Enabling Large-Scale Simulations With the GENESIS Neuronal Simulator.

In this paper, we evaluate the computational performance of the GEneral NEural SImulation System (GENESIS) for large scale simulations of neural networks. While many benchmark studies have been performed for large scale simulations with leaky integrate-and-fire neurons or neuronal models with only a few compartments, this work focuses on higher fidelity neuronal models represented by 50-74 compartments per neuron. After making some modifications to the source code for GENESIS and its parallel implementation, PGENESIS, particularly to improve memory usage, we find that PGENESIS is able to efficiently scale on supercomputing resources to network sizes as large as 9 × 10 neurons with 18 × 10 synapses and 2.

Patterns of brain reorganization subsequent to left fusiform damage: fMRI evidence from visual processing of words and pseudowords, faces and objects.

Little is known about the neural reorganization that takes place subsequent to lesions that affect orthographic processing (reading and/or spelling). We report on an fMRI investigation of an individual with a left mid-fusiform resection that affected both reading and spelling (Tsapkini & Rapp, 2010). To investigate possible patterns of functional reorganization, we compared the behavioral and neural activation patterns of this individual with those of a group of control participants for the tasks of silent reading of words and pseudowords and the passive viewing of faces and objects, all tasks that typically recruit the inferior temporal lobes.

Mental encoding and neural decoding of abstract cognitive categories: a commentary and simulation.

The premise of Multi-Voxel Pattern Analysis (MVPA) of functional Magnetic Resonance Image (fMRI) data is that mental encodings or states give rise to patterns of neural activation, which in turn, give rise to patterns of blood-oxygen level dependent (BOLD) responses distributed across sets of voxels. Statistical learning algorithms can then be used to detect relationships between mental encodings and BOLD responses, typically through pattern classification. Amongst many other applications, this technique has been used to evidence abstract category representation in an assortment of brain areas and across a range of cognitive domains.