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1.  Hallucinogens Causing Seizures? A Case Report of the Synthetic Amphetamine 2,5-Dimethoxy-4-Chloroamphetamine 
The Neurohospitalist  2015;5(1):32-34.
Although traditional hallucinogenic drugs such as marijuana and lysergic acid diethylamide (LSD) are not typically associated with seizures, newer synthetic hallucinogenic drugs can provoke seizures. Here, we report the unexpected consequences of taking a street-bought hallucinogenic drug thought to be LSD. Our patient presented with hallucinations and agitation progressing to status epilepticus with a urine toxicology screen positive only for cannabinoids and opioids. Using liquid chromatography high-resolution mass spectrometry, an additional drug was found: an amphetamine-derived phenylethylamine called 2,5-dimethoxy-4-chloroamphetamine. We bring this to the attention of the neurologic community as there are a growing number of hallucinogenic street drugs that are negative on standard urine toxicology and cause effects that are unexpected for both the patient and the neurologist, including seizures.
PMCID: PMC4272348  PMID: 25553227
seizures; epilepsy; neurotoxicity syndromes; neurochemistry; techniques; neuropharmacology; techniques
2.  Cortical Neuron Response Properties Are Related to Lesion Extent and Behavioral Recovery after Sensory Loss from Spinal Cord Injury in Monkeys 
The Journal of Neuroscience  2014;34(12):4345-4363.
Lesions of the dorsal columns at a mid-cervical level render the hand representation of the contralateral primary somatosensory cortex (area 3b) unresponsive. Over weeks of recovery, most of this cortex becomes responsive to touch on the hand. Determining functional properties of neurons within the hand representation is critical to understanding the neural basis of this adaptive plasticity. Here, we recorded neural activity across the hand representation of area 3b with a 100-electrode array and compared results from owl monkeys and squirrel monkeys 5–10 weeks after lesions with controls. Even after extensive lesions, performance on reach-to-grasp tasks returned to prelesion levels, and hand touches activated territories mainly within expected cortical locations. However, some digit representations were abnormal, such that receptive fields of presumably reactivated neurons were larger and more often involved discontinuous parts of the hand compared with controls. Hand stimulation evoked similar neuronal firing rates in lesion and control monkeys. By assessing the same monkeys with multiple measures, we determined that properties of neurons in area 3b were highly correlated with both the lesion severity and the impairment of hand use. We propose that the reactivation of neurons with near-normal response properties and the recovery of near-normal somatotopy likely supported the recovery of hand use. Given the near-completeness of the more extensive dorsal column lesions we studied, we suggest that alternate spinal afferents, in addition to the few spared primary axon afferents in the dorsal columns, likely have a major role in the reactivation pattern and return of function.
PMCID: PMC3960473  PMID: 24647955
area 3b; dorsal column lesion; multielectrode array; primate; somatotopy; tactile
3.  Multifocal subdural hematomas as the presenting sign of acquired hemophilia A: a case report 
BMC Research Notes  2014;7:134.
Acquired hemophilia A (AHA) is a rare coagulopathy linked to a variety of etiologies including autoimmune diseases, neoplasms, diabetes, respiratory diseases, and the post-partum state. While bleeding in AHA is often seen in mucocutaneous or intramuscular locations, intracranial and intraspinal bleeds are exceedingly rare.
Case presentation
We report an unusual case of spontaneous multifocal subdural hematomas in a 25 year old Asian woman with lupus who presented with headache and backache, and was found to have an elevated partial thromboplastin time (PTT) level and new diagnosis of AHA.
Subdural hematomas as the initial sign of AHA are all but unknown in the medical literature. We bring this entity to the attention of the neurology community because lumbar puncture and/or conventional angiogram are often indicated in the work-up of idiopathic multifocal subdural hematomas, but may be dangerous in patients with AHA.
PMCID: PMC4077029  PMID: 24606868
Acquired hemophilia A; Nontraumatic subdural hematoma; Intracranial hemorrhage; Secondary headache syndrome; Lupus; Spinal cord; Critical care
4.  Thalamocortical Connections of Functional Zones in Posterior Parietal Cortex and Frontal Cortex Motor Regions in New World Monkeys 
Cerebral Cortex (New York, NY)  2010;20(10):2391-2410.
Posterior parietal cortex (PPC) links primate visual and motor systems and is central to visually guided action. Relating the anatomical connections of PPC to its neurophysiological functions may elucidate the organization of the parietal–frontal network. In owl and squirrel monkeys, long-duration electrical stimulation distinguished several functional zones within the PPC and motor/premotor cortex (M1/PM). Multijoint forelimb movements reminiscent of reach, defense, and grasp behaviors characterized each functional zone. In PPC, functional zones were organized parallel to the lateral sulcus. Thalamocortical connections of PPC and M1/PM zones were investigated with retrograde tracers. After several days of tracer transport, brains were processed, and labeled cells in thalamic nuclei were plotted. All PPC zones received dense inputs from the lateral posterior nucleus and the anterior pulvinar. PPC zones received additional projections from ventral lateral (VL) divisions of motor thalamus, which were also the primary source of input to M1/PM. Projections to PPC from rostral motor thalamus were sparse. Dense projections from ventral posterior (VP) nucleus of somatosensory thalamus distinguished the rostrolateral grasp zone from the other PPC zones. PPC connections with VL and VP provide links to cerebellar nuclei and the somatosensory system, respectively, that may integrate PPC functions with M1/PM.
PMCID: PMC2936798  PMID: 20080929
intracortical microstimulation; motor cortex; premotor cortex; pulvinar; ventral lateral thalamus
5.  Cellular Scaling Rules for Primate Spinal Cords 
Brain, Behavior and Evolution  2010;76(1):45-59.
The spinal cord can be considered a major sensorimotor interface between the body and the brain. How does the spinal cord scale with body and brain mass, and how are its numbers of neurons related to the number of neurons in the brain across species of different body and brain sizes? Here we determine the cellular composition of the spinal cord in eight primate species and find that its number of neurons varies as a linear function of cord length, and accompanies body mass raised to an exponent close to 1/3. This relationship suggests that the extension, mass and number of neurons that compose the spinal cord are related to body length, rather than to body mass or surface. Moreover, we show that although brain mass increases linearly with cord mass, the number of neurons in the brain increases with the number of neurons in the spinal cord raised to the power of 1.7. This faster addition of neurons to the brain than to the spinal cord is consistent with current views on how larger brains add complexity to the processing of environmental and somatic information.
PMCID: PMC2980815  PMID: 20926855
Allometry; Number of neurons; Evolution; Connectivity
6.  Shaping of white matter composition by biophysical scaling constraints 
The brains of large mammals have lower rates of metabolism than those of small mammals, but the functional consequences of this scaling are not well understood. An attractive target for analysis is axons, whose size, speed and energy consumption are straightforwardly related. Here we show that from shrews to whales, the composition of white matter shifts from compact, slow-conducting, and energetically expensive unmyelinated axons to large, fast-conducting, and energetically inexpensive myelinated axons. The fastest axons have conduction times of 1–5 milliseconds across the neocortex and less than 1 millisecond from the eye to the brain, suggesting that in select sets of communicating fibers, large brains reduce transmission delays and metabolic firing costs at the expense of increased volume. Delays and potential imprecision in cross-brain conduction times are especially great in unmyelinated axons, which may transmit information via firing rate rather than precise spike timing. In neocortex, axon size distributions can account for the scaling of per-volume metabolic rate and suggest a maximum supportable firing rate, averaged across all axons, of 7 ± 2 Hz. Axon size distributions also account for the scaling of white matter volume with respect to brain size. The heterogeneous white matter composition found in large brains thus reflects a metabolically constrained trade-off that reduces both volume and conduction time.
PMCID: PMC2779774  PMID: 18400904
Allometry; Axon scaling; Conduction; Evolution; Optimization; Timing

Results 1-6 (6)