1/11/24

Biological psychology: branch of psychology concerned with the links between biology and behavior

Neural Communication

Neuron/nerve cell: basic building block of the nervous system and it is the basic unit of communication

• Dendrites: receive information from other cells

• Soma/cell body: maintains the health of the neuron

• Nucleus: maintenance of the neuron

• Axon: passes messages from the cell body to other neurons, muscles, or glands

• Myelin sheath: covers the axon of some neurons and helps speed neural communication

  • Multiple sclerosis (MS): The degeneration of the Myelin sheath resulting in a slowing down or interruption of communication to muscles and loss of muscle control

    • Characterized: loss of coordination, speech, visual disturbances, and muscular weakness

  • Nodes of Ranvier: gaps between the myelin sheath on axons

  • Glial: support cells that assist neurons by providing structural support, nutrition, removal of cell wastes, and manufacture Myelin, outnumber neurons 10:1

• Neurons communicate through an electrochemical process of communication

• Neurons fire an impulse when stimulated by pressure, heat, light, or chemical messages from adjacent neurons, the neural impulse is called the action potential

1. When a neuron is waiting for stimulation the neuron is said to be polarized or in the resting potential state. The resting potential occurs because the cell membrane is selectively permeable. In this state, there are positive ions outside and negative ions inside the axon.

2. When the neuron is stimulated the gates of the axon open causing the positive ions to pass through, this is the action potential: a brief electrical charge that travels down the neuron. Action potential causes depolarization in each segment of the axon.

3. Once it has reached the end the neuron enters the refractory period: when the neuron pumps the positively charged ions back outside. That electrical info is converted into chemical form called a neurotransmitter: chemical messengers that can cross the synapse: tiny fluid-filled gap between neurons that the action potential can not cross

• Axon terminals: hold the neurotransmitters until they are released

• Each neurotransmitter has its own unique shape, has to find a dendrite that can fit its shape, the neurotransmitters and receptor sites fit together like pieces of a puzzle

• An action potential is like a gun it will either fire or it won’t, it’s an all-or-none response, fires at 100% or 0%, if it is a stronger reaction it is because more neurons are firing or they fire more often

1/16/24

The individual neurons make decisions with the information they receive, and communicate through electrical signals, some are

• excitatory: pressing on an accelerator, if they are excitatory it continues communication

  • Like people that have to gossip

• inhibitory: like putting on the breaks, stopping the line of communication

  • Like people you know you can trust

In order for the action potential to occur the combined signals must exceed the stimulus threshold: the minimum level of stimulation needed to activate the next neuron

How Drugs alter neurotransmitters

some drugs work as

• Agonists: drug molecules that are similar enough to the neurotransmitter to mimic these effects

  • opiate drugs: oxycodone, heroin, fentanyl

• Antagonist: drug molecules that are similar enough to the neurotransmitter to occupy its receptor site and block its effect but not similar enough to stimulate the receptor

  • poisons and venom

The blood-brain barrier: enables the brain to fence out unwanted chemicals circulating in the blood and some chemicals don't have the right shape to slither through this barrier

• Can trick it to let some things through

  • The tremors of Parkinson’s disease result from the death of nerve cells that produce dopamine, giving a patient dopamine as a drug doesn't help because it can't get through the blood-brain barrier but L-dopa a raw material that the brain can convert to dopamine can sneak through which helps patients gain better muscular control

The Nervous System

Neurons communicate with other neurons through the nervous system, the nervous system has two divisions

• Central Nervous System: made up of brain and spinal cord

  • Studying the brain:

    • Lesion: destroying tissue in specific brain areas

    • Electroencephalogram (EEG): Amplified recording of the waves of electrical activity that sweep across the brain surface, the waves are measured by electrodes placed on the scalp

    • Computed Tomography Scan (CT/CAT scan): a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body

    • Positron emission tomography scan (PET scan):visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task

    • Magnetic Resonance Imaging (MRI): Uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue allowing us to see structures within the brain

• Peripheral Nervous System: everything else

  • Somatic/Skeletal NS: Contains all of the voluntary movements/functions

  • Autonomic NS: controls involuntary processes, internal organs

    • Sympathetic NS: arousal, fight or flight response

    • Parasympathetic NS: calming

• Nerves: neural cables containing many axons and these bundled axons which are a part of the peripheral nervous system that connects the central nervous system with our muscles, glands, and sense organs. Information travels within the nervous system through three types of neurons:

  • Sensory neurons: the neurons that carry incoming information from the sense receptors to the CNS

  • Interneurons: CNS neurons that internally communicate and intervene between the sensory inputs and the motor outputs

  • Motor neurons: the neurons that carry outgoing information from the CNS to the muscles and glands

• Reflexes: simple automatic inborn responses to sensory stimuli

  • Knee Jerk response and blinking

• Neural networks: interconnected neural cells that with experience can learn and as feedback strengthens or inhibits connections can produce certain results, enabling us to be able to do the variety of tasks we learn and progress through life, they grow as rapidly as stimulation allows

1/17/24

How the brain is divided

Hemisphere: half of the brain, each side seems to demonstrate specific differences

Right-brain thinkers: more creative thinkers that gather information by feelings and intuition, more visual, good with people, often daydream, often lose track of time, usually fun and witty, and spontaneous, many right brain people find it hard to follow verbal instructions, extroverted, energized by others

Left-brain thinkers: critical thinkers who collect information using logic and sense, have a daily task list, tend to be good at math and science, are more rational and logical, organized, follow directions, and don't let feelings get in the way, introverted, energized by themselves,

Corpus callosum: large bundle of neural fibers connecting the hemispheres and carrying messages between them

Split brain patients: condition in which the two hemispheres are isolated by cutting the connecting fibers mainly those of the corpus callosum

Have also had cases where a whole hemisphere is removed, due to seizures that make the patient unable to function

Divided into four lobes:

Cerebral cortex: convoluted area of interconnected neural cells that covers the cerebral hemispheres, it is the body's ultimate control and information processing center

• Frontal lobe: lies just behind the forehead, involved in speaking and muscle movements and in making plans, and judgement

  • tends to affect personality when injured

  • is this affecting me in some way, is it causing an emotional feeling

  • Motor Cortex/strip: located at the rear of the frontal cortex, controls voluntary movements

• Parietal lobes: at the top rear of the frontal lobe,

  • Sensory cortex/strip: front of the parietal lobe, registers and processes body sensations

• Occipital lobes: lying at the back of the head, including visual areas, detect what eyes are seeing and process what eyes are seeing.

• Temporal lobes: lying roughly above the ears, including auditory areas

In addition to these four lobes, there are association areas: areas of the cerebral cortex that are not involved in primary motor or sensory functions but are involved in higher-level mental functions such as learning, remembering, thinking, and speaking and enable us to make judgments and plan.

Language: the result of the intricate coordination of many brain areas, mostly controlled by left hemisphere

• Broca’s area: controlled by left frontal lobe and directs the muscle movements in speech

• Wernicke’s area: in the left temporal lobe, involved in language comprehension

  • Aphasia: impairment of language usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing understanding)

• Angular gyrus: involved in reading aloud, receives information from the visual area and re-codes it into the auditory form, from which Wernicke’s area derives its meaning, damage to this area leaves the person able to speak and understand but unable to read

Plasticity: the brain can repair itself and learn new functions, the younger a person is the greater the plasticity

Reticular formation: involved in waking us up/putting us to sleep/arousal

Pons: fine tune motor coordination

Cerebellum: involved in balance and coordination and movement

Corpus Callosum: bridges right and left hemispheres

Medulla: heartbeat and breathing

Cerebral Cortex: higher level learning

Thalamus: the relay station between senses and parts of the brain involved in processing sensation

Limbic System: amygdala, hypothalamus, hippocampus

amygdala: fear and rage center

Hypothalamus: included in hunger, regulating body temperature, thirst, emotions, reproduction

hippocampus: included in learning and memory

1/18/24

Endocrine System

glands that transmit information throughout the body via chemical messengers called hormones that are secreted into the bloodstream

slower chemical communication system whose effects are longer lasting

the nervous system and endocrine system are interlinked by the hypothalamus: a brain structure that controls the pituitary gland which controls the rest of the endocrine system

pituitary gland: located in the brain, regulates the activities of several other glands, it produces the growth hormone, it also produces prolactin: involved in production of milk in women (males have it but not sure of role), oxytocin: helps begin and continue labor stimulates the secretion of breast milk and is released by both males and females during orgasm,

pineal gland: located in brain, produces melatonin, which helps regulate the sleep-wake cycle, does so in the changes in the environment and light, so when it gets dark it will release melatonin, when the sun rises the production is decreased

thyroid glands: located in the neck, control the body’s metabolism rate: the way the body burns energy during exercise and at rest,

adrenal glands: located above the kidneys, they produce epinephrine (adrenaline) and norepinephrine (nor or non-adrenaline), which cause physical arousal in response to danger, fear, anger, stress, and other strong emotions, involved in the fight or flight response, it raises our blood pressure, increases blood sugar, which provides us with a surge of energy

pancreas: located behind stomach, regulates blood sugar and insulin levels and it’s involved in hunger

The sex hormones

• Females have ovaries that secrete estrogen and progesterone which regulate female development, reproduction, and influence sexual behavior

• Males have testis that secrete testosterone which regulates male sexual development, reproduction, and influences sexual behavior

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