Distributed Representations Meeting, 15 March 2012 Irina Simanova

Distributed Representations Meeting, 15 March 2012Irina Simanova

Materials and methods• 7 epileptic patients, 16 sessions

• Sites: hyppocampus, amygdala, enthorinal cortex, parahippocampal cotrex

• Microwire electrodes: 8 recording channels and the reference

• 11-20 objects (M = 16, SD = 3.1) presented, for each object: 3 pictures, a spoken name, a written name; 6 times each

• Firing units detected; also addressed if the firing was preferred to pictures (visual invariance)

• Out of 750 units 79 had a significant response to at least one stimulus

A neuron in the left anterior hippocampus

A neuron in the enthorinal cortex

A neuron in the amygdala

Response invariance• Visual invariance: ROC analysis, p<0.01

• Triple invariance: visual invariance + significant responses to spoken or visual names

N responses to the individual / total number of pictures of this individual (3).

N responses to the other pictures/total number of other pictures.

Amplitude thresholds:

Visual invariance

Triple invariance

Discussions:

Modality-independent decoding of conceptual information (fMRI study)(Simanova et al., submitted)

Searchlight SVM, generalization across the four modalities, group-level statistical results

Multimodal integration =

conceptual representation

?