Quantitative assessment of amygdala in Macaca fascicularis monkeys

• Published in: Journal of comparative neurology (1911) Vol. 529; no. 8; pp. 2091 - 2098
• Main Authors: Delgado‐González, José‐Carlos, Rosa Prieto, Carlos, Vallejo‐Calcerrada, Nuria, Tarruela‐Hernández, Diana‐Lucía, Cebada‐Sánchez, Sandra, Insausti, Ricardo, Artacho‐Pérula, Emilio
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01-06-2021; Wiley Subscription Services, Inc
• Subjects: Aging; Amygdala; Amygdala - anatomy & histology; amygdaloid complex; Animals; Cognitive ability; Macaca fascicularis; Macaca fascicularis - anatomy & histology; Male; Mental disorders; morphometric and stereological estimators; neuroanatomy; Neurological diseases; surface area; volume; surface area; volume; Macaca fascicularis; amygdaloid complex; neuroanatomy; morphometric and stereological estimators
• ISSN: 0021-9967; 1096-9861
• DOI: 10.1002/cne.25074

The amygdaloid complex (AC) is involved in very relevant cognitive and emotional pathways and exhibits changes in aging and in some neurological and psychiatric disorders. The quantitative estimators of AC could be useful to understand the impact of amygdaloid pathology in these processes, both globally and for each nucleus in particular, and their neurons. The present study analyzes morphometric and stereological estimators in the whole AC and its three main nuclei (lateral [La], basal [Ba], and accessory basal [AB]) in six Macaca fascicularis monkeys. All the brains were fixed and sectioned in the coronal plane; Nissl‐stained sections were used for estimation of size and form parameters in both, the AC, and the La, Ba, and AB nuclei separately. The study includes stereological estimates of the volume and surface area of the AC; also, volume of the neurons in the amygdaloid nuclei was estimated using the point‐sampled intercepts method. Our results show that the AB nucleus is smaller than both the La and Ba nuclei in both morphometric and stereological estimators. Brain hemispheric side had not significant influence on any of quantitative estimates. The neuron volume was higher in the AB nucleus relative to LA and Ba of the nuclei. These data describe some quantitative parameters of the amygdaloid complex and their main nuclei that could help us to detect small changes in neurodegenerative and other pathological processes.
The amygdaloid volume in Macaca fascicularis monkeys is of 174 mm3 with a surface area of 151 mm2. The accessory basal nuclei are smaller than the lateral and basal nuclei, showing no brain interhemispheric differences. In opposite, the greater size of neuronal volume appears in the accessory basal nuclei.