romikgosai/squad_modified huggingface dataset:
The first vertebrates appeared over 500 million years ago (Mya), during the Cambrian period, and may have resembled the modern hagfish in form. Sharks appeared about 450 Mya, amphibians about 400 Mya, reptiles about 350 Mya, and mammals about 200 Mya. Each species has an equally long evolutionary history, but the brains of modern hagfishes, lampreys, sharks, amphibians, reptiles, and mammals show a gradient of size and complexity that roughly follows the evolutionary sequence. All of these brains contain the same set of basic anatomical components, but many are rudimentary in the hagfish, whereas in mammals the foremost part (the telencephalon) is greatly elaborated and expanded.

Questions and answers:
['
Q: How long ago did the first vertebrate organisms appear?
A: over 500 million years ago', '
Q: During which scientific period did vertebrates appear?
A: Cambrian period', '
Q: Sharks appeared at about how many Mya?
A: 450 Mya', '
Q: The foremost part of the brain in mammals is known as what?
A: (the telencephalon', '
Q: At how many mya did mammals first appear in time?
A: 200 Mya']
Brains are most simply compared in terms of their size. The relationship between brain size, body size and other variables has been studied across a wide range of vertebrate species. As a rule, brain size increases with body size, but not in a simple linear proportion. In general, smaller animals tend to have larger brains, measured as a fraction of body size. For mammals, the relationship between brain volume and body mass essentially follows a power law with an exponent of about 0.75. This formula describes the central tendency, but every family of mammals departs from it to some degree, in a way that reflects in part the complexity of their behavior. For example, primates have brains 5 to 10 times larger than the formula predicts. Predators tend to have larger brains than their prey, relative to body size.

Questions and answers:
['
Q: Do predators have larger or smaller brains compared to their prey?
A: larger', '
Q: In mammals, brain volume and body mass follows a power law with an exponent of what?
A: 0.75', '
Q: Which group of animals have brains 5-10 times larger than the formula predicts?
A: primates']
All vertebrate brains share a common underlying form, which appears most clearly during early stages of embryonic development. In its earliest form, the brain appears as three swellings at the front end of the neural tube; these swellings eventually become the forebrain, midbrain, and hindbrain (the prosencephalon, mesencephalon, and rhombencephalon, respectively). At the earliest stages of brain development, the three areas are roughly equal in size. In many classes of vertebrates, such as fish and amphibians, the three parts remain similar in size in the adult, but in mammals the forebrain becomes much larger than the other parts, and the midbrain becomes very small.

Questions and answers:
['
Q: The forebrain during development is known as what?
A: prosencephalon', '
Q: The midbrain during development is known as what?
A: mesencephalon', '
Q: The hindbrain during development is known as what?
A: rhombencephalon', '
Q: Which group of animals does the forebrain grow the largest?
A: mammals', '
Q: During development, the brain is made up of three swellings at the front of what?
A: neural tube;']
The brains of vertebrates are made of very soft tissue. Living brain tissue is pinkish on the outside and mostly white on the inside, with subtle variations in color. Vertebrate brains are surrounded by a system of connective tissue membranes called meninges that separate the skull from the brain. Blood vessels enter the central nervous system through holes in the meningeal layers. The cells in the blood vessel walls are joined tightly to one another, forming the blood–brain barrier, which blocks the passage of many toxins and pathogens (though at the same time blocking antibodies and some drugs, thereby presenting special challenges in treatment of diseases of the brain).

Questions and answers:
['
Q: Brain tissue that is living is what color on the outside?
A: pinkish', '
Q: The color of the brain inside is what?
A: white', '
Q: Brains are surrounded by what system of tissues?
A: meninges', '
Q: Meninges separate what structure from the brain?
A: the skull', '
Q: The blood-brain barrier is made up of what?
A: cells in the blood vessel walls']
Neuroanatomists usually divide the vertebrate brain into six main regions: the telencephalon (cerebral hemispheres), diencephalon (thalamus and hypothalamus), mesencephalon (midbrain), cerebellum, pons, and medulla oblongata. Each of these areas has a complex internal structure. Some parts, such as the cerebral cortex and the cerebellar cortex, consist of layers that are folded or convoluted to fit within the available space. Other parts, such as the thalamus and hypothalamus, consist of clusters of many small nuclei. Thousands of distinguishable areas can be identified within the vertebrate brain based on fine distinctions of neural structure, chemistry, and connectivity.

Questions and answers:
['
Q: People who study the anatomy of the central nervous system are known as what?
A: Neuroanatomists', '
Q: The cerebral hemispheres of the brain are called what?
A: telencephalon', '
Q: The thalamus and hypothalamus comprise what region of the brain?
A: diencephalon', '
Q: The midbrain region of the brain is known as what?
A: mesencephalon', '
Q: Clusters of small nuclei comprise what parts of the brain?
A: thalamus and hypothalamus']
Although the same basic components are present in all vertebrate brains, some branches of vertebrate evolution have led to substantial distortions of brain geometry, especially in the forebrain area. The brain of a shark shows the basic components in a straightforward way, but in teleost fishes (the great majority of existing fish species), the forebrain has become "everted", like a sock turned inside out. In birds, there are also major changes in forebrain structure. These distortions can make it difficult to match brain components from one species with those of another species.

Questions and answers:
['
Q: The forebrain is everted in what type of fishes?
A: teleost fishes', '
Q: Which part of the brain has led to many distortions among different species?
A: forebrain area']
The most obvious difference between the brains of mammals and other vertebrates is in terms of size. On average, a mammal has a brain roughly twice as large as that of a bird of the same body size, and ten times as large as that of a reptile of the same body size.

Questions and answers:
["
Q: A mammal's brain is how many times larger than a birds relative to body size?
A: twice as large", "
Q: A mammal's brain is how many times larger than a reptiles relative to body size?
A: ten times", '
Q: The biggest difference between brains of mammals and other vertebrates is what?
A: size.']
Size, however, is not the only difference: there are also substantial differences in shape. The hindbrain and midbrain of mammals are generally similar to those of other vertebrates, but dramatic differences appear in the forebrain, which is greatly enlarged and also altered in structure. The cerebral cortex is the part of the brain that most strongly distinguishes mammals. In non-mammalian vertebrates, the surface of the cerebrum is lined with a comparatively simple three-layered structure called the pallium. In mammals, the pallium evolves into a complex six-layered structure called neocortex or isocortex. Several areas at the edge of the neocortex, including the hippocampus and amygdala, are also much more extensively developed in mammals than in other vertebrates.

Questions and answers:
['
Q: What part of the brain most strongly differentiates mammals from other vertebrates?
A: The cerebral cortex', '
Q: The three-layered structure covering the cerebrum in non-mammals is known as what?
A: pallium', '
Q: Mammals have a pallium that involved into what?
A: neocortex or isocortex', '
Q: The hippocampus and amygdala are ares inside what structure?
A: neocortex']
The elaboration of the cerebral cortex carries with it changes to other brain areas. The superior colliculus, which plays a major role in visual control of behavior in most vertebrates, shrinks to a small size in mammals, and many of its functions are taken over by visual areas of the cerebral cortex. The cerebellum of mammals contains a large portion (the neocerebellum) dedicated to supporting the cerebral cortex, which has no counterpart in other vertebrates.

Questions and answers:
['
Q: The superior colliculus is related to what sensual control of vertebrates?
A: visual', '
Q: The larger part of the cerebellum in mammals is called what?
A: (the neocerebellum', '
Q: The Neocerebellum supports what other part of the brain?
A: cerebral cortex']
The brains of humans and other primates contain the same structures as the brains of other mammals, but are generally larger in proportion to body size. The most widely accepted way of comparing brain sizes across species is the so-called encephalization quotient (EQ), which takes into account the nonlinearity of the brain-to-body relationship. Humans have an average EQ in the 7-to-8 range, while most other primates have an EQ in the 2-to-3 range. Dolphins have values higher than those of primates other than humans, but nearly all other mammals have EQ values that are substantially lower.

Questions and answers:
['
Q: Comparing brain sizes among different creatures is used most commonly by what?
A: encephalization quotient (EQ)', '
Q: What is the average EQ of a person?
A: 7-to-8 range', '
Q: Primates have an EQ in what range?
A: 2-to-3']
Most of the enlargement of the primate brain comes from a massive expansion of the cerebral cortex, especially the prefrontal cortex and the parts of the cortex involved in vision. The visual processing network of primates includes at least 30 distinguishable brain areas, with a complex web of interconnections. It has been estimated that visual processing areas occupy more than half of the total surface of the primate neocortex. The prefrontal cortex carries out functions that include planning, working memory, motivation, attention, and executive control. It takes up a much larger proportion of the brain for primates than for other species, and an especially large fraction of the human brain.

Questions and answers:
['
Q: Primates have a visual processing network of how many brain areas?
A: 30', '
Q: The visual processing areas occupy how much of the surface of the neocortex or primates?
A: more than half', '
Q: Planning, motivation, and attention are controlled by what area?
A: prefrontal cortex', '
Q: The prefrontal cortex is the largest in what animals?
A: primates']
For vertebrates, the early stages of neural development are similar across all species. As the embryo transforms from a round blob of cells into a wormlike structure, a narrow strip of ectoderm running along the midline of the back is induced to become the neural plate, the precursor of the nervous system. The neural plate folds inward to form the neural groove, and then the lips that line the groove merge to enclose the neural tube, a hollow cord of cells with a fluid-filled ventricle at the center. At the front end, the ventricles and cord swell to form three vesicles that are the precursors of the forebrain, midbrain, and hindbrain. At the next stage, the forebrain splits into two vesicles called the telencephalon (which will contain the cerebral cortex, basal ganglia, and related structures) and the diencephalon (which will contain the thalamus and hypothalamus). At about the same time, the hindbrain splits into the metencephalon (which will contain the cerebellum and pons) and the myelencephalon (which will contain the medulla oblongata). Each of these areas contains proliferative zones where neurons and glial cells are generated; the resulting cells then migrate, sometimes for long distances, to their final positions.

Questions and answers:
['
Q: The precursor of the nervous system is called what in vertebrates?
A: the neural plate', '
Q: The neural groove is a hollow cord of cells with what in the center?
A: fluid-filled ventricle', '
Q: The forebrain splits during development into vesicles called what?
A: telencephalon (which will contain the cerebral cortex, basal ganglia, and related structures) and the diencephalon', '
Q: The vesicle that contains the cerebral cortex is which one?
A: telencephalon', '
Q: The thalamus and hypothalamus are contained in which vesicle?
A: the diencephalon']
Once a neuron is in place, it extends dendrites and an axon into the area around it. Axons, because they commonly extend a great distance from the cell body and need to reach specific targets, grow in a particularly complex way. The tip of a growing axon consists of a blob of protoplasm called a growth cone, studded with chemical receptors. These receptors sense the local environment, causing the growth cone to be attracted or repelled by various cellular elements, and thus to be pulled in a particular direction at each point along its path. The result of this pathfinding process is that the growth cone navigates through the brain until it reaches its destination area, where other chemical cues cause it to begin generating synapses. Considering the entire brain, thousands of genes create products that influence axonal pathfinding.

Questions and answers:
['
Q: A growth cone of an axon is made up of a blob of what?
A: protoplasm', '
Q: What two structures does a neuron extend when it is in place during development?
A: dendrites and an axon']
In humans and many other mammals, new neurons are created mainly before birth, and the infant brain contains substantially more neurons than the adult brain. There are, however, a few areas where new neurons continue to be generated throughout life. The two areas for which adult neurogenesis is well established are the olfactory bulb, which is involved in the sense of smell, and the dentate gyrus of the hippocampus, where there is evidence that the new neurons play a role in storing newly acquired memories. With these exceptions, however, the set of neurons that is present in early childhood is the set that is present for life. Glial cells are different: as with most types of cells in the body, they are generated throughout the lifespan.

Questions and answers:
['
Q: The infant brain contains more of what type of cells in the brain than the adult brain?
A: neurons', '
Q: The olfactory bulb is related to what sense?
A: sense of smell', '
Q: What area of the hippocampus plays a role in storing new memories?
A: dentate gyrus of the hippocampus', '
Q: Which type of cells in the brain are generated throughout your lifetime?
A: Glial cells', '
Q: Neurogenesis is the process of what?
A: neurons continue to be generated throughout life']
The functions of the brain depend on the ability of neurons to transmit electrochemical signals to other cells, and their ability to respond appropriately to electrochemical signals received from other cells. The electrical properties of neurons are controlled by a wide variety of biochemical and metabolic processes, most notably the interactions between neurotransmitters and receptors that take place at synapses.

Questions and answers:
['
Q: The electrical properties of neurons are controlled by what?
A: neurotransmitters and receptors that take place at synapses', '
Q: What type of signals do neurons transfer from one another?
A: electrochemical']
Neurotransmitters are chemicals that are released at synapses when an action potential activates them—neurotransmitters attach themselves to receptor molecules on the membrane of the synapse's target cell, and thereby alter the electrical or chemical properties of the receptor molecules. With few exceptions, each neuron in the brain releases the same chemical neurotransmitter, or combination of neurotransmitters, at all the synaptic connections it makes with other neurons; this rule is known as Dale's principle. Thus, a neuron can be characterized by the neurotransmitters that it releases. The great majority of psychoactive drugs exert their effects by altering specific neurotransmitter systems. This applies to drugs such as cannabinoids, nicotine, heroin, cocaine, alcohol, fluoxetine, chlorpromazine, and many others.

Questions and answers:
['
Q: Chemicals called neurotransmitters are released at what part of the brain?
A: synapses', "
Q: What do neurotransmitters attach to?
A: receptor molecules on the membrane of the synapse's target cell", "
Q: Neurons that release the same chemicals are following what rule?
A: Dale's principle"]
The two neurotransmitters that are used most widely in the vertebrate brain are glutamate, which almost always exerts excitatory effects on target neurons, and gamma-aminobutyric acid (GABA), which is almost always inhibitory. Neurons using these transmitters can be found in nearly every part of the brain. Because of their ubiquity, drugs that act on glutamate or GABA tend to have broad and powerful effects. Some general anesthetics act by reducing the effects of glutamate; most tranquilizers exert their sedative effects by enhancing the effects of GABA.

Questions and answers:
['
Q: GABA is the abbreviation for what?
A: gamma-aminobutyric acid', '
Q: Which of two neurotransmitters is usually inhibitory?
A: gamma-aminobutyric acid (GABA)', '
Q: The neurostransmitter that usually excites targets is called what?
A: glutamate,', '
Q: Tranquilizers affect which of the two common neurotransmitters?
A: gamma-aminobutyric acid (GABA)']
There are dozens of other chemical neurotransmitters that are used in more limited areas of the brain, often areas dedicated to a particular function. Serotonin, for example—the primary target of antidepressant drugs and many dietary aids—comes exclusively from a small brainstem area called the Raphe nuclei. Norepinephrine, which is involved in arousal, comes exclusively from a nearby small area called the locus coeruleus. Other neurotransmitters such as acetylcholine and dopamine have multiple sources in the brain, but are not as ubiquitously distributed as glutamate and GABA.

Questions and answers:
['
Q: Serotonin comes from what part of the brain?
A: Raphe nuclei', '
Q: Antidepressants typically affect what chemical of the brain?
A: Serotonin', '
Q: Which chemical of the brain is involved with arousal?
A: Norepinephrine', '
Q: Norepinephrine comes from an area of the brain known as what?
A: locus coeruleus']
As a side effect of the electrochemical processes used by neurons for signaling, brain tissue generates electric fields when it is active. When large numbers of neurons show synchronized activity, the electric fields that they generate can be large enough to detect outside the skull, using electroencephalography (EEG) or magnetoencephalography (MEG). EEG recordings, along with recordings made from electrodes implanted inside the brains of animals such as rats, show that the brain of a living animal is constantly active, even during sleep. Each part of the brain shows a mixture of rhythmic and nonrhythmic activity, which may vary according to behavioral state. In mammals, the cerebral cortex tends to show large slow delta waves during sleep, faster alpha waves when the animal is awake but inattentive, and chaotic-looking irregular activity when the animal is actively engaged in a task. During an epileptic seizure, the brain's inhibitory control mechanisms fail to function and electrical activity rises to pathological levels, producing EEG traces that show large wave and spike patterns not seen in a healthy brain. Relating these population-level patterns to the computational functions of individual neurons is a major focus of current research in neurophysiology.

Questions and answers:
['
Q: An EEG of the brain stands for what?
A: electroencephalography', '
Q: MEG of the brain is an abbreviation of what?
A: magnetoencephalography', '
Q: What type of test is used to tell that a brain is active even during sleep?
A: EEG', '
Q: What type of brain waves are seen in mammals during sleep?
A: large slow delta waves', '
Q: What type of brain waves are sen when a creature is awake, but inattentive?
A: faster alpha waves']
All vertebrates have a blood–brain barrier that allows metabolism inside the brain to operate differently from metabolism in other parts of the body. Glial cells play a major role in brain metabolism by controlling the chemical composition of the fluid that surrounds neurons, including levels of ions and nutrients.

Questions and answers:
['
Q: What type of cells have a huge role in brain metabolism?
A: Glial cells', '
Q: Glial cells control what inside the brain?
A: chemical composition of the fluid that surrounds neurons']
Brain tissue consumes a large amount of energy in proportion to its volume, so large brains place severe metabolic demands on animals. The need to limit body weight in order, for example, to fly, has apparently led to selection for a reduction of brain size in some species, such as bats. Most of the brain's energy consumption goes into sustaining the electric charge (membrane potential) of neurons. Most vertebrate species devote between 2% and 8% of basal metabolism to the brain. In primates, however, the percentage is much higher—in humans it rises to 20–25%. The energy consumption of the brain does not vary greatly over time, but active regions of the cerebral cortex consume somewhat more energy than inactive regions; this forms the basis for the functional brain imaging methods PET, fMRI, and NIRS. The brain typically gets most of its energy from oxygen-dependent metabolism of glucose (i.e., blood sugar), but ketones provide a major alternative source, together with contributions from medium chain fatty acids (caprylic and heptanoic acids), lactate, acetate, and possibly amino acids.

Questions and answers:
['
Q: Where does the brain usually get most of its energy from inside the body?
A: glucose (i.e., blood sugar', '
Q: The energy used for metabolism of the brain in humans is what percentage?
A: 20–25%', '
Q: Other sources than glucose that provide energy to the brain are what?
A: ketones', '
Q: Most vertebrates usually devote how much metabolism to the brain?
A: 2% and 8%']
From an evolutionary-biological perspective, the function of the brain is to provide coherent control over the actions of an animal. A centralized brain allows groups of muscles to be co-activated in complex patterns; it also allows stimuli impinging on one part of the body to evoke responses in other parts, and it can prevent different parts of the body from acting at cross-purposes to each other.

Questions and answers:
['
Q: The function of the brain from an evolutionary-biological thought is what?
A: provide coherent control over the actions of an animal']
The invention of electronic computers in the 1940s, along with the development of mathematical information theory, led to a realization that brains can potentially be understood as information processing systems. This concept formed the basis of the field of cybernetics, and eventually gave rise to the field now known as computational neuroscience. The earliest attempts at cybernetics were somewhat crude in that they treated the brain as essentially a digital computer in disguise, as for example in John von Neumann's 1958 book, The Computer and the Brain. Over the years, though, accumulating information about the electrical responses of brain cells recorded from behaving animals has steadily moved theoretical concepts in the direction of increasing realism.

Questions and answers:
['
Q: Computers were invented in what decade in history?
A: 1940s', '
Q: Neuroscience spawned from what field of science in history?
A: cybernetics', "
Q: Who wrote the book, The Computer and the Brain?
A: John von Neumann's", "
Q: When was John von Neumann's book, The Computer and the Brain published?
A: 1958"]