General Flashcards
Neuroimaging doesn’t =
causation
except maybe …
TMS
Can we discriminate between excitatory and inhibitory activity?
Nope - • No dissociation between excitatory and inhibitory activity
Does more activation mean more processing?
Nope
Brain activity occurs in at least two modes important to contrast
1) active
2) resting state
Null activity results are difficult to interpret, why?
– The area was active in both tasks
– The area was not active in either of the task – Too subtle differences to detect
Two types of nerve cells =
1) Glial
2) Neurons
four different types of glial cells found in the central nervous system: ependymal cells, astrocytes, microglial cells, and oligodendrocytes.
Lots of diff kinds of neuron (purkinje)
glial cell details:
– More in Number (10-50 X Number of Neurons)
– Supporting neurons (re uptake / clearance of neurotransmitters / synaptic plasticity and synaptogenesis guiding growth and connections)
– No direct role in information transmission (?)
– No role in electrical signalling
neuron details:
– Basic building block
– 1011 neurons
– More than 1000 varieties but with shared basic architecture
– Complexity of behavior depends less on the specialization of individual cells but more on the connectivity
– Generates electrical signals
– Communicates mainly via electrochemical fashion
what is the Four Component Model of a Neuron?
1) input (dendrite)
2) integrative (cell body)
3) conductile (axon)
4) output (synapse)
What is an action potential?
action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory.
Information is conveyed not by the form but by the pathways
All-or-None phenomenon
(either it fires at its full amplitude or doesn’t fire at all)
What is the duration and mV of an action potential ?
• ~ 100 mV with 1 ms duration
does it propagate with the same amplitude along the axonal pathway?
yes
Nondecremental (same amplitude)
what is the myelin sheath made from
glial cells
