The claustrum is present in all mammalian species examined so far and its morphology, chemoarchitecture, physiology, phylogenesis and ontogenesis are still a matter of debate. Several morphologically distinct types of immunostained cells were described in different mammalian species. To date, a comparative study on the neurochemical organization of the human and non-human primates claustrum has...

Using axonal retrograde tracing, combined with morphometric analysis, we compared the distribution and number of claustral neurons projecting to the motor and somatosensory cortical areas in the Wistar rat. Comparable volumes of the retrograde tracer Fluoro-Gold, were injected into the motor or somatosensory cortices. Injections into these areas resulted in labeling of neurons along the entire ...

The cat's dorsocaudal claustrum was studied in Golgi preparations, by electron microscopy, and by anterograde and retrograde tracer techniques. It receives a convergent retinotopic projection from several visual cortical ares, including areas 17, 18, 19, 21a and PMLS (posteromedial lateral suprasylvian area). The projection arises from spiny dendrite cells (pyramidal and fusiform) in the middle...

In a cohort of 34 patients with autoimmune limbic encephalitis and/or epilepsy, we identified 4 patients exhibiting claustrum fluid-attenuated inversion recovery (FLAIR) hyperintensities. All 4 patients presented with explosive onset of seizures and developed medically intractable epilepsy, and 2 exhibited a marked response to immunotherapy. Associated features included cognitive and behavioral...

Long-survival [3H]thymidine autoradiography was used to quantitatively determine the time of origin of neurons in the endopiriform nucleus and the claustrum in rats killed on postnatal day 60 after their dams received two consecutive daily injections of [3H]thymidine on embryonic day E13 and E14, E14 and E15, ... E21 and E22. The claustrum originates late, on E15 and E16, and has a strong gradi...

A recent paper by Jankowski and O’Mara (2015) throws new light on the function of the claustrum. These authors took recordings from 874 claustral neurons in unanesthetized behaving rats that showed responses probably anchored to visual stimuli. These fell into three categories—“place” neurons (38) that responded to the location of the rat, “boundary” neurons (23) that responded to boundaries cl...

'Amygdala' and 'amygdalar complex' are terms that now refer to a highly differentiated region near the temporal pole of the mammalian cerebral hemisphere. Cell groups within it appear to be differentiated parts of the traditional cortex, the claustrum, or the striatum, and these parts belong to four obvious functional systems--accessory olfactory, main olfactory, autonomic and frontotemporal co...

We examined the pattern of retrograde tracer distribution in the claustrum following intracortical injections into the frontal pole (area 10), and in dorsal (area 9), and ventral lateral (area 12) regions of the rostral prefrontal cortex in the tufted capuchin monkey (Cebus apella). The resulting pattern of labeled cells was assessed in relation to the three-dimensional geometry of the claustru...

Citation: Deutch AY and Mathur BN (2015) Editorial: The Claustrum: charting a way forward for the brain's most mysterious nucleus. There are many reasons why investigators decide to expend their energy on studying a particular nucleus in the brain. Sometimes the choice of structures has little to do with new insights that may be gleaned but is more attributable to the tractability of the site t...