Chemistry Connections

Episode #16  

Welcome to Chemistry Connections, my name is Saarim Rizavi and I am your host for episode #16 called The Chemistry Behind Bad Habits. Today I will be discussing everything there is to know behind the formation of bad habits. I’ll first be going over exactly what habits are and more specifically what a bad habit is, and I’ll also be giving a brief description into why bad habits are formed in the first place. Afterwards, I’ll dive deep into the actual science behind habit formation which consists of topics mainly from neuroscience and as a result, chemistry which is foundational for neuroscience. In this segment, I’ll also be discussing the involvement and function of different parts of the brain in habit formation. Finally, I’ll be sharing my own personal connection to negative habits and why this topic really interests me and why the field of neuroscience and neurobiology and neuropsychology interest me as a whole. Let’s get started!

Segment 1: Introduction to Habits & Habit Formation

There are many ways you can define habits but the generally agreed upon definition is that they are rituals and behaviors that are performed automatically, allowing us to perform activities without thinking about them. They are actions that you do without having to decide if you want to do them each time you commence the action. Oftentimes, you don’t even really realize that you are doing that particular action; it just kind of happens and you don’t really know or understand why. Let’s first understand the concept of good and bad habits because the title of this podcast is, the chemistry behind bad habits so what do I mean by bad habits? By bad habits, I mean habits that are harmful to your mental and/or physical health. The most common ones are for sure smoking, drugs, excessive viewing of your phone or other electronic devices, drinking alcohol often, and eating more than you’re supposed to. Even things like procrastination, drinking coffee, and swearing are considered bad habits. Let’s use the excessive viewing of your phone example. When many people wake up, the first thing they do is go on their phones and start browsing instagram, or youtube, or text messages and it’s kind of like a ritual that is done every morning. You just do it without really thinking about why you’re doing it and so it is a habit. It is a bad habit because viewing your phone a lot results in eye strain, possible neck pain, sleep problems, and I won’t get into this, but social media is known to affect mental health in negative ways. So, in general, how does something like this become a habit, especially if it is affecting you in a negative way? Most psychologists go to the habit loop to explain this and will say that this neurological loop underlies all habits. The loop consists of a cue, a routine, and a reward. A cue is basically anything that triggers the habit by reminding you of it or initiating it. Cues can be a location, a time of day, an emotional state, and more. The cue tells our brains to go into this automatic processing mode or this routine, the routine being the actual habit. The habit, the first several times it is done, is done consciously and you choose to do that action but over time as a result of the reward, it becomes automatic. It is known as a routine because whenever a cue triggers the habit, you start following this routine that your brain has developed. The series of actions that make up the routine is the same or very similar every time the habit is unconsciously put into action. The reward provides positive reinforcement for the desired behavior, making it more likely that you will produce that behavior in the future. Once your brain associates a behavior with a reward, you begin to develop a craving for that reward which can become an addiction.Your nervous system is continuously monitoring which actions satisfy your desires, even if they affect you in a harmful way over time. Many scientists also believe that you are most vulnerable to fall to bad habits during times of stress and negative emotions since you oftentimes don’t have the willpower to prevent such behaviors from forming and mainly because at those times when you often run out of mental energy, our prefrontal cortex disengages, which is the part of the brain that is used for higher level thinking, and so you slip into habits because they take less mental energy and activity. It should also be noted that a process called chunking is the root of habits, which is a process in which the brain converts a sequence of actions into an automatic routine and it is essentially a way that the brain saves effort. Habits enable our brain to work less and be more efficient since you don’t have to concentrate on every component of the routine. The disadvantage with chunking is that when you continue to chunk something, the routine becomes outcome independent and over time, the chunked actions are performed without the need for a positive reward and this is what really results in a hard to break habit. The science behind this process of chunking will also be explained in a bit.

This was an introduction into habit and habit formation and you guys should now have an understanding of what a bad habit is and how they generally form. Now, let’s get into the actual science behind habit formation which again, will include topics from neuroscience and chemistry.

Segment 2: The Chemistry Behind Habit Formation

So, let’s get into it. Habit formation involves learned associations between an event and a behavioral response. Before we develop an automatic habit, we begin with an actual goal-directed behavior that involves complex thinking. The goal of habit formation is essentially so that the brain is able to free up processing space so that the thinking requirement for the routine that makes up the habit is turned off so that now the brain is free and can process other pieces of information. Habits are advantageous as they decrease the mental activity needed for mundane tasks. So what happens in the brain is, while learning goal-directed associations, connections between the prefrontal cortex, which is the part of the brain responsible for higher level cognitive functions like thinking and planning, and the basal ganglia, which is the part of the brain that controls voluntary movements and emotional expressions, change their activity to reflect a more automatic association. A signal arises during the early learning process in the dorsolateral striatum region of the basal ganglia. This part of the brain is able to chunk the task-related events together so the whole sequence of tasks becomes one single task. Neurons related to the task fire at the beginning and end of the task and as a result, the entire task is represented as a single event (at the beginning of the learning process, the neurons in striata emit a continuous string of signals but as actions begin to consolidate into habitual movements, the neurons fire their signals only at the beginning and end of the action performed). With repetition of the task, the strength of the chunked representation increases.

This was obviously a little confusing but a simple way to think about it is this: New neural pathways are formed when you repeat a behavior and the more a brain circuit fires, the easier it becomes for our brain to do whatever that circuit controls. As a result, information would then flow in a new, different way. Neural pathways are made of neurons connected by dendrites and dendrites increase with frequency when a behavior is performed. Neurons communicate through a process called neuronal firing, which is where the chemistry aspect can now come in. Besides containing all the normal components of a cell like a nucleus and organelles, and such, neurons also contain unique structures for receiving and sending electrical signals that make neural communication and signaling possible. Like other cells, neurons each have a cell body or soma that contains a nucleus, smooth and rough endoplasmic reticulum, a golgi apparatus, mitochondria, and other cellular components. Neurons also have dendrites, which are branch-like structures extending away from the cell body, and their job is to receive messages from other neurons and allow those messages to travel to the cell body. Neurons also contain tube-like structures called axons. These carry electrical impulses from the cell body or from another cell’s dendrites to the structures at the opposite end of the neuron, known as an axon terminal, which can then pass the impulse to another neuron. Neurons also contain synapses which are chemical junctions between the axon terminals of one neuron and the dendrites of another. It is a space between two neurons where they can pass messages to communicate. Neurons exist in a fluid environment - they are surrounded by extracellular fluid and contain intracellular fluid. The neuronal membrane keeps these two fluids separate which is important because the electrical signal that passes through the neuron develops as a result of these intracellular and extracellular fluids being electrically different. This difference in charge across the membrane, called the membrane potential, provides energy for the signal. The electrical charge of the fluids is possible due to the ions potassium and sodium dissolved in the fluid, which are known as electrolytes (they give the fluids the ability to conduct electricity since these dissociated ions freely move in the solution, allowing a charge to flow through the solution). A change or shift in this charge across the cell is very significant in cell communication). The semi permeable nature of the neuronal membrane somewhat restricts the movement of these charged molecules, and as a result, some of the charged particles tend to become more concentrated either inside or outside the cell. Between signals, the neuron’s membrane potential is in a state of readiness known as the resting potential. In this state, sodium and potassium ions (ions are just atoms that have lost or gained an electron and so they are now positively or negatively charged) are lined up on either side of the cell membrane, ready to rush across the membrane when the neuron goes active and the membrane opens its gates (ions in high concentration ready to go to low concentration areas and positive ions ready to move to areas with negative charge due to coulombic attractions. A coulombic attraction is simply an attraction that occurs between oppositely charged particles). A sodium-potassium pump allows this movement of ions across the membrane. The sodium potassium pump is an enzyme that transports sodium and potassium ions across the cell membrane against their concentration gradients in a ratio of 3 sodium ions out for every 2 potassium ions in. In order for it to function, the pump alternates between 2 major conformations: enzyme 1 and enzyme 2. In the enzyme 1 conformation, the metal binding sites have high affinity for metal cations (meaning that the metal binding sites bind to metal cations more easily) while in the enzyme 2 conformation, the metal binding sites have a lower affinity for metal ions, meaning they are less likely to bind with them. In the resting state, sodium ions are at a higher concentration outside the cell so they will tend to move into the cell while potassium ions are more concentrated inside the cell and so will move out of the cell. The inside of the cell is slightly more negatively charged compared to the outside of the cell in the resting state and so this also causes sodium to move into the cell due to Coulomb's law and the attraction of Na+ ions to the negative ionic charge inside the cell. From this resting potential state, the neuron receives a signal at the dendrites, in the form of a chemical messenger known as a neurotransmitter which binds to a chemical receptor on the dendrite. Neurotransmitters bind to receptors via intramolecular or intermolecular forces including ionic bonds (bonds that result from the electrostatic attraction between oppositely charged ions), hydrogen bonds (intermolecular force which occurs between 2 molecules where in one of the molecules, a hydrogen is bonded to a nitrogen, oxygen, or fluorine atom and the 2nd molecule contains a net dipole with an oxygen, nitrogen, or fluorine. The hydrogen of that first molecule is attracted to the partially negative O, N or F, of the second molecule), dipole-dipole forces (attractive forces that exist between polar molecules), and even london dispersion forces (temporary attractive force that results when the electron in 2 adjacent atoms occupy position that make the atoms form temporary dipoles. By dipoles, I mean partially positive and partially negative poles of the atom). Generally, neurotransmitters are molecules made up of covalent bonds and so their partially positive poles or partially negative poles are attracted to the charge of the receptor protein. So as a result of this binding, small pores open on the neuronal membrane, allowing sodium ions to move into the cell propelled by charge differences (clear instance of Coulomb's law in action) but also concentration differences. This then causes the internal charge of the cell to become more positive (since sodium ions are cations which are ions with a positive charge) which is a process known as depolarization - the charge reaches a certain level called the threshold of excitation and then the neuron becomes active and the action potential begins. An action potential is essentially a rapid change in polarity that moves along the nerve fiber from neuron to neuron as the internal charge of the cell changes from partially negative to partially positive. Many additional pores open, causing a massive influx of sodium ions (cations) and a huge positive spike in the membrane potential, known as the peak action potential. At this peak, the sodium gates close and the potassium gates open and potassium ions leave the cell. This ultimately results in the neuron’s membrane returning to its resting state. This is known as repolarization, which is another change in polarity which results in the restoration of a negative membrane potential of the neuron, meaning the inside of the neuron is partially negative inside. The action potential is an electrical signal that moves from the cell body down the axon to the axon terminals. The action potential is propagated at its full strength at every point along the axon due to the action potential being an all-or-none phenomenon. So, when this action potential arrives at the terminal button, the synaptic vesicles release their neurotransmitters into the synaptic cleft, which is a space that separates two neurons. The neurotransmitters travel across the synapse and bind to receptors of the dendrites of the adjacent neurons, and the process repeats itself in the new neuron and this means that cellular communication between neurons has been achieved. It is pretty clear that chemistry has a huge role to play in cell communication and therefore, habit formation, because it is all a result of the difference in charges and attractions across cell membranes.

So that’s how messages are transmitted from neurons and how brain cells communicate. When they communicate frequently, the connection between them strengthens and the messages get transmitted faster as they travel the same pathway over and over again until these behaviors become automatic and at this point, the prefrontal cortex isn’t even being engaged any longer. The capacity of our basal ganglia enables us to perform complex behaviors without even being mentally aware of them.

Initially when you adopt a new behavior, you engage your prefrontal cortex because you aren’t accustomed to the action yet; you need to think about each action in the routine. When something becomes a habit, you no longer think about each individual action since they are controlled by other parts of the brain like the DSL in the striatum as mentioned before which are involved with habitual and automatic behaviors. The striatum is known to release chemicals in the form of neurotransmitters that inhibit the complex thinking part of the brain. Neurons in the brain fire and give chemical rewards and once a habit and reward are tied together in the brain, reward neurons start firing before the behavior is done which results in craving.

Segment 3: Personal Connections

I am a very easily distracted individual and habits such as fingernail biting/picking, or nose picking, or any other so-called “gross” habit is a huge distraction for me but it doesn’t seem to be for most others. My brother has been a fingernail biter/picker his whole life and no matter how much I berate him or tell him to stop, he doesn’t. I never truly understood how people developed such habits but I still found it interesting how such individuals don’t even realize that they do it. Other members of my family and many individuals I know seem to have such habits and I just found it disgusting and annoying and so part of the reason why I picked this topic is to better understand such habits so I myself can just be better educated on the topic since it really isn’t their fault. It’s similar to why millions of people wake up and automatically turn to their smartphones or why 70% of all Americans wake up and go brush their teeth automatically. It’s all due to complex neural patterns in our brains and it can be frustrating because you may not know why you feel inclined to check your phone whenever you see a notification apparent, but it’s the genius of neuromarketing at play here. I have always been curious about the inner workings of our brain as well as it’s impact on cognition and overall function. I actually plan on studying neuroscience and neurology in the future because it is just something that I have an interest in for one, and because several close members of my family have neurological disorders and as a result, they also experienced mental health issues later in life due to having trouble coping with such conditions. Since I find the development of bad habits intriguing and since I already had an interest in neuroscience and mental health, I thought that it would be a pretty cool idea to connect the two by discussing the neuroscience of bad habits which includes topics from chemistry.

So, what is the importance of this topic? First of all, every person in the world has habits that control their lives, from our daily routine to the rate of our success. It’s pretty scary how much of our lives are controlled by habits, from waking up to looking at our phones, to then brushing our teeth and taking a shower, to having a cup of coffee, to chewing on the tip of your pen while thinking through a problem, to maybe shopping later in the day, and on and on. Your entire routine is controlled by habits, actions that are done automatically without you really having to think about them which enables your brain to