Psych 275 Pre Midterm 1

Mechanism (Causation)

How does the behaviour occur

Ontegeny

How does the behaviour develop in the individual

Adaptive Value

What function does the behaviour serve

Phylogeny

How did the behaviour evolve in the species

Niko Tinbergen’s 4 Q’s

Mechanism, Ontogeny, Adaptive Value, Phylogeny

Reductionist techniques

This is needed to study the brain, in order to try and control variation and simplify the incredible complexity present in the brain

Human subject pros

Communication, low maintenance, cost effective, have the brain we are trying to study

Human subject cons

Need ethics, uncontrolled lifestyle

Animal subject pros

Can be invasive, direct measurement/manipulation, comparative approach, controlled lifestyle, simple NS

Animal subject cons

No communication, high maintenance, ethics cost

3 R’s

Reduce, refine, replace (trying to use less and less animal subjects)

Descriptive Research

Observing - creates a snapshot of the current conditions. Able to show the full picture but unable to assess relationships between the various variables present

Correlational Research

Assesses the relationships between variables present. Can assess them in everyday life scenarios but unable to definitively prove causation

Experimental Research

Assesses the causal relationship between manipulated variables on a dependent variable. Difficult to simulate real world scenarios, as so many of the conditions need to be controlled

Between subjects

2 different groups participate in different stages of the experiment

Within subjects

The same group goes through all the stages of the experiment

Analogous traits

Similar traits which evolved separately due to convergent evolution. Not related.

Homologous traits

Traits which arose from the same origin (related)

Cerebrum - Brain Stem size

Best indicator of intelligence. Bigger the number = smarter the animal.

Epigenetics

The turning “off and on” of genes, through various factors or tagging done at the molecular level. In other words, just because something is present in our genotype does not mean it will be expressed

1%

Only __ of our DNA actually codes for genes

99%

__ of our DNA are introns, mRNA and serve to regulate coding

Histones (beads on a string)

We need relaxed DNA, in the form of ______ in order to begin transcription.

Chromosomes or Chromatin

When DNA is in the form ______ it is too big to undergo transcription

Heterochromatin

DNA is unable to undergo transcription

Euchromatin

Transcription is possible, genes can be expressed

Structuralism

A now unpopular theory that aimed to understand the human mind by breaking it down into its simplest components to understand the “structure”

Functionalism

A more popular theory that treats the whole mind as a computer, and tries to understand the purpose/development of mental process.

CNS

Brain and spinal cord

PNS

Motor and sensory nerves outside of brain and spinal cord

Somatic Nervous System

Voluntary reactions/movements.

Autonomic Nervous System

Involuntary actions and changes to homeostasis. 2 types

Parasympathetic Nervous System

The efferent nerves in the autonomic division which aid in digestion, relaxation, energy storage etc. Winding down. Nerves from Cranial/Sacral

Sympathetic Nervous System

The efferent nerves in the autonomic division which stop digestion, increase heart rate, increase breathing, constrict pupils etc. Winding up. Nerves from Thoracic and lumbar

Afferent Nerves

Approach the CNS, bring info (Sensory)

Efferent Nerves

Exit the CNS, do actions (motor)

Cranial nerves

12 pairs of nerves in periphery that originate on ventral surface of  brain instead of spinal cord. 2 purely sensory (eyes and nose), rest are autonomic

Meninges

3 layers, providing protection to the brain underneath the skull

Dura Mater

First layer of brain protection after skull. Hard, contains sinus’ to clean waste.

Arachnoid Mater

Second layer of brain protection, weblike, contains subarachnoid space with blood vessels and CSF

Pia Mater

Covers entire area of brain (even in between folds), third layer of protection

CSF

Perfect cocktail of nutrients, ions etc for the brain, also provides some shock absorption

Ventricles

4 fluid filled cavities/gaps within the brain, produce and circulate CSF

Blood brain barrier

Tightly packed cells surrounding the blood vessels and glial cells. Electrochemically isolates the PNS from the CNS, keeps “bad” molecules from the entering the brain, semipermeable.

High lipid solubility

Molecules (drugs for ex) which possess this quality are more easily able to pass through the blood brain barrier

Dendrite

A

Axon

D + E

Nodes of Ranvier

E

Soma (Cell body)

B

Buttons

F

Axon Hillock

C

Glia

Nervous system cell that is able to regenerate/divide, makes up 90% of brain and do not form synapses

Astrocytes

Largest type of glia cell, thought to be correlated with cognition, clean up neurotransmitters, able to rearrange synapses, all connected and star shaped. Very important in GABA cleanup

Microglia

Very small glia cell, macrophage, mediates cell death and has roles in immunity

Oligodendrocytes

Glia cell found only in the CNS, wraps around axons and forms the myelin sheath and white matter in the brain

Schwann Cells

Glia cell found only in the PNS, guides axon regeneration and forms myelin sheath

First axis

Anterior and Posterior (from front to back) - flips when changing from brain to spinal cord

Second axis

Dorsal and ventral (top to bottom) - flips when changing from brain to spinal cord

Third axis

Medial (inner side) vs Lateral (outer side)

Axial Plane

Top - down view

Coronal Plane

Front on view

Sagittal Plane

Side view

Cervical cord

Top region of spinal cord, rich in white matter

Thoracic cord

Second region of spinal cord

Lumbar cord

Third region of spinal cord

Sacral cord

Lowest region of spinal cord, highest grey : white matter ratio

3

Early brain development starts as ___ swellings

5

Once the brain further develops it forms ___ swellings/areas

Mylencephalon

Most posterior, makes up the lower part of the hindbrain. Contains medulla, reticular formation

Reticular formation

The central core network of brain stem made of 100 nuclei located in the myelencephalon. Involved in sleep, attention, movements, muscle tone, circulatory and respiratory reflexes.

Metencephalon

Posterior, located in the front part of hindbrain. Contains the cerebellum (tiny brain) and the pons, as well as ascending and descending tracts

Mesencephalon

The midbrain, where the reticular formation ends. Contains the tectum roof (inferior and superior colliculi), and tegementum (red nucleus, substantia nigra, periaqueductal grey)

Diencephalon

Back part of frontal lobe. Contains the thalamus, hypothalamus, pituitary, mammillary bodies and optic chiasm

Telencephalon

Biggest portion of brain. Contains the corpus callosum, Limbic system (hippocampus, amygdala, fornix and septum), basal ganglia and the 4 lobes.

Outside cell

Where is Na+ concentration higher?

Inside cell

Where is K+ concentration higher?

Sodium/K pumps

Moving 3 Na out and 2 K in via 1 ATP

Excitatory Postsynaptic Potentials

Cause the neuron to depolarize and get closer to an action potential. Able to be built upon (graded response). Causes Na to flow in

Inhibitory Postsynaptic potentials

Causes the neuron to hyperpolarize. Graded response, Cl ion flow inwards.

Bigger IPSP or EPSP

Stronger stimuli will produce

decay over time

Unlike AP, EPSP and IPSP gradually _______

Spatial summation

Occurs at axon hillock, where multiple different IPSP or EPSP are combined together at a given time to determine what action the cell should take. Oftentimes EPSP and IPSP cancel each other out

Temporal Summation

Where a single input is monitored and if it is sending rapid/multiple signals, a EPSP or IPSP is much more likely to occur.

Action Potentials

After the cell EPSP goes past -65 mV, an AP is generated where the cell is depolarized in a domino effect to pass along a message - does not degrade along the axon due to gated voltage channels. Has an equal strength (all or none)

Na+ Voltage gated ion channels

Initially open due to AP to allow sodium in, but close soon after depolarization to allow the domino effect to continue along and make it all the way through the axon

K+ Voltage gated ion channels

Open after the sodium channels, allow for K+ to rush out of the cell. Remain open for a while after sodium channels close to allow the cell to re-polarize appropriately

Absolute Refractory period

1 msec post AP, blocks the Na channels and prevents the signal from travelling backwards back towards the soma

1000x per second

Max neuron firing rate

Relative refractory period

AKA hyperpolarization - cell still able to fire, it just needs a stronger AP during this time

Increase speed of transmission

Increase myelination and diameter of axon

Saltatory conduction

Ion exchange in myelinated cells, happens at the nodes of ranvier (this is why they are faster, since it concentrates this process to only specific places along the axon - “jumping”)

Orthodromic conduction

Normal spreading of the signal (hillock to buttons)

Antidromic conduction

Reverse spreading of the signal (buttons to hillock/soma)

Neurotransmitter steps

AP reaches axon terminal, Ca floods cell, NT release and binding, receptors cause PSP, NT reuptake/recycling

MS (multiple sclerosis)

Scarring of the myelin, attacks both schwann and oligocytes

Axosomatic

Common for inhibitory signals, as this overrides PSP from generating an AP

Directed synapse

Pre and post synaptic neuron are close together and form a tiny cleft where NT are released into. Most common

Undirected synapse

NT released as “beads on a string” along the length of the axon (Varicosities). NT have a long way to travel, common in monoamines

Muscles NT

Only acetylcholine (Ach). 

Monoamines

CLASSICAL NT group all derived from either phenylalanine/tyrosine (Dopaminem = DA, norepinephrine = NE, epinephrine = E) or from tryptophan (5HT = serotonin)