The Cortex Machina project has its origins in a deeply rooted fascination with neurobiology in general, and the biological origins of consciousness in particular. Unfortunately, it can often be very challenging to discuss and share these fascinating concepts, simply because they generally require a lot of prior knowledge which is, to say the least, quite unfamiliar to most people. That’s why we have started this series of short columns: to kindle interest in the fields of neuroscience and neurobiology and to provide my readers with enough general knowledge on the human brain and cognition to start exploring and sharing these fascinating concepts themselves. We will start with a series of articles on brain anatomy, to provide the reader with an understanding of brain architecture and nomenclature, which will be helpful later on when we discuss other topics. So without further ado, let’s get into the major divisions of the brain. What are ‘Brains’? The brain is a peculiar organ. With only 1.5kg of white, grey and glial matter it manages to control all the function of our bodies, interprets the outside world, gives rise to consciousness, controls memory and speech and, in humans, generates our minds and sense of individual self. It is the product of hundreds of millions of years of evolution, first arising as simple nerve nets in the first multicellular organisms over 500 million years ago and then evolving into ever more complex nervous systems in a relentless arms race driven by natural selection. Brains are found all over the animal kingdom, even among some animals lacking a nervous system altogether but still having the ability to circulate electrical impulses in other ways (for instance the ‘glass sponge’). In this column however, we will focus more specifically on the brains and nervous systems of the animal Class of ‘Mammalia’, i.e. mammals. This Class of Mammalia is of particular interest because it includes our own species, Homo sapiens, and the evolution of the brain in this lineage has been particularly impressive. The brain constantly receives information about the outside world through its sensory systems and combines this with memories about prior experiences and with input from subconscious neural processes to generate an image of the world surrounding us. This constantly updating image in our heads is what we’d call our ‘conscious experience’. But to start understanding “how” our brain does all this, we first have to get a grasp of basic human brain anatomy (and by extension most placental mammals). Brain Architecture The brain is just one part of our nervous system, which is composed of the central nervous system (containing the brain and the spinal cord) and the peripheral nervous system (‘spinal nerves’ branching from the spine and ‘cranial nerves’ branching from the brain). The brain itself, defined as the part of the central nervous system contained in the skull, can be divided in a number of different ways. Labels and divisions are tools to make it possible to talk about the brain in meaningful ways, and depending on your field of study, different divisions and classifications can be useful. Table 1 below presents two of the most common “divisions of the brain” that are in use: I personally prefer to use the division based on nervous system development as the division based on physical appearance doesn’t reflect well the actual biological divisions between neuron clusters and basically leaves out the whole diencephalon. So it’s this classification in “Forebrain, Midbrain, and Hindbrain” that I will present here. To better appreciate this classification system, let’s observe how our nervous system starts out in the early development in the womb and compare it with the nomenclature used in table 1: Our whole nervous system starts out as a neural tube, which divides into three vesicles which in turn give rise to the three major divisions of the brain: forebrain, midbrain and hindbrain (see Fig.2). Later on these three vesicles subdivide into a further 5 sub-vesicles: the telencephalon, diencephalon, mesencephalon, myelencephalon and metencephalon. These 5 vesicles in the neural tube, present at the start of the development of the nervous system in the womb, end up forming all the cortical structures of the brain. Table 1 lists some of the principal structures in which ‘vesicles’ they are generated during embryonic and fetal development. A big thanks for your reading from the entire Cortex Machina team! You can find all our stories already published on our blog.

We'll start with a series of articles on brain anatomy, to provide the reader with an understanding of brain architecture, which will be helpful later on when we discuss other topics. So, let’s enter now into the Language area’s! Human language is one of the most complex and powerful communication tools in the animal kingdom. Unlike other animals, humans have exceptional language and speech capabilities, which is evident in the human brain. Our brain has a much larger percentage of cortical circuits dedicated to language-related functions than in other animal brains. Language in humans is not just another cortical function; it is a unique and complex trait that has evolved over time, co-evolving with our capacity for Theory of Mind, creating a cultural natural pressure that has given rise to our sense of individual self. Let us take a closer look at the anatomy of language processing in the brain. Language is a lateralized function, located in the dominant hemisphere of the brain, usually the left hemisphere. The main language areas in the left hemisphere are the Broca's area and the Wernicke's area. Broca's area, located in the left frontal lobe, is responsible for the motor functions related to language, such as speaking and writing. Damage to this area results in Broca's aphasia, where the patient can still understand spoken language and read but has difficulty moving their tongue or facial muscles to produce sounds, and struggles with writing. On the other hand, Wernicke's area, located in the left temporal lobe, is responsible for language comprehension. If this area is damaged, the patient may speak in long sentences with no meaning, routinely add unnecessary new words, and have difficulty understanding speech. They are generally unaware of their mistakes or that their sentences have no meaning. The complex and interconnected nature of language in the human brain is fascinating. The study of language areas in the brain has advanced our understanding of how we communicate, think, and learn. It has also helped in the development of therapeutic treatments for language disorders such as Broca's aphasia, Wernicke's aphasia, and others. The more we learn about the anatomy and functionality of language areas in the brain, the more we can understand this unique human trait.

The human brain is a complex and highly organized structure that controls all of our thoughts, actions, and emotions. It is composed of various regions, each with its own unique function and set of connections. Among these regions, the Telencephalon, also known as the cerebrum, is the largest and most complex. In this article, we will focus on the deep structures of the Telencephalon and their specific functions. Deep structures are defined as structures located deep within the brain, beyond the cerebral cortex. These structures are responsible for a range of essential functions, including emotion regulation, movement control, and memory consolidation. Basal Ganglia: The Main Deep Structure in the Telencephalon The basal ganglia is the primary deep structure located within the Telencephalon. It is a complex network of subcortical nuclei that are located at the junction of the Telencephalon and the Diencephalon. The basal ganglia is responsible for a range of functions, including voluntary movement, cognitive processes, and emotion regulation. The basal ganglia is composed of several distinct nuclei, including the caudate nucleus, putamen, globus pallidus, and substantia nigra. The caudate nucleus and putamen are collectively referred to as the striatum, which is responsible for motor function and learning. The globus pallidus is involved in the regulation of voluntary movement, while the substantia nigra is involved in the regulation of motor function and reward-based learning. Other Deep Structures in the Telencephalon While the basal ganglia is the main deep structure in the Telencephalon, there are other structures that are also located deep within the brain. These structures include the amygdala, claustrum, and septal nuclei. The amygdala is located within the temporal lobe and is involved in the regulation of emotion and memory consolidation. It plays a crucial role in the processing of fear and other negative emotions. The claustrum is a thin sheet of neurons located between the insular cortex and the putamen. While its function is not well understood, studies suggest that it may be involved in conscious awareness and attention. The septal nuclei are located in the midline of the Telencephalon and are involved in the regulation of emotion and motivation. They are connected to the limbic system, which is responsible for the regulation of emotional responses and behaviors. Conclusion In summary, the deep structures of the Telencephalon play a crucial role in regulating a range of essential functions, including emotion regulation, movement control, and memory consolidation. The basal ganglia is the main deep structure in the Telencephalon and is responsible for a range of functions, including voluntary movement, cognitive processes, and emotion regulation. Other deep structures, including the amygdala, claustrum, and septal nuclei, also play important roles in the regulation of emotion and behavior. Further research is needed to fully understand the functions of these deep structures and their role in human brain function.

The Cortex Machina project has its origins in a deeply rooted fascination with neurobiology in general, and the biological origins of consciousness in particular. Unfortunately, it can often be very challenging to discuss and share these fascinating concepts, simply because they generally require a lot of prior knowledge which is, to say the least, quite unfamiliar to most people. That’s why we have started this series of short columns: to kindle interest in the fields of neuroscience and neurobiology and to provide my readers with enough general knowledge on the human brain and cognition to start exploring and sharing these fascinating concepts themselves. We will start with a series of articles on brain anatomy, to provide the reader with an understanding of brain architecture and nomenclature, which will be helpful later on when we discuss other topics. So without further ado, let’s enter now into your Diencephalon! As we’ve seen, different areas of the cerebral cortex are connected to each other through an extensive network of dendrites and axons forming the white matter in the Cerebrum. It isn’t completely disorganized though. We can identify defined pathways where white matter fibers are grouped together, called ‘white matter tracts’. These connect various areas of the cortex, like gyrus to gyrus connections and white matter tracts going all the way to the other hemisphere, passing through the corpus callosum. But they also connect the cerebral cortex with what we call “deep structures”. These are structures with specific functions that are mostly found in the diencephalon (though the basal ganglia are located in the telencephalon (= cerebrum)) and which will sound familiar as a couple of these deep structures have already been mentioned before. Let’s review the most important of these deep structures. In the Diencephalon The diencephalon contains the vast majority of deep structures. We’ll give a brief overview of the main ones as well as their location in the brain. Thalamus Hypothalamus Pituitary gland Pineal gland Limbic system Figure 22: Thalamus, Hypothalamus, Pituitary gland, Pineal gland and Limbic system. A big thanks for your reading from the entire Cortex Machina team! You can find all our stories already published on our blog.