Cognitive Neuroscience Flashcards
What is cognitive neuroscience?
It is the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes
Where does visual info from our environment come in through?
Visual info from our environment comes in through the pupil goes through the lens
What do photoreceptor cells do?
They convert the visual info from the environment into electrochemical energy that the brain can then process
What does the lens do?
The lens focuses the visual info on the back of your eye
Where are photoreceptors located?
on the back of the eye
Where are there no photoreceptors?
On the optic nerve
Why are there no photoreceptors on the optic nerve?
There are no photoreceptors because the photoreceptor cells have axons which take the info from photoreceptor cells up to the brain to be processed. These axons gather to make up the optic nerve
What does the nervous system do?
They coordinate our actions and sensory information by transmitting signals to and from different parts of the body
What does the nervous system detect?
It detects environmental changes that will impact the body and respond to these events
What does the nervous system regulate?
It regulates the internal functions and produces motor actions
What are genes?
They are molecules of DNA that carry info on how to build bodies
What are cells?
Cells are basic units of structure and function of all living things
What are tissues?
Tissues are groups of cells of the same kind
What are organs?
Organs are structures composed of one or more types of tissues which work together to perform a specific function
What are systems?
Systems are groups of organs that work together to perform a certain function
Why is the structure of a living cell important?
It is important to understand the structure of the living cell because if the cell is damaged, this can produce changes in behaviour and cognition
What is the membrane?
The membrane is a thin semi-permeable membrane that surrounds the cell
What are the two functions of the membrane?
The membrane protects the integrity of the interior of the cell e.g. allows certain substances inside the cell but keeps others outside
It also helps support the cell and maintain it’s shape
What does the nucleus contain?
The nucleus contains the cells genes and controls the cells growth and reproduction
What does the nucleolus do and where can it be found?
The nucleolus contains chromosomes and is within the nucleus
Where are channels found?
Channels are found on the membrane of the cell
What are channels made of?
Channels are made of proteins
What do channels do?
Channels allow the exchange of various materials in and out of the cell
What does the mitochondria do?
The mitochondria converts nutrients into ATP for chemical energy
What is ATP?
ATP is a complex organic chemical that provides energy to drive many processes within the cell
What are the two main types of cell in the nervous system?
Neurons and glia cells
What are neurons thought to be?
Neurons are thought to be building blocks of the nervous system
What do neurons do?
Neurons communicate with one another to perform information processing tasks
What are the different types of glia cells?
Astrocytes, Schwann cells and oligodendrocytes
What do the different types of glia cells do?
Different types of glia cells provide support to the neurons within the nervous system
What do oligodendrocytes do?
They provide the myelin sheath around the axon of the neurons in the central nervous system
What does the insulation formed by the myelin sheath allow?
It allows the communication along the cell to be much faster and more efficient
What do Schwann cells do?
They form the myelin sheath around the axons in the peripheral nervous system
What do astrocytes do?
Astrocytes provide nutrients to the neurons and help the cell to maintain their extracellular environment. They also provide structural support
Where is the nucleus of a neuron found?
It is found within the cell body or soma
What happens at the cell body of a neuron?
Coordination of the info processing tasks are said to take place at the cell body. It is also important for keeping the cell alive
Where are dendrites of a neuron found?
Dendrites are found surrounding the cell body
What do dendrites do?
They receive info from other neurons and relay it to the cell body
Cells tend to only have one axon. What does it do?
This axon transmits info to other neurons from this neuron
What happens at the axon hillock?
The axon hillock is where inputs from other cells are summated before being transmitted along the axon of the cell
What is the myelin sheath formed by?
The myelin sheath is formed by glial cells
What is myelin sheath?
Myelin sheath is the fatty layer of insulation which surrounds the axon of the neuron
What are the nodes of Ranvier?
They are the little gaps in the myelin sheath
What do the nodes of Ranvier do?
They allow the electrical signals to jump across the myelin sheath, making communication quicker
Where are the axon terminals found?
Axon terminals are found at the end of an axon
What happens at the axon terminals?
This is where axons will form synapses with the dendrites of other neurons
How do neurons communicate?
Neurons communicate using electrochemical signals
What’s the difference between the signals within the cell itself and the communication across the synapse?
The signals within the cell itself is thought to be electrical in nature whereas the communication across the synapse is thought to be chemical in nature
What do dendrites form synapses with?
Dendrites form synapses with other presynaptic cells
What happens if the cell receives enough stimulation from enough presynaptic cells?
It will reach a threshold and will fire and send an electrical impulse called an action potential along the cell
What is an action potential?
It is an electric signal that is conducted along the length of a neuron’s axon to the synapse
What is spatial summation?
Spatial summation refers to the stimulation of several spatially separated neurons at the same time
When does the communication between cells change?
When a cell sends an action potential along its axon, it comes down to the bottom of the cell where it synapses with a neighbouring cell, and its here where the communication changes and it becomes a chemical signal rather than electrical
What is present in presynaptic cells that if stimulated enough gets released into the synapse?
Chemicals or neurotransmitters
What do neurotransmitters do one it crosses the synapse?
It will attach itself to receptors in the dendrites of the post-synaptic cell
What is specific about neurotransmitters?
They only attach to certain receptors e.g. lock and key
What is temporal summation?
Temporal summation is when there’s an input from one cell, but that input occurs repeatedly
Why do neurons fire?
Neurons fire to allow us to carry out specific functions
What are ions?
They are charged atoms
What is an electric potential?
An electric potential is an overall difference in charge between nearby areas
(negative ions are attracted to the are where the more positively charged ions are)
In an action potential why do particles diffuse?
They diffuse to equate concentration across space
How can positive ions cross the cell membrane
They can cross via ion channels
What is the resting potential of a cell?
It is the difference in electric charge between the inside and outside of the cell. The resting potential is -70mv
What is the sodium potassium pump?
It is a protein pump that is continually moving three sodium ions outside of the cell and two potassium ions inside the cell
Looking at the sodium potassium pump, what happens when the cell is stimulated by either spacial or temporal summation?
The cell reaches a threshold and so there is a rush of sodium ions inside the cell
Looking at the sodium potassium pump, what happens to the cell when there is an influx of sodium ions in the cell?
The cell becomes more positively charged inside rather than on the outside, reaching its max of 40mv
Looking at the sodium potassium pump, when the cell becomes more positively charged on the inside what happens?
The sodium ion channels close again and the potassium ion channels will open. The potassium crosses the channel to the more negatively charged outside of the cell restoring the charges back to the original
Looking at the sodium potassium pump, once the charges have been restored inside and outside of the cell, what happens?
The membrane potential lower and we have repolarization in which the inside of the cell is more negatively charged than outside
What is hyperpolarization and when does it take place?
Hyperpolarization is where the inside of the cell becomes even more negatively charged, and it takes place when the cell overcompensates
Looking at the sodium potassium pump, how do the neurons return to its resting state?
The sodium potassium pump moves three sodium ions outside the cell and two potassium ions inside the cell
What is saltatory conduction?
It is the propagation of action potentials along the myelinated axons from one node of Ranvier to the next node
What happens if saltatory conduction is disrupted?
If disrupted it can cause damage
e.g. multiple sclerosis
What is multiple sclerosis?
It is an autoimmune disease in which one’s own immune system damages the myelin sheath
What are the three main types of neuron?
Motor, sensory and inter
What are motor neurons?
Motor neurons are the neurons that carry signals from the spinal cord to the muscles
What do motor neurons produce?
They produce a movement