Assignment Code:BPCC 102/ASST/TMA/2022-23

Course Code: BPCC-102

Assignment Name: BIOPSYCHOLOGY

Year: 2022-2023

Verification Status: Verified by Professor

Total Marks: 100

NOTE: All questions are compulsory.

PART A

Assignment One

2 x 20 = 40

Answer the following questions in about 500 words each. Each question carries 20 marks.

1. Define hormone. Explain the structure and functioning of pituitary gland. Support your answer with a suitable diagram.

Ans) This mechanism is very fast and affects neurons that are in immediate proximity to the originating neuron. In the same way, some structures, like glands, release chemicals. There are two kinds of glands: those that make hormones and those that get rid of waste. The glands that affect behaviour are known as endocrine glands, whereas there are glands that do not affect behaviour, like salivary gland and sweat gland, which fall in the category of exocrine glands. Exocrine glands have ducts and release chemicals into the ducts. On the other hand, endocrine glands don't have ducts. When they are stimulated, they release chemicals directly into the bloodstream. Hormones are the chemicals that are made by endocrine glands. The word hormone is derived from the Greek word "hormaein" which means to excite. cells. These chemicals travel in the body and bring about the physiological changes inside the body. There are target tissues or organs that have the right receptors to let hormones in.

The pituitary gland is also called the "master gland" because it controls all the other glands and organs in the body. The tropic hormones make up most of its hormones. The pituitary gland is a small structure that weighs about 0.5 gms. It comes from the word "pituita" in Latin. It is at the bottom of the head and is connected to the hypothalamus. Another name for it is hypophysis. It is connected to the hypothalamus in the brain by a small stalk called the infundibulum. It has two distinct glands, the adenohypophysis or anterior pituitary gland, and the neurohypophysis, or posterior pituitary gland, formed during embryonic development. Each gland makes hormones that work in different ways.

Anterior Lobe

The anterior lobe of your pituitary gland is made up of different kinds of cells that make and release different hormones.

1. Growth Hormone: Growth hormone controls how much you grow and how your body changes. It can make almost all of your cells grow faster. Bones and muscles are its main targets.

2. Thyroid-stimulating Hormone: This hormone tells your thyroid to start making hormones. Your metabolism needs your thyroid gland and the hormones it makes.

3. Adrenocorticotropic Hormone: This hormone stimulates your adrenal glands to produce cortisol and other hormones.

4. Follicle-stimulating Hormone: Follicle-stimulating hormone is involved with estrogen secretion and the growth of egg cells in women. It’s also important for sperm cell production in men.

5. Luteinizing Hormone: Luteinizing hormone is involved in the production of estrogen in women and testosterone in men.

6. Prolactin: Prolactin helps women who are breastfeeding produce milk

7. Endorphins: Endorphins have pain-relieving properties and are thought to be connected to the “pleasure centers” of the brain.

8. Enkephalins: Enkephalins are closely related to endorphins and have similar pain-relieving effects.

9. Beta-melanocyte-stimulating Hormone: This hormone helps to stimulate increased pigmentation of your skin in response to exposure to ultraviolet radiation.

Posterior Lobe

The hormones are also made by the pituitary glands back lobe. Most of the time, your hypothalamus makes these hormones and stores them in your posterior lobe until they're needed. The posterior lobe stores hormones such as:

1. Vasopressin: This is also called antidiuretic hormone. It helps your body conserve water and prevent dehydration.

2. Oxytocin: This hormone stimulates the release of breast milk. It also stimulates contractions of the uterus during labor.

2. Describe the functioning of forebrain. Illustrate the lateral view of human brain.

Ans) The two parts of the forebrain are called the telencephalon and the diencephalon. The cerebral cortex, the basal ganglia, and the limbic system are all parts of the telencephalon. It is the most important part of the brain. The cerebral cortex covers the two hemispheres of the brain, while the basal ganglia are in the subcortical area of the brain. The thalamus, the hypothalamus, the optic chiasma, and the pineal body are all parts of the diencephalon.

Telencephalon: Cerebral Cortex

The cortex of the brain is between 2 and 4 mm thick. It is at the top of the brain. It is the part of the brain that can be seen. There are millions of dendrites that connect to other neurons in this area. The cerebral cortex is grey because it is made up of small neurons that haven't been myelinated. This is why it is also called "grey matter." The white matter is the layer below the cortex. It is made up of large axons that have been myelinated, which gives them a white colour. Convolution is the name for both small and large bumps. Between the bumps are grooves. The smaller grooves are called sulci, and the bigger ones are called fissures. The cerebral cortex does a lot of different things. The postcentral gyrus is a general sensory area for the body. It knows what touch, temperature, and pressure feel like.

Telencephalon: Basal Ganglia

The Basal Ganglia are found under the cortex of the brain. It is mostly made up of white matter, which is made up of many tracts. There, the grey matter, which is different from the white matter, is deep inside the cortex. The caudate nucleus, the putamen, the globus pallidus, and the amagdaloid nucleus are the parts that make up the basal ganglia. The striatum is made up of the caudate nucleus and the putamen, which look like they have been stripped.

Telencephalon: Limbic System

The limbic system (limbic means "ring") surrounds the corpus callosum, which connects the left and right sides of the brain. It has parts like the amygdala, septal, nucleus, hypothalamus, and thalamus, which are connected to the cingulated gyrus and hippocampus. The limbic system, also called the "old brain," is in charge of feeling, expressing, and being motivated by emotions. Along with the cortex, it is also called the emotional brain because it helps us feel different emotions like fear, anger, sadness, hunger, sexual behaviour, fighting, etc.

Diencephalon: Thalamus

The thalamus is a big structure with two lobes that sits on top of the brain stem. There are many neurons in the nuclei of the thalamus, which is in the middle of the forebrain. These important nuclei are called "geniculate bodies," and they are in the middle of the forebrain. The geniculate bodies are an important part of how the brain processes what it hears and sees. So, the thalamus is in charge of how we feel pain, temperature, touch, and are conscious. The brain stem sends signals to the nuclei in the thalamus, which then send those signals to the different parts of the cortex.

Diencephalon: Hypothalamus

The hypothalamus is located below the anterior thalamus. The word "hypo" means "below." It's a small piece of the brain that only weighs about 7 grammes. Even though it is small, it is very important for its function. It has three important nuclei called supraoptic nuclei, paraventricular nuclei, and mamillary bodies. The middle part grows a stalk called the infundibulum, which is linked to the back of the pituitary gland. The hypothalamus is in charge of both staying alive and having fun.

Assignment Two

6 x 5 = 30

Answer the following questions in about 100 words each. Each question carries 5 marks.

3. Amnesia

Ans) Amnesia is a big loss of memory that doesn't affect other parts of the brain. It can be caused by an infection, a stroke, a tumour, a drug, a lack of oxygen, epilepsy, or Alzheimer's. Amnesia can also be caused by trauma or suggestions made under hypnosis. In the classic case of HM, amnesia was caused by damage to both sides of the medial temporal lobe, which is where the hippocampus is located. Perception, cognition, intelligence, action, and sometimes working memory, distant memories, and nonconscious memories (implicit memory) that don't make you aware of what you've already experienced are the functions that stay. There are two kinds of amnesia. Anterograde amnesia is memory loss after the damage, and retrograde amnesia is memory loss right before the damage.

4. Cranial Nerves

Ans) You can count and name the nerves in your head. There are 12 pairs of cranial nerves that go from the brain stem to the rest of the body. One of each pair is on the right side and the other is on the left. There are groups of axons in the cranial nerves. There are three different kinds of cranial nerves based on what they do. Sensory cranial nerves have sensory axons and help with sensory functions. Motor cranial nerves have axons that help with motor functions, and mixed cranial nerves help with both sensory and motor functions. The spinal cord is where the other nerves of the peripheral nervous system come out.

5. Babinski Reflex

Ans) The Babinski reflex helps babies' bodies stay steady and gets their feet ready for their first steps. It even makes sure that the hips, legs, and spine work together well. When babies are born and don't have a Babinski reflex, it means that their central nervous system hasn't fully developed or that there is a problem with their spinal cord. Children with cerebral palsy or hemiplegia (partial paralysis of the body) will still have reflexes in the part of the body that has been affected. Babies with autism also have a Babinski reflex that lasts longer than usual. If a child still has this baby reflex when they are two years old, it will be hard for them to put their foot on the ground easily. They might also have trouble keeping their balance because their toes are always pointed outward. This makes it hard for them to walk around comfortably.

6. Hemispheric Specialization

Ans) Hemispheric specialisation, which is also called cerebral dominance or lateralization of function, is a key part of how the human brain is set up. This specialisation is relative, though, because, with a few exceptions, both sides of the brain can process most kinds of information, though in very different ways. The right side of the brain is better at processing information in a more global and coarse way, while the left side is better at processing information in a more analytical and fine-grained way. The relative specialisation of the two sides of the brain makes them different processors and gives the brain two different ways to analyse information. When there are a lot of tasks to do, these two processors can work together to increase the brain's processing power.

7. The Z Lens

Ans) The Z lens: Patients with split brains couldn't be studied with the usual method for limiting visual input to one hemisphere because they couldn't see things that took more than 0.1 second to see. In 1975, Zaidel made the Z lens to get rid of this problem. It's a contact lens that is clear on one side and opaque on the other. The Z lens only lets one side of the split-brain person's brain take in visual information while they look at something complicated, like the pages of a book. Since the lens moves with the eye, it only lets visual information into one side of the brain, no matter how the eye moves.

8. Importance of Synapse

Ans) It helps connect neurons to each other through synapses and sends information that controls how we act. If there is a problem with the way synapses work, it could cause a change in behaviour and lead to things like depression, schizophrenia, etc. Synapses make sure that nerve impulses that travel between neurons only go in one direction. But how do neurons make sure that impulses only go in one direction? Since transmitters are only found in the pre-synaptic membrane and receptor molecules are only found on the post-synaptic membrane. Since this is the case, impulses can only move in one direction. It helps filter out things that aren't needed or wanted. An action potential of +40mV is needed for an impulse to cross a synaptic cleft. If an impulse is weak, or less than +40mV, it won't be able to make enough neurotransmitters. This means that neurons won't be able to talk to each other.

PART B

Tutorial

2 x 15 = 30

Note: You need to complete the activities according to the given instructions. Please attempt the activities in a coherent and organized manner. The word limit for each activity is around 700 words. Each activity is of 15 marks. For the activities, you need to refer to the relevant offline or online resources. Some useful resources are also listed at the end of each unit of the self-learning material (BPCC 102).

1. Explain the role of neurotransmitters in the effect of black widow spider venom.

Ans) Neurotransmitter is a chemical that is found in synaptic vesicles and affects the next cell when it is released. Like its name says, it is inside a neuron and sends a message. Neurotransmitters are released from the ends of neurons when they fire. More than 100 different neurotransmitter chemicals have been found. There are three types of small-molecule neurotransmitters: amino acids, monoamines, and acetylcholine. In this group, there is a fourth group called "unusual neurotransmitters." The neuropeptides are a group of neurotransmitters with large molecules. Most of the time, neurotransmitters either stimulate or calm nerve cells. But a few neurotransmitters can make the brain excited in some situations and calm it down in others.

As excitatory neurotransmitters, acetylcholine (ACh), catecholamines, glutamate, histamine, serotonin, and some neuropeptides are some examples. The first neurotransmitter to be found was ACh. ACh is important for the way nerves and muscles work, how sleep works, learning, and remembering. It also makes the skeletal muscles contract, but it makes the heart muscles contract more slowly. Gamma-Aminobutyric Acid (GABA), glycine, and some peptides are examples of neurotransmitters that make nerve cells less active. Amine neurotransmitters are in charge of how we feel, how we move, etc. Dopamine, nor-epinephrine, epinephrine, melatonin, and serotonin are all monoamines. Both epinephrine and nor-epinephrine help the body move. The brain contains dopamine (DA). It helps the body stay in balance. When it isn't enough, it can cause tremors and overactive muscles, which can lead to Parkinsonism. If there is too much DA in the brain, it could lead to Schizophrenia. Dopamine (DA) can make a synapse more active or less active, depending on which synapse it is in. It plays a role in controlling mood, emotions, sleep, and hunger. The most common neurotransmitters that help make proteins are called amino acids. When glutamate kills certain neurons, any imbalance in the neurotransmitter GABA can also make people more likely to have a stroke. GABA is a big neurotransmitter that slows down nerve impulses.

Black widow spiders are notorious for their painful bites and lethal venom. The venom is potent enough to let these spiders and their close relative’s prey upon small reptiles and mammals that other arachnids wouldn't ever eat. This brings up the question of why widow spiders are so poisonous. And how did they get so dangerous in the first place? Dr. Jessica Garb of the University of Massachusetts, Lowell, and a group of researchers from the US and the UK have been trying to answer these questions by looking at the spider's genes, proteins, and venom to find out how it got to be so dangerous.

Latrotoxins are the most powerful neurotoxins in black widow venom. They get their name from the group of widow spiders called Latrodectus. The most dangerous of these latrotoxins is alpha-latrotoxin, which is a terrible chemical that takes over the nervous system's electrical and chemical signals to stop the body from talking to itself. "If you got bitten by a black widow," says Garb, "alpha-latrotoxin would travel to the pre-synaptic regions of your neurons: this is the juncture right between the synapse of one neuron and your muscle cells or another neuron, and it inserts itself into the membrane. All of the neurotransmitters are dumped out of the vesicles of the neuron. And that's really what's painful." In other words, alpha-latrotoxin makes nerve cells send out all of their chemical signals at once, which overwhelms the nervous system and causes a lot of pain.

In fact, neuroscientists, not spider biologists, have been studying alpha-latrotoxin for a long time as a way to learn how neurons work. But until recently, people thought that the latrotoxins were just a small group of proteins. Garb's research has shown that latrotoxins are a much bigger group than anyone thought. Even the common house spider has latrotoxins in its body. But don't worry, the common house spider is not usually considered dangerous to humans, even though it is related to the black widow. The difference in venom potency between the widow spiders and the house spider may largely be a matter of the production of toxins, but not the genetic ability to do so. "It's not just about how many of these latrotoxins there are," says Garb. "It's also about how they are expressed." Even though house spiders have the genes for multiple latrotoxins, they seem to make much less of them in their venom than black widows do.

References

a)     https://phys.org/news/2015-01-fast-evolution-black-widow-spider.html#:~:text=%22If%20you%20got%20bitten%20by%20a%20black%20widow%2C%22,the%20neuron%27s%20vesicles%20to%20dump%20out%20their%20neurotransmitters.

b)     Pons, T.P.,Garraghty, P.E., Ommaya, A.K., Kaas, J.H., Taub, E., & Mishkin, M. (1991). Massivecortical reorganization after sensory deafferentation in adult macaques. Science, 252, 1857-1860.

c)     Henry Gustav (2011). In Simply Psychology. Retrieved October 30, 2018, from https://www.simplypsychology.org/anterograde-amnesia.html

Note: Diagrams or illustrations maybe used in support of your answer. Write the answers in your own words. Please mention reference details of the articles/books, at the end of your write-up.

2. ‘Older adult brains can generate new cells.’ Is this a myth or a reality? Support your argument with case studies and evidence.

Ans) Using brain tissue from people who had died, researchers found that healthy older adults had the same ability as young adults to make new cells in the hippocampus area of the brain. According to the Alzheimer's Association, the hippocampus shrinks in most people with Alzheimer's disease. This is because the hippocampus helps control memory and emotions. The researchers said that the new findings show a "positive" picture of a healthy brain as it ages. In general, both young and old brains could make the same number of new neurons from cells in the hippocampus called "progenitor" cells. "It's good news that these cells are there in older adults' brains," said lead researcher Dr. Maura Boldrini, an associate professor at Columbia University in New York City.

That doesn't mean that a healthy 79-year-brain old's looks just like a healthy 29-year-brain. old for example, the researchers found that the brains of older adults had less "angiogenesis," or the growth of new blood vessels. So, Dr. Ezriel Kornel said, it's not clear if the new brain cells would have the same connections or work the same way as younger adult brain cells. He works at Weill Cornell Medical College in New York City as an assistant clinical professor of neurosurgery. But Kornel, who was not part of the study, said that the results are "hopeful." "Even as we age," he said, "we still have the capability of producing new neurons." Kornel also said that more research is needed to find out what factors can "stimulate" the brains of older people to make more neurons and connect them better.

Researchers in the lab have found that as rodents and non-human primates get older, their hippocampus loses the ability to make new cells. But different studies of the brain have led to different conclusions. Boldrini said that this was in part because researchers weren't always able to take into account any brain diseases a person might have had before they died. Her team looked at brain tissue from 28 people between 14 and 79 years old who had died suddenly but had been healthy before. None of them had dementia or any kind of neurological or mental disorder. Overall, the study found, older and younger brains had similar numbers of "intermediate" progenitor cells and "immature" neurons — signalling that older people had a similar capacity for generating new cells as young people.

Maura Boldrini, an Associate Professor of Neurobiology at Columbia University, and the study's lead author, said, "We found that both young and old people can make thousands of new neurons in the hippocampus from progenitor cells. We also found that the hippocampus was the same size at all ages." The hippocampus is a part of the brain that is important for learning, remembering, and processing emotions. Studies on non-human primates and rodents have shown that this part of the brain loses its ability to make new neurons as it ages. According to the new research, this is not true for people.

But having more neurons doesn't always mean that the brain is working better. The research also showed that older people's brains had fewer new blood vessels in this area, which the researchers think may affect the ability of these neurons to connect with each other. In an area of the hippocampus called the dentate gyrus, which is important for making memories, older people also had fewer neural stem cells, which are cells that can grow into full-fledged neurons.

Even though the brain bank was important to the study, the researchers also had to come up with very precise ways to measure the neurogenic potential of each hippocampus. The human hippocampus is much too big to be able to count and study all of the cells. Boldrini instead used mathematical models to estimate the number of different types of cells and the distribution of certain protein markers in the whole hippocampus by extrapolating from smaller sections. Boldrini said, "We found that both the youngest and the oldest people we looked at had thousands of neuroprogenitor cells and immature neurons." But the analysis showed that the older brains had less development of blood vessels and that the neurons in the older hippocampi had lower levels of proteins linked to plasticity, which is the process of making new connections between neurons.

Now, the researchers want to use stem-cell culture techniques and work with the Columbia University Stem Cell Initiative to find out how the changes they found in older brains work. Boldrini said, "With these techniques, we should be able to learn more about how new neurons grow and how that could be changed."

Reference

a)     https://www.cuimc.columbia.edu/news/even-old-brains-can-make-new-neurons-study-finds

b)     https://www.forbes.com/sites/victoriaforster/2018/04/05/older-people-can-still-produce-new-brain-cells-new-study-shows/?sh=70fe152ffa0b

c)     https://www.cbsnews.com/news/older-adults-can-grow-new-brain-cells-study-finds/

Note: Diagrams or illustrations maybe be used in support of your answer. Write the answers in your own words. Please mention reference details of the articles/books, at the end of your write-up.