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)