W4 Neuroscience 2

Nueraxis

an imaginary line drawn through the center of the length of the central nervous system, from the bottom of the spinal cord to the front of the forebrain

- level of the head = dorsal up

- level of the spinal cord = dorsal back

Dorsal

back of the axis

Ventral

to the belly/front of the axis

Rostral

top of the axis

Caudal

towards the bottom of the axis

Medial

central/towards the midline

Lateral

regions outside the brain

what are Lesion studies

creating damage to a brain region and observing different brain behavior

advantage of Lesion studies

direct measure of a brain structures function

disadvantage of Lesion studies

hard to selectively target particular regions and draw conclusions

solution to Lesion studies

specific brain lesions can be studied in animal models

how does a CT scan work?

produces structural slices of the brain by taking a series of x-ray slices of brain and pieced together to create an image

CT scan advantage & limitation?

- helpful to diagnose brain injuries

- low resolution

how does an MRI work?

powerful magnetic fields are generated, aligning hydrogen atoms found throughout the brain

MRI advantage and limitation?

- used to localize tissue very percisely throughout the brain, clearer imagery compared to CT

- takes longer & more expensive

how does a PET scan work?

radioactive tracer of glucose or oxygen is injected into bloodstream, radioactive molecules make their way to brain and are used in metabolic processes

PET scan advantage and limitation?

- shows how brain function relates to cognitive tasks

- requires radioactive tracer to be injected = invasive

how does an fMRI work?

measures the blood oxygen dependent signal and uses many of the same principles as MRI

fMRI advantage and limitation?

- produces clear image of the brain activity without need for radioactive tracer

- oxygen used by the brain spikes a few seconds later than spikes of functional activity in the brain (not percise)

how does an EEG work?

electrical activity of the brain can be recorded through the scalp by wearing a cap of very sensitive electrodes, recording from a population of neurons to provide rough image of brain's overall activity

what are the 3 distinct regions of the brain?

1) Hindbrain

2) Midbrain

3) Forebrain

Hindbrain

all information into and out of the brain travels through the cranial nerves and spinal cord at the base of the skull, forced with regulating bodily functions

what does the hindbrain consist of?

(RCMP) reticular formation, cerebellum, medulla, pons

what does the Reticular formation control?

arousal & motivation, aircadian rhythms, posture & balance

what does the Cerebellum control?

coordinated movement

what does the Medulla control?

breathing, digestion, heart rate and autonomic reflexes

what does Pons control?

movement auditory perception, emotional processing

Midbrain

small region including two major subdivisions involved in a variety of functions including perception, arousal, and motor control

what are the 2 major subdivisions of the midbrain?

1) Tectum

2) Tegmentum

Tectum function

perception & action

what are 2 primary Tectum structures

1) Superior Colliculi

2) Inferior Colliculi

what is the function of the Superior Colliculi?

eye movements, visual reflexes

what is the function of the Inferior Colliculi?

auditory integration

what are the Tegmentum structures?

1) Red nucleus

2) Substantial nigra

what is the Red nucleus' function?

motor control

what is the Substantial nigra function?

reward related behaviour through release of the neurotransmitter, dopamine

Forebrain function

largest region of the brain, involved in emotion, memory, perception, and thought

what are the 2 sections in the forebrain

1) Limbic System

2) Cortex

what are structures are in the Limbic system?

(PHAT-H) pituitary gland, hypothalamus, amygdala, thalamus - hippocampus

what does the Hypothalamus do?

directing stress responses, regulating energy metabolism by influencing feeding, digestion, and metabolic rate, regulating production through hormonal control of mating, pregnancy and lactation

what is the function of the Pituitary gland?

regulates and releases vital hormones

what are the 2 sub regions of the Pituitary gland?

1) Anterior

2) Posterior

what is the function of the Anterior PG?

receives signals from the brain via hypothalamus and releases stimulating hormones to regulate other important endocrine glands

what is the Postpperituitary?

extension of the hypothalamus and releases oxytocin and vasopressin

what does Oxytocin do?

lactation and uterine contractions in women, bonding, love, trust

what does Vasopressin do?

regulates levels of thirst by interacting with kidneys to regulate glucose levels

what is the function of the Amygdala?

almond shaped structure below temporal lobe, receiving sensory information and plays a role in decoding emotions, particularly stimuli that may be threatening

what is the function of the Hippocampus?

horseshoe shaped structure in the temporal lobe, involved in the process of memory, spatial mapping, neurogenesis

what does the Cortex do?

controls information processing and cognition

when the cortex folds over itself what does it form?

1) Gyri

2) Sulci

Gyri

ridge on cortex/bulge outward

what is the point of the Gyri?

linked on cortex/buldge outward

Sulci

shallow grooves that separate the gyri

what is the point of the Sulci?

useful in indicating where neural tissue responsible for one function ends and the next function begins

what are the 4 lobes the cortex is organized into?

1) Frontal

2) Occiptial

3) Parietal

4) Temporal

Frontal lobe function?

motor processing, decision making & higher-order thought

Occipital lobe function?

visual processing

Parietal lobe function?

touch processing, spatial representation

Temporal lobe function?

higher visual processing, basic auditory processing, memory & language

Broca's Area

motor production of speech

what happens when the Broca's Area is damaged?

expressive aphasia

when Broca is broke, he uses broken words

Wernicke's Area

language comprehension

what happens when the Wernicke's Area is damaged?

receptive aphasia:

when Werncike won't work, we wonder 'what'?

what does the Corpus Callsum do?

carries information between the two hemispheres of the brain

what can a severed corpus callosum lead to?

Split Brain Syndrome