Capuchin Monkey (Cebus apella) Telencephalon: Macroscopic Anatomic Study

Comparative anatomy goes back to antiquity, since Aristotle (384-323 a.C.) already studied animals, emphasizing their anatomical forms and structural organization. The study of anatomical characteristics, mainly with comparative approach, also associates “modus vivendis” of individual or taxonomic group. In this sense, this paper purposes to study and describe macroscopic anatomy of Capuchin Monkey telencephalon, in view to knowledge about biology system of this animal, as an important faunal component of Cerrado biome. For this, one male and one female specimen of Capuchin Monkey were analyzed, obtained from accidental death on the roadsides of Brazilian Southeast of Goiás, under authorization of SISBIO no 37072-2 and procedures conducted in accordance with ethical principles approved by Institutional Ethics in Research Committee of Federal University of Uberlândia (CEUA/UFU no 067/12). Capuchin Monkey (Cebus apella) telencephalon is relatively large in relation to the size of this animal, with globose aspect and slightly long laterolaterally, narrowing abruptly in rostral sense. In general terms, it resembles human brain, however, presents little convolute and less number of sulcus and gyrus and less prominent giving somewhat lisencecephalic aspect. Keywords— Comparative Anatomy, Dissecation, Neuroanatomy, Cerrado Biome and Primates. I. INTRODUTION The study of primate ́s biology (morphology and behavior) attracted attention, mainly, in relation to similarities to humans. The knowledge of these animals, through comparative anatomy, makes possible understand evolutionary issues by locating taxonomic groups as inferior or superior in phylogenetic scale [1-4]. Among them, medium and large mammals suffer effects of habitat alterations and fragmentation, usually in response to human occupation and the particular specie of Capuchin Monkey (Cebus apella) that is a small mammal endemic to Brazilian Cerrado, represents the second group with greatest diversity among vertebrates that inhabit this biome, composing approximately 15% of knowledge species [5,6]. However, for better understanding of this specie biology is essential point out that Cerrado is a complex biome, which makes it more important to understand all elements involved [5,7,8] and distribution of Capuchin Monkey is not restrict to Cerrado, that can be found from northwest Colombia to south Paraguay and most Brazilian territory (HILL, 1972) [9], where represents essential importance to biodiversity, since it is an omnivore’s animal [1,10]. The anatomy of Capuchin Monkey is little known and attracts more attention because its rate cephalization, that is higher than other monkeys like Chimpanzee (Pan troglodytes) and Gorilla (Gorilla gorilla), besides phylogenetically close to human [11-13]. It is in Cebidae line that presents larger brain than Hapalids even some authors claim that brain-weight ratio of Cebidae reaches the best rates among primates, including man. In most Cebidae line, cerebral hemispheres exhibit more globular forms than Hapalids, as well more developed sulcus and developed gyrus [9]. The lateral faces of hemispheres present in sylvian sulcus, parallel to post-sylvian or temporal superior and intraparietal arcuate on dorsal end of sylvian and post-sylvian sulcus. In the frontal lobe, there are arched sulcus and surgically, rectum sulcus (inferior frontal fissure) [9,11,12,14]. Human brain constitutes the anterior and most evolved part of neural system and general aspects exhibits ovoid shape, where the largest axis is anteroposterior disposed and whose thickest end is posteriorly gyros. The dorsolateral face is strongly convex, while inferior face is irregular and medial face International journal of Rural Development, Environment and Health Research(IJREH) [Vol-3, Issue-1, Jan-Feb, 2019] https://dx.doi.org/10.22161/ijreh.3.1.7 ISSN: 2456-8678 www.aipublications.com/ijreh Page | 72 flat and vertically disposed [15]. The surface of brain exhibits numerous sulcus and the largest is Medial Longitudinal Fissure (MLF), disposed anteroposterior over sagittal plane. MLF divides the brain into right and left part, similar called cerebral hemispheres. A lateral fissure is also evident which is located anteriorly on lateral face and divides two lobes called parietal and temporal [15,16]. Telencephalon of domestic canids is also divided by MLF into two parts or right and left hemisphere and is possible identify four lobes (frontal, temporal, parietal and occipital), separated by gyrus and similar fissures to human brain. The sulcus and gyrus travel throughout hemisphere and arise uneven development between cortex and bone [17]. In addition, sulcus gyrus orbiter for most part, a sylvian fissure that is equivalent to lateral fissure in humans [17-19]. In this sense and considering the importance of Capuchin Monkey to Cerrado biome and that its nervous system anatomy is little know, the present work aimed dissect and made a comparative study about the telencephalon of this animal, contributing to its biological system knowledge. II. MATERIAL AND METHODS The present paper is a descriptive and comparative anatomical study with one male and one female specimen of Capuchin Monkey, obtained from accidental death on the roadsides of Brazilian Southeast of Goiás, under authorization of SISBIO no 37072-2. Considering the descriptive approach of this work, statistical analysis is not necessary. All procedures were conducted in accordance with ethical principles and were approved by the Institutional Ethics in Research Committee at the Federal University of Uberlândia (CEUA/UFU no 067/12). The study was made in the research laboratory of human and comparative anatomy from the Federal University of Goiás – RC, where the head skin was removed using scissors, scalpel and anatomical tweezers. The epicranium was dissected and temporal muscles removed, with subsequent removal of skull cap (with help of a gypsum saw and an osteotome), exposing the brain. Then was removed severing cranial nerves, blood vessels and meninges at points where was adhered to the bone, proceeding with removal of dura mater and arachnoid and finally pia mater (with the help of magnifying glass 10X) and thorough removal of blood vessels, making the piece fit for analysis and description. Subsequently, was made a fixation with aqueous 10 % formaldehyde solution to conservation. The preparation of anatomical pieces was performed under consecrated techniques in Macroscopic Anatomy. The Sony Cyber® digital camera was used to the photographical documentation and the description nomenclature adopted is the standard of Nomina Anatomica Veterinaria [20], elaborated by the International Committee on Veterinary Gross Anatomical Nomenclature.


I. INTRODUTION
The study of primate´s biology (morphology and behavior) attracted attention, mainly, in relation to similarities to humans. The knowledge of these animals, through comparative anatomy, makes possible understand evolutionary issues by locating taxonomic group s as inferior or superior in phylogenetic scale [1][2][3][4]. Among them, medium and large mammals suffer effects of habitat alterations and fragmentation, usually in response to human occupation and the particular specie of Capuchin Monkey (Cebus apella) that is a small mammal endemic to Brazilian Cerrado, represents the second group with greatest diversity among vertebrates that inhabit this biome, composing approximately 15% of knowledge species [5,6].
However, for better understanding of this specie biology is essential point out that Cerrado is a complex biome, which makes it more important to understand all elements involved [5,7,8] and distribution of Capuchin Monkey is not restrict to Cerrado, that can be found from northwest Colombia to south Paraguay and most Brazilian territory   [9], where represents essential importance to biodiversity, since it is an omnivore's animal [1,10].
The anatomy of Capuchin Monkey is little known and attracts more attention because its rate cephalization, that is higher than other monkeys like Chimpanzee (Pan troglodytes) and Gorilla (Gorilla gorilla), besides phylogenetically close to human [11][12][13]. It is in Cebidae line that presents larger brain than Hapalids even some authors claim that brain-weight ratio of Cebidae reaches the best rates among primates, including man. In most Cebidae line, cerebral hemispheres exhibit more globular forms than Hapalids, as well more developed sulcus and developed gyrus [9].
The lateral faces of hemispheres present in sylvian sulcus, parallel to post-sylvian or temporal superior and intraparietal arcuate on dorsal end of sylvian and post-sylvian sulcus. In the frontal lobe, there are arched sulcus and surgically, rectum sulcus (inferior frontal fissure) [9,11,12,14]. Human brain constitutes the anterior and most evolved part of neural system and general aspects exhibits ovoid shape, where the largest axis is anteroposterior disposed and whose thickest end is posteriorly gyros. The dorsolateral face is strongly convex, while inferior face is irregular and medial face flat and vertically disposed [15]. The surface of brain exhibits numerous sulcus and the largest is Medial Longitudinal Fissure (MLF), disposed anteroposterior over sagittal plane. MLF divides the brain into right and left part, similar called cerebral hemispheres. A lateral fissure is also evident which is located anteriorly on lateral face and divides two lobes called parietal and temporal [15,16].
Telencephalon of domestic canids is also divided by MLF into two parts or right and left hemisphere and is possible identify four lobes (frontal, temporal, parietal and occipital), separated by gyrus and similar fissures to human brain. The sulcus and gyrus travel throughout hemisphere and arise uneven development between cortex and bone [17]. In addition, sulcus gyrus orbiter for most part, a sylvian fissure that is equivalent to lateral fissure in humans [17][18][19]. In this sense and considering the importance of Capuchin Monkey to Cerrado biome and that its nervous system anatomy is little know, the present work aimed dissect and made a comparative study about the telencephalon of this animal, contributing to its biological system knowledge.

II.
MATERIAL AND METHODS The present paper is a descriptive and comparative anatomical study with one male and one female specimen of Capuchin Monkey, obtained from accidental death on the roadsides of Brazilian Southeast of Goiás, under authorization of SISBIO nº 37072-2. Considering the descriptive approach of this work, statistical analysis is not necessary. All procedures were conducted in accordance with ethical principles and were approved by the Institutional Ethics in Research Committee at the Federal University of Uberlândia (CEUA/UFU nº 067/12).
The study was made in the research laboratory of human and comparative anatomy from the Federal University of Goiás -RC, where the head skin was removed using scissors, scalpel and anatomical tweezers. The epicranium was dissected and temporal muscles removed, with subsequent removal of skull cap (with help of a gypsum saw and an osteotome), exposing the brain. Then was removed severing cranial nerves, blood vessels and meninges at points where was adhered to the bone, proceeding with removal of dura ma ter and arachnoid and finally pia mater (with the help of magnifying glass -10X) and thorough removal of blood vessels, making the piece fit for analysis and description. Subsequently, was made a fixation with aqueous 10 % formaldehyde solution to conservation. The preparation of anatomical pieces was performed under consecrated techniques in Macroscopic Anatomy.
The Sony Cyber ® digital camera was used to the photographical documentation and the description nomenclature adopted is the standard of Nomina Anatomica Veterinaria [20], elaborated by the International Committee on Veterinary Gross Anatomical Nomenclature.

III. RESULTS
The telencephalon of Capuchin Monkey (Cebus apella) is relatively large compared to its size. The aspect is globose and slightly long laterolaterally, narrowing abruptly in rostral sense. In general, resembles human brain, however, presents little convolute and less number of sulcus and gyrus and are less prominent, giving somewhat lisencecephalic aspect. The Medial Longitudinal Fissure, Sylvian Fissure, Central Sulcus and Parietoccipital Sulcus, subdivides hemisphere into Lobes: Frontal, Parietal, Occipital and Temporal. In ventrorostral face of each frontal lobe, there is a deep depression caused by contact with dorsal wall of orbit. Like three-dimensional organ that Capuchin Monkey telencephalon exhibits Frontal, Temporal and other Occipital, one dorsolateral face, one medial, one ventrorostral, and one ventral. Irregularities are repeated on all faces and are mostly represented by sulcus and gyrus.
Sulcus and gyrus of dorsolateral face: Dorsolateral face of Capuchin Monkey telencephalon is larger than others. Throughout its extension are present tortuous and sometimes irregular elongated depressions, sulcus of varying extent and depth. Each two or more sulcus delimits relatively smooth, or gyrus, uneven areas. Some sulcus is deeper than others. The Medial Longitudinal Fissure (MLF) is the deepest gyrus of telencephalon and disposed in sagittal plane or divides the hemp in right and left hemisphere. Dorsolateral face of each hemisphere cut by a deep sulcus arranged rostrocaudally, is the sylvian fissure or lateral fissure, which rostral half is slightly inclined ventrodorsally, but caudal part inclines strongly, becoming almost vertical in interior of parietal lobe.  (1953, 1972a and 1972b) [9] in dogs, humans and cebids respectively, Dorsolateral Face of the brain is larger than others , a characteristic also observed in Capuchin Monkey. Testut and Latarjet (1979) [21] and Hill (1953, 1972a and 1972b) [9] report a division of telencephalon in right and left hemispheres by FLM and in Frontal, Parietal, Occipital and Temporal lobes, separated by sulcus or fissures more clearly marked as FL, the central sulcus and parietooccipital, characteristics also observed in Capuchin Monkey. Miller, Christensen and Evans (1964) [17] do not describe the existence of wolves in cerebral hemispheres of dogs, but show sulcus and sulcus arranged throughout the hemisphere. As described by Testut and Latarjet (1979) [22] in Humans and Hill (1953Hill ( , 1972aHill ( and 1972b [9] in Cebidae, sylvian fissure separates Temporal Lobe from Frontal; central sulcus is the border between frontal and parietal lobe, just as parietal occipital sulcus establishes a border between parietal and occipital lobes. This condition is also present in Capuchin Monkey. Testut and Latarjet (1979) [21] describe that humans gyrus and sulcus are circumscribed to the respective lobes, however Miller, Christensen and Evans (1964) [19] describe that in dog, the sulcus always extending throughout the hemisphere, while Hill (1953Hill ( , 1972aHill ( and 1972b [9] states in Cebidae that sulcus and sulcus overtake the lobe. In this aspect, Capuchin Monkey shows similar conditions to descriptions in other cebids, since sulcus are circumscribed to a lobe and some gyrus occupy more than one lobe.

Fig.2: Right Side View of Capuchin
According to Miller, Christensen and Evans (1964) [17], dorsally to Sylvian Fissure there are several concentrically arranged sulcus, which in the ventrodorsally sense, are called: Ecto Sylvian Sulcus, Supra Sylvian Sulcus and Lateral Sulcus. On the other hand, Capuchin Monkey does not present this arrangement of sulcus and gyrus, in dorsolateral face of telencephalon, but an organization of the same intermediary between domestic and human canids. In addition, lateral face is cut longitudinally by a deep gyrus, the Sylvian Fissure, which is also present in Capuchin Monkey, but is slightly inclined ventrodorsally in 2/3 caudally and vertically in rostral third, and can be subdivided into Horizontal Branch and Ascending Branch.
As described by Miller, Christensen and Evans (1964) [17], Ectosylvian and Supra Sylvian sulcus are semicircular in shape and can be divided into parts: Caudal, Medial and Rostral. The lateral sulcus is the most rectilinear of sulcus of this face and disposed parallel to LMW, rostrally called Coronal Sulcus. According to Testut and Latarjet (1979) [15], in humans a Central Sulcus is observed that positioned vertically in medial part of hemisphere and later delimits Frontal Lobe and previously the Parietal Lobe. In Capuchin Monkey, halfway between Rostral and Caudal Pole of each Hemisphere, Central Sulcus is disposed perpendicular to Medial Lateral and Longitudinal Fissures, which is well marked and relatively deep, but circumscribed to the face width.
The Ectosylvian and Supra Sylvian sulcus are semicircular in shape and can be divided into Caudal, Medial and Rostral [17]. Lateral sulcus is the most rectilinear of sulcus in this face and disposed parallel to LMW, rostrally is called Coronal Sulcus. In humans, according to Testut and Latarjet (1979) [15], a Central Sulcus is observed positioned vertically in medial part of hemisphere and later delimits Frontal Lobe and previously Parietal Lobe. In Capuchin Monkey, halfway between Rostral and Caudal Pole of each Hemisphere, Central Sulcus is disposed perpendicular to Medial Lateral and Longitudinal Fissures, which is well marked and relatively deep, but circumscribed to the face width.
The rostral part of Lateral Sulcus, in dog, is called Coronal Sulcus and caudally called Caudolateral Sulcus. Occasionally an Ectolateral Sulcus can be observed between Caudal Suprasylvian Sulcus and Caudolateral Sulcus. A crossed sulcus located near coronal sulcus, arranged transversely. There may also two other gyrus, Post-Crusader and Pre-Crusader. Is still possible observe a Pre-Sylvian Sulcus, which is divided into Caudal and Rostral Branches, which together constitute the Proreus Sulcus. The rostral prolongation of Proreus sulcus is called Olfaction Sulcus.
In humans, as mentioned by Testut and Latarjet (1979)  Capuchin Monkey presents a Dorsolateral Face of Telencephalon with pattern of sulcus and gyrus that approaches more of humans and canids, but smaller number of sulcus and gyrus, since frontal faces of lobes are basically two gyrus. A transversal arranged gyrus, which dorsal end divides into rostral and caudal branch, resembling a letter T, is the prefrontal sulcus, which is lower and less defined than humans. Rostral to Precentral Sulcus is obliquely arranged, in rostocaudal sense, a rectilinear sulcus, the Frontal Sulcus or Sulcus Straight. As described in Cebids by Hill (1953Hill ( , 1972aHill ( and 1972b [15]. In Capuchin Monkey, only an Intratemporal sulcus is observed, in accordance with cebids brains as described by Hill (1953Hill ( , 1972aHill ( and 1972b

V.
CONCLUSION The present study demonstrated that anatomic standard of Capuchin Monkey (Cebus apella) shows an external aspect similar to humans, nevertheless inferior convoluted and detailed analysis the brain showed inferior complex sulcus and gyrus, small number of sulcus and gyrus than domestic dog, besides located in higher phylogenetic scale. Our findings contribute to description and knowledge of an essential system to biological system of Capuchin Monkey.

CONFLIT OF INTESREST
The authors declare no conflicts of interest associated with this manuscript.