Date post: | 31-Dec-2015 |
Category: |
Documents |
Upload: | rose-leblanc |
View: | 19 times |
Download: | 1 times |
behavior analysis in a natural environment in the laboratory
cells, synapses & circuits basic properties of nerve cells synaptic transmission neuronal architecture & behavior
relating nerve cells to behavior
summary
#04: CELLS, SYNAPSES & CIRCUITS
behavior analysis in a natural environment in the laboratory
cells, synapses & circuits basic properties of nerve cells synaptic transmission neuronal architecture & behavior
relating nerve cells to behavior
summary
#04: CELLS, SYNAPSES & CIRCUITS
behavior analysis in a natural environment in the laboratory
cells, synapses & circuits basic properties of nerve cells synaptic transmission neuronal architecture & behavior
relating nerve cells to behavior
summary
#04: CELLS, SYNAPSES & CIRCUITS
behavior circuits of interacting neurons, 3 types:
SENSORY INPUT
CENTRAL PROCESSING
MOTOR OUTPUT
BEHAVIOR
NEURONAL ARCHITECTURE OF BEHAVIOR
behavior circuits of interacting neurons, 3 types:
sensory neurons... signal input specialized receptor cells convert features of environment neural signals
interneurons... central processing
motor neurons... motor output (behavior) drive muscle activity @ neuromuscular junction generate excitatory junctional potentials (EJPs)
NEURONAL ARCHITECTURE OF BEHAVIOR
electrical recordings:
electrode type
position ~ cells extracellular V, intracellular mV, advantages & disadvantages
p.24, fig.1.10
NEURONAL ARCHITECTURE OF BEHAVIOR
extracellular electrode
motor neurons
“unit” activity (>1)
~ current flow in extracellular space
p.24, fig.1.10
NEURONAL ARCHITECTURE OF BEHAVIOR
intracellular electrode
single motor neuron
p.24, fig.1.10
NEURONAL ARCHITECTURE OF BEHAVIOR
extracellular electrode
records propagation of action potentials along axons
p.24, fig.1.10
NEURONAL ARCHITECTURE OF BEHAVIOR
intracellular electrode
muscle fiber
EJPs signals... motor neuron others
p.24, fig.1.10
NEURONAL ARCHITECTURE OF BEHAVIOR
extracellular electrode
electromyogram (EMG)
whole muscle activity
p.24, fig.1.10
NEURONAL ARCHITECTURE OF BEHAVIOR
behavior circuits... simple ones (in mammals)
e.g., human knee jerk reflex...
tap knee below patella
stretches receptors in quads (muscle spindles)
activates sensory neurons (Ia)
synapse motor neurons ()
contraction of quads
p.25, fig.1.11
NEURONAL ARCHITECTURE OF BEHAVIOR
behavior circuits... simple ones (in mammals)
e.g., human knee jerk reflex...
simple ?
sensory-motor ?
monosynaptic ?
no, other neurons involvedp.25, fig.1.11
NEURONAL ARCHITECTURE OF BEHAVIOR
circuit complexity
e.g., primate visual cortex
boxes = assemblies of
103 s of neurons
106 s of synapses
2 main pathways V1 PG... object location V1 TE... visual form
p.25, fig.1.11
NEURONAL ARCHITECTURE OF BEHAVIOR
circuit complexity
e.g., primate visual cortex
Q: how to study cellular properties of neurons among such complexity ?
A: chose:
accessible behavior
in model organism providing special advantages
p.25, fig.1.11
NEURONAL ARCHITECTURE OF BEHAVIOR
advantages & disadvantages
interesting... it is ALL interesting (not only ~ humans)
maintenance, availability & access to sufficient #s
model system... biology & tools available behavior anatomy / physiology cell biology pharmacology genetics / genomics / proteomics
NEURONAL ARCHITECTURE OF BEHAVIOR
advantages & disadvantages
e.g., C. elegans (nematode)
+ cheap, maintenance, sample sizes, simple behavior, simple anatomy, small simple & well- characterized nervous system, development & cell biology, genetic & pharmacological tools good
– boring behavior, few properties of neuronal assemblies or structures, small neurons (electrophysiology difficult but accessible)
NEURONAL ARCHITECTURE OF BEHAVIOR
advantages & disadvantages
e.g., H. sapiens (humans)
+ interesting behavior, need to knowing how we function (medical), sequenced genome, ~ easy research funding arguments
– prohibitively complex in every respect, moral issues for invasive & experimental study, expensive, inconvenient & uncooperative subjects
NEURONAL ARCHITECTURE OF BEHAVIOR
behavior analysis in a natural environment in the laboratory
cells, synapses & circuits basic properties of nerve cells synaptic transmission neuronal architecture & behavior
relating nerve cells to behavior
summary
#04: CELLS, SYNAPSES & CIRCUITS
investigating how neurons behavior
e.g., crayfish response to tail tactile stimulus
record lateral giant interneuron (LGI) correlation (A): always stimulus behavior ?...
p.27, fig.1.12
RELATING NERVE CELLS TO BEHAVIOR
investigating how neurons behavior
e.g., crayfish response to tail tactile stimulus
record lateral giant interneuron (LGI) correlation (A): always stimulus behavior ?... sufficient (B): trigger LGI alone response ?...
p.27, fig.1.12
RELATING NERVE CELLS TO BEHAVIOR
investigating how neurons behavior
e.g., crayfish response to tail tactile stimulus
record lateral giant interneuron (LGI) correlation (A): always stimulus behavior ?... sufficient (B): trigger LGI alone response ?... necessary (C): shut off LGI no response ?...
p.27, fig.1.12
RELATING NERVE CELLS TO BEHAVIOR
investigating how neurons behavior
e.g., crayfish response to tail tactile stimulus
record lateral giant interneuron (LGI) correlation (A): always stimulus behavior ?... sufficient (B): trigger LGI alone response ?... necessary (C): shut off LGI no response ?...
should always attempt to ask these 3 questions, but
we rarely find this type of simplicity in nature
RELATING NERVE CELLS TO BEHAVIOR
investigating how synapses behavior
e.g., Drosophila escape response (mutants, pharmacological agents)
inject current across brain
RELATING NERVE CELLS TO BEHAVIOR
investigating how synapses behavior
e.g., Drosophila escape response (mutants, pharmacological agents)
inject current across brain
measure speed of transmission in down-stream motor neurons
chemical synapses: slow
RELATING NERVE CELLS TO BEHAVIOR
investigating how synapses behavior
e.g., Drosophila escape response (mutants, pharmacological agents)
inject current across brain
measure speed of transmission in down-stream motor neurons
chemical synapses: slow electrical synapses: fast (middle leg) escape behavior
RELATING NERVE CELLS TO BEHAVIOR
investigating how restricted neural networks behavior
e.g., lobster ingestion
food esophagus 3 chamber stomach:
cardiac sac gastric mill pylorus
RELATING NERVE CELLS TO BEHAVIOR
investigating how restricted neural networks behavior
e.g., lobster ingestion
food esophagus 3 chamber stomach:
cardiac sac pylorus (A) gastric mill (C) } rhythmic
p.28, fig.1.13
RELATING NERVE CELLS TO BEHAVIOR
investigating how restricted neural networks behavior
e.g., lobster ingestion
stomatogastric ganglia (STG) rhythm
all 30 neurons known circuits mapped (B,D) functions in isolated preparations (A,C)
p.28, fig.1.13
RELATING NERVE CELLS TO BEHAVIOR
p.30, fig.1.14
neural control behavior in complex organism
e.g., selective attention in monkeys (stimulus choice)
unit recordings in cortex cellular response to peripheral light (A)
RELATING NERVE CELLS TO BEHAVIOR
p.30, fig.1.14
neural control behavior in complex organism
e.g., selective attention in monkeys (stimulus choice)
unit recordings in cortex cellular response to peripheral light (A) response > if animal pays attention (B)
RELATING NERVE CELLS TO BEHAVIOR
p.30, fig.1.14
neural control behavior in complex organism
e.g., selective attention in monkeys (stimulus choice)
unit recordings in cortex cellular response to peripheral light (A) response > if animal pays attention (B) response >> if animal ~ behavior (C)
RELATING NERVE CELLS TO BEHAVIOR
neural control behavior in complex organism
e.g., selective attention in monkeys (stimulus choice)
visual system response due to ~ stimulus other neural systems ~ attention (& ~ activity ?)
gain some understanding of mechanism, even at this simple level of analysis
RELATING NERVE CELLS TO BEHAVIOR
behavior analysis in a natural environment in the laboratory
cells, synapses & circuits basic properties of nerve cells synaptic transmission neuronal architecture & behavior
relating nerve cells to behavior
summary
#04: CELLS, SYNAPSES & CIRCUITS
behavior... examples discussed: field studies ethology
ethograms FAP, SS, IRM, releasers, interlocking releasers
laboratory studies associative learning classical / Pavlovian conditioning, US, CS, UR, CR operant/instrumental conditioning
SUMMARY: INTRODUCTION & TERMS
nervous system neurons
channels, resting potentials, action potentials synapses
chemical, electrical, EPSPs, IPSPs plasticity, synaptic depression & potentiation, presynaptic inhibition & facilitation
circuits sensory neurons, interneurons, motor neurons recording neural activity
SUMMARY: INTRODUCTION & TERMS
relating nerve cells to behavior neurons behavior
crayfish tail flip response synapses behavior
Drosophila escape response restricted circuits behavior
lobster digestion whole organism behavior
monkey selective attention
SUMMARY: INTRODUCTION & TERMS
nervous system development and plasticity… neurogenesis, apoptosis and necrosis growth cell adhesion and axon pathfinding formation, maintenance and plasticity of synapses organogenesis
general brain and nervous system anatomy… humans other vertebrates invertebrates
SUMMARY: WE HAVE NOT DISCUSSED…
brains are not merely composed of neurons… glia… oligodendrocytes* and astrocytes (CNS) Schwann cells (PNS)*
form myelin sheath (vertebrates)
neuron cell structure… general categories… microfilaments, neurofilaments and microtubules axon transport structure and functional details at synapses ion channel anatomy
SUMMARY: WE HAVE NOT DISCUSSED…
details about signals transmission… action potentials frequency coding signal propagation myelin function “types” of signalling
silent, beating, bursting effects of sustained neural stimulation changing neuron properties
SUMMARY: WE HAVE NOT DISCUSSED…
measuring currents and channels… electrophysiology… criteria for ion channel activities
conductance, selectivity, gating, pharmacology activation, inactivation whole cell voltage clamp patch (voltage) clamp ion channel molecular biology and manipulation maintenance of ion concentration gradients
SUMMARY: WE HAVE NOT DISCUSSED…
intercellular communication… gap junctions and neurosecretion neurotransmitter release transmitters and hormones receptors and transduction mechanisms neuromoduation
SUMMARY: WE HAVE NOT DISCUSSED…