Temporal Amygdala Research Articles

A Case Report of Lipoid Proteinosis with Brain and Laryngeal Presentation

: Lipoid proteinosis (LP) is a rare autosomal recessive genodermatosis. Genetic mutation leads to deposition of abnormal amounts of hyaline like material in the skin and viscera, which is the cause of clinical manifestations. It mostly involves the skin, intracranium, and the larynx. In this case report, we present a case with a long history of hoarseness. Imaging findings include bilateral true vocal cord (TVC) mucosal irregularity with hyperdense depositions, bilateral medial temporal amygdala parallel bean shape calcification (pathognomonic sign), and bilateral striatal (caudate and putamen) hypoattenuation. The patient also had multiple warty papules on the hands. Biopsy of the right TVC showed submucosal deposition of periodic acid-Schiff (PAS)-positive amorphous hyaline material and confirmed the diagnosis of lipoid proteinosis. Typical imaging findings especially in the brain could be very helpful in interpretation of laryngeal imaging findings in cases of lipoid proteinosis who manifest with long term voice changes and hoarseness.

Magnetic Resonance Imaging of the Brain of a Monotreme, the Short-Beaked Echidna (Tachyglossus aculeatus)

We used magnetic resonance imaging to study the anatomy of cortical regions, nuclear groups, and major tracts in the brain of a monotreme, i.e., the short-beaked echidna (Tachyglossus aculeatus). Our specimens were from a collection held at the Australian Museum in Sydney and had been stored in formaldehyde solution for at least 70 years. Despite this, we were able to detect fine detail in the nuclear divisions of structures as well as in fiber tracts. In particular, we could detect the medial lemniscus as it approached the ventral posterior thalamic nucleus, subdivisions within the ventral posterior thalamic nucleus, lamination and subdivisions within the hippocampal formation, components of the olfactory pathways, and nuclei within the temporal amygdala. We were able to map the topography of subcortical white matter and relate it to cortical regions determined on the basis of physiology, as well as chemical and cytoarchitecture. As expected, dense aggregations of fibers were noted in association with the primary sensory areas of the isocortex (somatosensory, visual, and auditory) and connecting primary olfactory regions (intrabulbar anterior commissure and associated fibers). We found longitudinal fibers in the basal forebrain (medial forebrain bundle) and brainstem (corticopontine and corticospinal tracts), as well as a dense array of fibers associated with the vermal and paravermal zones of the anterior lobe of the cerebellum. We also observed previously unrecognized fiber systems, i.e., commissural connections between the paired frontal isocortical fields (dorsal Fr1), dense fibers to the retrosplenial association cortex, and prominent, paired longitudinal fiber bundles in the dorsal forebrain (longitudinal fasciculus) that intersected the dorsal anterior commissure. The connectome results are consistent with the known neuroanatomy of this monotreme and they extend our knowledge of the fiber topography within this unusual brain. Our findings demonstrate the feasibility of using this sort of imaging of archived brains to analyze the neuroanatomy of rare, endangered, and evolutionarily significant species.

Cyto- and chemoarchitecture of the amygdala of a monotreme, Tachyglossus aculeatus (the short-beaked echidna)

We have examined the cyto- and chemoarchitecture of the temporal and extended amygdala in the brain of a monotreme (the short-beaked echidna Tachyglossus aculeatus) using Nissl and myelin staining, enzyme histochemistry for acetylcholine esterase and NADPH diaphorase, immunohistochemistry for calcium binding proteins (parvalbumin, calbindin and calretinin) and tyrosine hydroxylase. While the broad subdivisions of the eutherian temporal amygdala were present in the echidna brain, there were some noticeable differences. No immunoreactivity for parvalbumin or calretinin for somata was found in the temporal amygdala of the echidna. The nucleus of the lateral olfactory tract could not be definitively identified and the medial nucleus of amygdala appeared to be very small in the echidna. Calbindin immunoreactive neurons were most frequently found in the ventrolateral part of the lateral nucleus, intraamygdaloid parts of the bed nucleus of the stria terminalis and the lateral part of the central nucleus. Neurons strongly reactive for NADPH diaphorase with filling of the dendritic tree were found mainly scattered through the cortical, central and lateral subnuclei, while neurons showing only somata reactivity for NADPH diaphorase were concentrated in the basomedial and basolateral subnuclei. Most of the components of the extended amygdala of eutherians could also be identified in the echidna. Volumetric analysis indicated that the temporal amygdala in both the platypus and echidna is small compared to the same structure in both insectivores and primates, with the central and medial components of the temporal amygdala being particularly small.