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What percentage of body energy does the brain consume?
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How many pairs of Cranial nerves are there?
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What is the main function of DNA?
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What are the building blocks of DNA?
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How many types of nucleotide bases are found in DNA?
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Which part of the neural tube develops into the forebrain?
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What is an evidence that supports evolution?
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What percentage of their body weight is the brain in humans?
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How many groups of spinal nerves are there?
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What is the primary function of the superior colliculi?
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What is the term for the genetic makeup that is not physically visible?
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What is the function of DNA in the nucleus?
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What is the location of the lumbar and thoracic spinal levels where sympathetic nerves leave?
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What is the primary function of cranial nerves?
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Which of the following is a characteristic of motor cranial nerves in the autonomic nervous system?
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What is the function of the meninges?
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How many ventricles are present in the CNS?
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What is the primary function of the parametal cells in the neocortex?
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What is the characteristic of neurons in the dorsal horn of the grey matter?
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What is the benefit of the wrinkled structure of the cerebral cortex?
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What is the function of the hippocampus?
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What is the part of the brain that is responsible for arousal, sleep, attention, movement, muscle tone, and cardiac circulatory and respiratory reflexes?
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What is the function of the pons?
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What is the result of fertilization in terms of chromosome number?
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During meiosis, what happens to the chromosomes?
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What is the role of ribosomes in the process of translation?
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What prevents the flow of toxic substances from the blood to the brain?
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What direction does the term 'Anterior' refer to in the nervous system?
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What type of section is a 'midsagittal section' in the CNS?
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What is the function of oligodendrocytes in the CNS?
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What is the function of astrocytes in the CNS?
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How many groups of spinal nerves are there in the spinal cord?
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What is the function of the microtubules in neurons?
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What is the term for the genetic makeup that is not physically seen?
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What is the number of chromosomes found in humans?
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What is the basic building block of all living organisms?
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Study Notes
Introduction to Biopsychology
- Brain consumes 25% of body energy while making up only 2% of body weight
- Brain communicates via neurons using electrical and chemical signals, with infinite possible signal paths
- Neuroscience is the scientific study of the nervous system, including biopsychology, which focuses on how the brain generates behavior and cognitive functions
The Brain and Behavior
- Biopsychology is a rapidly growing field that combines psychology (study of behavior) and biology (study of biological processes)
- Dr. D.O. Hebb's work, "The Organization of Behaviour" (1949), was influential in integrating physiological and chemical processes with cognitive functions
Divisions of Biopsychology
- Physiological psychology
- Psychopharmacology
- Neuropsychology
- Psychophysiology
- Cognitive neuroscience
- Comparative psychology
- These divisions often overlap, suggesting that organisms have evolved from a common ancestor
Evolution and Behavior
- Natural selection drives evolution, where heritable traits that increase survival chances are more likely to be passed on
- Behaviors that increase reproductive success, such as finding food, defending young, and protecting oneself, are more likely to be selected
- Social dominance among male and female members of a species can lead to increased reproductive success
- Courtship displays can lead to reproductive success, and changes in courtship behavior can lead to reproductive barriers
Evolution of Human Brain
- Scientists study the evolution of absolute brain size, which was once thought to be directly related to intelligence
- The genetic code, stored in DNA, contains the instructions for protein production
- DNA is a polymer molecule made up of nucleotide bases, with four different types (adenine, thymine, guanine, and cytosine)
DNA Structure and Function
- DNA is a double-helix molecule with two intertwined strands of nucleotide bases
- The sequence of nucleotide bases constitutes the genetic code
- Non-gamete cells have 23 pairs of chromosomes, while gamete cells have 23 single chromosomes
- After fertilization, the number of chromosomes doubles
Genetic Expression
- Genetic code needs to be expressed for organisms to exhibit their traits
- Gene expression involves the synthesis of proteins, where the DNA code is used to make proteins
- Proteins are polymers made up of individual amino acid monomers
Nervous System Structure and Function
- The spinal cord has an H-shaped grey matter, surrounded by white matter
- Spinal nerves are connected to each side of the spinal cord and are divided into dorsal and ventral routes
- Dorsal routes are composed of sensory neurons, while ventral routes are composed of motor neurons
- The neural tube is an embryo part that develops into the nervous system, with three swellings that develop into four major divisions of the CNS: forebrain, midbrain, hindbrain, and spinal cord
Brain Structure and Function
- Across species, humans do not have the largest brain; larger organisms need a greater amount of neural tissue to control their larger bodies.
- The weight of the brain with respect to the weight of the entire body as a percentage is 2.3% for humans and 0.2% for elephants.
- The cerebrum is responsible for complex, higher-order cognitive and executive functions (learning, perception, motivation, decision-making), and its size increases at a greater rate over evolution than that of the brainstem.
Mendelian Genetics
- Charles Darwin did not understand what caused members within the same species to be different from each other or how genes were passed across generations from parent to child.
- Gregor Mendel studied dichotomous traits of seeds and discovered that one trait would be dominant, and one would be recessive.
- Mendel created a true-breeding line and cross-bred plants to observe the traits, finding that the dominant trait is observed ¾ of the time and the recessive trait is observed ¼ of the time.
- Mendel's work showed that what we see is the "phenotype" of the trait.
Brain Development and Environment
- In a study on maze-bright and maze-dull rats, the rats were bred over 21 generations, and the outcome showed that maze-bright offspring were better at the maze, and maze-dull offspring were worse at the maze.
- To control for effects, maze-bright/dull rats were reared with parents of the opposite skill than their biological parents, and the results showed that the rats still performed similarly to their biological parents.
- The study found that experience and environment do matter, as the maze-dull rats made more errors than the bright rats only if they were reared in an impoverished environment.
- The dull rats did equally well as the bright rats only if both groups were reared in enriched environments.
Nervous System
- Second-stage neurons have a shorter travel distance, which conserves energy and is involved in psychological relaxation.
- Cranial nerves travel from the brain and consist of 24 nerves, 12 of which leave the right side and 12 of which leave the left side.
- Cranial nerves bring in sensory information to the brain (sensory cranial nerves) or take out motor signals to move muscles in the head (motor nerves).
- Motor cranial nerves in the autonomic nervous system are only part of the parasympathetic nervous system.
Meninges and Ventricles
- Meninges protect the CNS and consist of dura, arachnoid, and pia mater, located inside the skull.
- The sub-arachnoid space between the arachnoid and pia mater has large blood vessels and cerebral spinal fluid.
- Ventricles are interconnected series of chambers, four in total, and provide support and cushioning to the brain.
- Ventricles are part of the blood-brain barrier and constrict or dilate blood vessels in the CNS.
Directionality in the Nervous System
- The nervous system has a 3-axis system of directionality, with anterior towards the nose, posterior towards the tail end, dorsal towards the surface of the back or top of the head, ventral towards the surface of the chest or bottom of the head, medial towards the midline of the spine, and lateral away from the midline of the spine.
- Proximal refers to structures close to the CNS, and distal refers to structures far from the CNS.
- The CNS can be sectioned in three planes: horizontal plane (transverse section), frontal plane (coronal section), and sagittal plane (midsagittal section).
Spinal Cord and Brain
- The spinal cord and brain have different groups of axons (nerves) that enter the spinal cord at multiple places.
- There are 5 groups of 31 spinal nerves.
Mesencephalon
- The mesencephalon is the midbrain, which consists of the dorsal tectum and the ventral tegmentum.
- The tectum has two pairs of swellings on the dorsal surface: the superior colliculi, involved in visual-motor function and directing orientation, and the inferior colliculi, involved in auditory function.
- The ventral tegmentum has the periaqueductal grey, which mediates the pain-reducing effects of opioids, and the red nucleus and substantia nigra, both involved in sensory-motor function.
Diencephalon
- The diencephalon consists of the thalamus and the hypothalamus.
- The thalamus is made of two lobes, one in each hemisphere, and is connected to each other by an intermediate mass.
- The thalamus has sensory relay nuclei, which receive information from sensory receptors and relay it to the appropriate sensory cortices, and non-sensory relay nuclei, which receive information from the cerebral cortex and relay it within the cerebral cortex.
- The hypothalamus is located below the anterior component of the thalamus and regulates motivated behaviors, such as eating, sleeping, and sex, by regulating the release of hormones from the pituitary gland.
Telencephalon
- The telencephalon consists of the cerebral cortex, which has four major lobes: the occipital lobe, involved in vision, the parietal lobe, involved in analyzing bodily sensations and perceptions of locations, the temporal lobe, involved in hearing, language, and certain types of memory, and the frontal lobe, involved in motor function, decision-making, and complex cognitive functions.
- The neocortex, which is 90% of the cerebral cortex, is a result of recent evolution and is responsible for higher-order cognitive functions.
Genetics and Genotype
- A person's genetic makeup that we don't physically see is their "genotype".
- 4 central ideas from Mendel's work:
- Each dichotomous trait is controlled by genes.
- Two genes (alleles) control each dichotomous trait.
- Heterozygous means the two alleles for a trait are different, while homozygous means they are identical.
- One gene is dominant, and the other is recessive.
Chromosomes
- A cell is the basic building block of life and contains the nucleus, which holds DNA (genetic material).
- DNA is coiled and packaged into chromosomes.
- Humans have 23 chromosomes, each with a pair having one of the two alleles in the same location.
- Cell division produces two identical cells from a single cell, with the same genetic material.
Nervous System
- The sympathetic nervous system stimulates, organizes, and mobilizes energy resources in threatening situations, and is involved in psychological arousal.
- The parasympathetic nervous system conserves energy and is involved in psychological relaxation.
- Cranial nerves bring in sensory information to the brain (sensory cranial nerves) or take out motor signals to move muscles in the head (motor nerves).
- Motor cranial nerves in the autonomic nervous system are only part of the parasympathetic nervous system.
Meninges
- Meninges protect the CNS.
- The three meninges (dura, arachnoid, and pia mater) are located inside the skull.
- The sub-arachnoid space contains large blood vessels and cerebral spinal fluid.
Ventricles and Cerebrospinal Fluid
- Ventricles are interconnected series of chambers (4 in total) that provide support and cushioning to the brain.
- The ventricles are unipolar with only one extension.
- Ventral routes contain motor neurons (efferent) that are part of the somatic and autonomic nervous system.
Neural Tube
- The neural tube is a fluid-filled tube that develops into the nervous system.
- It has three swellings that develop into four major divisions of the CNS: forebrain, midbrain, hindbrain, and spinal cord.
Brain Divisions
- Forebrain: telencephalon (cerebral hemispheres) and diencephalon.
- Midbrain: mesencephalon.
- Hindbrain: metencephalon (pons and cerebellum) and myelencephalon (medulla).
Myelencephalon and Metencephalon
- Myelencephalon: medulla, with tracts carrying info between brain and body, and a network of tracts (reticular formation) that stretch from the posterior end to the anterior end of the midbrain.
- Metencephalon: pons and cerebellum.
- Cerebellum: sensory-motor structure that helps with precise movements and adapting to changes in the environment.
Neocortex
- The neocortex has different types of cells, including parametal cells (multipolar neurons with a parameter shape) and stellate cells (shaped like stars, mainly interneurons).
- The neocortex has differences in layer thickness, cell body size, and density, and relative proportions of parameter and stellate cells.
- The neocortex has a columnar organization due to vertical connections across layers.
- The neocortex has a wrinkly structure with folds, increasing cortical area without increasing the size of the cranium.
Old Cortex Structure
- The hippocampus is located on the medial edge of the cerebral cortex, with three layers, and is involved in memory function.
- The hippocampus has a wrinkly structure with folds.
Research Approach to Biopsychology
- Involves humans and animals, where humans are participants and animals are subjects.
- The main advantage of using humans is the ability to use the human brain.
- Nonhuman subjects are used because they allow for experimental procedures that cannot be performed on humans, and their brains are similar to human brains.
Types of Experiments
- True experiments involve random assignment and allow for the study of cause and effect relationships.
- Non-experiments include quasi-experiments and case studies, which have low generalizability.
- Quasi-experiments do not have random assignment, and case studies focus on a single or few participants.
Research Goals
- Research can be pure (conducted out of curiosity) or applied (conducted for real-life application).
- Translational research combines pure and applied research.
Model of Biology of Behavior
- Biopsychology working model: behavior is a product of interaction between genes, unique experiences, and the individual's perception of their life situation.
- Genes are influenced by evolution and express traits that maximize survival.
- Unique life experiences modify the expression of genes.
- The way we behave in an environment is a result of the interaction between our unique neural makeup and our perception of the situation.
Darwin's Theory of Evolution
- Published in "The Origin of Species" in 1859.
- Three types of evidence support the theory:
- The evolution of fossils across progressively higher geological layers.
- Chromosome replication and meiosis.
- Genetic diversity in offspring.
Genetics
- Chromosome replication: DNA replication → cell division (mitosis) → two diploid cells with the same amount of genetic material as the parent cell.
- Meiosis: produces gametes, the sex cells, with half the amount of genetic material as the parent cell.
- Gamete fertilization: 23 single chromosomes from the egg cell + 23 single chromosomes from the sperm cell → non-gamete cell with 23 pairs of chromosomes (a zygote forms).
Cause of Genetic Diversity in Offspring
- Random allocation: after meiosis II, chromosomes need to align along the equator, and the side they align on is random, increasing the chances of producing a daughter cell with genetic diversity.
- Genetic recombination: during meiosis, chromosomes exchange genetic material, increasing the chances of producing a daughter cell that is different from the parent cell.
Epigenetics
- Epigenetics is the study of causes in differences in gene expression other than changes to the gene sequence of DNA.
- Life experiences can affect gene expression through:
- DNA methylation: attachment of a methyl group to the DNA nucleotide base, increasing or decreasing gene expression.
- Histone remodeling: changing the shape of histone proteins, which can increase or decrease gene expression.
The Central Nervous System (CNS)
- The blood-brain barrier prevents the flow of toxic substances from the blood to the brain.
- The barrier is composed of tightly packed cells that make up the walls of the blood vessels that supply the blood system.
Neurons and Glial Cells
- Neurons have a membrane with embedded proteins, dendrites, a cell body, axon, and synapse.
- Glial cells include:
- Oligodendrocytes (CNS only): myelinate axons of multiple neurons.
- Schwann cells (PNS only): myelinate a part of an axon of only one neuron.
- Microglial cells: respond to injury or disease.
- Astrocytes: largest glial cells, part of the blood-brain barrier, constrict or dilate blood vessels, and make contact with neurons.
Directionality in the Nervous System
- 3-axis system of directionality:
- Anterior → towards the nose, Posterior → towards the tail end.
- Dorsal → towards the surface of the back OR top of the head, Ventral → towards the surface of the chest OR bottom of the head.
- Medial → towards the midline of the spine, Lateral → away from the midline of the spine.
- Proximal → close to the CNS, Distal → far from the CNS.
- Sections of the CNS:
- Horizontal plane/transverse section.
- Frontal plane/coronal section.
- Sagittal plane → intersects the frontal section of the brain, right in the middle (midsagittal section).
Research Approach to Biopsychology
- Biopsychology research involves humans and animals, with humans being participants and animals being subjects.
- The main advantage of using humans is that we can study the human brain, while using animals allows for experimental procedures that cannot be performed on humans.
- Experiments in biopsychology involve true experiments or paired experiments, which require random assignment and study the effects of an independent variable on a dependent variable.
- Non-experiments include quasi-experiments and case studies, which cannot have random assignment and provide a more in-depth picture with low generalizability.
Model of Biology of Behaviour
- The biopsychology working model states that behaviour is a product of interaction between genes, unique experiences, and the individual's perception of their life situations.
- Genes are influenced by evolution and express traits that maximize our ability to survive, and are modified by unique life experiences.
- Behaviour is a result of the interaction between our unique neural makeup and our perception of the situation.
Darwin's Theory of Evolution
- Published in "The Origin of Species" in 1859, the theory of evolution is the single most influential theory in the biological sciences.
- Three types of evidence support the theory: fossils, brain size, and brain structure.
- Humans have a brain size of 2.3% of their body weight, compared to 0.2% for elephants.
Mendelian Genetics
- Charles Darwin did not understand how genes were passed across generations or what caused differences within species.
- Gregor Mendel studied dichotomous traits and discovered that one trait is dominant, while the other is recessive.
- Mendel's work led to four central ideas: each trait is controlled by genes, two genes (alleles) control each trait, one gene is dominant, and one allele is inherited from each parent.
Chromosomes
- A cell is the basic building block of life and contains the nucleus, which contains DNA.
- DNA is coiled and packaged into chromosomes, with humans having 23 chromosomes.
- Each chromosome has a pair with one allele in the same location that controls dichotomous traits.
- Cell division produces two identical cells with the same genetic material as the parent cell.
DNA
- DNA is a nucleic acid that contains the code for the production of proteins.
- DNA is a polymer molecule made up of nucleotide bases, with four different types: adenine, thymine, guanine, and cytosine.
- The sequence of these bases constitutes the genetic code.
Genetic Expression
- Genetic code needs to be expressed for organisms to exhibit their traits.
- Gene expression involves the synthesis of proteins, which are polymers made up of amino acids.
- The central dogma of molecular biology states that the code in DNA is used to make proteins.
Spinal Cord
- The spinal cord has an H-shaped grey matter made up of unmyelinated interneurons and cell bodies.
- White matter surrounds the grey matter, made up of myelinated axons.
- Spinal nerves are connected to each side of the spinal cord, entering on their respective sides.
- Each nerve is divided into two routes: dorsal and ventral routes.
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Description
Explore the basics of biopsychology, including the brain's energy consumption, communication methods, and the intersection of psychology and neuroscience. Learn how the brain generates behavior and cognitive functions.