Extension of Superior Colliculus Based Models of Multisensory Integration to

the Cortex

Michael Hadley

Multisensory Integration

Windows of interaction

Convert physical properties to neural firings

Integrate to create a more accurate representation

Sensory StructuresInformation is information

Similar hierarchy

Plasticity rules

Topographical maps• SOM

Multisensory Integration in the Cortex

Traditional View New Evidence

Major DiscoveriesConnections between sensory areas

ERP time frames of integration Earliest window defies traditional view Later windows fit traditional view

Convergence Single/multi-cell recordings Population recordings

Traditional vs Recent

Computational ModelingTest hypotheses

Generation of testable predictions

My ProposalMove subcortical model to cortexChange the model to fit cortical dataStart to put the puzzle together

Definition

Anastasio & Patton’s Model of the SC

Modulatory projections come from parietal regions

DSC stands for the deep layer of the SC

Primary inputs come from sensory receptors

V = visualA = auditoryS = somatosensory

A&P Two Stage TrainingHebb

Primary connections Uses SOM Extracts information

Hebb-anti-Hebb Modulatory connections Loosely based on opposite

of Hebb Training to produce MSE

Fit with LiteratureAscending/descending from literature

Modulatory role of descending

Developmental window

Does not show MSD

No inhibition

My Model

Stage 1

Training of the forward sensory projections with SOM

Training of the projections to association areas with SOM

Stage 2

Hebb-anti-Hebb training according to traditional theories

Hebb-anti-Hebb training according to new evidence

EvaluationUse definition of multisensory integration

Determine which theories are plausible

Information theory

Incorporate inhibition

Supervised learning

Future