5 perspectives for exploring the biology underlying behavior
- Descriptive
- Evolutionary
- Developmental
- Mechanistic
- Application
Descriptive
Perspective for exploring biology underlying behavior.
- Structural: what is it? & Functional: what does it do?
*the connection determines importance!
Ex: Lobes in the brain. They are categorized into major function of parts.
Evolutionary
Perspective for exploring biology underlying behavior.
- Continuity of behavior(we are all alike).
- Species-specific differences in behavior: (we are all unique).
Developmental
Perspective for exploring biology underlying behavior.
- Ontogeny: how individuals change across the lifespan
How do we change over time?
Ex: fear in the brain of a teenager, vs. fear in the brain of an adult
*The brain is plastic, moldable, & can change.
Mechanistic
Perspective for exploring biology underlying behavior.
- The brain is like a machine.
- There are mechanisms within the brain that make behavior possible.
Applications
Perspective for exploring biology underlying behavior.
Somatic (physical, structure) and behavior (response) affect each other.
*Correlation does not equal causation.
Precentral Gryus
Primary Motor Cortex
Sigmund Freud’s Developmental Theory
Was WRONG!
His stages of development ended in teenage years based on maturity, and was solely introspective.
We now know, people develop over a lifetime.
Primary development of brain
Most brain connections are developed by mid 20’s.
The frontal lobe is the last to develop.
Amygdala
Almond shaped structure in the brain.
Located close to the hippocampus, in the frontal region of the temporal lobe.
Two major underlying assumptions regarding neuroscience
- The brain has something to do with our behavior
2. Different parts of the brain do different things.
Where did neuroscience all begin?
1700 BC
Edwin Smith had a surgical papyrus with the word ‘brain” written in medical writings.
He described a number of head injuries.
Phrenology
Established end of 1700’s
Tried to map the brain, was incorrect and proven wrong
Broadmann’s Areas
Established beginning of 1900’s
Successfully mapped regions of the brain based on functionality.
Is still used today by neuroscience field.
SMRI
Structural MRI
Usually black and white. Looks at components; is a structure missing, is something damaged, tumor, etc…?
FMRI
Functional MRI
Gives a color gradient based on function, assumed by blood flow of BOLD signal (blood oxygen level dependent) of oxygen and glucose.
Pros/Cons of SMRI vs. FMRI
They both gives details to the story, but you can’t get the full picture unless you overlay the scans.
Tractography
Diffusion Tensor Imaging
Demonstrates the direction of flow (or nerve tract) by color. It is a form of diffusion MRI
Ventral
Toward the belly (front)
In the brain, this becomes the anterior of head at the brainstem
Dorsal
Toward the back
In the brain, this becomes the top of the head, or more superior position at the brainstem
Anterior
In front of
Rostral
Toward the nose, anterior
Caudal
Toward the tail, posterior
Superior
Toward the top of the head/body
Inferior
Toward the feet or bottom of the body
Lateral
Away from the midline
Medial
Toward the midline
Bilateral
On both sides
Unilateral
On one side
Ipsilateral
On the same side
Contralateral
On the opposite side
Forebrain
The "mushroom" Cerebrum Cerebral Cortex Cortex Contains the telencephalon & diencephalon
Midbrain
Tucks underneath the forebrain as development continues in baby.
Sits dead center on ventral surface, looks like Mickey.
Hindbrain
Becomes the brainstem and cerebellum, minus the midbrain
Brainstem
Midbrain, pons, and medulla oblongata
Brain structure
Generally contains the forebrain, midbrain, and hindbrain. We begin with these structures before any major development.
Telencephalon
Part of the forebrain Cerebral cortex (or cortex), basal ganglia (nuclei), and limbic system
Diencephalon
Part of the forebrain
Thalamus, hypothalamus, and epithalamus
Mesencephalon
MES
Part of the midbrain
Myelencephalon
MYE
Part of the hindbrain
Medulla Oblongata
Metencephalon
MET
Part of the hindbrain
Pons & cerebellum
Location order of midbrain and hindbrain
Superior to Inferior, alphabetical STY
Mesencephalon (MES)
Metencephalon (MET)
Myelencaphalon (MYE)
Gray matter
Exterior
Cell bodies composition
The cell bodies spread out and function
> Neuronal bodies in the CNS
White matter
Connecting pathways
Insulating fatty myelin
> Axons in the CNS
Sulci
Also “fissures”
Grooves
Gyri
Bumps
Components of the Telencephalon
Also “cerebral cortex”
Gray matter, white matter, sulci, gyri
Collections of neurons
Cell bodies
Collection of axons
Pathways
Cortex
Exterior
Sheet of neurons
Nucleus
Distinguishable grouping of neurons
Subtantia
Grouping of neurons deep within the brain, less distinct borders
Ganglion
Neuronal bodies in PNS
Nerve
Bundle of axons in the PNS
Tract
CNS axons with a common origin & destination
Bundle
Axons that run together but do not have the same origin and destination
Capsule
Connects the cerebellum to the brainstem
Commissure/Lemniscus
Connects one side of the brain with the other
Central sulcus
CSul
Longest and deepest
Longitudinal fissure
LonFis
Divides left and right regions
Sylvain fissure
Divides the pre-central (motor) and post-central (somatosensory).
Because they are so close, there is a lot of cross talk!
Supramarginal gyrus
Appears as a horseshoe
Angular gyrus
Is inferior to the supra marginal, appears also as horseshoe
Lobes of the Cerebrum
Frontal
Parietal
Occipital
Temporal
Frontal Lobe
Reasoning Planning Speech Movement Emotions Problem solving Personality - Generally language is left and emotion is right
Parietal Lobe
Sensation
Orientation
Recognition
Perception of stimuli
Occipital Lobe
Vision
Temporal Lobe
Has three major gyrus based on location (superior, middle, inferior temporal gyrus’)
Audition
Memory (formation, not storage)
Speech
- Contains hippocampus & Hershels gyrus
- Has three major gyrus based on location (superior, middle, inferior temporal gyrus’)
Hershels gyrus
Located in the temporal lobe
Processes all sounds, tones, pitches
Limbic System
Involved with emotions
Parahippocampus
Exterior landmark for hippocampus. Surrounds hippocampus
Uncus
Chemical senses, triangular shape, points medially off the temporal lobe
Insula
On the back wall of lateral fissure.
Very connected to addictive processes.
Infundibulum
Connects hypothalamus to pituitary gland. Base is called “tuber cenereum”.
Tuber Cenereum
Base of the infundibulum
Mamillary bodys
Connected to the limbic system.
Looks like breasts.
Ventricles
Spaces where fluid flows through, not structures.
Corpus Callosum
Sits in the center of the medial view of brain. Is a major curve anteriorly. It has four components (anterior > posterior):
Rostrum, Genu, Body, Splenium
Lateral Ventricle
Can be seen on left and right, is separated by the septum pellucidum
Singulate gyrus
Involved with limbic system. Emotions
Subcallosal
Underneath the corpus callosum. Sense of smell
Fornix
Separates the thalamus & hypothalamus. Also the base for the mammilary bodys.
Pineal gland
Regulates melatonin for sleep
What connects the hemispheres of the brain?
Corpus callosum, anterior commissure, posterior commissure
What is a commissure?
Communicating connection between both sides, but doesn’t carry as many fibers as the callosum.
What are the three structures that form the walls of the 3rd ventricle?
Thalamus, hypothalamus, epithalamus
Thalamus
Central relay for most sensory information.
Made up of many different types of nuclei (sensory, motor, etc.);
Acts as grand central station (a sensory filter for ALL senses except olfactory).
Hypothalamus
Arousal and motivation. Homeostasis and reproduction. Autonomic nervous system.
Hormone control. Is very flat from midline view, appears as a ridge.
Epithalamus
Limbic system.
Hypothalamic sulcus
The only sulcus that is interior
Interior components of midbrain
Tectum & tegmentum
Interior components of hindbrain
Metencephalon & Medulla (Myelencephalon)
Tectum
Dorsal half of midbrain. Function is orientation.
Tegmentum
Ventral half of midbrain. Function is movement and arousal.
Metencephalon
Contains pons (bridge) and cerebellum (little brain)
Medulla
Also called myelencephalon. Contains reticular formation.
Reticular formation
Regulates sleep, wakefulness, and levels of arousal with respect to consciousness.
Cerebellum
Mostly responsible for coordination.
Cerebellar Peduncles
All on Dorsal side.
Superior - attaches midbrain to cerebellum
Middle - largest and lateral to 4th ventricle
Inferior - smallest
Corpora Quadrigemina
Looks like 4 sets of U’s. Includes the superior and inferior colliculus.
Superior Cerebellar Peduncle
Attaches midbrain to cerebellum.
Middle Cerebellar Peduncle
Largest and lateral to 4th ventricle
Inferior Cerebellar Peduncle
Smallest
Four components of the corpus callosum
Anterior > Posterior Rostrum Genu Body Splenium