PSYC201 Week 1 REVISED

What is Monism?

The belief that the mind and the brain are one thing and are inseparable.

What is Dualism?

The belief that the mind and the brain are two seperate things entirely.

Motor Neuron

Has its soma in the spinal cord, dendrites receive excitement, conducts impulses along the axon to a muscle.  

Sensory Neuron

Designed to be highly sensitive at one end to a certain type of stimulation. 

Afferent axon

Brings information into the structure 

Efferent axon

Carries information away from the structure 

Different types of Glia cells:

Astrocytes, Microglia, Oligodendrocytes, Schwann cells, Radial Glia

What are Astrocytes?

Star shaped, They shield neurons from other surrounding chemicals. They also take up and release ions and transmitters that were previously released by the neurons. They’re important for generating rhythm.  

What are Microglia?

They’re part of the immune system, functioning to remove viruses and fungi from the brain as well as dead or damaged neurons after incidents such as brain damage. They prune synapses of neurons.

What are Oligodendrocytes?

They are found in the brain and spinal cord, they respond to neural activity through altering the myelin sheaths thereby affecting the timing of the axon. 

What are Schwann cells?

They are found “In the periphery of the body build the myelin sheaths that surround and insulate certain vertebrate axons” They help give axons the proper nutrients they need to function.

What are Radial Glia?

They help the guide the placement of neurons and axons and dendrites during embryonic development. 

What chemicals are able to pass through the blood brain barrier freely?

Oxygen, Carbon Dioxide, Vitamin A, Vitamin D. (Easily dissolve in fats)

What chemicals require pumps (active transport) to cross the blood brain barrier?

Glucose and Amino acids.

Korsakoff’s syndrome is where…

There is a deficiency in thiamine which leads to the death of neurons as well as memory impairments.

Neuron resting potential

-70mV

Hyperpolarization is when…

The action potential becomes more negative (e.g -80mV) than the resting potential 

Depolarize is when…

The cells action potential reduces its polarization towards zero 

The absolute refractory period is when…

During the peak of the action potential the sodium channels shut for a millisecond. 

The relative refractory period is when…

Potassium ions have rapidly left the cell, leading to the potential to become much more negative.  

saltatory conduction is…

The ‘jumping’ of action potentials across the nodes of Ranvier

Transcranial Magnetic stimulation (TMS) is where…

A magnetic stimulation to the scalp is produced, causing the neurons to be inactive. 

Optogenetics is where…

Light is used to control a limited number of neurons at a time. This works through proteins which when exposed to light either open a sodium channel which in turn excites the neuron or instead opens a chloride channel which inhibits the neuron. 

Electroencephalograph (EEG)

Records electrical activity of the brain through electrodes on the scalp, non invasive.

Magnetoencephalograph (MEG)

Measures faint magnetic responses that are generated by brain activity. 

Positron-emission tomography (PET)

Produces an image of brain activity, the individual receives an injection of glucose containing radioactive atoms. When radioactive atoms decay, they release a positron which then collides with an electron creating gamma rays, which are picked up by the gamma ray detectors surrounding the individual’s head.

FMRI – Functional Magnetic resonance imaging

A safe and non invasive procedure that detects the changes in the flow of blood, Increases in blood flow are correlated with neuronal activation. You cannot infer causality from this however.

Both produce precise information about the timing, but not as accurate about the location. 

EEG and MEG

Are both able to provide more comprehensive detail on location of brain activity however, they are not as accurate with the timing. They both also require a lot more time and effort. 

PET and fMRI

Computerized axial tomography (CT or CAT scan)

Used for observing brain anatomy. Dye is injected into the blood, X-rays are then passed through the head  

Sex-limited genes are…

Present within both sexes but only really in one sex. Examples of sex-limited genes are the amount of chest hair in men, breast size in women, or the rate of egg production in hens. 

Sex -linked genes are found…

On the sex chromosomes either the X or Y. typically when talking about sex-linked genes it would be talking about the X chromosome.  

Adding an acetyl group to a histone tail causes…

The histone’s tail to losen its grip on the DNA therefore allowing the expression of genes.

Removing an Acetyl group from a histone tail causes…

The histone’s tail to tighten its grip on the DNA preventing the gene from being expressed. 

Adding a methyl group to the beginning of a gene causes…

The gene to be turned off

Removing a methyl group from the beginning of a gene causes…

The gene to be turned on

What does a neuron release once it has lost input from an axon?

neurotrophins

neurotrophins prompts what?

Axons to form new branches or collateral sprouts. Areas sounding the damage form new synapses and sprouting at a higher rate than usual. The results of whether or not this helps with recovery largely depends on if the new sprouting axons are conveying the same or similar information that the previous ones did. 

Denervation supersensitivity is when…

Some synapses may become inactive, possibly due to damage, and therefore the remaining synapses become more responsive and easily stimulated. Occurs within dendritic receptors. 

David Marr’s three levels of understanding process information in machines

Computation

Algorithm/representation

Implementation

Implementation

How are the processes and representations realized physically? 

Algorithm/representation

How can the computation be carried out? (what are the steps what are the procedures?) 

Computation

Asking a broad question (what is this machine bulit for, what kind of information is processed etc.)