Anatomy of the Human Brain

Introduction:

The brain anatomy is complicated because of its convoluted structure and the function. The organ serves as the control centre of the body and performs the following functions such as receiving and interpreting the sensory information and directing the information all throughout the body. The two major parts of the central nervous system are the brain and spinal cord. The structure of the brain has got three major subdivisions such as the forebrain, mid brain and hind brain.

Anatomy of brain

Divisions of the brain:

Forebrain: This division of the brain performs a wide range of functions such as receiving and deducing the sensory information, perceiving, reasoning, understanding and producing the language along with control of the motor associated functions. The forebrain is divided into two major parts: the diencephalon and telencephalon. The diencephalon part of the brain comprises of the thalamus and hypothalamus which plays the major role in controlling the function associated with the motor system, communicating of the sensory information along with the control of functions which are autonomic in nature. The telencephalon comprises of largest part of the brain, i.e., the cerebrum. The cerebral cortex performs the major function of processing the actual information (Willis, et al, 1965; Bartels, et al, 2004).

Midbrain: The midbrain and hindbrain all together form the brain stem. The midbrain is also known as mesencephalon and it is a part of the brainstem which forms the connection between the forebrain and hindbrain. This particular region of the brain is also well associated with the function of visual, auditory and motor functions (Willis, et al,1965; Bartels, et al, 2004).

Psychodynamic Theory

Hindbrain: This part of the brain lengthens from the spinal cord and comprises of two major parts the metencephalon and myelencephalon. Metencephalon comprises of the pons and cerebellum. These regions are associated with functions of movement and coordination, in establishing the posture balance and equilibrium and it helps in transmission of the sensory information. Another part, myelencephalon consists of medulla oblongata which helps in the control of autonomic functions such as digestion, breathing and heart rate (Willis, et al, 1965; Bartels, et al, 2004).

The brain comprises of several other structures that are responsible for multitude of functions:

Basal Ganglia: This part of the brain is responsible for voluntary movement and cognition. Any damage in this part of the brain is responsible for Parkinson and Huntington diseases.

Broca's Area: responsible for the production of speech and processing of language.

Central Sulcus also known as Fissure of Rolando: It is a deep groove that results in the separation of the frontal and parietal lobes (Willis, et al, 1965; Bartels, et al, 2004).

The different lobes of the cerebral cortex:

Frontal lobes: This part is concerned with making of decision, planning and solving of problems.

Occipital Lobes: associated with visual process and recognition of colour.

Parietal Lobes: It accepts and processes the sensory information

Temporal Lobes: This region of the brain is associated with memory, speech process and responses of emotional in nature.

Corpus Callosum: It is a thick band of fibres which forms the connection between the right and left hemispheres of brain.

Fissure of Sylvius (Lateral Sulcus): This groove forms the separation between the parietal and temporal lobes (Kolb, et al, 2013; Spear, et al, 2000).

The different structures of limbic system: It includes amygdala, cingulate gyrus, fornix, hippocampus, hypothalamus, olfactory cortex and thalamus. These structures are associated with varied range of functions such as secretion of hormones, memory, processing of sensory information, emotion and controlling of behaviour which is aggressive in nature, transferring the memories to appropriate part of cerebral cortex where it can be stored and retrieved when needed, maintenance of the homeostatic condition of the body, recognition of colour and different odours (Bastian, et al, 1869; Phillips, et al, 1984; Van Essen, et al, 1979).

Pineal gland: this is endocrine glands responsible for the secretion of hormone melatonin and also involved in the biological rhythm.

Pituitary Gland: It helps in the regulation of the other endocrine glands and in maintenance of the body homeostasis.

Wernicke's Area: This part of the brain is associated with the processing of spoken language (Bastian, et al, 1869).

The other parts of midbrain:

Cerebral Peduncle: It is the anterior portion of midbrain which results in the connection of forebrain to hindbrain.

Reticular Formation: This region is composed of nerve fibres residing within the brainstem and the tegmentum responsible for the regulation of sleep and awareness.

Substantia Nigra: This part of the midbrain helps in controlling the voluntary movements and in regulation of mood.

Tectum and Tegmentum: The dorsal and ventral region of mesencephalon respectively responsible for the auditory and visual reflexes.

The ventricular system of brain: It is the connecting system of the internal cavities of brain filled up with cerebrospinal fluid.

Meninges: These are the membranes of brain and spinal cord which protects it from injury (Bastian, et al, 1869; Kolb, et al, 2013; Spear, et al, 2000).

The methods to investigate the relationship between brain and behaviour and their strengths and weakness:

The term localisation of function is a concept which highlights that certain functions such as decoding of language, memory are carried out within certain areas of brain. Therefore any damage to this area of the brain hampers the specific functioning capability of the individual. Thus it provided the evidence to the theory of localisation of the brain function. There are broadly two different methods to understand the relationship between the brain and the behaviour namely: Neuroscientific method and Behavioural Methods (Anderson, et al, 2013). In the present study the behavioural methods have been considered to decode the human behaviour.

Rationale of choosing these methods:

The Behavioural Methods is the research based methods that elaborates the objective behaviour and measures it. This particular method is used to explore about the complicated patterns of communication, in the identification of chronological orders within the cognitive processes and also provides with the detailed explanation of the cognitive limitations such as when a stroke patient is compared with a normal person. This method also guides in the detection of abilities and characteristics of human beings at the individual centred level and then comparing it with the general public (Konopka, et al, 2015). The various methods are:

Systematic Behaviour Observation: This research based tool allows in the investigation of the possible links between the psychological process and behaviour which is recorded. In this process the behaviour of individual will be videotaped and then it will be analysed with the help of computer having the specialized software. For example, Akzelerometrie is a tool which allows the tracking of body activities of people with the help of mobile devices such as wristband. This also permits the evaluation of the patterns of activities and its frequency within the daily life. This method is considered to be advantageous because of its high ecological validity parameter. It should be also noted that observational research are very time consuming and therefore costly when compared with other methods. Another weakness of this approach is that it is vulnerable to observer’s bias (Paolisso, et al, 2009; Shaughnessy, et al, 2000).

Facial Action Coding: This technique allows the investigation of detailed visible movements of muscles of face with the application of films or photos and a complex coding system known as Facial Action Coding System (FACS). The associated advantages of using this technique are that it detects even the delicate, complicated emotional expressions on face. Therefore, this tool is mainly applied in the field of Emotion Psychology or Affective Neurosciences (Dismukes, et al, 2010; Jack, et al, 2015).

Eye tracking: This task observes the movement of eye while performing various tasks. The eye position is investigated with the help of video images and infrared light which is not visible to the human eye. The benefit of using this technique is that based on the movements of eye a detailed elaboration can be obtained on the selection and processing of information. This method can also be used for those people who are unable to speak or use their hands (Brunyé, et al, 2019).

Reaction Times: This is a computer based technology which permits to measure the reaction within milliseconds. The tool guides in the deduction of specific information of the processing activities. It allows the measurement of reactions within simple tasks that are recorded. As in the laboratory environment high control can be exercised along with the definite manipulation of single parameters within the experimental tasks, this tool can be easily applied to identify the causal relationship. There are various factors that affect the reaction time such as gender, age, the level of physical fitness, distraction, fatigue, alcohol and also the type of personality (Dehaene, et al, 1999).

Virtual Reality: The application of this tool can be used to explain the facts which are complicated in nature. It is used to envisage situations and in association with the 3D animation or characters that are interactive we can get various scenarios of usage. By the application of this tool one can travel through the virtual space such as the towns or museum or it can be made possible to shift things within the virtual reality which depends on “real”. Though this tool has immense potential in research on psychology, there are certain parameters that need to be considered such as the sole concept of presence and immersion may not be sufficient for the subject to feel the presence and absence of the virtual object. Another situation can become a matter of concern when the goal is an exact replication of the subject in the physical world (Wilson, et al, 2015).

Flight Simulation: The application of modern flight simulation guides to conduct the psychophysiological research of experimental in nature. This can be done only under well defined conditions and only when the task follows the well structured experimental paradigms. With the application of this method task having high ecological validity can be studied in comparison to the classical laboratory research. There are varied types of simulators available for the research of human factors in Graz, Austria. Specific paradigm exercises have been developed within the aviation psychophysiology which helped to conduct comparison on direct basis among varied studies and simulator mock up within the laboratory. This was achieved with the application of optimized training and test hypothesis within the simulator and also to test in the cockpit. Psychophysiological research based on simulator had been conducted for topics concerned with the management of air traffic. The major limitation of this approach is the involvement of high cost of operating such simulators and restricted availability of similar research simulators. Therefore, the numbers of published articles with these simulators are few in number with few numbers of participants within the study and negligible statistical significance (Celesia, et al, 2013).

Psychoacoustics: The approach of psychoacoustics explores how the events of objective acoustics are getting translated to subjective auditory sensation. The experience of an individual plays a significant role in this respect such as the training which involved music increases the auditory system sensitivity and in the discrimination of delicate acoustic differences. This assessment technique involves the measurement of peripheral and central auditory functions, but for efficiently addressing the central function a more individual centred approach is required (Pally, et al, 2000).

Evidences to understand between the brain and behaviour:

To study about the negative components of emotion as an activity of Behavioural Inhibition and Activation System (BIS/BAS), several components can be used as significant factors for studying the differences in personality. A descriptive research analytical study had been conducted to investigate the association between the activation of the brain/ behavioural systems and the mental health status of students such as the rate of depression, stress and anxiety. The study included 100 students who had been referred to the clinic of psychotherapy and convenience sampling method was applied for this purpose. Garry-Wilson personality questionnaire (GWPQ) was utilised for the evaluation of the rate of activities of brain/behavioural systems and the associated components. Pearson Correlation Coefficient was used to analyse the significance of the relationship. The result revealed a significant association between the behavioural acting system and the three mental health indicators such as depression, stress and anxiety (P<0.01). The study highlighted the motivational theory of Gray, who stated that the behavioural inhibition system (BIS) is a neurological system which gets stimulated by clues such as punishment or lack of reward. This activation causes inhibition of this system and finally results in anxiety and depressive disorders. Another similar study conducted by several authors in the year 2012-13 included 360 samples via the method of random stratified sampling using the table of Morgan. The instruments used for this study were Buss and Perry Aggression Questionnaire, Carver and White scale for BAS/BIS and NEO Personality Inventory. Finally the analysis of the data was conducted with SPSS. The findings highlighted that there is a significant positive association between the neurosis and the personality factors such as aggression and a significant negative relationship between openness, extroversion and aggression. The statistical regression analysis focused on the personality traits and the brain behavioural systems and also predicted 29% the changes due to aggression. Therefore, the neurobiological domain involves the brain and physical causes whereas the psychological domain involves people and domain (Aubi, et al, 2011; Pally, et al, 2000; Komasi, et al, 2016; Rose, et al, 2016; Dehaene, et al, 1999).

Conclusion:

Thus the greatest challenge is to understand the myriad functions of human behaviour and how these are reflected within the structures of brain. This also helps to evaluate the alterations in the behaviour of human and functions of brain because of a diseased state. Therefore, the field of behavioural and cognitive neuroscience explores the overall computational, psychological and neuroscientific methods to understand the basis of normal and abnormal behaviour of an individuals.

References

Willis, T., 1965. Anatomy of the Brain and Nerves: Volumes 1 & 2. McGill-Queen's Press-MQUP.

Bartels, A. and Zeki, S., 2004. The chronoarchitecture of the human brain—natural viewing conditions reveal a time-based anatomy of the brain. Neuroimage, 22(1), pp.419-433.

Spear, L.P., 2000. The adolescent brain and age-related behavioral manifestations. Neuroscience & biobehavioral reviews, 24(4), pp.417-463.

Kolb, B., 2013. Brain plasticity and behavior. Psychology Press.

Anderson, M.L., Kinnison, J. and Pessoa, L., 2013. Describing functional diversity of brain regions and brain networks. Neuroimage, 73, pp.50-58.

Van Essen, D.C., 1979. Visual areas of the mammalian cerebral cortex. Annual review of neuroscience, 2(1), pp.227-261.

Wilson, C.J. and Soranzo, A., 2015. The use of virtual reality in psychology: A case study in visual perception. Computational and mathematical methods in medicine, 2015.

Brunyé, T.T., Drew, T., Weaver, D.L. and Elmore, J.G., 2019. A review of eye tracking for understanding and improving diagnostic interpretation. Cognitive research: principles and implications, 4(1), pp.1-16.

Shaughnessy, J.J., Zechmeister, E.B. and Zechmeister, J.S., 2000. Research methods in psychology. McGraw-Hill.

Celesia, G.G. ed., 2013. Disorders of Peripheral and Central Auditory Processing1: Disorders of Peripheral and Central Auditory Processing (Vol. 10). Elsevier Health Sciences.

Aubi, S. and Alimoradi, L., 2011. Relationship between Brain/Behavioural systems and mental health among students. Procedia-Social and Behavioral Sciences, 30, pp.1683-1687.

Komasi, S., Saeidi, M., Soroush, A. and Zakiei, A., 2016. The relationship between brain behavioral systems and the characteristics of the five factor model of personality with aggression among Iranian students. Journal of injury and violence research, 8(2), p.67.

Dehaene, S., Spelke, E., Pinel, P., Stanescu, R. and Tsivkin, S., 1999. Sources of mathematical thinking: Behavioral and brain-imaging evidence. Science, 284(5416), pp.970-974.