Psyc 375- Brain and Behaviour Exam 1

What are the 2 elements of the nervous system?

CNS (brain and spinal cord) & PNS(cranial and spinal nerves)

Embodied behaviour

movements we make and the movements we perceive in others are central to our behaviour

-we understand one another not only by listening to words but also by observing gestures and other body language

-the brain as an intelligent entity cannot be

divorced from the body's activities

Neurons

specialized nerve cells engaged in info processing

- carry signals from one location to another

- ~86 billion

Glia

Supports cells within the nervous system

1. Act as nerve glue

2. Supply nutrients to neurons

3. Act as insulation around axons

4. Remove pathogens and dead neurons

Behaviours

patterns in time

5 types of glial cell

Behaviour types

Innate (inherited ways of responding) & Learned (require experience & practice, depend on brain neuroplasticity)

3 historical perspectives

mentalism, dualism, materialism

Mentalism

Aristotle (intellect = psyche, brain just cools the blood)

Behaviour as a function of the non-material mind

Beginning of modern psychology

Dualism

Descartes (mind = pineal gland to direct flow of fluids)

Both non-material mind and material body contribute to behaviour

Mind-body problem = how does the mind and body interact

Materialism

Darwin & Wallace

Behaviour is a function of the NS w/o recourse to the mind

Evolution = explains unity & diversity of life

Evolution (2)

1. species today are descendants of ancestral species (descent w/ modification - movements = new stresses = adaptations)

2. Natural Selection is the mechanism for Evolution (heritable genetic variations + competition for resources = reproductive success)

Rules of Natural Selection

1. Individuals don't evolve, populations do

2. Heritable genes, not acquired traits

3. evolution is not goal directed (random variation)

Evolution of Nervous Systems

1. Neurons and muscles. Brain cells and muscles evolved together,

enabling animals to move. Neurons and muscles likely have their

origins in single-cell animals such as amoeba

2. Nerve net. The nervous system representative of evolutionarily

older phyla, such as jellyfishes and sea anemones, is extremely

Simple

3. Bilateral symmetry. In more complex animals such as flatworms,

the nervous system is more organized, and it features bilateral

Symmetry, The human nervous system is also bilaterally

symmetrical

4. Segmentation. The body of an animal such as an earthworm

consists of a series of similar muscular segments. Its nervous

system has similar repeating segments. The human spinal cord and

brain display such segmentation

5. Ganglia. In still more recently evolved invertebrate phyla,

including clams, snails, and octopuses, are clusters of neurons

called ganglia that resemble primitive brains and function

somewhat like them in that they are command centers

6. Spinal cord. In relatively highly evolved chordates—animals that

have both a brain and a spinal cord—a single nervous system

pathway connects the brain with sensory receptors and muscles.

7. Brain. The chordate phylum, of which amphibians, reptiles, birds,

and mammals are class members, displays the greatest degree of

Encephalization, a true brain

Topographic maps

represent the different functional areas—

For instance, areas that control vision, hearing, touch, olfaction,

and movement

Connectome maps

represent the connections through which

each of these regions influences each other

Cladogram

displays groups of related organisms as branches on a tree

radiator hypothesis

the brain's radiator, the circulating blood, adapted into a more effective cooling system, brain size could increase.

-important because the brain's metabolic activity generates a great deal of heat and is at risk for overheating

-Homo skulls contain holes through which cranial blood vessels pass. Homo species had a much more widely dispersed blood flow from the brain

Measuring Intelligence

Spearman g factor: g for general intelligence factor

Flynn effect: the trend towards higher IQ

-the score change has not been accompanied by a similar increase in brain size. It is more likely that education and other life experiences explain the Flynn effect.

Gardner: proposed that humans have a number of intelligences — verbal, musical, mathematical, social, and so on

Weschler: adult intelligence scale

Plane of section

Views of brain

meninges 3 layers

Dura mater- "hard mother", tough fibrous outer layer

Arachnoid layer- "spiders web", thin sheet delicate connective tissue

Pia mater- "soft mother", moderately tough inner layer that clings to brains surface

Meningitis

inflammation of the meninges

-puts pressure on brain

-headache, stiff neck, stupor, coma, drowsiness, death

-treat with antibiotics

a group of organisms that can interbreed and produce fertile offspring

Species

Phenotype vs. Genotype

- Phenotype: expressed physical traits

- Genotype: Genetic make-up

discrete unit of heritable info & it's variations

Gene & allele

Mendelian Genetics

The pattern of inheriting characteristics that follows the laws formulated by Gregor Mendel

genetics = scientific study of heredity

heredity

passing on of genes from one generation to the next

(genes producing NS in different orgs. tend to be similar)

Stroke

the sudden appearance of neurological symptoms as a result of server interruption of blood flow

Stroke Symptoms

-weakness on contralateral side

-slowed behaviour

-vision problems

-loss of coordination/balance

Natural Selection + genetic inheritance + epigenetics =

foundations of materialistic approaches to neuroscience

Taxonomy

a system of naming and classifying species

Evolutionary descent of different species (simple -> complex)

Phylogeny

Encephalization Quotient

Quantitative measure of brain size obtained from ratio of actual brain size:expected brain size

Scientific method

attempt to obtain knowledge through the process of inquiry

Theory

A well-substantiated & widely accepted explanation for of natural phenomena

Natural Law

events in nature that happen the same way every time given specific conditions

Brain's primary function

Produce behaviours

Functions of the Nervous system

1. sensory input - conduct signals from sensory receptors to CNS

2. integration - analysis/interpretation of the sensory signals and forming responses

3. motor output - send commands to effector cells to carry out responses

Functions of CSF

1. Buoyancy

2. Protection

3. Chemical stability (removes waste products)

4. Prevention of ischemia (reduced blood flow, and therefore, oxygen)- decrease in CSF deceases intracranial pressure, aiding blood perfusion

cerebral cortex

outermost layer of cerebrum

Coup

Site of impact for concussion

countercoup

An area of brain damage that occurs on the opposite side of the head from the original site of the blow, or coup

Chronic Traumatic Encephalopathy (CTE)

atrophy of the brain (result of neuronal death), enlargement f ventricles, and increases in the brain proteins associated with Alzheimer's disease

Cerebral arteries

Anterior cerebral artery

Middle cerebral artery

Posterior cerebral artery

4 lobes of the cerebral cortex

Temporal - audition, memory, learning

Occipital - Visual processing

Parietal - tactile, visual movement, attention

Frontal - execuitive functioning

Nuclei vs. ganglia

nuclei: in CNS, group of similar neurons forming a cluster

ganglia: like nuclei but in the PNS

Tracts vs. nerves

Tracts: large collections of axons coursing together in the CNS

Nerves: large collections of axons coursing together in the PNS

Brainstem

Evolutionarily oldest brain structure, receives afferent signals & sends efferent signals

Responsible for most unconscious, life sustaining behaviour

Hindbrain/midbrain/diencephalon

Hindbrain

Reticular Formation: nuclei & fiber pathways (sleep-wake/arousal)

Pons: bridge between cerebellum and rest of brain (vital body movements)

Medulla: vital functions (breathing/CV)

Cerebellum: motor learning/balance/posture/movement coordination)

Diencephalon

Thalamus: relay center - all sensory info organized/integrated/ projected

Hypothalamus: nuclei associated w/ temp/eating/drinking/sex, controls hormones

Pituitary Gland: contains/releases hormones

Midbrain

Tectum: Posterior sensory structure (superior colliculus = visual, inferior colliculus = auditory)

Tegmentum: Anterior Motor structure (pain, innate species-specific)

substantia nigra

An area of the midbrain that is involved in motor control and contains a large concentration of dopamine-producing neurons (damaged in parkinsons)

Forebrain

evolutionarily newest - coordinate advanced cognitive functions

cerebral cortex = cortex, olfactory system, basal ganglia

lateral geniculate

Receives info from the optic tract and relays it to visual regions in the cortex

suprachiasmatic nucleus

a cluster of neurons in the hypothalamus in the brain that governs the timing of circadian rhythms

Neocortex

Outermost layer - perception/planning/emotions/memory

Olfactory system

Send information from the olfactory bulb to the cortex pyriform

Limbic cortex

Emotional/motivational states, some learning/memory

Hippocampus: memory consolidation, spatial navigation

Amygdala: fear

Basal Ganglia

coordination of voluntary movements

Caudate Nucleus, Putamen, Globus Pallidus (collectively known as the striatum)

Somatic NS

Cranial Nerves - 12 pairs, sensory/motor of head, neck, & organs

Spinal Nerves - each associated with a dermatome (surface)

(cervical, thoracic, lumbar, sacral, coccygeal)

Law of Bell & Megendie

dorsal; Sensory info= afferent

Ventral; motor info = efferent

toxoplasmosis

a parasite that is most commonly transmitted from cats to humans by contact with contaminated feces

-On immune cells, specific calcium receptors act like 'mailbox' for the parasite to transmit its messages

Long term illness; -intermittent explosive disorder

-schizophrenia

-suicide

-Brain inflammation, cognitive impairments, dementia and permanent rewiring of the brain

Sensory neurons (2 types)

Bipolar neuron: found in retina, conduct afferent info to the visual centres of the brain (SIGHT)

Somatosensory neuron: afferent info into the spinal cord (TOUCH)

motor neurons

-Complex dendrites, long axons that connect to muscles

-Located in the lower brainstem and spinal cord (exits via ventral route)

Autonomic NS

unconscious regulation of internal organs/glands

Sympathetic = fight/flight = primarily thoracic origin

Parasympathetic = calm = Primarily vagal origin

Camillo Golgi (1843-1926)

Golgi stain = silver nitrate solution stains 5-10% in entirity

Nerve Net Hypothesis = NS is an interconnected continuous network of fibres

Santiago Ramon y Cajal

Neuron Theory = NS made up of discrete cells

Anatomy of a Neuron

Dendrites - collect info (afferent)

cell body - protein synthesis/organelles

axon hillock

axon initial segment - signal integration (summation)

axon - singular process carries messages to other neurons

telodendria - end axon branches (terminal buttons) synapse on to next cells dendrites (efferent)

Neuron Doctrine (4 Tenets)

1. The basic functional unit of the nervous system us the neuron

2. Neurons are discrete cells

3. The neuron is composed of 3 par (dendrites, cell body, axon)

4. Information flows along the neuron in one direction

Neuron

Information processing units -> underlie plasticity

neural networks - functional groups connecting large areas of the brain/SC

Axon collaterals

branches of axon

Teleodendria

end branches of an axon

terminal buttons (end feet)

Knobs at the tip of an axon and points of near contact with the dendrites of other cells.

axon Hillock

Cone shaped region of an axon where it joins the cell body. Juncture of soma and axon where the action potential begins

Classes of Neurons

1. Sensory - transduction, carry sensory info to CNS

2. Inter - association (CNS, complex dendrite arbour)

3. Motor - largest, stimulate muscle contraction

Interneurons (2 types)

Pyramidal cell- long axon, two set of dendrites

Purkinje cell- extremely branched dendrites, info from the cerebellum to the rest of the brain

Glial Cells

Ependymal - CSF

Astrocyte - BBB, nutrition/support/repair

Microglial - defensive/immune

Oligodendrocyte - myelin in CNS

Schwann - myelin in PNS

Enteric Nervous System (ENS)

neural tissue associated with the digestive system that is responsible for nervous control through autonomic connections

Biological Molecules

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic Acids

Proteins

~50% dry mass

-polymers of amino acids (distinguished by R groups)

-biologically functional molecule consisting of 1+ peptides

-shape determines function

Nucleic Acid

-DNA/RNA

-chains (polymers) of nucleotides

-Phosphate groups + sugar + nitrogenous base

Transcription

synthesis of an RNA molecule from a DNA template

Phospholipid bilayer

phospholipids = cell membrane

-hydrophobic tails = create selectively permeable membrane (only small, non-polar molecules can cross)

translation

Process by which mRNA is decoded and a protein is produced (enters endoplasmic reticulum where ribosomes are )

Hydrocephalus

accumulation of fluid in the spaces of the brain, more dangerous in adults than babies

Blood-brain barrier

Protective barrier formed by astrocytes in combination with blood vessels

-Prevent toxins from entering brain

-Also prevents useful substances from getting through (antibiotics, etc)

-Protects brain except for a few areas

Multiple Sclerosis

myelin sheath destruction. disruptions in nerve impulse conduction (both sensory and motor pathways)

Huntington's disease

A human genetic disease caused by a dominant allele; characterized by uncontrollable body movements and degeneration of the nervous system; defect in huntingtin gene that results in abnormal huntingtin protein that increases the number of CAG repeats on chromosome 4

-Results in brain cell death in basal ganglia and cortex

CRISPR

"Clustered Regularly Interspaced Short Palindromic Repeats"

Cas9- enzymes that snips DNA

Brain derived neurotrophic factor (BDNF)

Protein important for health of neurons

Val allele- most common

Met allele- produced slightly less effective form of BDNF protein

-Less retention among people with Met alleles

epigenetics

Examines the differences in gene expression related to environment and experience

Epigenetics: Histone modification

adding chemical modifications to proteins called histones

Methylenation either opens up and allows for transcription or blocking them

Epigenetics: DNA modification

Methyl groups bind to CG base pairs to block transcription

Epigenetics: mRNA modification

NcRNA binds to mRNA preventing translation

Gene/environment interaction

Methylation higher in hippocampus of people that have committed suicide

-Child abuse results in methylation of the GR gene

Conventional kinesin and cytoplasmic dynein

major microtubule-based motor proteins powering axonal transport of membrane-bounded organelles

circumventricular organs

structures that permit polypeptide hypothalamic hormones to leave the brain without disrupting the blood-brain barrier (BBB) and permit substances that do not cross the BBB to trigger changes in brain function

motor proteins involved in axonal transport

Kinesin and Dynein. Kinesin anterograde transport