chapter 2 - biology of the mind

phrenology

claim that bumps on the skull reveal our mental abilities and character traits

what are neurons

• nerve cells

• respond to stimuli

• transmit signals

• vary in size, shape and function

3 functional types of neurons

sensory, motor and inter

sensory (afferent)

• transmit input from our sense receptors

• receive information from external world

motor (efferent)

• transmits impulses to our muscles and glands

• carry signals from spinal cord to produce movement

interneurons (association)

• transmit information between the other 2 types

• connect sensory and motor neurons and other interneurons

agonist

molecule that increases neurotransmitters action (ex. to treat Parkinson’s)

antagonist

molecule that inhibits or blocks neurotransmitters action (ex. to treat schizophrenia)

• botulin (botox) blocks release of acetylcholine

reuptake inhibitor

prevents neurotransmitter from being transported back to pre-synaptic neuron (ex. selective serotonin repute inhibitor (SSRI) to treat depression)

agonist molecule

fills the receptor site and activates it, acting like the neurotransmitter

antagonist molecule

fills the lock so that the neurotransmitter cannot get in and activate the receptor site

parkinson’s diseasse

movement disorder characterized by tremors and difficulty initiating movement, caused by loss of neurons that use the neurotransmitter dopamine

• neurons that supply dopamine to basal ganglia degenerate and die basal ganglia lose ability to function

how is dopamine is created

in neurons by a modification of a common molecule called L-dopa

• ingesting L-dopa (agonist) elevates amount in brain and spurs surviving neurons to produce more dopamine

THC effects to ones brain

• binds to cannabinoid receptors

• impacts learning, memory, planning, coordination, movement

• limits both excitatory and inhibitory neurotransmitter

CBD effects ones brain

• interacts with various neurotransmitter receptors (ex. serotonin)

• anti-anxiety, anti-inflammatory and anti-psychotic properties

• may reverse negative cognitive impacts related to THC

Is caffeine an agonist or antagonist

antagonist, as it inhibits there activation which results in increased wakefulness and receding feeling of fatigue

peripheral nervous system (PNS)

connects central nervous system to body organs and muscles

• autonomic and somatic nervous system

somatic nervous system

• contains sensory neurons, transmit messages from sense receptors and motor neurons to muscles that control voluntary movements

• axons of sensory neurons from sensory nerves

• axons of motor neurons from motor nerves

dual functions of autonomic nervous system

sympathetic and parasympathetic

sympathetic

arouses fight or flight

parasympathetic

calms rest and digest

central nervous system

• consists of the brain and spinal cord

• composed of interneurons

• makes decisions for the body

cortical mapping

research conducted on conscious patients during neurosurgery

mapped motor cortex

areas requiring precise control (ex. fingers, mouth) occupy greatest amount of cortical space

brain stimulation

directly stimulating parts of the brain with electrodes

transcranial Magnetic stimulation (TMS)

• less invasive procedure used to stimulate the brain

• EEG knocks out parts of the brain, like a virtual lesion

electroencephalogram (EEG)

recording of waves of electrical activity sweeping across brains surface

magnetoencephalography (MEG)

measures brains isolated magnetic fields to determine how certain tasks influence brains activity

Ct scan

• x-ray technology (100 times more sensitive than standard X-ray)

• pinpoint areas of damage/deterioration

positron emission tomography (PET)

allows us to see which part of brain is active by tracing where a radioactive form of glucose goes while brain performs a given task

MRI

makes images from signals produced by brain tissue after magnets along the spin of atoms

functional MRI

reveals brain activity and functions

• compares successive MRI images taken a split second apart and shoes changes in level of oxygen in blood flow in the brain

4 cerebral lobes

frontal, parietal, occipital, and temporal

frontal lobe

• active in executive functions such as judgment, planning, and inhibition of impulses

• active in use of working memory and processing of new memories

• involved in speech and skeletal motor functions

parietal lobe

information about touch (sensory cortex)

• managing input from multiple senses

• performing spatial and mathematical reasoning

• monitoring sensation of the moment

occipital lobe

visual information (visual cortex)

• includes visual areas; they revise visual information from the opposite visual field

temporal lobe

hearing (auditory cortex) and language comprehension

• manages sensory input related to sound, which helps the understanding of spoken words

brain is separated into two hemispheres

• control the opposite sides of the body (contraleral control)

• are connected by corpus callous (communication link)

• are functionally symmetrical in some respects (ex. motor and sensory cortex)

• have specialized abilities

cerebral cortex

the outer covering of 2 hemispheres of the brain

• responsible for most complex aspects of perception, emotion, movement and thought

• bark (tree bark covers the areas)

motor cortex

• located at the back of the frontal lobe

sensory cortex

included portions of the cerebral cortex, that wrinkly outer layer of the brain that process and make sense out of information gathered by our five senses: vision, audition (sound), olfaction (smell), gustation (taste), and somatosensation (touch).

chronic traumatic encephalopathy (CTE)

• degenerative brain disease

• associated with receptive brain trauma

• can only be confirmed after death

concussion

immediate symptoms, violent shaking of the brain, cell damage

sub-concussive impact

shaking of the brain but no symptoms; below the threshold

• longer playing athlete more at risk - tackles and collisions

treatment (for CTE)

• no cure

• prevention (fewer sub-concussive hits; later age of impact)

• cognitive behavioural therapy (CBT)

neuroplasticity

changing of the brain

• the lifelong capacity of the brain to change and rewire itself in response to the stimulation of learning and experience

3 ways the brain can change to support learning

chemical, structural, and functional

what drives neuroplastic change in the brain

behaviour

how can neuroplasticity be both positive and negative

positive - physical activity, education, social interaction, intellectual pursuits, and cognitive remediation.

negative - poor health, poor sleep hygiene, poor nutrition, substance abuse, and depression and anxiety.

how does personalized medicine work

uses an individual's genetic profile to guide decisions made in regard to the prevention, diagnosis, and treatment of disease

a major limitation to developing therapies to treat stroke patients

each person is different so it is hard to find one method that works for all as some might not help others

sings and symptoms of CTE

• changes in thinking and memory (dementia)

• changes in personality and behaviour (erratic, aggressive, depression)

• difficulty with balance and mortar skills (walking)

punch drunk syndrome —> CTE (what can cause CTE)

boxing, football, military, hockey, rugby, soccer, wrestling, bull riding, intimate partner violence

what is going on in the brain (when one has a CTE)

• axons and microtubules damages

• tau proteins move into cel and form tangles

• also, see this in Alzheimer’s but in CTE tau angels first form in brains cortex

medulla

• controls the most basic functions such as heartbeat and breathing

• nerve tracts cross over within the medulla (ex. left side of the brain receives sensory information from right side of body)

brain stem

supports life-sustaining bodily functions

Pons

helps coordinate automatic and unconscious movements

• controls movements such as swallowing, posture, facial expression and eye movements

• involved in vital functions such as breathing

cerebellum (hindbrain)

helps coordinate reflexive and voluntary movement such as playing a sport

• especially involved in timing and coordination

• easily impacted by alcohol

• many other factors including enabling nonverbal learning and skill memory

midbrain

contains clusters of sensory and motor neuros + sensory and motor fibre tracts that connect higher and lower portions of nervous systems

reticular formation (midbrain)

regulates sleep, wakefulness and levels of arousal

• a nerve network in the brainstem

• enables alertness (arousal) from coma to wide awake

• filters incoming sensory information

• damage to the area can result in permanent coma

forebrain (cerebrum)

• size and complexity sets humans apart from other animals

• contains 2 large cerebral hemispheres (left and right)

• covered by cortex

thalamus (forebrain)

• sensory switchboard or router

• all sensory messages, except smell, are routed through thalamus on the way to the cortex (higher, outer brain)

• also sends messages from the cortex to the medulla and cerebellum

• located near the bottom and in the center of forebrain

  • receives neural messages for all senses except for smell

  • directs those messages to various parts of the brain

basal Ganglia (forebrain)

• group of structures that surround and envelop thalamus

• important for initiation of deliberate movement

hypothalamus (biological drives - forebrain)

• temperature regulation, feeding, fighting, fleeing, sex, emotional regulation

• hunger and feeding: digestion and detection of nutrients

• flight and fight: blood pressure and circulation

• sexual behaviour: behavioural and hormones responses

forebrain - limbic system

includes hippocampus and amygdala

• closely connected to hypothalamus

• coordinates: emotions such as fear and aggression, basic drives such as hunger and sex and formation of episodic memories

hippocampus (forebrain - limbic system)

• creates new memories

• integrates memories into a network of knowledge

• consolidates and stores memories

• helps us retrieve memories

amygdala (forebrain - limbic system)

• located at the tip of each side of the hippocampus

• plays a central role in the emotional process

• plays a significant role in the formation of emotional memories

• attaches significance to events associated with fear, punishment, or reward

stereotypical zombie

• lack of emotion

• increase rage, aggression

• in-stable hunger for human flash

• changes in balance

• motor control

• lack of inhibition

• inability to make complex decisions