Biopsychology

The Nervous system (Read: Behave: The Biology of Humans at Our Best and Worst)

  • Sensory nervous – carry input messages from sense organs to brain and spinal cord
  • (Study Tip: senses to brain)
  • Motor neurons – carry output impulses from brain and spinal cord to the body’s muscles and organs
  • (Study Tip: motor as in running which requires muscle. Therefore, takes messages from brain to muscles through the spinal cord)
  • Interneurons – perform connective or associative functions within the nervous system
    • most in number
  • (Study Tip: Inter =in-between)
  • Glial cells do not send or receive nerve impulses but hold the neurons and their surroundings areas together.
  • (Study Tip: G for Glial, G for gluing. Holding neurons together)
  • The Nervous System is divided into two major parts
    • Peripheral Nervous System – all neural structure that lie outside the brain and spinal cord
    • Further divided into two parts
      • Somatic nervous system
      • Autonomic nervous system
    • Somatic nervous system – transmits messages from brain & spinal cord to and from voluntary controlled muscles.
    • Autonomic nervous system – Responsible for controlling body’s internal, involuntary (smooth) muscles and glands. 
      • Further divided into two categories:
        • Sympathetic nervous system
        • Parasympathetic nervous system
  • Sympathetic nervous system- works on the arousal function and acts as a total unit.
    • Responsible for ‘fight or flight’ response.
    • The response is seen with the following behaviour:
      • Increased sweating, 
      • pupil dilation, 
      • heartbeat increase,
      • breathing increases, 
      • lump digestion
  • Parasympathetic division affects specific organ(s) at a time. In opposition to the sympathetic division it slows down body processes to maintain equilibrium.
    • The responses are opposite to the ‘flight or fight response’.
  • (Study Tip: Periphery meaning everything away from brain and spinal cord)
  • (Study Tip: two parts, Somatic meaning body and related to voluntary body parts;
    Autonomic meaning automatic, therefore, involuntary parts. Further subdivided into Sympathetic and parasympathetic)
  • (Study Tip: Sympathetic is sympathetic to body and responds to stimuli by fight or flight. Parasympathetic is opposite and slows everything down similar to a slight crude form called paralysis; Remembering anyone will bring the meaning of the other to mind)
  • Body and Brain are in constant flux to attain Homeostasis i.e. state of internal balance
  • The Central Nervous System – contains the brain and spinal cord.
    • It connect most parts of the Peripheral Nervous System with the brain.
  • Spinal cord – is 16 to 18 inch long and 1 inch in diameter. 
    • It is protected by the vertebrae
    • Spinal reflexes are stimulus response sequences that can be triggered without the involvement of the brain. This reduces reaction time and helps in emergency situations. 
      • 31 pairs of spinal nerves
      • Arranged from top to bottom:
        • Cervical (8)
        • Thoracic (12)
        • Lumbar (5)
        • Sacral (5) 
        • Coccygeal (1)
  • (Study Tip: CT (as in ct scan)-VSCo (as in instagram camera)
  • 3 meninges protect it as well (arranged innermost-outermost)
    • Pia
    • Arachorid
    • Dura
  • (Study Tip: PADding)

Structure of the Brain (HIND-MID-FORE)

  • The Hindbrain – lowest and the primitive part of the brain; 
  • Consists of the areas of the brain stem and the cerebellum
  • Brain stem – supports vital life functions. Consists of the medulla and pons.
  • Medulla is responsible for: 
    • Heart rate and perspiration
    • Crossover point for sensory and motor nerves from and to right and left sides of the brain
  • Pons 
    • Above the medulla and is responsible for
      • Carrying nerve impulses between the higher and lower levels of nervous system
      • Sleep and respiration
  • Cerebellum
    • Looks like a mini brain
    • Wrinkled cortex of gray matter and is responsible for
      • coordinating muscular movement, 
      • learning and memory
    • Alcohol consumption diminishes coordination
    • Trivia: Cats have a highly functional cerebellum
  • (Study Tip: Hind brain = MPC-bellum)
  • The Midbrain
    • Located above the hindbrain
    • Consists of the reticular formation, tectum, the cerebral aqueduct, tegmentum, and the cerebral peduncles. 
    • Contains clusters of sensory and motor neurons
    • Responsible for:
      • Visual and auditory relay centres → forebrain
      • eye movements
    • Reticular formation
      • Finger shaped, deep within forebrain
      • Acts as a sentry, alerting higher centres and allowing or blocking incoming messages
      • Responsible for: Consciousness, sleep and attention
  • (Study Tip: mid brain has only reticular formation that important)
  • The Forebrain
    • The most advanced portion from an evolutionary standpoint
    • Consists of the Cerebrum
      • All parts such as Thalamus, Hypothalamus, Limbic System, Cerebral cortex, are located in the Cerebrum
    • Cerebrum
      • Wraps around the brain stem
      • Two large hemispheres (left and right)
    • Thalamus
      • Located above the midbrain
      • Part of the cerebral spheres
      • Switchboard function: sends sensory nerve impulse to appropriate areas
      • Visual, auditory and body senses (balance and equilibrium)
      • Schizophrenia patients have an abnormally functioning thalamus that relays information to parts that do not need that information.
    • Hypothalamus
      • Located at the base of the brain, 
        • below Thalamus
      • Responsible for:
        • Motivation & emotion, 
        • temperature regulation, 
        • sleeping, 
        • eating, 
        • drinking and aggression
        • Regulates endocrine and pituitary gland
      • James Olds found that hypothalamus has pleasure areas where dopamine works and is responsible for rewards and punishments
    • Limbic system
      • Located deep within the cerebral hemisphere
      • Responsible for:
        • Satisfying  urges that occur in the hypothalamus related to motivation and emotion
        • Inbred in memory as well
      • Two structures exist within the limbic system:
        • Hippocampus
          • Responsible for the formation and retrieval of memories
            • Damage can lead to severe impairment of recent memories
        • Amygdala
          • Also known as the fear centre
          • Organises motivation and emotional patterns related to aggression and fear
          • Reward and punishment centres for motivation sectors of limbic system
    • The Cerebral Cortex
      • Made up of gray (unmylenated) cells forming the outermost layer of the brain
      • 80% of brain tissue
      • It has fissures that are divided into four lobes based on sensory and motor function
        • The folds of wrinkled cortex looks like a canyon
        • Some division made by the fissures don’t involve sensory or motor function and are known as Association cortex
          • Responsible for mental processes of thought, memory and perception
      • Frontal lobe (planning and execution)
        • self-awareness, planning, initiative and responsibility and emotional experience
        • Prefrontal cortex 
          • Located behind forehead, 
          • Responsible for: 
            • executive functioning, 
            • goal setting, 
            • judgement, 
            • impulse control
        • Motor cortex
          • Responsible for more than 600 voluntary muscles in body
          • Located at the rear end of frontal lobe
          • Body parts are arranged upside down in the motor cortex
            • Information from legs is responded from the top portion of the frontal lobe
            • Information from the upper portions of the body is responded by the lower portion of the frontal lobe 
      • Parietal (temperature)
        • The sensory cortex
          • Receives inputs for heat, touch and cold
            • Balance and body movements
          • Located behind motor cortex, and in front of parietal lobe
          • Same upside down principle as motor cortex
      • Temporal lobe is responsible for hearing
      • Occipital is responsible for vision and sight 
    • Speech Comprehension and Production
      • Werwick’s area
        • located in the temporal lobe (left hemisphere)
        • Responsible for speech comprehension (written or spoken)
      • Broca’s area
        • located in the frontal lobe (left hemisphere) close to motor cortex 
        • Responsible for facial muscle movement and speech production
      • Damage to either leads to:
        • Agnosia – inability to recognise familiar objects
        • Aphasia – inability to comprehend and formulate language due to damage to specific brain regions   
    • Association cortex
      • mental function of perception, language and thought
        • responsible for superior cognitive ability
  • (Study Tip: Everything else is here!)
    • Brain lateralization
      • Refers to the relatively greater localization of functions in each hemisphere
        • Corpus callosum – connects left and right hemisphere
      • Left hemisphere
        • Responsible for speech production, comprehension, math/arithmetic ability, logical abilities, and positive emotions
        • Right portions of the body are controlled by the LH
      • Right hemisphere
        • spatial relations, face recognition, and negative emotions
        • Left portions of the body are controlled by the RH
  • (Study Tip: link one attribute of left brain and right brain to right and left handed people respectively. Consolidate that information)
    • Split Brain – Roger Sperry
      • When the corpus callosum is damaged and the hemisphere begin acting independently of one another
    • Brain Plasticity also known as neuronal plasticity – ability of the neurons to change in structure and function.
    • The production of new neurons in the nervous system is called Neurogenesis.
      • Neural stem cells – uncommitted cells that can mature into any neuron of a degenerative area

Neurotransmitters

  • Acetylcholine (Ach) – muscle activity and memory. Reduced when suffering from Alzheimer’s disease 
    • Affects areas of Pons and basal forebrain
  • (Study Tip: Ach as in ache, muscular ache, affects muscles)
    • Norepinephrine
      • excitatory and inhibitory, depending on site
      • neural control of learning, memory, wakefulness and eating
      • Depression, stress and panic disorders
  • (Study Tip: Neither/nor-ephinephrine – meaning both inhibitory and excitatory)
    • Serotonin
      • excitatory and inhibitory
      • mood, sleep, eating, arousal
      • Depression, sleeping-eating disorders, OCD
      • secretion – Ralphe nuclei
  • (Study Tip: nin/non: meaning both inhibitory and excitatory)
    • Dopamine
      • excitatory, 
      • movement, emotional arousal
      • Parkinson, depression and schizophrenia
  • (Study Tip: DopaMine is exciting; excitatory)
    • GABA
      • inhibitory, 
      • motor system
      • Huntington’s disease, loss of motor control and personality change
  • (Study Tip: GABAsounds boring. It’s definitely inhibitory)
    • Endorphin
      • Inhibitory
      • inhibits pain transmission
      • Insensitivity to pain, hypersensitivity, immune problems
  • (Study Tip: End-orphine is inhibitory)
    • Neuromodulators are messengers released from neurons in the central or peripheral nervous system to affect a group of neurons
      • They have a more generalized effect on synaptic transmission

Behavioural genetics and environment

  • Behaviour genetics – study how genetics and environment factors influence psychological characteristics
    • Degree of similarity of responses of genetically similar people gives an indication of the impact of genetics
  • Heritability
    • Heritability statistic estimates the extent to which the difference in specific phenotype within a group of people can be attributed to their differing genes.
  • Genetic basis of behaviour
    • Genotype – the specific genetic makeup of an individual
      • compared to a computer software
      • Genes present from birth
      • May or not may not manifest 
        • dependent upon other genes which hinder or help this gene activate
    • Phenotype – are the observable characteristics of the individual.
      • The genes that are present and are expressed, 
      • Difference between genotype and phenotype is that the genotype has all the genes but not necessary that all will be expressed
  • Major contributor of gene understanding
    • Gregor Mendel
  • Organic factors of genes affect characteristics. 
    • Nucleus of all cells constituted by chromosomes 
      • 22 identical pairs in humans called autosomes
    • Sex cells are called allosomes as the gene is different in shape, size and length compared to other chromosomes 
    • A chromosome is a double stranded, tightly coiled molecule of deoxyribonucleic acid (DNA).
    • All information of heredity are in four chemical bases:
      • Adenine
      • Cytosine
      • Thymine
      • Guanine
  •  (Study Tip: ACT-G)
    • Alleles are alternative characteristics that are developed due to alternative genes/mutation
    • Dominant genes will display characteristics
    • Recessive genes will not display characteristics unless two similar recessive genes are combined.
    • Polygenic transmissions occurs when many genes contribute to make one single dominant trait
  • Experience shapes behaviour in two ways:
    • Fixed action pattern
      • an unlearned automatic response triggered by a particular stimulus
    • Species adaptation
      • learning is not transferred by genes but through natural selection genetically based characteristics that enhance the ability of a species to adapt is transferred
  • Two types of  research studies to test genetics and heritability of behaviours
    • Family studies – Degree of similarity of behaviour of genetically similar relatives in specific traits to the person in question
    • Adoption studies – Degree of similarity of behaviour of adopted children with genetically similar (biological) parents and adoptive parents

Brain and other concepts

  • Intelligence
    • Identical twins reared together
      • correlation is high
    • Identical twins reared apart
      • correlation nearly as high
    • Fraternal twins
      • IQ of adopted children correlate similarly with both their biological parents and adoptive parents
      • (no single gene for intelligence)
      • Genetics/Heredity account for 50-70% change in intelligence
    • Siblings reared together have a high correlation in their IQ
    • Correlation of .32 between unrelated adopted children living together
    • Difference of home environment is more important in lower socio-economic conditions
      • Evidence: children in impoverished homes moving to better homes show increase in IQ by 10-12 points.
  • Schizophrenia: Studied by Seymour Ketty
    • Schizophrenia (12% similar genes)
    • Twin studies
      • compared trait similarities in identical and fraternal monozygotic twins
      • Trait similarity a.k.a. high concordance rates
      • High correlation in case of schizophrenia with family members
  • Personality (Reading: Personality Psychology)
    • Genetic differences account for .50 correlation between similar genotype individuals
    • Important finding was that family environment played very limited role in determining personality, except when extremes of neglect and abuse occur.
    • Similar results for twin and adoptive studies.
  • Gene-environment interaction
    • The environment cannot affect the genotype but only its expression and phenotype
    • Reaction range
      • Is the measure of how much the environment can affect genes
    • Intellectual growth depends on both factors i.e. genes and environment
    • Evocative influence
      • A child’s genetically influenced behaviour may evolve certain responses from others
      • Introvert/extrovert children
    • Gene experimentation
      • Knockout procedure
        • A particular function of a gene is removed
  • All vertebrates have a bilaterally symmetrical body plan
  • Anatomy of dissected in the following manner
    • Proximal – closer to the trunk
    • Distal – away from the trunk
    • Lateral – away from midline
    • Medial – closer to midline
    • Anterior – front side
    • Posterior – back side
  • Endocrine system – consists of numerous hormone secreting glands distributed throughout the body.
    • Messages to the body are distributed through hormones secreted via glands
    • Hormones are chemical messengers secreted into the bloodstream
  • Brain decides which impulse to send, between endocrine and nerve impulse, or both
  • Hormones affect us from prenatal stage
    • They affect aggressiveness, sex differences, immune system and so on
  • Immune system
    • foreign substance (antigens) are removed by antibodies
    • Stress, depression, negative thinking reduce immune functioning
    • Candence Pest suggested that the nervous, endocrine and immune system are related
  • Glands are organs in the body that secrete chemicals
    • Endocrine glands
      • secrete enzymes into the ‘bloodstream’ called hormones, usually from sympathetic division of ANS
      • Hormones affect behaviour and emotions through organs like heart, pancreas, sex organs.
    • Pituitary gland also known as Master gland
      • controls all other glands
      • located below hypothalamus
      • influences events related to pregnancy – production of milk, onset of labos, salt and water
  • Growth hormone
    • regulates and controls increase in size of body parts
  • Pineal gland
    • secretes melatonin
    • located nearer to the back of brain
    • regulates sleep wake cycle (Read: Why We Sleep)
  • Thyroid gland
    • secretes thyroxin
    • located inside neck
    • regulates metabolism
  • Pancreas
    •  secretes insulin and glucagon
      • low insulin = diabetes
      • high insulin = hypoglycaemia
    • located in torso
    • regulates blood sugar
  • Gonads
    • secretes androgens, oestrogen, progesterone, and testosterone
    • located in the ovaries (females) and testes (males)
    • regulates sexual behaviour along with the brain
  • Adrenal gland
    • on top of each kidney
    • Two types:
      • Adrenal medulla
        • secretes epinephrine and norepinephrine
        • regulates stress and sympathetic arousal
      • Adrenal cortex
        • secretes 30 different hormones called corticoids (steroids)
        • regulates salt intake, stress reaction, sex hormones
      • Cortisol
        • released under stress 
        • releases glucose into bloodstream
        • provides energy to body and brain by burning fatty acids from fat cells

Suggested Reading(s):

Why We Sleep

Behave: The Biology of Humans at Our Best and Worst

Sapiens: A Brief History of Humankind

Who We Are and How We Got Here: Ancient DNA and the new science of the human past

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