Human prefrontal cortical response to the meditative state: a spectroscopy study.

The effect of Qigong meditation on the hemodynamics of the prefrontal cortex was investigated by spectroscopy with a single-wavelength probe (650 nm) and confirmed by standard near-infrared spectroscopy with a dual-wavelength probe. Deoxyhemoglobin changes were recorded with the single-wavelength probe over the left prefrontal cortex during meditation by Qigong practitioners, and non-practitioners instructed in the technique. Practitioners showed a significant decrease in deoxyhemoglobin levels suggesting an increase in prefrontal activation during meditation.

Chaos game representation of human pallidal spike trains.

Many studies have demonstrated the presence of scale invariance and long-range correlation in animal and human neuronal spike trains. The methodologies to extract the fractal or scale-invariant properties, however, do not address the issue as to the existence within the train of fine temporal structures embedded in the global fractal organisation. The present study addresses this question in human spike trains by the chaos game representation (CGR) approach, a graphical analysis with which specific temporal sequences reveal themselves as geometric structures in the graphical representation.

Near-infrared spectroscopy study of language activated hyper- and hypo-oxygenation in human prefrontal cortex.

Oxygenation changes in the left prefrontal cortex during language processing were assessed with near-infrared spectroscopy (NIRS). Oxyhemoglobin and deoxyhemoglobin concentrations at the Fp1 site during 5 min of resting with eyes closed (control), followed by 5 min of reading aloud, were monitored. A statistically significant change in the oxyhemoglobin concentration was observed by NIRS in all the subjects after execution of the experimental task.

Charting epilepsy by searching for intelligence in network space with the help of evolving autonomous agents.

The problem of demarcating neural network space is formidable. A simple fully connected recurrent network of five units (binary activations, synaptic weight resolution of 10) has 3.2 *10(26) possible initial states.

Evolutionary autonomous agents and the nature of apraxia.

Background: Evolutionary autonomous agents are robots or robot simulations whose controller is a dynamical neural network and whose evolution occurs autonomously under the guidance of a fitness function without the detailed or explicit direction of an external programmer. They are embodied agents with a simple neural network controller and as such they provide the optimal forum by which sensorimotor interactions in a specified environment can be studied without the computational assumptions inherent in standard neuroscience.

Methods: Evolutionary autonomous agents were evolved that were able to perform identical movements under two different contexts, one which represented an automatic movement and one which had a symbolic context.

Human cortical perfusion and the arterial pulse: a near-infrared spectroscopy study.

Background: The pulsatile nature of the arterial pulse induces a pulsatile perfusion pattern which can be observed in human cerebral cortex with non-invasive near-infrared spectroscopy. The present study attempts to establish a quantitative relation between these two events, even in situations of very weak signal-to-noise ratio in the cortical perfusion signal. The arterial pulse pattern was extracted from the left middle finger by means of plethesmographic techniques.

Abnormal single-unit activity recorded in the somatosensory thalamus of a quadriplegic patient with central pain.

We have performed single unit analysis of the activity of cells located in the ventral nuclear group of thalamus in a patient with dysesthetic pain below the level of a clinically complete traumatic spinal cord transection at C5. Cells located in the parasagittal plane 14 mm lateral to the midline responded to tactile stimulation in small facial and intraoral receptive fields, which were characteristic of patients without somatosensory abnormality [30]. In this patient the 16 mm lateral parasagittal plane contained cells with receptive fields located on the occiput and neck instead of the upper extremity as would normally be expected.