Chapter 2: Biology of Mind

Neural & Hormonal System

• Gall (German physician)

  • Phrenology- studying bumps on the skull could reveal a person's mental abilities and their traits

  • Different parts of the brain control different things

  • Biological psychologist- scientific study of the links between biological and psychological process

    • Behavioral neuroscientist

  • Bio psychologists gave us

    • Brain is wired by experiences

    • Nerve cells conduct electricity and communicate with one another sending chemical messages

    • Specific brain systems serves specific function

    • Use info given to use to construct of our experiences

      • Sounds

      • Sight

      • Memories

      • Passion

    • Systems have subsystems turn into smaller subsystems

    • Biopsychosocial system - we as humans is this system

Power of Plasticity

• Brain formed by experience and genes

  • Constantly changing

  • Plasticity- ability to change, especially during childhood, through the use of reorganizing ager damage or by building new pathways based on experiences

Neural Communication

• Human & animal operate the same

Neurons

• Nerve cell, building blocks of the nervous system

  • Contain a cell body (Soma), Dendrite, Axon

    • Cell body

      • Contains the nucleus

        • If cell body dies the rest of the neuron goes with it

Like a snake

• Dendrite- receive and integrate info passes info through the body to the axon

  • Listener

  • Short

  • Axon- takes the message and gives it the other neurons

    • Speaker

    • Long

    • Covered in a myelin sheath

      • Fatty tissue that can speed up their impulses

  • Glial cells

    • Cells in the nervous system that help to protect neuron

      • Like a bodyguard or a nurse

    • More complex brain the increase amount of glia

Neural Impulses (action potential)

• Neurons transmit messages when stimulated through a sources

  • Other neurons

  • Or our senses

  • Message sent through firing an impulse

    • Action potential

  • Action potential- neural impulses, electrical charges that travel down an axon

  • Neuron generate impulses through chemical events

    • Ions are exchanged

      

  • Axons outsides are positive the inside is negative

    • Axons surface is selectively permeable

      • Changes when a neuron fires

        • Axon opens and positive ions flow through and you get depolarization

        • Inflow of positive ions is the action potential

  • Neural signals are excitatory or inhibitory

    • Pushing on the gas (excitatory - excited)

    • Pushing on the brakes (inhibitory- hibernate)

  • Excitatory signal pushes past the threshold of inhibitory signal → trigger an action potential that travels to the respective place it goes

    • Threshold- the level of stimulation required to trigger neural impulse

  • Neurons get a short break called refractory period

    • Brief resting pause that occurs after neuron is fired

      • Action potential can’t be fired until axon gets back to resting state

  • If there is increase of stimulation above threshold → no intensity increase of the action potential

  • All or none response- neurons reaction of firing full strength or not firing

How Neurons communicate

• Synapse- the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

  • Tiny gap between neurons - synaptic gap

  • Neurotransmitters allow for communication between neurons

    • Chemical messenger that cross the synaptic gaps

      • Travel across the synapse and bind to the receptors sites

        

      • Excess transmitters are broken down or reabsorbed by the sending neuron (reuptake)

Neurotransmitters influence on us

• Influence our motion & emotions

  

  • Types of neurotransmitters

    • Dopamine

      • Influence

      • movement, learning, emotions

    • Serotonin

      • Affects mood, hunger

    • Endorphins

      • Influence perception of pain or pleasure

  • Body makes natural opiates

Drugs & chemicals effects on neurotransmitters

• Drugs like heroin can stop the production of natural opiates

  • Withdraw from the drug → deprivation of any form of opiates → discomfort

  • Drugs & chemicals affect brain chemistry

    • Set off other put down neural firing

    • Agonist molecules- increases a neurotransmitters action

      • Can increase production or release of neurotransmitters

      • Block reuptake

    • Antagonists molecules - inhibits / blocks neurotransmitters actions

      • Can occupy receptor sites

Nervous system

• Body's speedy, electrochemical communication network consisting of all the nerve cells of the peripheral and central nervous system

  • Takes in info from the world & body’s tissues

    • Makes decisions

    • Send back info & orders to the body’s tissues

  • Brain & Spinal cord - Central nervous system

    • Body’s decision maker

  • Peripheral nervous system - sensory & motor neurons that connect the CNS to the rest of the body

    • Gathers info for transmitting

  • Nerves - bundled axons that form neural cables connection the CNS to muscles, glands, and sense organs

    • Electrical cables

  • Three types of neurons

    • Sensory

      • Carry messages from the body’s tissues & sensory receptors to the brain & spinal cord

    • Motor

      • Carry info from the brain & spinal cord to the muscles & glands

    • Interneurons

      • Neurons within the brain & spinal cord, communicate internally & process info between sensory inputs & motor outputs

The peripheral nervous system

• Somatic & autonomic

  • Somatic nervous system - division of the peripheral nervous system that controls the skeletal nervous system

    • Report to the brain on our skeletal system

  • Autonomic nervous system - controls the glands & muscles of the internal organs

    • Sympathetic nervous system - arouses the body, using its energy

      • Expends & arouses energy

        • When challenged w/ something SNS accelerate heartbeat

    • Parasympathetic nervous system - calms the body

      • Converse energy - help to calm you

Central nervous system

• Brain enables our humanity

  • Thinking

  • Feeling

  • Neurons work in groups called neural networks

    • Neurons that fire together wire together

  • Spinal cord

    • Two way information chain connects to the PNS (peripheral nervous system)

  • Neural pathways govern our reflexes - response to stimuli

  • Spinal reflex pathway

    

    • Made up one sensory neuron and one motor neuron

      • Communicate through an interneuron

  • Different neural circuits do different things

    • One enables pain reflex

      • Touch a flame → neural activity travels by sensory neurons to interneurons in spinal cord → activate motor neurons → hand jerking away from the flame before brain receives and responds to the info

The endocrine system

• Body chemical communication system - slower system

  • Glands that secrete hormones into the bloodstream

  • Hormones - chemical messengers that are created by endocrine glands

    

Endocrine system & Nervous system

• Both produce molecules that act on receptors elsewhere

  • Endocrine message are slower and take longer

    • Have longer lasting affect

      • Lasting anger even after the cause of the anger is resolved

  • Nervous system are faster in sending messages

  • Body has more than one type of gland

    • Adrenal Glands - glands that sit above the kidney and secret epinephrine and norepinephrine arouse the body in times of stress

      • Increase heart rate, blood pressure, blood sugar

      • Provide energy

    • Pituitary gland - under influence of the hypothalamus, regulates growth and controls the other glands

      • The ruler of other glands

      • Most influential

Tools of Discover

• Scientist study the brains activity

  • Damage to one side of the brain can cause numbness or paralysis

  • Body’s right side is wired to the left side of the brain and vise-versa

  • Damage to the back of the brain

    • Blurry vision

  • Damage to left-front

    • Speech difficulties

  • Scientist can lesion tiny clusters of normal or detective brain cells

    • Lesion - tissues deconstruction, brain lesion is a natural or experimental caused destruction of brain tissue

Types of neural measures

• Electroencephalogram - amplified recording of the waves of electrical activity sweeping across the brain’s surface - measure by electrodes placed on the scalp

  • Listening to the hums like a car engine

  • Magnetoencephalography (MEG) - brain-imaging technique that measure magnetic field from the brain’s natural electrical activity

    • Understand how certain task influence brain activity

  • PET (positron emission tomography) scan - visual display of the brain’s activity that detects where a radioactive form of glucose goes while the brain perform a task

  • MRI (magnetic resonance imaging) - uses magnetic fields & radio waves to produce computer-generate images of soft tissue

    • Show brain anatomy

  • fMRI (functional MRI) - reveals blood flow and brain activity by comparing successive MRI scans

    • Show brains function as well as structure

Older brain Structures

• Amount of capabilities stem from ones brain structure

  • Sharks - have basic survival skills

    • Less complex brain

  • Mice - have emotions and greater memory

    • More complex brain

Brain stem

• Oldest and innermost region

  

  • Responsible for automatic survival functions

  • Medulla is the base of the brain stem

    • Controls heartbeats and breathing

  • Pons - coordinate movements and controls sleep

  • Thalamus - attached to the top of the brainstem

The Thalamus

• Sits atop the brain stem

  • Egg-shaped structure acts as the brain's sensory control center

  • Receives info from all the sense except smell and brings it higher into the brain

    • Can receive brain messages → directs to the medulla and then to cerebellum

Reticular Formation

• Inside the brain brain - between your ears

  • Network that extends from the spinal cord up to the thalamus

  • Control arousal, filters incoming stimuli, relay important info to other brain areas as well as sleep

Cerebellum

• The little brain at the rear of the brainstem

  • Processing sensory input, coordinate movement output & balance, enable nonverbal and memory

  • Injury to the cerebellum → difficulty walking, balance issues, shaky hands

Limbic system

• Neural system comprised of the amygdala, hypothalamus, and hippocampus

  • Located below the cerebral hemisphere

    • Associated with emotions and drives

The amygdala

• Linked to aggression and fear

  • Emotions

  • Those with amygdala lesions → reduced arousal to fear & anger

The Hypothalamus

• Small structure

  • Directs several maintenance activities

    • Eating, drinking, sexual behavior

    • Maintain homeostasis

  • Helps govern the endocrine system through the pituitary gland

    • Linked to emotion & reward

The Hippocampus

• Seahorse shaped structure

  • Processes conscious, explicit memories, and decreases in size & function as we grow

    • If ever concussed → poor memory

Cerebral Cortex

• Body’s ultimate control and information-processing center

  • The bigger organism you are the bigger cerebral cortex you have

  • Thin surface layer of interconnected neural cells

  • Makes us distinguishable from less complex animals

Structure of the cortex

• Each hemisphere’s cortex have four lobes separated by fissures

  • Frontal lobe

    • Involved with speaking & movement, making plans & judgment

  • Parietal lobe

    • Receives sensory input for touch & body position

      

  • Occipital lobe

    • Receive information from the visual fields

  • Temporal lobe

    • Receive information primarily from the opposite ear

Motor functions

• Motor cortex - area at the rear of the frontal lobe that controls voluntary movement

Mapping the motor cortex

• Your right side of the brain control the left side of your body

  • Your left side of the brain controls the right side of your body

  • Amount of cortex devoted to a body part in the frontal lobe or the parietal lobe is proportioned to body size

    • Devoted to areas requiring more precise control

Sensory Functions

• Somatosensory cortex - area at the front of the parietal lobes that registers & processes body touch and movement sensations

  • More sensitive the body region → larger the somatosensory cortex area devoted to that region

    • Lips

  • Information you see goes to the visual cortex in the occipital lobe

    • Visual info travels from the occipital lobe to other areas that specialize in task such as identifying words, detecting remtion, recognizing faces

      

  • Visual cortex (occipital lobe) → receive info from eyes

  • Auditory cortex (temporal lobe) → receive info from your ears

    • Sound info from ears travel a route from one ear to the auditory receiving area above your opposite ear

      • If hearing phantom ringing in one ear activity in the temporal lobe on the opposite side is active

• Association areas

  • Areas of the cerebral cortex that are not involved with sensory or motor function

    • Involved in higher mental functions

      • Learning, remembering, thinking

  • Found in all four lobes

  • Prefrontal cortex

    • Enables judgment, planning, and processing of ne memories

  • Frontal lobe damages → altered personalities & removal of person's inhibitions, moral judgment unrestrained

  • Frontal lobe → steer us away from violent actions

Practice questions

• RP 1- What do phrenology & biological psychology have in common

  • Focus on the link between the brain & behavior

  • RP 2- When a neuron fires an action potential, the info travels through the what order

    • Dendrites, cell body, axons

  • RP 3- How does our nervous system allow us to experience the difference between a slap and a tap on the back

    • Stronger stimuli cause more neurons to fire and to fire more frequently than with weaker stimuli

  • RP 4 - What happens in the synaptic gap

    • Neurons send neurotransmitters across the space

  • RP 5- What is reuptake? What two other things can happen to the excess neurotransmitters after a neuron reacts

    • Can be reabsorbed by sending neuron or broken down by enzymes

  • RP 6 - Serotonin, dopamine, and endorphins are all chemical messengers called

    • Neurotransmitters

  • RP 7 - Curare poisoning paralyzes its victims by blocking ACh receptors involved in muscle movements. Morphine mimics endorphin actions. Which is an agonist, and which is an antagonist?

    • Morphine is an agonist; curare is an antagonist

  • RP 8 - Match the neuron type to its description. Type 1. Motor neurons 2. Sensory neurons 3. Interneurons Description a. carry incoming messages from sensory receptors to the CNS. b. communicate within the CNS and process information between incoming and outgoing messages. c. carry outgoing messages from the CNS to muscles and glands

    • 1. C, 2. A, 3. B

  • RP 9 - What bodily changes does your ANS direct before and after you give an important speech

    • ANS sympathetic division arouses you. Accelerate your heartbeat and after ANS parasympathetic division reserves those effects

  • RP 10 - Why is the pituitary gland called the “master gland”

    • Responding to singlands from the hypothalamus, it releases hormones that trigger other glands to secrete hormones which then includes the brain and our behavior

  • RP 11 - How are the nervous system & endocrine similar and different

    • Similar that they produce messages to send throughout the body, differ in that the speed in which they do send those messages

  • RP 12 - Match the scanning technique with the correct description. Technique 1. fMRI scan 2. PET scan 3. MRI scan Description a. tracks radioactive glucose to reveal brain activity b. tracks successive images of brain tissue to show brain function. c. uses magnetic fields and radio waves to show brain anatomy

    • 1. b, 2. a, 3. C.

  • RP 13 - The ____ is a crossover point where nerves from the left side of the brain are most linked to the rise of the the body

    • Brainstem

  • RP 14 - What brain region would damage be most likely to disrupt (1) your ability to skip rope? (2) disrupt ability to hear? (3) leave you in a coma (4) cut off the very breath & heartbeat of life

    • 1. Cerebellum 2. Thalamus 3. Reticular formation, 4. Medulla

  • RP 15 - Electrical stimulation of a cat’s amygdala provokes angry reactions. Which autonomic nervous system division is activated by such stimulation?

    • Sympathetic nervous system

  • RP 16 - What are the three key structures of the limbic system, and their functions

    • Amygdala (involved in aggression and fear response), Hypothalamus (bodily maintenance, pleasurable rewards, control of hormonal system), Hippocampus (process memory of facts & events)

  • RP 17 - Which area of the human brain is most similar to that of less complex animals? Which part of the human brain distinguishes us most from less complex animals

    • The brainstem; the cerebral cortex

  • Rp 18 - Why is it hard to try to move your right hand in one direction and your right foot in the opposite direction? Why is it easier to move your left foot opposite to your right hand?

    • The right limbs are both controlled by the half of the brain. Left brain. Opposite sides of the brain control your left and right limbs; the movements don’t interfere with the brain's control.

  • RP 19 - Our brain’s ____ cortex registers and processes body touch and movement sensations. The ____ cortex controls voluntary movements.

    • Somatosensory: motor

• Defining Consciousness

  • Our subjective awareness of ourselves and our environment

    • Allows us to assemble information

    • Focus our attention when we learn a complex concept or behavior  

  • Different states of consciousness

  • Allows us to cope with novel situations and act in our long term interest

  • Promote survival → anticipating how we seem to other and helping us read their minds