What is Biological Psychology? - BulletPoints 0

• There are many questions about the relationship between physics and psychology, but also about our existence. Questions that cover this subject are ‘Why is there something instead of nothing?’ and ‘How did the universe develop?’.

• Biological Psychology is the study of the physiological, evolutionary, and developmental mechanisms of behaviour and experience. Biological psychology tries to find a link between the build-up of the brain and the behaviour an organism shows.

• Mental activity and certain types of brain activity are inseparable. This is called monism (the universe exists out of one type of material). The opposite of this is dualism (the brain exists out of one type of substance and matter is something else). Most scientists and neuroscientists support monism.

What are nerve cells and nerve impulses? - BulletPoints 1

• The nervous system consists of two kind of specialized cells. Neurons process and transmit information by electrical and chemical signalling; and glia maintain homeostasis, form myelin, provide support and protection for neurons.

• The myelin sheath is an insulating layer around the axon. It has intervals called the nodes of Ranvier. The myelin sheath accelerates the action potential. An afferent axon is an axon that imports information into a structure. An efferent axon is an axon that exports information from a structure. An interneuron is a neuron that connects afferent neurons and efferent neurons in neural pathways.

• The vertebrate brain does not replace damaged neural cells, as damaged cells in other parts of the body are being replaced. This is why we need a blood-brain barrier. The blood-brain barrier blocks out most viruses, bacteria and harmful chemicals.

• The membrane of a neuron is electrically loaded. This means that there is a difference in charge between within and outside of the membrane. In case of polarisation, there is a difference in electrical charge of the two locations. The resting potential is the difference in voltage in a resting neuron.

• Nerve impulse is an action potential. It is an event in which the electrical membrane potential of a cell rapidly rises and falls. Electrical gradient refers to the difference in electrical charge between the inside and outside of the cell. The inside of a cell in the phase of the resting potential is negatively charged (approximately 70mV). Concentration gradient is the difference in distribution of ions across the membrane. Molecules tend to move from areas of greater concentration to areas of lesser concentration. 

• The refractory period is the time after action potential when the cell resists further action potentials. This can be divided into the absolute refractory period (approximately 1 ms, when the action potential is impossible in any case) and the relative refractory period (extra 2-4 ms, when the new action potential requires greater stimulus).

What is the function of synapses? - BulletPoints 2

• A reflex is an involuntary and nearly instantaneous muscular movement in response to a stimulus. A reflex arc is a neural pathway from the sensory neuron to muscle response. The velocity of the conduction through a reflex arc is less than through an axon: this happens because of synapses, when the neurons communicate with each other.

• The nervous system has many complex patrons of connections that produce a great amount of different reactions. Synapses differ in their duration of produced effects. The effect of two synapses at the same time can be more than the doubled effect of each synapse apart, or less than the doubled effect.

• Researchers sometimes call neuropeptides neuromodulators, because they have certain characteristics that differ from other transmitters. Neuropeptides are released by cell bodies, dendrites and the sides of axons. Neuropeptides are synthesised in the cell body and then transported to other parts of the cell, while most other neurotransmitters are synthesised in the presynaptic terminal.

• Hormones are chemicals which are released by glands in a part of the body. These hormones are then transported through the blood stream to influence other cells. Neurotransmitters send a message to an intended receiver. Hormones send a message to every receiver on the same frequency. Neuropeptides are between these two: they are like hormones, but they are only transported throughout the brain and not to other parts of the body by blood. One of the most important glands for hormones is the pituitary gland.

What does the human vertebrate nervous system look like? - BulletPoints 3

• Each part of the nervous system has specialized functions. The cerebral cortex is the largest structure and elaborately processes sensory information and provides fine control of movement. How do the areas work together? Neuroanatomy is the anatomy of the nervous system.

• The peripheral nervous system consists of nerves which run through the whole body. The somatic nervous system is the part of the PNS, that transmits messages from the sense organs to the brain and also from the brain to the muscles. The autonomic nervous system is the part of the PNS which controls the heart, intestines, and other organs. Its cells are in the brain, in the spinal cord and along the spinal cord.

• The autonomic nervous system consists of the sympathetic (responsible for fight or flight reactions, located next to the centre of the spinal cord, work in synchrony, uses neurotransmitter norepinephrine) and parasympathetic (responsible for relaxation, located along the spinal cord close to each organ, work more independently, uses acetylcholine) nervous system.

• The cerebral cortex is the outer layer one sees when opening a skull. Its two hemispheres communicate through the corpus callosum and the anterior commissure. The cerebral cortex is organized similarly in mammals and occupies 13% of the brain in mammals.

• Brain damage can show which function a damaged part had. On lab rats, ablations (removal or a brain area) and lesions (damages by a stereotaxic instrument-electroshock) are performed to find out about functions of brain areas. After death of the animal the brain is cut in slices and analysed as to find out which area exactly had been damaged to verify the resulting outcomes. Sham lesions are performed to compare if the effect might not rather develop because of the operation than the electric lesion.

How did the human vertebrate nervous system develop throughout evolution? - BulletPoints 4

• Genes are units of heredity, which come in pairs. Chromosomes are strands of genes and they also occur in pairs (with the exception of a male mammal who has unpaired X and Y chromosomes). DNA (deoxyribonucleic acid) is a molecule which contains genetic instructions. Its function is to work as a model for the RNA synthesis (RNA is ribonucleic acid). DNA has four fundaments: adenine, guanine, cytosine and thymine. The order of these fundaments determines the order of the corresponding fundaments on a RNA-molecule.

• Sex chromosomes are named X and Y. Women have chromosomes XX and men have chromosomes XY. Genes that are carried by either sex chromosome are said to be sex linked. Sex-limited genes are genes which are present in both sexes but turned on in only one sex.

• This is a classic dilemma, but the conclusion is that every behaviour is caused by both heredity and environment! The implications of heredity and environment can be studied by comparing monozygotic (having shared one zygote and therefore identical) and dizygotic twins or adopted children.

• Evolution is the change over time in one or more inherited traits found in populations. Evolution looks at every change in the frequency of genes; it doesn’t matter if the genes are good or bad for the species in the long run. We wonder how certain species have developed and how species are developing at this time. In order to answer some of these questions, we can look at fossils.

• Evolutionary psychology examines psychological traits from a modern evolutionary perspective. It seeks to identify which human psychological traits are evolved adaptations. The emphasis of this field lies on giving an evolutionary and functional explanation. An interesting example that is studied in evolutionary psychology is altruism.

• Neural Darwinism means that synapses form randomly and the process of selection keeps some and rejects others. However, in evolution mutations are random events but when it comes to neurons neurotrophins guide axonal branches in the right direction.

• Brain damage occurs for several reasons: radiation, tumours, infections, toxic chemicals and degenerative conditions (e.g. Alzheimer's disease). In young people the most common reasons are closed head injury and blood clots in the veins of the brain.

How does visual perception work in the human brain? - BulletPoints 5

• The law of specific nerve energies, first proposed by Johannes Müller, states that the nature of perception is defined by the pathway over which the sensory information is carried. The origin of the sensation is not important.

• The pupil is the centre of the eye that allows light to enter the retina (inner surface of the eye). The cornea is a transparent part of the eye that covers the pupil. Together with the lens, the cornea refracts light.

• Overall vision consists of different aspects which are processed on different parts of cortex. All the optic nerves from both eyes meet at the optic chiasm, where approximately half of the axons lead to the other side of the brain.

• After the information reaches the lateral geniculate nucleus, it goes to primary visual cortex (also called area V1 or striate cortex) in the occipital cortex, which is important for conscious visual perception. A damage on V1 can lead to Blind sight: a condition in which the person responds to visual stimuli without consciously perceiving them.

• From the primary visual cortex, the information goes to secondary visual cortex (area V2) which conveys it further after processing it. The connections in the visual cortex are reciprocal. Different pathways within the cerebral cortex respond to different stimuli. The ventral streams are visual paths in the temporal cortex and their function is to identify and recognize objects. That path is also called the ‘what-path.’ The dorsal streams are visual paths in the parietal cortex which help the motor system find and use objects.

• In the inferior temporal cortex, it is rather complicated. That brain area takes care of the capacity of shape constancy (the ability to recognize the shape of an object even when its position or angle is changing). Visual agnosia is the inability to recognize or interpret objects in the visual field. It is caused by damage in the temporal cortex.

How do the other senses work? - BulletPoints 6

• Physically sound waves are compressions of air, water etc. The amplitude of a wave refers to its intensity. Loudness differs from amplitude. The frequency refers to the number of compressions per second (in hertz, Hz).

• One way for localizing sound is the difference in intensity between the ears. A sound shadow is created for sounds with a high frequency. Another way is the difference in time of arrival to the ears. A third way is phase difference between the ears. Low frequencies are localized by phase differences.

• The mechanical senses detect mechanical stimuli, e.g. touch, pain and balance. Also audition is a mechanical sense because the hair cells are a form of touch receptors.

• The vestibular system is a sensory system that provides the leading contribution about movement and sense of balance. The vestibular organ function is to detect the direction of tilt and the acceleration of the head.

• The somatosensory system refers to the movements and sensations of the body. It includes different senses including pressure, cold, warmth, pain, tickle, itch, discriminative touch and the position and movement of joints. Most of the receptors respond to different kinds of stimuli, e.g. to pain, warmth and cold.

• Taste buds contain taste receptors on the tongue (on the papillae), and actually they are modified skin cells. Taste receptors are also replaced rather often, like skin cells. Flavour refers to a combination of taste and smell. Both taste and smell axons are connected to the endopiriform cortex.

• Olfaction refers to the sense of smell. Membranes inside the nose respond to chemicals. Olfaction is important for most of the mammals, though it is not that important to humans anymore. However, it can be improved a lot with practice. Olfaction’s function is to detect eatable foods.

How can the human brain control body movement? - BulletPoints 7

• Muscle contractions produce movements. Three different kinds of muscles are distinguished: smooth muscles (inner organs, cells are long and thin), skeletal (striated) muscles (movements of the body, cells are striped and long), cardiac muscles (heart contractions, cells are connected to each other, and therefore they all contract at once).

• Proprioception is the sense of the relative position of neighbouring parts of the body. A proprioceptor is a receptor of this sense, they detect the tension and stretch of a muscle. When the muscle is stretched, a reflex will contract it as well.

• It is important to know how the brain controls movement. With this knowledge, you can help people with a damaged spinal cord or amputated limbs.

• Mirror neurons are neurons which activate while preparing for the action and while watching someone else performing. This is interesting, because mirror neurons can be important for understanding other people, identifying with them and learning from them.

• The cerebellum is an important area for balance and coordination. Damage to that area produces clumsiness, speaking problems, and inaccurate eye movements. The individual has problems with activities requiring timing and aiming. However, the cerebellum also responds to sensory stimulation without movements.

• The basal ganglia refer to a group of subcortical structures in the forebrain, such as the caudate nucleus, the putamen and the globus pallidus. Not everyone agrees which structures belong to the basal ganglia, but all scientists do agree that the three previous mentioned structures belong to the basal ganglia.

• Parkinson's disease is characterized by slow movements, shaking, rigidity, and difficulties in mental and physical activities. Many patients are also depressed and have impairments in memory and reasoning. In the age class +65 years approximately 1-2% have the disease. Researches have been curious about what determines the speed of movements. According to one hypothesis we balance between speed and accuracy. The symptoms of Parkinson's disease do not support this theory.

• Huntington's disease is a disease that affects muscle coordination and leads to cognitive decline and dementia. Usually it starts with tremors, which later start to affect walking, speech etc. Also psychological symptoms are present: depression, drug abuse, alcoholism, sexual problems, sleep disorders and anxiety. Sometimes psychological symptoms start before physiological and therefore the patient can be misdiagnosed. Usually Huntington's disease starts at the age 30-50. However, the disease is relatively rare.

What is sleep and why is it important for the human brain? - BulletPoints 8

• Endogenous circannual rhythm refers to innate rhythm for seasonal changes. Endogenous circadian rhythm refers to innate rhythm that lasts approximately a day. The rhythm can be altered moderately, but major abnormalities from the 24-hour norm do not work out.

• Sleep is a state that is produced actively by the brain and it is characterised by a decrease in brain activity and reaction to stimuli. Coma is a state of unconsciousness, in which a person cannot be awakened and fails to respond normally to any stimuli. It is caused by stroke, disease or damage in the head. A person in a vegetative state shows partial arousal instead of true awareness, without purposeful activities. A person in a minimally conscious state can have moderate purposeful activities. Both states can last for months or even years. Brain death is a condition in which all the brain activity ends.

• In the fifties, Jouvet accidentally discovered that there are periods of sleep in which the neck muscles are completely relaxed, but there is a lot of brain activity. This is called the paradoxical or REM-sleep. Stages 1-4 are also known as NREM sleep (non-REM). Dreams are usually seen during REM sleep, but also in other sleep stages. The sleeping process goes through stages 1-4, then back to 3 and 2 and then to REM. This cycle lasts about 90 minutes and is repeated again. REM sleep is most common in the morning.

• Most adults need approximately 8 hours of sleep per night. However, individual differences are huge. Insomnia refers to sleeping difficulties. Insomnia is caused by several reasons including noise, too hot or cold environment, pain, stress, (mental) disorders (depression and Parkinson’s disease), medications etc. Prolonged use of tranquilizers or alcohol can also cause insomnia, since the person is not able to fall asleep without those substances. Some cases of insomnia are related to changes in the circadian rhythm. People with a phase delayed rhythm have a hard time falling asleep and have trouble waking up. Someone with a phase advanced rhythm falls asleep easily, but wakes up early.

• There are different hypotheses on the function of dreaming. The activation-synthesis hypothesis states that the function of a dream is to give meaning to disturbed information. This hypothesis also states that when you dream about flying or falling, it’s because your body is in another position than during the day and your brain feels vestibular sensation and interprets this as flying or falling.

• The neurocognitive hypothesis states that dreaming is in fact the same as thinking, but under unusual circumstances. Dreams start with spontaneous brain activity, caused by recent memories. During sleep, the brain doesn’t receive a lot of sensory information. Therefore, certain brain areas have more room to create images. This is what shapes the dream.

How does the human body regulate temperature, thirst and hunger? - BulletPoints 9

• Homeostasis refers to biological processes that keep the body in a stable, constant condition. The body has a range in which values have to fit. Usually this range is so narrow that it is also called a set point. For example: blood levels of oxygen, glucose, sodium chloride, protein, fat and acidity need to be stable. Set points can have seasonal changes, for example many animals increase their body fat before cold winter. The term allostasis refers to this adaptive mechanism the body uses to change its set points. Negative feedback is a process that reduces alterations from the set point.

• The brain areas which are related to the control of body temperatures are in and around the hypothalamus. These areas are called preoptic area/anterior hypothalamus (or POA/AH) and they send output to the raphe nucleus in the hind brain that regulates physiological mechanisms. If these areas are cold, an animal acts like the environment is cold even though it was warm.

• The digestive system works to break the food down into a form that cells can use. The enzymes in the mouth start to break down carbohydrates, food goes to the oesophagus and stomach where the enzymes in the stomach start to break down proteins, then food goes to the small intestine where the enzymes break carbohydrates, proteins and fats.

• Stomach distention is the signal which stops us eating. The vagus nerve sends information about the stretching of the stomach walls and the splanchnic nerves sends information about nutrients. Also signals from the duodenum (part of small intestine) report about the satiety. Food in the duodenum causes secretion of cholecystokinin (CCK) which closes the sphincter muscle between the stomach and the duodenum and stimulates the vagus nerve.

• Nowadays, we have more food than we have ever had before and a lot of people are overweight. Therefore, much research is conducted into the question why some people become obese and others do not. People used to be afraid of not getting enough food, but nowadays we are afraid to be obese. Researchers wonder how it’s possible that two people, who have access to the same amount of food, differ in weight.

How can hormones influence sexual behaviour? - BulletPoints 10

• Organising effects during a sensitive period decide whether an embryo becomes male or female. The amount of testosterone determines the differentiation of external genitals and certain aspects of brain development. A high amount of testosterone will result in a male pattern; a low amount will result in a female pattern. Estradiol has a large effect on the internal genitals, but a small effect on the external genitals. Without testosterone in an early stage of development, an individual will become female, but without estradiol during the early sensitive stage, there will be no complete female development.

• In general, there are a lot of differences between the brains of men or women. Some brain areas are bigger in men, and others are bigger in women. The mechanisms that cause these differences, differ for different brain areas. Sex hormones also affect the hypothalamus, amygdala and some other brain areas. The hormones cause physiological and anatomic differences between sexes.

• Evolution theory states that some species will produce more offspring, which makes them exist longer. The second part of this theory is called sexual selection. This means that genes that make someone more attractive, have a bigger chance of reproducing. However, in some cases surviving is more important than attractiveness.

• The term sex refers to biological aspects of men or women, whereas gender is related to people’s ideas about sexes. Some people feel their sex is not consistent with their gender. Sex identity is how we sexually identify ourselves and how we call ourselves. The biological differences between men and women are called sex differences.

• The anterior commissure and the suprachiasmatic nucleus are bigger in homosexual men than in heterosexual men. It isn’t clear yet how these parts influence sexual orientation. Research doesn’t show if differences in brain anatomy lead to sexual orientation – or if sexual orientation leads to differences in brain anatomy.

What are the relationships between emotions, stress and health? - BulletPoints 11

• Emotion is a difficult concept to define as we can’t easily observe it. Emotion is usually shattered into four components: cognitions, feelings, actions and physical changes.

• Emotions have different functions. Fear is a sign that something is threatening us, anger helps us to attack and disgust tells us when to avoid something that might be harmful. Emotions can also be useful at the moment of quick decision.

• The aggressive behaviour of males is often dependent on testosterone. Men with more testosterone are also more prone to show aggressive behaviour and more violent crimes. These men show more violent behaviour. Testosterone influences emotional and cognitive responses on angry facial expressions. It reduces the ability to recognize facial expressions consciously, but it enhances the reactions in emotion-related parts of the brain. Among animals, most aggressive behaviours are due to males fighting for partners and females fighting for their offspring.

• A tendency for anxious feelings, avoidance, or approach depends on the situation. Genetic factors also play a role. The nucleus accumbens is an important brain area. The amygdala is a key player in the regulation of anxiety. The startle reflex (the response to loud noise) is used to measure fear or anxiety. The amygdala has cells which respond to rewards, punishments and surprises.

• A panic disorder is characterised by periods of fear that arise often and periods of faster breathing, heightened heartbeat, sweating and shivering that arise once in a while. It’s more common in women than in men and also more common in adolescents and young adults than in older people. Some abnormalities in the hypothalamus have been found, but not in the amygdala. A panic disorder is also associated with a decreased activity of GABA and increased levels of orexin (activity). Post-traumatic stress disorder (PTSD) is a psychological disorder. Not everyone who experiences a trauma, develops PTSD. Most victims have a smaller hippocampus than average. The amygdala seems to be essential for the extreme emotional impact that produces PTSD.

• The immune system fights against viruses, bacteria and other threats with the help of certain cells. The most important cells are the leukocytes, white blood cells. These are produced in the bone marrow. The system recognises strange material on unknown proteins in the body. These are called the antigens. This will result in the white blood cells attacking the unknown proteins. An autoimmune disease is a condition in which the immune system is too efficient and attacks the body’s own cells.

What is the biology of learning and memory? - BulletPoints 12

• Psychologists define memory and learning as separate concepts. Researchers that study learning, use different methods than researchers that study memory. However, you can’t separate memory and learning. You can’t learn anything without remembering, and you can’t remember something without learning.

• The working memory only saves information when someone uses this information. this is especially done in the prefrontal cortex. One hypothesis suggests that the working memory can save temporary information by enhanced levels of calcium, which enhances responses later on. Delayed response task is a commonly used procedure to test working memory. In these tests, someone has to react to a stimulus that he/she has heard or seen. Elderly people tend to have problems with working memory, maybe because of changes in the prefrontal cortex.

• Many parts of the cortex and subcortical structures contribute to memory. The amygdala is most important for learning fear. The parietal lobe is important for associations. The semantic memory is influenced by anterior and inferior parts of the temporal lobe. Parts of the prefrontal cortex are important for learning punishment and reward.

• Long-term potentiation (LTP) refers to the strengthening of response in some synapses because of an intense series of stimuli conducted toward a neuron. Some properties make LTP a plausible possibility for the molecular basis of learning and memory: specificity, cooperativity and associativity. Long-term depression (LTD) is the opposite process to LTP. It occurs at the same time: as one synapse strengthens, another weakens.

• Many mammals have the same brain structure, but the brains do differ a lot in size. Some research in animals show that animals with bigger brains are better at finding food and running. Humans have the most neurons in the brains. This could have a correlation to intelligence. However, it remains difficult to compare different kinds of mammals to each other, because the way of living is so different.

What is the biology of cognitive functions? - BulletPoints 13

• Most information is processed in the contralateral hemisphere. However, taste and smell are uncrossed and both hemispheres have control over the trunk and facial muscles. The corpus callosum is the place where two hemispheres exchange information. Other areas with similar functions are the anterior commissure, the hippocampal commissure and few other commissures. Lateralization refers to the fact that the hemispheres operate on different tasks.

• The left visual field (field that is visible all the time) projects onto the right half of the retina, which sends information to the right hemisphere. The opposite pattern is seen on the right visual field. The auditory system is a bit different, as each ear sends information to both sides of the brain.

• Language learning probably has an early sensitive period, even though there is no sharp cut-off age. When learning a new language, children become familiar with pronunciation and grammar quicker, but adults learn the vocabulary easier.

• Dyslexia is a specific reading impairment, when a person has otherwise proper academic skills and vision. Dyslexic people have some minor brain abnormalities, for example bilaterally symmetrical cerebral cortex. Reading problems differ from each other. One distinction is made between dysphonic dyslexics (problems in sounding out words) and dyseidetic dyslexics (failure to recognize the word as a whole). Many people with dyslexia have auditory problems and trouble detecting the temporal order of sounds, as well as problems with attention. It might be helpful for a dyslexic person to focus on just one word at a time.

• The mind-body problem asks what the relation is between mind and body. Two ways of thinking about this problem exist: dualism and the monism. Dualists think that mind and body are different substances that exist independently. Monism thinks that the universe consists of one substance.

• Inattentional blindness (change blindness) refers to the fact that we are conscious of only the things to which we direct our attention. The consciousness of a stimulus is linked to the amount and spread of brain activity. A conscious stimulus also induces precise synchrony of responses in several areas of the brain.

How can mental disorders be explained and defined biologically? - BulletPoints 14

• It seems like addiction is a paradox: you’re doing something that is actually really bad for you. When we talk about addiction, we often talk about alcohol or drugs. However, there are also other forms of addiction, like gambling, gaming and overeating.

• Most people take things in moderate amounts, while others develop a habit to take many addictive substances. Research with sibling pairs, with one of the siblings having an addiction and the other having no addiction, shows that siblings have the same abnormalities in their brain (in the grey matter, white matter and some brain areas are bigger or smaller than average). It thus seems that some aspects of behaviour and brains are present at the very beginning, regardless of developing an addiction or not.

• Major depression differs from normal sadness in that it is a prolonged condition. The symptoms are suicidal thoughts, concentration problems, lack of energy and pleasure, sleeping problems and feelings of helplessness. It is more a lack of happy feelings than just sadness. Depression is quite a common disorder, as 10% of people have it during the lifespan. It is more common in women than men. Most depressed people can name the event that triggered the condition. However, depression usually occurs in episodes and later episodes do not necessarily need a trigger.

• Schizophrenia is characterized by hallucinations, delusions, impairments in thinking and moving, and inappropriate emotional expressions. The symptoms vary between individuals to a great extent. Schizophrenia can manifest itself either as acute or chronic. Acute schizophrenia has a sudden onset and the probability of recovery is high. In chronic schizophrenia the onset is gradual and the possible recovery takes longer. The term schizophrenia refers to ‘split mind’, which denotes the differentiation between the emotional and intellectual side of experience.

• Schizophrenia has a genetic basis, at least to some degree, but no certain gene causes it. The closer a relative is with schizophrenia, the greater the risk to develop it. Monozygotic twins show about 50% concordance (agreement). Studies exploring the genes related to schizophrenia are controversial. One of the genes that seems to be more common among schizophrenics is DISC1 (disrupted in schizophrenia 1).

• The autism spectrum disorder contains people that differ in the severity of their difficulties. Therapists used the label Asperger syndrome for people with a mild form autism. The label autism spectrum disorder is used to indicate autism and what used to be called Asperger syndrome. The autism spectrum disorder is used to indicate different disorders that vary in their severity (relatively mild to really severe). Some people have small autistic behaviours, but these are not enough to get a diagnosis. Autism is more common in boys than in girls. It is common all over the world and researchers haven’t found proof that it’s related to one area, ethnicity or socio-economic status.