Brain structure Flashcards
What is neuroscience?
It is the study of the brain as a physical system. Central to it is mathematical modelling, description of neurons and circuits in terms of equations which capture how one state of the system leads to the next
What is the complex systems approach?
When elements are brought together to make a complex system, and properties emerge that none of the constituent elements have on their own.
what is a model
a picture of what might be going on in the brain, if it has a wider perspective it becomes a theory
how do you know if your model is right?
you can never know whether the model is right, but you can only falsify a model, which helps to understand what might actually be right.
scientific model
circle making scientific progress possible, when new observations contradict the predictions > it can lead to a paradigm shift.
Cerebral cortex
wrinkled layer surrounding the rest of the brain. Involved in most cognitive functions
thalamus
inside: it is a relay station in the pathways from sensory receptors of the visual, auditory and somatosensory systems to the cortex. It helps controlling sleep, wakefulness, attention and consciousness.
hypothalamus
regulates functions that are essential for maintaining the normal state of the body and reproduction. It controls hunger, body temperature, thirst, fatigue, sleep and hormones.
What is the limbic system and what makes it up
Regulates emotion and memory > includes thalamus, hypothalamus, hippocampus, amygdala, cingulate gyrus and basal ganglia
cerebellum
sensorimotor control, learning, languange and other cognitive functions.
brainstem
connects the spinal cord to the brain
Where are the four parts of the brain and what are they called and what do they do
frontal (decision making), temporal (down) (analysing sound), occipital (back) (visual information), paretial (above) (sensorimotor processing and sensory integration).
difference between gyrus and sulcus
gyri are at the top, sulcus is the sulk
what are the fissures called?
central fissure/sulcus > separates the frontal and paretial lobe
lateral/sylvial fissure > separates the temporal from the others above.
anatomical directions:
rostral (frontal), caudal (posterior)
dorsal (up), ventral (down)
medial (middle), lateral (outside)
what does the membrane of the neuron do and what’s at its interior
It separates the outside from the inside so that they don’t interact, it’s fatty and both outside and inside are packed with ions: positive > sodium, potassium, calcium; negative > chloride. ALL THESE REPEL EACH OTHER.
Ion channels:
specialized protein structures that will let through specific ions
Ion pumps:
they activeley transport ions across the membrane.
What is the membrane potential
Also called resting potential, it’s at -70 mV
What has more positive ions, outside or inside?
outside
How many steps does the action potential go through? And describe them
- the neuron is triggered at the axon hillock in the soma when the voltage difference in the soma becomes more positive - it POLARIZES TO THE THRESHOLD OF -55mV
- Sodium channels open up and sodium comes into the cell causing a rapid DEPOLARISATION, that climbs to +20mV.
- Potassium channels open up letting potassium out which leads to a REPOLARISATION back to -70mV > HYPERPOLARISATION when the potential sinks below the resting action potential.
- The membrane goes back to its resting stage > RESTING POTENTIAL
How long does the spike last
Around 5ms
what is the synapse?
connection between the two neurons - the neuron who signals is pre-synaptic, the receiver is post-synaptic.
What happens in the synaptic terminal?
It containes the neurotransmitters. The depolarisation makes them be reseased into the synaptic cleft. From there they attach themselves to receptors in the receiving neuron. This makes ion channels open and changes the membrane potential of the receiving neuron.
what is a synaptic current
flow of ions caused by synaptic activity
what happens in an excitatory synapse?
it depolarises the post-synaptic cell
what happens in an inhibitory synapse?
it lowers the membrane potential
Present the two synaptic currents:
primary current > current flowing along the dendrite.
Some of the current leaks via the LEAK CHANNELS into the extracellular space. There we have ions being pulled towars the neuron and ions being pushed away. This extracellular movement is called: secondary current or volume current
