Download Neurons

Memory, Brain (Chapter 8.1)
Vengertsev Dmitry
Agenda
Goals:
1) provide general overview of what we do know
about underlying biological processes and brain
structures that support memory
2) introduce difficulties in conducting this kind of
research
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The Neuron
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The Brain
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Methods of Investigation the way memory stored in the brain
The Neuron
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Memory involves a persistent change in the
relationship between neurons:
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Structural modification
Biochemical events within neurons that change the
way in which neighboring neurons communicate
Squire, 1987
The Nervous system
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Glia cells (support, maintenance)
Neurons – cells that process and
transmit information
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Sensory neurons (take information
outside the system – light, touch…)
Motor neurons (provide instructions to
muscles and affect glands)
Inter-neurons (majority)
Simplified drawing:
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Dendrites, Axon, Soma (cell body)
Myelin sheath
Signal processing (1)
Signal processing (2)
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Synapse – gap between
the end of the axon of
one neuron and the
dendrites of another
Neurotransmitters –
chemicals that transmit
the neural impulse over
synapse
PSP – postsynaptic potential – change in membrane potential:
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increase the likelihood that receiving neuron will process
remain or decrease action potential (in this case neurotransmitters are
killed by enzymes)
The Brain

Hindbrain (connect the brain and
spinal cord, includes medulla, pons,
cerebellum)
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Midbrain (between hindbrain and
forebrain, includes tectum)
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Forebrain (includes thalamus,
hypothalamus, cerebrum)
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Each cerebral hemisphere divided
into four lobes: frontal, parietal,
temporal and occipital
Methods of Investigation
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Invasive (involve damage to brain)
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accidents
animal studies
recording from single neurons
Noninvasive (little risk)
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measuring blood flow, electrical activities at the
brain,…
Invasive method
Memory centered on the hippocampus.
Hippocampus is responsible for getting together the contextual features of a
situation and create a representation of every experience.
Animal studies
1. Rats (have similar anatomy of hippocampus)
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2. Monkeys (have similar brain structure)
Micro-electrode implanted in the brain
recorded activity of single group of neurons.
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Problems:
 Generalizing from laboratory animals to human
 How can be such complex system investigated if we make a hole in the
center of it
Noninvasive methods (1)

CT (computer tomography)
 shows brain structure
 measure difference in absorption of X-rays by
tissues with different density

PET (position emission tomography)
 shows activity
 neurons use glucose as a source of energy.
Patient’s injected with radioactive glucose and do
task
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MRI (magnetic resonance imaging)
 shows brain structure
 magnetic resonance
Noninvasive methods (2)
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functional MRI
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Electroencephalograms (EEGs)
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MRI + tracking blood flow in the brain
the more active brain area is the more blood flows to it
produce picture of brain activity
measure pattern of electrical activity through electrodes
attached to the scalp
Event-related potentials (ERPs)
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instantaneous changes in EEG associated with a
presentation of particular stimulus
Noninvasive methods (3)
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Behavioral studies
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Kinsbourne and Cook: compare performance on a
balancing task when subject (right-handed
person) either vocalize or remain silent
Results:
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right hand: better not to speak (reason: left hemisphere
controls the right hand and also is the seat of language)
left hand: speak! speak! (reason: verbalizing helped by
distracting the subjects enough that they didn’t focus too
much attention on balancing)
Thank you!