Interneuron diversity and the cortical circuit for attention
Paul TiesingaComputational Neurophysics Lab at UNC
http://neuro.physics.unc.edu
Title art: from the 2005 Science and Engineering Visualization Challenge organized by Science Magazine
A “VSD” Experiment
Map(s), connectivity:suppression, facilitation, biased competition, STRFs, synchrony
LGN Input to cortex
Output of cortex
1. Interneurons
Interneuron diversityFFI: PV+/FS
TDI CR+/CB+
Markram et al (2004) NRN
Circuit of CR+ interneurons
RatMacaque
Meskanaite, CerCor (1997)
2. Stimulus competition (V4)
The model
E
FFI
TDI
E
FFI
TDI
Column 1 Column 2
Picture from Okinawa course website
Symbols for Stimulus conditions
Neuron 1 Neuron 2
Pref.stimulusNonpref.stimulus
Receptive fieldNeuron 2
Receptive fieldNeuron 1
+ + Stimulus location 2
Stimulus location 1
The model (1250 synaptically-coupled single-compartment neurons with Hodgkin-Huxley-type channels)
E
FFI
TDI
E
FFI
TDITopdown: FEF
Column 1
Feedforward: V2
TDI: top-down interneuronFFI: feed-forward interneuronFEF: frontal eye fields
50
75
500
Stimulus competition requires a switch
E E
E
FFI
E
E
FFI
Buia & PT,JNP 2008
3. Attention modulation (V4)
Task and so on
Attend away from receptive field
Attend into receptive field
Salinas & Sejnowski NRN 2001
Feature attention
Attend the feature red (preferred feature neuron 1)
Attend the feature blue (preferred feature neuron 2)
+ +
+ +
Feature attention
E
FFI
TDI
F-att
Feature attention biases competition
Response-gain like
A B
0 0.5 10
20
40
60
E1 ra
te (H
z)
P Contrast0 0.5 10
20
40
60
E1 ra
te (H
z)P Contrast
Spatial attention
+ + Spatial attention to location 1
+ + Spatial attention to location 2
Spatial attention
E
FFI
TDI
S-att
Spatial attention biases competition
Contrast-gain like
Hypothesis
Feature attention versus spatial attention
• Top-down (first) versus bottom-up (later)
• Response gain versus contrast gain
4. Back to interneurons
Contrast response surface of E-cells
Stimulus competition
R min(Rp ,Rnp )Rp Rnp
The FFI always increase their rate with spatial attention
With feature attention, FFI rate changes are in
opposite direction to those of E-cells
5. Oscillations and synchrony
Stimulus competition is signaled by beta oscillations
E1
FFI1
E2
FFI2
Stimulus onset
Buia & PT,JNP 2008
In the pair condition, synchrony during feature-attention has a beta and gamma component
E
FFI
TDI
E
Beta vs Gamma
E
FFI
TDI
E
FFI
TDI
Gamma(ING)
Beta (PING)
Summary•For the first time the responses at the ‘four corners’ under different attention conditions are reproduced using a single, spiking network model (Exp: many).
• Two types of interneurons (FFI, TDI) are needed.
•During spatial attention the FFI increase their rate, whereas during feature attention they decrease their rate. (Exp: Mitchel et al 2007)
•The TDI increase their rate with feature attention and synchronize their home column. (Exp: none)
•Strong competition between the two columns leads to beta oscillations, whereas feature attention leads to gamma oscillations. (Exp: Bichot et al 2005)
•Hypothesis: TDI are CR+ (or CB+) double bouquet cells, possibly adapting,FFI are PV+ basket cells, fast spiking.
Experimental confirmation
Monkey model
• Task combining feature and spatial attention with same stimulus
• Distinguish interneurons from pyramidal cells
• Rabies/herpes virus based transsynaptic tracing
Mice model
• Interneuron specific promoter coupled to fluorescent protein
• Two photon calcium imaging
• Develop behavioral task
Thanks to
•Calin Buia (Harvard Medical School)
•Amelia Cohen (UNC)
•Terry Sejnowski (Salk institute)
•Jorge Jose (SUNY Buffalo/Northeastern University)