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To better understand the spatial extent of the direct effects of deep brain stimulation (DBS) on neurons, we implemented a geometrically realistic finite element electrical model incorporating anisotropic and inhomogenous conductivities. The model included the subthalamic nucleus (STN), substantia nigra (SN), zona incerta (ZI), fields of Forel H2 (FF),(More)
Unitary event analysis is a new method for detecting episodes of synchronized neural activity (Riehle, Grün, Diesmann, & Aertsen, 1997). It detects time intervals that contain coincident firing at higher rates than would be expected if the neurons fired as independent inhomogeneous Poisson processes; all coincidences in such intervals are called unitary(More)
Voltage-gated ion channels in neuronal membranes fluctuate randomly between different conformational states due to thermal agitation. Fluctuations between conducting and nonconducting states give rise to noisy membrane currents and subthreshold voltage fluctuations and may contribute to variability in spike timing. Here we study subthreshold voltage(More)
One fifth of neurons in the medial-temporal lobe of human epilepsy patients respond selectively to categories of images, such as faces or cars. Here we show that responses of hippocampal neurons are rapidly modified as subjects alternate (over 60 sec) between two tasks (1) identifying images from a category, or (2) playing a simple video game superimposed(More)
A potentially powerful information processing strategy in the brain is to take advantage of the temporal structure of neuronal spike trains. An increase in synchrony within the neural representation of an object or location increases the efficacy of that neural representation at the next synaptic stage in the brain; thus, increasing synchrony is a candidate(More)
Deep brain stimulation has been used for over a decade to relieve the symptoms of Parkinson's disease, although its mechanism of action remains poorly understood. To better understand the direct effects of DBS on central neurons, a computational model of a myelinated axon has been constructed which includes the effects of K(+) accumulation within the(More)
OBJECTIVE Statistical testing for effects of stimuli on the responses of large populations of recorded neurons is a key technique for analyzing data generated using multi-channel recording systems. Combining statistical tests for differences of the responses to different stimuli and tests for changes from background firing, while appealing as apparently(More)
OBJECTIVE Clinicians often use depth-electrode recordings to localize human epileptogenic foci. To advance the diagnostic value of these recordings, we applied logistic regression models to single-neuron recordings from depth-electrode microwires to predict seizure onset zones (SOZs). APPROACH We collected data from 17 epilepsy patients at the Barrow(More)
Different structures within the medial-temporal lobe likely make distinct contributions to declarative memory. In particular, several current psychological and computational models of memory predict that the hippocampus and parahippocampal regions play different roles in the formation and retrieval of declarative memories [e.g., Norman, K. A., & O'Reilly,(More)
We investigated whether synchrony between neuronal spike trains is affected by the animal's attentional state. Cross-correlation functions between pairs of spike trains in the second somatosensory cortex (SII) of three macaque monkeys trained to switch attention between a visual task and a tactile task were computed. We previously showed that the majority(More)