Biological Psychology Flashcards
What is biological psychology
Biological psychology is the study of biological (both brain and body) mechanisms of normal and abnormal behaviour
Main assumption underpinning biological psychology
That the biological and observable behaviour are no more than different levels of the same multi-layered phenomenon
Monism
Some mental processes and brain activity are inseparable
Histological staining of biological tissue
Stain certain elements of cells allow to see structure of cell underneath, combined with a microscope enables us to create detailed and accurate drawings of the nervous system
Allows us to understand nervous system is comprised of millions of cells (neurons)
Franz Nissel: Nissel stain
Stained the nuclei of the cell and surrounding tissue, allows us to visualise the cytoarchitecture of brain areas
However limited as couldn’t really see structure of individual cells so don’t know how they are connected together
Camillio Golgi : Golgi stain
Darkly stained some neuroma entirely. This allows us to visualise the structure of the neuron (soma, dendrites and axons)
Clues on how individual cells were connect
- still some debate on how they were connected
Santiago Ramon Y Cajal
Used Golgi stain to create accurate drawings of the structure of many brain regions
Helped to understand that their is multiple different neurons with their own structure, individual cells that aren’t connected but communicated by different means
Fundamentals of biological psychology
The structure of the nervous system as a whole and as individual cells
How neurons send signals and communicate with each other
Information is ‘coded’ in terms of frequency abs sometimes timing of action potentials (electrical signals)
Signalling between neurons happens at the synapse abs is chemical in nature (neurotransmitters)
Brain development and adult plasticity have a fundamental impact on cognition and behaviour
How do we interact with our environment
Input: Sensory systems (proprioception)
Output: Motor systems (gross and fine motor skills)
Influence on behaviour: (emotion and motivation)
Learning and memory: (plasticity)
Psychological disorders (schizophrenia)
Histology
EM
Study of body tissue at the microscopic level
Psychopharmacology
EM
Study of the effects of drugs on the brain and behaviour
Immunohistochemistry
EM
Labelling newly formed DNA proteins
Transcranial Magnetic stimulation
EM
Non-invasive method for altering brain activity
Inactivation of brain areas
EM
Reversible inhibition of brain activity (usually in animal studies)
Chromosomes
Humans have 46 chromosomes
Inherit 23 from your mum and 23 from ur dad
DNA can be compacted into a chromosomes by wrapping it around protein structure (histones)
Each human cell contains approximately 2m of DNA but the nucleus of a human cell is only about micro metres in diameter
DNA
Deoxyribonulic Acid
It is a type of nucleus acid (information carrying biomolecule
Nucleic acids are made up of Nucleotides
They contain 3 elements:
Phosphate
Deoxyribose (a sugar)
Nitrogenous base (4 versions, combined in pairs to code for different traits eg eye colour
DNA bases
Adenine - Thymine
Cytosine - Guanine
Apple in the tree
Car in the garage
Gene
Few thousand to 2 million base pairs
AT, GC
Genes code for proteins
Gene code for sequence of amino acids that will be assembled into proteins (note some parts are non - coding
There are 20 kinds of amino acids which can combine to make many different kinds of proteins which perform many kinds of proteins which perform many kinds of functions eg receptors, neurotransmitter)
Gene Expression
The final product of gene expression are remarkable molecules called proteins. These proteins come in various shapes and sizes and perform a variety of functions eg Protein synthesis
Protein synthesis
The assembly of protein molecules
This is located in the Cytoplasm
Gene expression (mRNA)
At protein synthesis occurs in the cytoplasm and DNA never leaves the nucleus
There needs to be an intermediary that carries the genetic message from nucleus to the site of protein synthesis. This job is performed by a long molecule called messenger ribonucleic acid (mRNA)
Gene expression Transcription
Transcription is the first of several steps of DNA based gene expression in which a particular segment of DNA is copied into mRNA (like a transcript) by the enzyme RNA polymerase
Gene expression Translation
Ribosomes link amino acids together to form the proteins based on the message delivered by the mRNA
Ribosome
A ribosome is a cell organelle that acts like a micro-machine for making polypeptides and proteins
In cytoplasm
Transfer RNA (tRNAs)
Are in the cytoplasm abs they carry amino acids
tRNAs gave anticodons that attach to the complimentary codons on the mRNA
Peptide
Two of more amino acid joined together by peptide bonds (short chains)
Polypeptide
A chain of many amino acids (larger chains)
Amino acids
The building blacks of behaviour
Protein
Contain either one complex polypeptide (long > 50-100) or more than one polypeptides joined together
Therefore, proteins are long chains of amino acids held together by peptide bonds
Protein structure
Primary structure (Amino acid sequence) - the sequence and length of amino acids in a polypeptide chain
Secondary structure (eg a helix) - the local folded structure that form within a polypeptide
Tertiary structure (polypeptide chain) - three dimensional structure of polypeptide
Quaternary structure (assembled subunits) - some proteins are made up of multiple polypeptide chains, also known as subunits
Protein folding
Properties of the amino acids and how they interact produce the folding
Essential vs non essential amino acids
Non essential - get from the body eg proline
Essential - get from environmental eg valine
Neurotransmitters
Amino acid - GABA, Glutamate
Monoamine - Epinephrine, Norepinephrine, Dopamine, Serotonin
Peptide - Endorphins
Others - Acetylcholine
Hormones
Protein / polypeptide - Insulin, Oxytocin, Ghrelin, Leptin, CHR, ATCH
Other functions of amino acids
Dopamine receptors, NMDA receptors, COMT enzyme, HSP Chaperone, Monoamine Transporter, Histones structures
Single Nucleotide Polymorphisms
During cell development we need to make a copy of our DNA, sometimes process goes wrong and a substitution is made, which is the wrong nucleotide being inserted
Can alter the effectiveness of the assembled protein
Catechol - On- methyltransferase gene
Codes for an enzyme (comt) that is involved in the metabolism of catecholamines, including dopamine, epinephrine and norepinephrine
Active Catecholamines (dopamine) —> COMT (reactor uses a methyl group) —> inactive metabolite (gets excreted)
Polymorphism + Alleles
Polymorphism- Are naturally occurring multiple forms of a single gene
Alleles - alternative forms of a gene (eg coding of valine or methionine
Genotype
The genetic makeup of an organism which is a combination of alleles responsible for determining characteristics and traits of the organism
Alleles same vs alleles different
Same = homozygous genotype Different = heterozygous genotype
COMT val/met SNP
A functional polymorphism in the COMT gene (val158 met) accounts for a four-fold variation on enzyme activity impacting catecholamines metabolism eg dopamine, epinephrine and norepinephrine
Heinz & Smolka (2006) fMRI study
Your COMT genotype
Val/Val, Val/MET, MET/MET
MET/MET - more focused response in the prefrontal correct during WN task & cingulate cortex in attention control task
Also increased reactively to unpleasant stimuli correlation to number of met158 alleles in the amygdala- more anxious and strong stress response than Val type
Apolipoprotien E (APOE)
(APOE) is a protein (229 amino acids long) involved in the metabolism and transport of lipids eg cholesterol
There are 3 APOE isoforms (ie proteins that have similar but not identical strings of amino acids) which contain SNPs at the 112th and 158th position in the polypeptide string
APOE4 allele is strong risk factor in developing Alzheimer’s and cardiovascular disease, Someone with no APOE4 alleles, the increased risk factor is 2-3 fold for one copy and 12- food with two copies (Bertram et al., 2007)
Epigenetics
Above genetics
What part of dna to express and what part not to
Cell differentiation
Each cell has its own functions which is dictated by which cells are turned on or off (epigenetic tags)
Epigenome
How much genes are expressed in certain cells
Methylation
Methyl groups control the genome by binding to genes you do not want to express. These markers are different depending on the type of cell, essentially dictating the cells function
Histone modification
DNA is wrapped around the histones (proteins). Tight binding results in less gene expression due to reduced accessibility. The tightness of this wrapping can also be impacted by epigenetic markers
Chromation
Repeating Nucleosome
A nucleoside is where the 147 nucleotide pairs of DNA is wrapped around 8 histone proteins
Nervous system - Two major divisions
Central (CNS)
Peripheral (PNS)
Central (CNS)
Brain & Spinal cord
Recognises input from PNS, does computations, then transmits output instructions
Peripheral (PNS)
Nerves connecting CNS to muscles and organs
Detects transmits information about internal and external states to the CNS
Executes output instructions from CNS
Organisation of the nervous system
Nervous system
Peripheral NS Central NS
Somatic NS Autonomic NS Brain spinal cord
Sympathetic/Parasympathetic
NS
Brain
Brain is approx 1.5kg and sits within the hard bony skull
Made of three distinct parts
Brainstem (joins the brain to spinal cord)
Cerebrum (two hemispheres which consist of a folder outer surface called the cerebral)
Cerebellum (mini brain)
Spinal cord
A tube shaped structure that runs from the brain down through a series of bony rings (vertebrae)
31 spinal nerves that connect the spinal cord to various body regions:
Cervical nerves C1-C8
Thoracic nerves T1-T12
Lumber nerves L1-L6
Sacral nerves S1-S5
Coccygeal nerve Co
Cerebrum subdivisions (lobes)
Frontal
Parietal
Occipital - vision
Temporal
Cerebellum
A position of the brain between the brain stem and cerebrum
Brain stem
Connects the brain to the spinal cord, consists of multiple elements including the medulla oblongata, midbrain and pons
The cerebrum - features
Gyrus- A ridge on the surface of the cerebral hemisphere caused by the unfolding of the cerebral cortex
Sulcus- a shadow furrow on the surface of the brain
Fissure - a deep furrow on the surface of the brain (natural divide)
Cranial nerves
Connect the brain to the face, sensory organs and some internal organs:
Afferent: Nerves incoming(sensory-red)
Efferent: Nerves outgoing (motor- blue)
Somatic nervous system
Voluntary control of the skeletal muscles of the body, allowing us to move in our environment. This includes gross motor control (eg walking) and fine motor control (eg writing)
Autonomic nervous system
Involuntary movement (eg heart beat, blood pressure, respiration etc). Slight monomer as we are now releasing we do have some conscious influence over these processes
Three divisions of autonomic system
The sympathetic nervous system that is activated by conditions that promote alertness (eg fight or flight, exams)
The parasympathetic NS which is activated by conditions of recovery and relaxation and slows things down to conserve energy
Electric nervous system (intrinsic nervous system) consists of a mesh-like system of neurons that governs the function of the gastrointestinal system
Neurons
A cell that transmits nerve impulses
Perform information processing and communication functions of the NS
Vary in shapes and sizes; the human NS contains about 100 billion neurons
Glia
A supporting cell
Have a support function and enhance neural activity
Are one-tenth the size of neurons
10x as many glia cells as neurons
Structure of neuron
3 major parts
Soma: the cell body that contains DNA enveloped in the nucleus and other organelles required for protein production
Dendrites: A projection that conducts the electrochemical stimulation received from other neurons towards the soma
- dendrites are covered in minute projections known as dendritic spines, making their surface area large
- dendritic structure can vary between neurons and is related to complexity of neurons info processing
(Dynamic structures that continually remodelling)
Axon: structure that extends from the elk body of a neuron to the terminal endings and transmits neural signals via synapse. The longest axons in the human body are those of the sciatic nerve, which run from the base of the spine to the big toe of each foot
Structure types of neurons
Unipolar
One projection from the cell body, which decides into 2 branches
Single dendritic tree extends towards the outside of the organism, axon towards the brain (touch)
Bipolar
Has one dendritic tree and one axon at the opposite ends of the cell body (vision)
Multipolar
Many dendritic trees extending from the cell body and one long axon (most common)
Types of neurons: Functional division
Sensory neurons: Neurons with neuritis in the sensory surfaces of the body (eg sensory receptors in skin) Afferent (inwards) - Carry sensory messages from the PNS to the CNS so we can detect info from our environment
Interneurons: Form connections only with other neurons (can be found in the brain and spinal cord). Connection - Connect sensory and motor neurons together or connect other interneuron together
Motor neurons: Neurons with axons that form synapses with muscles and command movement (and some internal organ). Efferent (outwards) - Carry motor messages from the CNS to the PNS so we can produce action within our environment
The synapse
The point of functional connection
Three components:
Presynaptic neuron - the axon terminal
Postsynaptic neuron - the dendrites or cell body
Synaptic cleft - a gap that aerpartes the membranes. The width of the synaptic cleft is about 20 nanometres
Celia cells
6 sub types of glia cells within NS
PNS:
Schwann cells -wrap round axons/ protection layer (myelin sheaths
Satellite cells- nutrients and protection
CNS:
Astrocyte - Protect + support
Oligodendrocyte - wrap around neurons / electrical insulation called myelin sheaths
Microglia - surround +digest damaged/ invading cells
Ependymal cell- manufactures cerebrospinal fluid
Myelination
Process in which glial cells wrap axons with a fatty sheath, called myelin. This acts to insulate and speed up nerve conduction. There are small gaps in the myelin sheath along the axon which have been called the nodes of Ranvier
Nodes of Ranvier
The electrical signal is propagated by the nodes of Ranvier, before jumping to next and being regenerated. This structure enables the electrical signals to travel rapidly along the axon
Neurons & Glia cells
Are high specialised cells that work together in a system that produces effective communication within NS
A gene
A distinct sequence of nucleotides
DNA is compacted into chromosomes by wrapping it around what type of protein structure
Histones
How many different kinds of amino acids
20
The process in which DNA is copied to mRNA is called
Transcription
The mRNA codes for amino acids in
Codons
The process in which Ribosomes like amino acids together to form peptide chains is called
Translation
How does tRNA transfer the correct amino acid based on the codes in the mRNA
Complimentary anticodons
All SNPs result in a change in the amino acids coded for?
False
What three neurotransmitters are catecholamines?
Epinephrine, dopamine and norepinephrine
A SNP on which gene is associated with risk of Alzheimer’s
APOE
Alternate forms of a gene are referred to as
Alleles
All cells in your body have the same DNA?
True
Kinds of epigenetic markers
Methylation & Acetylation
At the embryonic stage, are the epigenetic tags that dictate cell type in place?
Yes
Why does histone modification impact gene expression
It impacts gene accessibility
In Jirtle et al (2013) what was the result of feeding a diet rich in B-Vitamins to rat carrying the Agouti gene during gestation
Offspring displayed normal features despite having the agouti gene
Can lifestyle factors influence your epigenome
Yes
