Psych notes 3-4

Chapter 3 GENES, EVOLUTION, AND ENVIRONMENT

Behavioural gentics:

Behvioural genetics is an interdisciplinary Field of study concerned with genetic contributions to individual difference in behaviour and personality. (They adopt a nature and nurture approach in their investigations)

The Genetic Code:

Chromosomes: structures in the cell nucleus that contains the genes an individual inherits

DNA (deoxyribonucleic acid): a double-helix molecule that contains four types of nucleotides (A, C, T, G) (sex cells dont have all -only half, when they go together u have all)

Genes: the basic unit of heredity; guides protein synthesis

Genes and proteins

Nucleotides A & T, G & C) sequences (The specific genes) represent the instructions used to create all the proteins in the human body.

Every cell (other than egg & sperm, B & T cells) contains the same Chromosomes and genes. However, depending on the cell, different genes are “turned on” or “expressed” and those proteins will be made.(You have the same cells in each body (DNA) but different ones get turned on) audio 10 min)

Genotypes vs Phenotypes (know the difference!) -19.50 for ex

Example of question that will be similar to question on exam (first photo, audio 16.30)

Bb BB if theres a big b that means its dominant so if dad is Bb brown eyes and mom is BB brown eyes then there is a 0% chance you will have blue eyes. There is no chance for bb (resetive genotype)? What

All of our genes, together with noncoding DNA, make up the Human Genome.

Most traits depend on more than ne gene pair.

Human Genome Project finished mapping the entire human genome in 2003.. Or 85%

Genome wide association studies: Scientists look for genes that vary across people and determine whether those genetic variants are consistently observed in those who have a specific disease or trait, compared to those without it.

Linkage studies:Take advantage of the tendency of genes lying close together on a chromosome to be inherited together across generations. (They help determine where a gene for a particular trait is likely to be located)

Researcher starts by looking for Genetic Markers, which are DNA segments that vary

considerably among individuals and whose locations on the chromosome are already know.

Epigenetics studies stable changes in the expression of a particular gene that occur without changes in D N A base sequences.

Evolutionary psychologists are interested in the origins of many human behaviors, such as smiling and laughter, which are universal among primates and are part of our shared evolutionary heritage.

Evolution can now be thought of as the change in frequency of genes occurring in a population over generations - natural selction

Natural Selection: The evolutionary process in which individuals with genetically influenced traits that are adaptive in an environment tend to survive and reproduce in greater numbers, results in those traits becoming more common. - still happens today but in less obvious ways (ex some people being born without wisdom teeth / only 1 or 2)

Innate human characteristics (instincts / reflexes babies are usually born with) (nfant Reflexes, An Interest in Novelty, A Desire to Explore and Manipulate Objects, An Impulse to Play and Fool Around, Basic Cognitive Abilities)

Sociobiology is an interdisciplinary field that emphasizes evolutionary explanations of social behaviour in animals, including human beings.

Sociobiologists contend that evolution breeds tendency to act in ways maximizing chances of passing on our genes and to help our close biological relatives (with whom we share many genes) do the same.

Genes hold culture on a leash, but how long and tight? Too short and tight to allow much change Or, long and flexible to permit many possible customs?

• Sociobiologists: The leash is short and tight.

• Evolutionary psychologists: Elastic to permit culture to modify evolved biological tendencies; those tendencies can be pretty powerful.

• Critics: Cultural variations mean that no single, genetically determined sexual

strategy exists for human beings. Evolution has bestowed on us an amazingly flexible brain.

• In matters of sex and love, as in all other human behaviors, the leash is long and flexible.

Heritability is an estimate of the proportion of the total variance in some trait that is attributable to genetic differences among individuals within a group.

An estimate of heritability applies only to a particular group living in a particular environment. (height of malnourished kids vs height of well nourished kids) so you cant apply it to 2 different groups of people or the results with be different because of environmental factors

Heritability estimates do not apply to a specific person, only to variations within a group of people.

Even highly heritable traits can be modified by the environment.

Chapter 4 - The brain and the nervous system

The function of a nervous system is to:gather and process information, produce responses to stimuli, coordinate the workings of different cells

Somatic nervous system permits sensation and voluntary actions

Autonomic nervous system which regulates blood vessels, glands, and internal (visceral) organs

The autonomic system usually functions without conscious control.

The autonomic nervous system is further divided into the:

Sympathetic nervous system, which mobilizes the body for action

Parasympatheic nervous system, which conserves energy

(These two parts work together, but in opposing ways, to adjust the body to changing

circumstances)

The neron

Dendrites: Small Branches radiating from cell body that receive signals from other cells and transmit them to the axons.

Cell Body/Soma: The part of the neural that houses the nucleus. This is where the DNA of the cell is stored.

Axon: Transports information in the form of electrochemical reactions from the cell body to the end of the neuron.

Axon Hillock/Nodes of Ranvier: If stimulation is strong enough and action potential is reached at the hillock it moves down the Axon. The action potential is propagated at each node and jumps to the next, regenerating the charge of the transmission.

Myelin Sheath: An insulating layer that forms around the axon of the nerves. Allows electrical impulses to be transmitted quickly and efficiently along the nerve cells.

Glial cells: a variety of cell types that serve support functions for neurons:

Microglia, Oligodendrocytes, Astrocytes

3 Main Nerons:

Sensory Neuron: Gather info from inside and outside the body - spot on elbow doesn’t have any, so if you lick someones elbow they wont feel it (Perhiral)

Interneuron: Receive info from sensory neurons and decide what to do. (central)

Motor Neuron: Responds to the stimulation from the sensory neuron if it is deemed strong enough. (pherifreal)

Listen to 24 for ex about somatic

Central ns is basically the spine (22 min?)

How neurons communicate

Communcation between 2 neurons occurs at the synapse

When a wave of electrical voltage (action potential) reaches the end of a transmitting axon, neurotransmitter molecules are released into the synaptic cleft.

Action potential: Audio 27! Listen

Nerve impulses, A. Resting Potential - at rest, the Neron cell membrane is polarized (More positive outside than inside) to -70mv

Depolarization,

Reploarization

Hyperpolarization

MULTIPLE SCLEROSIS 36 m

Microglia isnt functioning properarly, body attacks myelin sheath and Nodes of Ranvier

facilitate the rapid conduction of neural impulses.

MS is the result of malfunctioning glila cells

Neurotransmitters 40 m - specific nerotransnmitters can only unlock specific neurons (42.45) - (receptor sites)

Synaptic cleft is the small space between the terminal button and the dendrite of another neuron

Reuptake: a process whereby released neurotransmitters are reabsorbed into the axon terminals of the pre-synaptic neuron

Selective serotonin reuptake inhibitors (SSRI)

Flash cards:

Excitatory neurotransmitters: Increase the likelihood of an action potential occurring

Inhibirotory neurotransmitters: Decrease the likelihood of an action potential occurring

Hormones are produced mainly by the Endocrine Glands: pg 22 chapter 4

Chapter 4 part 2

Lesion Method: The removal or disabling of a non-human animal’s brain structure to gain better understanding of it function. (We obviously cannot use this method on humans)

MANIPULATING THE BRAIN AND OBSERVING BEHAVIOR (TMS, tDCS,tACS) All three use electrical stimulation to stimulate or suppress different areas of the brain. (pg 3 part 2)

Brain scans;

E EG: A recording of Neural Activity detected by electrodes.

E R P s: Waveforms of neural activity associated with specific stimuli or events

With ERPs, we still don’t know where the activity is occurring, but we know when it is occurring.

To see where the activity is coming from, you can do: PET scans, MRIs, fMRI

Controversies and cations: listen to audio 21 mins

We need to understand that technology cannot replace critical thinking.

• Researchers make a variety of choices that can leave small contrasts looking more dramatic than they really are or larger ones seeming insignificant.

• Simply including an image of brain activity can be enough to make a study’s conclusions seem more compelling, even

when they are not.

THE BRAIN STEM AND CEREBELLUM

The reticular activating system (R A S):

• screens incoming information

• is responsible for alertness

The Cerebellum

• contributes to balance and muscle coordination

• plays a role in cognitive and emotional learning

• If your cerebellum were damaged, you would: become clumsy, uncoordinated

The amygdala is responsible for:

• evaluating sensory information

• quickly determining its biological impact

• This affects the initial decision to approach or withdraw from the situation.

The Hippocampus is a key brain structure in the formation of new memories.

The brain typically contains two hippocampi, one on each side (hemisphere) of the brain.

It plays a critical role in the formation of longterm memories for facts and events and other aspects of memory.

Cerebral cortex: Collection of several thin layers of cells

covering the cerebrum, largely responsible for higher mental

functions.

The lobes of the cortex have specialized (but partially overlapping) functions:

• occipital

• parietal

• temporal

• frontal

The parietal lobe Includes the Somatosensory Cortex, which receives information about pressure, pain, touch, and temperature from all over the body. Parts of the parietal lobes that lie behind the

somatosensory cortex are involved in attention and awareness of spatial relationships.

• damage to this cause Hemispatial Neglect. (cant see left side of things)

Flash cards on Brocas area and Werniks (what part of the brain, what happens when damaged?)

The association cortex appears to be responsible for higher mental processes.

• The frontal lobes, particularly areas in the

prefrontal cortex, are involved in:

• social judgment

• making and carrying out plans

• decision making

• Case of Phineas Gage

SPLIT BRAIN PATIENTS

Both eyes send information to both sides of the brain. However, the left field of hemifield of vison goes to the right brain and the right hemifield goes to the left brain.

The left hemisphere is generally specialized for:

• logical, symbolic, and sequential tasks

(left is speech)

(Right would be pointing) but they cross over so technically the left side sees what the right side points to but the right side gets the information

The right hemisphere is associated with:

• visual–spatial tasks

• facial recognition

• the creation and appreciation of art and music

Culture: A program of shared rules, values, symbols, communication systems, and conventions that governs the behavior of members of a community.

Cultural neuroscience: Study of how links between neural and cultural forces can create different patterns of behaviour, perception, and cognition.

• Research includes investigation of bilingualism, literacy, and cross-cultural studies. (babies who learn multiple languages actually use different parts of their brain to understand and communicate)