranvier and travel faster
Unmyelinatied action potential speed vs myelinated speed
1 meter per second compared to up to 100 metres per speed
3 types of glial cells
Oligodendrocytes, Schwan Cells, Astrocytes
Function of Astrocytes
- Repair and provide support to neurons
- Brings nutrients from the blood stream to the neurons using the blood brain barrier
Function of Schwan Cells
Form myelin sheaths in the PNS - increases speed of info travelling through the axon
Function of Oligodendrocytes
Form myelin sheaths in CNS to increase speed of action potential travelling through the axon
How do Oligodendrocytes and Schwan cells work differently
Oligodendrocytes consist of a cell body with multiple arms, and wrap these arms around axons to form a tight sheath. In comparison, Schwan cells wrap their entire cell body around the axon (instead of using extensions)
Excitatory Signals
Increase likelihood of the neuron firing
Inhibitory Signals
Decrease likelihood of the neuron firing
What is summation
The sum of all incoming signals determine whether the neuron fire
What is the voltage a neuron must reach to fire
-55mv
What voltage is the resting membrane potential
-70mv
What is the difference in concentration of ions inside and outside the cell (Na and K)
Inside of the cell has higher conc of K+ ions and is more negatively charged than the outside of the cell, which has higher conc of Na+ ions.
What are voltage gated ion channels
Selectively permeable to certain ions and open once certain voltages are reached (usually v = -55mv)
Leaky Potassium Channels
All cells in the body contain leaky potassium channels that are only permeable to potassium, allowing potassium to diffuse outside the cell. This makes inside of the cell more negative than extracellular space as positive ions are LEAVING.
Passive diffusion -concentration gradient
Ions move from areas of high conc. and toward lower conc. until equilibrium is reached
Passive diffusion - eletrical gradient
Charged particles will move across membrane until equilibrium occurs (same charge on both sides)
What is an action potential
The change in the voltage inside a cell (relative to outside the cell) taking place at one section of the neuron at a time (not all at once).
Where are action potentials generated?
Axon Hillock
What happens once the threshold of -55mv is reached
Voltage-gated Na Channels open, causing sodium to flood into the cell (due to concentration & electrical gradient)
What is depolarisation?
When a voltage of -55mv is reached and Na+ flows into the cell, the cell becomes more positive (also causes K+ ions to rush outside of cell).
What is the Na+/K+ close threshold
30mv
What happens once the voltage becomes 30mv (overshoot)
Voltage gated Na channels close, resulting in repolarisation as Na stops flooding in and K+ leaves.
Refractory Period
Voltage drops below resting potential (hyperpolarised)
How does the cell return to RMP after refractory period
Na+/K+ pump comes in. (3Na+ out, 2K+ in) to return voltage to -70mv
Saltatory Conduction
Occurs in myelinated action potentials, resulting in an increased rate of propagation causing the signal to move faster. This is because the action potential occurs only at the nodes of Ranvier, not down the whole axon.
What does electrochemical communication mean
Neurons use both eletrical and chemical communication to transmit and recieve signals
Electrical communication in neurons
Action potential generation and modulation
Chemical communication in neurons
Interneural communication (at synapses, using neurotransmitter)
Synapse
Space between one cells dendrite and another cells axon terminal
What does the Pre-synaptic neuron do?
Neuron that sends signal
Post-synaptic neuron
Neuron that recieves signal
Neurotransmitter
chemicals that are released by presynaptic cell into synaptic cleft
Vesicles
“vehicles” that enclose and transport neurotransmitters
3 types of synapses
- Neuron-Neuron
- Neuron-skeletal muscle (neuromuscular joints)
- Neuron-Gland Cells (neuroglandular synapses)
Axodendritic Synapse
synapse directly from the axon terminal to the dendrites
Axosomatic synapse
synapse directly onto cell body
Axoaxonic synapse
synapse onto axon
Role of calcium
Essential for allowing neurotransmitters in presynaptic cell to exit the cell and enter the synaptic cleft
Role of chloride
Helps neurons send inhibitory signals
What happens when action potential arrives at presynaptic terminal
It depolarises it
What does depolarisation of the axon terminal cause?
Allows voltage-gated Ca2+ channels to open, allowing for the influx of Ca2+ in the axon terminal
What happens when presynaptic cell has an influx of Ca2+
Allows vesicles to fuse with the membrane and the neurotransmitter to be released into the synaptic cleft through exocytosis.
What happens once the neurotransmitter is released into the synaptic cleft
It binds to receptors, causing channels to open (or close)
Function of receptors (on post-synaptic neuron)
Once these receptors connect with the right shape/number of neurotransmitter, the receptors release ions into post-synaptic cell. These ions can be excitatory (positive ions) or inhibitory (negative ions)
Effect of receptor sending ions into post synaptic cell.
Influx of ions either depolarises or hyperpolarises the cell, making another action potential more or less likely.
How are neurotransmitters removed from synaptic cleft
glial uptake (to be reused) or through enzymatic degradation.
What are ligand gated ion channels
require certain ligand (neurotransmitter) to release ions into postsynatic cell.
What is glutamate
Most common excitatory neurotransmitter
What is GABA
Most common inhibitory neurotransmitter
EPSP (excitatory postsynaptic potential)
- When glutamate triggers opening of ligand gated channels lets Na+ and Ca2+ ions into postsynaptic cell.
The cell depolarises and becomes more excited, more likely to fire
ISPS (inhibitory postsynaptic potential)
- When GABA triggers opening of ligand gated channels, they let Cl- flow into the cell
The cell hyperpolarises, becomes inhibited and is less likely to fire
What is reuptake and why is it beneficial
Neurotransmitter is transported back into presynaptic cell. Allows cell to reuse neurotransmitter to conserve energy and lower amount of neurotransmitter that needs to be made
How does reuptake occur
The pre-synaptic cell membrane has neurotransmitter-specific “transporter” proteins to recieve and reuptake the chemicals
What are neurotransmitters
Chemical messengers that transmit signals across synapses from one neuron to another neuron (or to muscle/gland cell)
Is dopamine excitatory or inhibitory
Can be both - depending on receptors on post-synaptic cell. Different ligand channels that can release different ions to make this excitatory or inhibitory
Role of dopamine
- Motivation
- Thoughts and feelings
- Experiencing pleasure
- Association of certain behaviours with reward
- Attention, mood regulation
- Coordinating Movement
What neurotransmitter is deficient in those with Parkinsons
Parkinsons disease = progressive loss of dopamine-producing neurons)
What is serotonin involved in
- Regulation of mood, sleep, eating, arousal, pain
How do antidepressents work (think what neurotransmitter is reduced with depression_
Antidepressants target neurons that produce serotonin to boost serotonin levels
How can sunlight boost serotonin
Sunlight exposure stimulates production of Vit. D in the skin. Vit D is involved in serotonin synthesis.
Why does alcohol lead to sedation and anxiolytic effects.
Acts as an agonist for GABA. It binds to a part of GABA receptors to make them even more inhibitory, making neurons that release GABA stronger at inhibiting the firing of the next neuron. The impact of this is drowsiness and anxiety reducing effects.
Agonist
Drugs that occupy receptors and activate them
Antagonists
Drugs that occupy receptors but block receptor activation
What are SSRIS
Reuptake inhibitors that don’t effect post synaptic receptor but instead target reuptake
How do SSRI’s work
Block reuptake = more neurotransmitter left in synapse for longer = more is taken up by ion channels = stronger effect of neurotransmitter
Function of Glia
help support the work of neurons
The basic assumption of all modern neuroscience and psychology
Mental functions are the product of activity in the nervous system
Functions of the nervous system (4)
- Receives sensory information from the environment
- Integrates and processes information
- Regulates internal functions
- Produces motor actions
What can autonomic nervous system be broken down into:
Sympathetic (arousing) and Parasympathetic (calming)
Autonomic Nervous system function
Involuntary, automatic activity. Controls and regulates blood vessels, organs (including the heart) and glands
Somatic nervous system function
Skeletal muscles - conscious movement/activity
What is a nerve
bundle of axons (like an electrical cable).
Structure of nerve
Within the nerve, axons are bundled into sub bundles and this is held together by connective tissues. Nerves contain blood vessels to provide axons with nutrients.
Somatic nerves
form synapses onto skeletal muscles
Sympathetic Nervous system
-Increases arousal
- Prepares the body for survival-related action
- (4F’s) Fight, flight, flee, Mate (fuck) - increase HR, BP, slowed digestion, dilation of pupils
Parasympathetic nervous system
Performs opposite actions to sympathetic. Reduces arousal, Redirects blood to other locations (digestive tract), Returns the body to resting state
Neuraxis
Central axis of the nervous system
Most creatures vs humans neuraxis
Most creatures (quadrapedal mammals) have spinal cord and brain along a single line. Since we stand on two legs and look forward, our neuraxis is like an upside down L and changes.
Rostral/Anterior end of nervous system
- Forehead or front of face
- Towards the top end of our spine (towards skull)
Caudal or Posterior
- Back of head
- Towards the feet
Dorsal
Above the neuroaxis (top of brain, back of spinal cord)
Ventral
Below the neuroaxis (bottom of brain, front of spinal cord)
Lateral
- Towards the side, outside surface
Median
In or towards the middle
What is structure and function of the spinal column?
It is the structure of bone and cartilage within which the spinal cord lives (protects spinal cord.) It consists of many vertebrae connected with rings of flexible cartilage (allow us to move flexibly)
Top part of spinal column (C1-C6)
Cervical vertebrae
2nd part of spinal column (under cervical vertebrae) C7 - C12
Thoracic vertebrae
Spinal column under the thoracic vertebrae (L1 - L5)
Lumbar vertebrae
Botton part of spinal column (S1 - S5)
Sacral
What is grey matter comprised of
Mostly Cell Body
What is white matter comprised of
Mostly myelinated axons
where is the spinal Nerve located?
Located on either side of spinal cord (on each side it comes out in two parts that come together to form a single nerve)
Where does information come into spinal cord through
Dorsal horn
Dorsal Root Ganglion
Dorsal nerve soma collected together here outside of the spinal cord
Where does information leave the spinal cord through
Ventral Root/ventral horn
Difference between root and horn
Root (within spinal cord)
Horn (outside the spinal cord)
Ganglion
A collection of cell bodies outside of the spinal cord
Is the cell body of motor neurons located within or outside the spinal cord
Cell body of motor neurons are inside the spinal cord, info flows out from cell body outside to spinal nerve
General orientation of grey and white matter in the brain.
Grey matter lines the outside of the brain (opposite to spinal cord)
Most of the white matter is concentrated inside the deep portion of the brain
Horizontal/axis/transverse section of brain
Parallel to the floor
Sagittal section of brain
Parallel to profile
Coronal section of brain
Parallel to face
What section of the brain is phylogenetically ancient and evolutionarily preserved among basically all animal species
Hindbrain
Main function of hindbrain
Coordinates information flow to/flow from the spinal cord
Medulla
- Part of hindbrain
- Extension of the spinal cord
- Controls basic physiological functions (heart rate, circulation, respiration)
What 4 parts are within the hindbrain?
Medulla, Reticular formation, Cerebellum, Pons
Reticular formation
- Part of hindbrain
- Regulates sleep/wake and arousal
Cerebellum
- Part of hindbrain
- Controls fine motor activity
- Doesn’t initiate movements, but refines and smooths them
- Requires computational power = big structure (mini brain)
Pons
- Part of hindbrain
- Collection of cells and white matter
Relays info between cerebellum and rest of the brain
How do we know that the cerebellum functions as it does
Cerebellar ataxia (damage to the cerebellum)
- Cause tremor and lack of coordinate muscle movements. This shows the importance of the cerebellum in refining and adding precision to our movements
What are the two main subdivisions of the midbrain
Tegmentum and Tectum
Main function of midbrain
- Coordinates basic functions in relation to perception and action
Tectum
- Dorsal area of the midbrain
- Spatial orienting to the environment (eg. turning your head to look over at something you heard)
- Consists of 4 bubble-like structures (colliculi)
What are superior colliculi?
Part of tectum (midbrain) involved in vision
What are Inferior colliculi
Part of tectum (midbrain) involved in audition
Tegmentum
- Ventral part of mid-brain
- Movement (allows us catch a ball without thinking about it)
- Arousal
- Pleasure seeking
Where is the Substantia Nigra
A part of the tegmentum
Substantia Nigra and Parkinsons
High level of dopamine gives this area a dark colour (Dopamine = involved in movement & pleasure seeking). In patients with Parkinson’s (deficiency in dopamine) this portion of the brain is pale
Forebrain
Evolutionary the newest, involved in higher brain functioning with portions unique to humans
Basal Ganglia
- Part of forebrain
- Movement and reward
- Plan initiation of intentional movements
- Decide which muscles need to move to reach out intentionally
Thalamus
- Part of forebrain
- Sensory gateway
- Egg-shaped structures
- Relays & filters information from the senses to the cortex
- Most sensory information goes first to the thalamus before being sent to relevant processing areas in the cortex
4 parts of the limbic system
Hypothalamus, Pituitary Gland, Hippocampus, Amygdala
Function of limbic system overall
Related to arousal and emotional processing
Hypothalamus
- Part of limbic system (forebrain)
- Regulates internal bodily functions
- Body temp, hunger, fight, flight, flee, mate
One way we can know the function of the hypothalamus
- Experimental lesion to the hypothalamus in rats - eats insatiably and gets fat as it does not receive cues that its “full”
Pituitary Gland
- Part of limbic system (forebrain)
- Releases and regulates hormones into the bloodstream
Hippocampus
- Part of limbic system (forebrain)
- Important in spatial navigation
- Creates and integrates new memories (but not long term storage)
Amygdala
- Part of limbic system (forebrain)
- Almond shapes
- Responds to emotional processing
- Particularly related to threats and fear
- Evolutionarily, the brain has evolved to scan and register threats (spiders and snakes) faster than other, non-dangerous things
Sulcus
Folds into brain
Gyrus
Visible part of fold on surface of brain
4 lobes that are in each hemisphere of the brain
Frontal, Parietal, Occipital, Temporal
What is the corpus callosum
Wide band of white matter that connects the two hemispheres of the brain
What is the “pool of liquid” that the brain floats in
Cerebro-spinal Fluid (CSF)
Function of Cerebro-spinal Fluid (CSF)
Liquid that provides shock absorption when the brain moves against the skull
4 layers of external membrane of the brain
- Dura Mater (closest to skull)
- Arachnoid (legs that give it spongy texture) - where CSF flows
- Pia mater (closest to cortex)
Ventricles inside the brain
4 ventricles (“empty spaces” containing CSF?
Choroid Plexus
Collection of blood vessels between ventricles that are designed to secrete CSF
Primary somatosensory Cortex
- Sense of touch
- Processes touch on skin anywhere in the body
Primary Motor Cortex
Allows muscles to move
1950 Penfield brain stimulation
During neurosurgery, he stimulated the exposed cortical surface with an electrode. He found these causes (sensation, movement, memories)
This can be used to map functions, help knowledge of the brain, and allow surgeons to know what areas to cut out of the brain
Occipital Lobes
- Located at rear of brain
- Vision
- Posterior location of occipital lobe is primary visual cortex
Temporal lobe
Semantic knowledge (meaning of words, identifying objects)
- Audition
Parietal Lobe
- Spatial attention
- Sensory integration
- Object location (where objects are in space)
- Numerical cognition, quantities
Frontal lobe
- Planning
- High level executive function
- Self control
- Abstract thinking
