Bio

Mentalism

• An immaterial mind (psyche) controls behavior 

• Aristotle: 384-322 B.C.E.

• Inspired by story of Cupid and Psyche: thought Psyche was a good representation of human

mentalism - The Cardiac Hypothesis

He thought psyche produced behavior by communicating with heart which he believed controlled the body

Dualism

• Two entities, an immaterial mind (psyche) and a material body control behavior 

• Descartes: 1596-1650

• Thought that bodies were kinda like robots/body consisted of very complex reflexes 

how dualism worked

• First to contribute some importance to brain, specifically what we now call pineal gland 

• He thought ventricles were important and rest of brain was a cushion to protect pineal gland 

• Claimed his theory could explain both reflexive and voluntary movements 

problem with dualism

• how does an individual know if others have a mind or if there just an automaton 

• They came up with test: to have mind you need language and memory skills 

- babies don’t have mind till about 7, people with disabilities may have troubles passing test, most animals can't pass test

- cant feel pain or distress if you can’t pass test so allows excuse for abuse and neglect

Materialism

• the brain and nervous system control behavior 

• Body form, behavior and environments of animals 

• Darwin: 1809-1882/book: The Origin of Species

• Theory all animals originate from single animal and evolution began to create diverse animals, bodies, behaviors

• Theory of Natural Selection lead to materialism 

• Behavior and mind is result of brain and bodies that have evolved to suit our environments

• No immaterial mind

How does the brain produce behavior? The Brain Theory

• Donald O. Hebb: 1904-1985/Organisation of Behavior

• When you produce behavior it activates group of cells 

• Neurons that fire together, wire together (connections between those neurons strengthen and you improve each time you do that behavior because connection continues to strengthen (you create neural circuit/memory))

• Most modern theory 

• True or False: neurons, are similar in all animals with nervous system

true

Sea slugs

used to understand learning 

zebra finches

used to study learning languages + dialects 

fruit flies

used to study because easy to manipulate their genes: study chromosomes 

extra chromosomes causes what?

down syndrome

cladograms

• Graph that depicts predicted evolutionary relationships between organisms

• Each branch point identifies a change 

• Each species in branch share new feature 

neurons original purpose

allow organisms to move

Simple animals to complex animals

• Neurons + muscles -> Nerve net -> Bilateral symmetry -> segmentation (clear top and bottom)  -> Ganglia (knots of neurons) -> Spinal cord -> Brain 

common relative to hominids

• australopithecus

Why Did the Hominid Brain Get So Big?

• Climate changes (adaptable brain and behavior)

• Primate lifestyle (large social groups + diets)

• Physiology (effective brain cooling systems (big brains produce lots of heat) and smaller jaws - because of change in diet)(smaller jaw = larger brain)

• Altered maturation (neoteny and prolonged development)

• Genetic mutations (SARGP2 responsible for determining number of neurons in cortex - appears to have duplicated at least 3 times)

• Prolonged development time period 

• Neoteny

Neoteny

Juvenile features of the ancestors are retained in the mature form of the descendents (ex juvenile apes)

is the central or the peripheral nervous incased in bone?

the central nervous system

Structures near top of brain

dorsal / superior

Structures near midline of brain

medial

Structures on side of brain

lateral

Structures near bottom of brain

ventral / inferior

Structures near front of brain

anterior / rostral

Structures near back of brain

posterior / caudal

Coronal section

a cut from top to bottom / produces a frontal view of brain 

Horizontal section

creates dorsal view / cut front to back 

Sagittal section

cut front to back on vertical axis / creates medial view 

Frontal view

white ventricles

dorsal view

black ventricles

bilateral

two of something / one per side

unilateral

one thing

contralateral

opposite side

Ipsilateral

same side

proximal

close to

distal

far from

meninges

membranes

dura mater is soft - true or false

false its hard

Arachnoid membrane

looks like spider

pia mater is soft - true or false

true

another name for sub arachnoid space

cerebral spinal fluid

what is cerebral spinal fluids purpose

removes toxins from brain and back into blood stream and is made by the choroid plexus

where are ventricles located and how many are there

1. four ventricles

2. in the middle of the brain and filled with fluid

the right and left ventricles are…

bilateral

cerebral spinal fluid is made by…

the choroid plexus

what are ventricles lined with?

glial cells

what prevents the brain from crushing itself?

cerebral spinal fluid

hydrocephalus (what & treatment)

• born with condition / build up of fluid in ventricles that can't escape / pushes brain tissue into skull and causes brain to die 

• Surgery insert shut into base of skull to release fluid from ventricle into abdomen (blood stream) 

brain organization (original three areas → new 5 areas)

original three:

• forebrain

• midbrain

• hindbrain

new five:

• telencephalon

• diencephalon

• mesencephalon

• mesencephalon

• mylencephalon

what allows nervous system to develop?

neural tubes

parts of forebrain

1. Telencephalon

2. Diencephalon

telencephalon - neocortex / general info

• Six layers of cells / Thin (2-4mm)

• Layers number I-VI in roman numerals

• gyrus / gyri = outer bump

• Sulcus / sulci = inner dips

• Deep sulci = fisher

• Grey matter: neuron cell bodies of neurons (no wrap) (absorb die in tests)/sends axons with messages = white matter 

• White matter: axons wrapped in glia sending signals

• Corpus callosum = allows hemispheres to communicate 

• 2 sheets of neocortex (one in each side of brains)

• Neocortex is cerebral cortex (generally)

Grey matter

neuron cell bodies of neurons (no wrap) (absorb die in tests)/sends axons with messages = white matter 

White matter: axons wrapped in glia sending signals

axons wrapped in glia sending signals

Corpus callosum

allows hemispheres to communicate 

telencephalon - neocortex / structure info

• Four lobes: frontal (motor),  parietal (somatosensory), occipital (visual), temporal (auditory) 

• Named by bones structure above it

• Between frontal and parietal = central sulcus (splits brain in half) 

• Lateral fissure/sylvian fissure = separates temporal lobe from frontal and parietal 

neocortex - Brodmann's Area 312

• post central gyrus (its a bump)

• primary somatosensory cortex

broadmanns areas

• Each brodmann's area has different shape or structured cells (neurons)

• Structure determines function = each area has a different function 

• Dendrites receive info for neurons 

• Ex. more dendrites = more info coming in

• Became most used map because it was good at predicting functions of neocortex

• Sensory perceptions are created by neocortex (responsible for making you feel like yourself)  

neocortex - broadmanns area 4

• the primary motor cortex = darkest shades in brain pic on slides is the primary part of that brain 

• Darkest areas are most closely connected to inputs and outputs from the body (info arrives there first) 

• Lighter areas called association areas - further from inputs and outputs / responsible for processing higher/more complex details of info

• Primary motor cortex = send info to spinal cord (does not receive much input its responsible for sending inputs) 

neocortex - braodmanns area 17

Primary visual cortex also called striate cortex

what’s broadmanns area 41?

primary auditory cortex

allocortex

• 3-4 layers of cells

• Also called limbic system/boarder system

Cingulate cortex:

• Bilateral structure

• Produces emotional expression and behaviors 

• Anterior cingulate cortex is overactive in major depressive disorder

allocortex - hippocampus

• Bilateral structure 

• Latin for seahorse (due to shape) 

• Important for explicit memory / memories you can talk about / episodic or personal memories (very specific memories not habits/implicit memories) 

• Involved in retrieval of memories as well as making new memories

• Involved in social navigation 

• Forms a cognitive map of environment

• Personal memories are put on cognitive map to prevent bad things from rehappening which is why it is housed in the same structure

allocortex - amygdala

• Responsible for processing emotions especially fear

• Important to attributing value/intensity to emotional stimulus 

• Ptsd is overactivity of amygdala

Basal Ganglia (base knot) pathways

• Direct pathway: responsible for the excitation of the muscles/movement 

• Indirect pathway: inhibits unwanted movements 

Basal Ganglia (base knot)

• Bilateral 

• Motor behavior - connected to motor cortex: they produce voluntary movements 

• Motor cortex is responsible for initially organizing/sequencing your movement  

• Basal ganglia observes the sequence to do something (ex. Brush teeth) / the more you do it the stronger the connection become until it is habit - once its a habit the neocortex is not involved in the action only the basal ganglia is 

• Stores procedural memories 

• Caudate, Putamen, Globus pallidus, Nucleus accumbens = basal ganglia

• Diseases involved with basal ganglia = tourettes, huntington's chorea, parkinsons 

• huntington's chorea: deterioration of caudate, putamen, globus pallidus 

• caudate, putamen and globus pallidus = the striatum

forebrain - diencephalon (the rooms)

• Bilateral structure 

• Epithalamus (epi means above)

• Thalamus

• Hypothalamus (below)

diencephalon - Epithalamus (epi means above)

• Seasonal rhythms (pineal gland - waking and sleeping behavior)

• Pineal gland releases melatonin 

• Regulates Circadian rhythm

diencephalon - thalamus

• Cortical relay system/station: redirects and filters information

• Cortical relay system integrated info entering and leaving cerebral cortex

• View slide 9 - lecture 2 (pulvinar and lateral geniculate body)

• Contains many nuclei 

diencephalon - hypothalamus

• Maintain body homeostasis via regulatory behaviors 

• Physiological symptoms maintained

• Many nuclei compete for control of the pituitary gland 

• Pituitary gland: master endocrine gland/master hormone producer/releaser

• Hypothalamus regulates: drinking, eating, temp regulation, sleep salt regulation, sexual behavior, parental behavior 

midbrain (location & structure)

• below hypothalamus

• mesencephalon (tectum + tegmentum)

mesencephalon - Tegmentum (floor)

1. Periaqueductal gray matter: species typical behaviors (ex. Cat stalking bird, sexual, hunting, fighting behaviors behaviors) / motor circuits & pain relief circuits (opioid receptors)

2. Reticular formation: goes through mid and hindbrain

3. Red nucleus: older motor pathway (basal ganglia to spinal cord) 

4. Substantia nigra: produces dopamine and projects to basal ganglia

5. Ventral tegmental area (NuAcc): produces dopamine and projects to nucleus accumbens (basal ganglia) / high activity is associated with drug addiction 

mesencephalon - tectum

• four bumps - sensory / older systems 

1. Superior colliculi (top bumps) - visual map

2. Inferior colliculi (bottom bumps) - auditory map

• Only visual and auditory systems on reptiles and amphibians 

• The colliculi allow you to respond to loud sound or sudden movement to keep you safe / evolutionary old visual orienting system 

substantia nigra

• Cells make dopamine 

• When not making dopamine (no pigment) - parkinsons 

• Less dopamine - less able to initiate movement 

• Hypokinesia 

1. Bradykinesia - slowness of movements

2. Akinesia - difficulty initiating voluntary movements 

3. Rigidity - increased muscle tone 

• Dopamine is not about pleasure its about motivation (wanting to seek reward) / initiating and motivating movements 

• Awakenings / Oliver Sacks: gave patients L-Dopa 

• Certain stimuli elicited movements = certain motor circuits intact just difficulties activating them 

• They are conscious just cant move 

• L-Dopa allows them to move but eventually it stops working - before it completely stops working it creates weird side effects (choreic movements) 

• Visual motion may help initiate movements 

Bradykinesia

slowness of movements

Akinesia

difficulty initiating voluntary

Rigidity

increased muscle tone 

reticular formation

• Arousal (ex. Waking up) 

• Moruzzi and Magoun - cats / electrode in neck

• Coma patients - small subset 

• Narcolepsy 

hindbrain

Metencephalon:  

• Pons (bridge)

• Cerebellum (little brain) 

Myelencephalon 

• Medulla oblongata 

hindbrain - metencephalon / Cerebellum (little brain) 

• Dorsal structure (motor but mostly sensory)

• Behind fourth ventricle 

• 12 lobes, cerebellum cortex, cells that form gray and white matter 

• Purkinje cells: receives lots of sensory input (gray matter) - uses info to refine your motor behavior (smooth movements) 

• Cerebellar Ataxia - clunky, jerky movements (look drunk when walking) 

• More skilled motor behaviors = larger cerebellum 

hindbrain - metencephalon / Pons (bridge)

• Mostly made up of nerve fibers that connect cerebellum and neocortex 

• Helping regulate unconscious actions (breathing, swallowing, bladder control…) 

• Ventral portion of brain stem (motor control) 

hindbrain - mylencephalon / Medulla oblongata 

• Bottom of brainstem 

• unconscious behaviors 

• Older than pons = less sophisticated behaviors 

nervous system division

autonomic nervous system -

• Involuntary movements and functions of organs (beating of heart, pupil movement …)

• Unconscious control (unless using mindfulness) 

• Divided into 2 sections sympathetic and parasympathetic 

autonomic nervous system - enteric

• Responsible for gut 

• Gut lining = plexus 

• Gut extends through esophagus, stomach, small intestine, and colon 

• Millions of neurons embedded in it to control bowel motility, nutrient absorption, enzyme secretion 

• Little input from brain (unless regarding emotions in relation to stomach issues) 

• Processes signals in gut (microbiome = our individual gut bacteria) that can influence physiological and psychological processes 

• Microbiome in gut produces majority of our serotonin 

• Lots of gut brain feedback

autonomic nervous system - parasympathetic

• Stores energy reserves 

• Rest and digest system 

• Long term survival 

• Neurons originate in brain stem and sacral area (2 neuron system) 

• Opposite function of sns

• Preganglionic neuron is long and synapse with second postganglionic neuron right before final destination/organ or in target organ 

autonomic nervous system - sympathetic

• Activate energy stores in body 

• Fight or flight - because energy stores are released (increase heart and breathing rate)(energy sent to skeletal muscles) 

• Shuts down activity in unnecessary organ systems (ex. Immune and digestive system) 

• Thoracic and lumbar are of spinal cord - neurons sent in body synapse in body then travel to right part of body 

• First neuron is preganglionic neuron (closer to spinal cord) then postganglionic neuron travels to final destination / organ 

• If active long term could cause physical/neurological damage

Camillo Golgi (1843 - 1925)

• The reticular theory (rete = net): a web or net of tubes and fluid flowed through tubes and that's how information was transferred 

• Developed dies for staining body tissues

• Golgi stain on brain showed image of tree like images 

• Golgi stain made of silver absorbed by tissue 

Ramony Cajal (1852 - 1934)

• Used golgi stain and saw what he believed were individual cells that communicate with one another 

• Developed the neuron doctrine = brain made of individual cells (now called neurons) 

• Golgi and Cajal shared nobel prized in 1906 (they hated each other) 

the neurone doctrine

1. The neuron: main info processing unit of brain 

2. The synapse: individual units communicate with each other at specific points (now called synapse) 

3. Connection specificity: in well working brain pattern/rhyme for neuron communication / neurons form larger info processing circuits 

4. Dynamic polarization: info flow through neuron in particular direction 

Somatic Nervous system

Voluntary controls of spinal muscles; 1 neuron (generality stimulatory effect)

cranial nerves

head, neck, and face

spinal nerves

•  originate in spinal cords

• voluntary controls skeletal muscles – both motor neurons (spinal cord to nerves), sensory neurons (originate in skin, muscles, joints → project sensory input back to the spinal cord)

segmentation

Repetition of parts

Doral (Posterior) nerve

sensory

Ventral (Anterior) nerve

motor

spinal cord segmentation

• Evolutionary conserved system

• Divided into four main segments (cervical, thoracic, lumbar, sacral, coccygeal (tailbone))

  Each Segment Receives and sends information to specific dermatome or specific section of body

• Segments determined by genes → Hox genes (master genes for building bodies)→ transcription factors (protein that combines other genes in DNA that turn on and turn off other genes responsible for growing legs/arms, ect.)→ basically found in all animals with segmentation 

• Dermatomes: Segment of spinal cord linked to a specific segment of body
  

Rostral: near top

Caudal: near bottom

Dermatomes

• Segment of spinal cord linked to a specific segment of body

1. Localized spinal cord injuries 

2. Distinguishing real and hysterical symptoms 

3. Guiding the reattachment of limbs

The Bell-Magendie Law

• Dorsal relays sensory info from the body to brain

• Ventral relays motor info from the brain to body

• Afferent:  incoming; Carry incoming information

• Efferent: exciting; Carry information away from body

where are Cell bodies of motor neurone located?

the centre of the spinal cord