Fine-Scale Spatial Organization of Face and Object Selectivity in the Temporal Lobe: Do Functional Magnetic Resonance Imaging, Optical Imaging, and Electrophysiology Agree?

The spatial organization of the brain's object and face representations in the temporal lobe is critical for understanding high-level vision and cognition but is poorly understood. Recently, exciting progress has been made using advanced imaging and physiology methods in humans and nonhuman primates, and the combination of such methods may be particularly powerful. Studies applying these methods help us to understand how neuronal activity, optical imaging, and functional magnetic resonance imaging signals are related within the temporal lobe, and to uncover the fine-grained and large-scale spatial organization of object and face representations in the primate brain

The 2008 Methoni earthquake sequence: the relationship between the earthquake cycle on the subduction interface and coastal uplift in SW Greece

Seismological, GPS and historical data suggest that most of the 40 mm yr$^{-1}$ convergence at the Hellenic Subduction Zone is accommodated through aseismic creep, with earthquakes of $\textit{M}$W ≲ 7 rupturing isolated locked patches of the subduction interface. The size and location of these locked patches are poorly constrained despite their importance for assessment of seismic hazard. We present continuous GPS time-series covering the 2008 MW 6.9 Methoni earthquake, the largest earthquake on the subduction interface since 1960. Post-seismic displacements from this earthquake at onshore GPS sites are comparable in magnitude with the coseismic displacements; elastic-dislocation modelling shows that they are consistent with afterslip on the subduction interface, suggesting that much of this part of the interface is able to slip aseismically and is not locked and accumulating elastic strain. In the Hellenic and other subduction zones, the relationship between earthquakes on the subduction interface and observed long-term coastal uplift is poorly understood. We use cGPS-measured coseismic offsets and seismological body-waveform modelling to constrain centroid locations and depths for the 2008 Methoni $\textit{M}$W 6.9 and 2013 Crete $\textit{M}$W 6.5 earthquakes, showing that the subduction interface reaches the base of the seismogenic layer SW of the coast of Greece. These earthquakes caused subsidence of the coast in regions where the presence of Pliocene–Quaternary marine terraces indicates recent uplift, so we conclude that deformation associated with the earthquake cycle on the subduction interface is not the dominant control on vertical motions of the coastline. It is likely that minor uplift on a short length scale (∼15 km) occurs in the footwalls of normal faults. We suggest, however, that most of the observed Plio-Quaternary coastal uplift in SW Greece is the result of thickening of the overriding crust of the Aegean by reverse faulting or distributed shortening in the accretionary wedge, by underplating of sediment of the Mediterranean seafloor, or a combination of these mechanisms.AH is supported by a Shell Exploration studentship. This study forms part of the NERC- and ESRC-funded project “Earthquakes Without Frontiers” under grant NEJ02001X/1, and was partly funded by the NERC grant “Looking inside the Continents from Space”

Large-Scale, High-Resolution Neurophysiological Maps Underlying fMRI of Macaque Temporal Lobe

Maps obtained by functional magnetic resonance imaging (fMRI) are thought to reflect the underlying spatial layout of neural activity. However, previous studies have not been able to directly compare fMRI maps to high-resolution neurophysiological maps, particularly in higher level visual areas. Here, we used a novel stereo microfocal x-ray system to localize thousands of neural recordings across monkey inferior temporal cortex (IT), construct large-scale maps of neuronal object selectivity at subvoxel resolution, and compare those neurophysiology maps with fMRI maps from the same subjects. While neurophysiology maps contained reliable structure at the sub-millimeter scale, fMRI maps of object selectivity contained information at larger scales (>2.5 mm) and were only partly correlated with raw neurophysiology maps collected in the same subjects. However, spatial smoothing of neurophysiology maps more than doubled that correlation, while a variety of alternative transforms led to no significant improvement. Furthermore, raw spiking signals, once spatially smoothed, were as predictive of fMRI maps as local field potential signals. Thus, fMRI of the inferior temporal lobe reflects a spatially low-passed version of neurophysiology signals. These findings strongly validate the widespread use of fMRI for detecting large (>2.5 mm) neuronal domains of object selectivity but show that a complete understanding of even the most pure domains (e.g., faces vs nonface objects) requires investigation at fine scales that can currently only be obtained with invasive neurophysiological methods.National Eye Institute (Grant R01-EY014970)National Eye Institute (Grant K99-EY022671)McGovern Institute for Brain Research at MITNational Institutes of Health (U.S.). Ruth L. Kirschstein National Research Service Award (Postdoctoral fellowship F32-EY019609

Ictal laughter and crying: Should they be classified as automatisms?

Gelastic seizures (GS) describe ictal laughter and are associated with hypothalamic lesions, as well as other cortical areas. Dacrystic seizures (DS), characterized by ictal crying, also have been reported in hypothalamic lesions and focal epilepsy. We describe a young girl with drug resistant focal dyscognitive seizures associated with gelastic and dacrystic features. However, neither laughter nor crying was correlated with a stereotyped electroencephalographic (EEG) pattern or involvement of a particular brain region. Additionally, based on the variety of epileptogenic foci associated with GS and DS in the literature, laughter and crying appear to represent ictal or peri-ictal automatisms

Adult-onset Rasmussen's Syndrome with associated cortical dysplasia

We describe a 23-year-old woman with previous right temporal lobe surgeries for underlying cortical dysplasia, presenting with drug-resistant right hemispheric seizures and epilepsia partialis continua (EPC). After anti-seizure medication adjustments, she developed focal status epilepticus with progressive EEG and neuroimaging changes. Cerebrospinal fluid and serum autoimmune panels were negative except for an elevated serum acetylcholine-receptor antibody titer, but she underwent immunosuppressive therapy. Stereotactic-EEG evaluation demonstrated multifocal independent ictal patterns in the right hemisphere. Rasmussen's Syndrome was confirmed by brain biopsy, and a hemispherectomy was performed. This patient demonstrates the rare association of adult-onset EPC with cortical dysplasia, precipitously evolving into Rasmussen's Syndrome. Keywords: Adult-onset Rasmussen Syndrome, Epilepsia partialis continua, Cortical dysplasia, Functional hemispherectom

Fine-Scale Spatial Organization of Face and Object Selectivity in the Temporal Lobe: Do Functional Magnetic Resonance Imaging, Optical Imaging, and Electrophysiology Agree?

The spatial organization of the brain's object and face representations in the temporal lobe is critical for understanding high-level vision and cognition but is poorly understood. Recently, exciting progress has been made using advanced imaging and physiology methods in humans and nonhuman primates, and the combination of such methods may be particularly powerful. Studies applying these methods help us to understand how neuronal activity, optical imaging, and functional magnetic resonance imaging signals are related within the temporal lobe, and to uncover the fine-grained and large-scale spatial organization of object and face representations in the primate brain.status: publishe