Psych 377 First Midterm

Nuclei

Groups of Neurons in CNS

Tracts

Groups of axons in CNS

ganglia

cell body grouping axon bundles only in PNS

Nuclei

cell body groups in CNS

Rostral Caudal

Nose to tail axis of the body

synonymous ish with anterior posterior

Dorsal Ventral

Back-to-front axis of the body

synonymous ish with superior-inferior

Medial-lateral

Medial: toward the middle

Lateral: toward side

Ipsilateral

Structures on the same side of the body

eg pain receptors, as they are connected to the spinal cord reflex so it needs to be a quick response

Contralateral

structures on the opposite side of the body

Proximal

structures are close together

Distal

Structures are far apart

Afferent

Movement toward the CNS

outside affects body

Efferent

movement away from CNS

body has an effect on the outside

Coronal Section

Transverse(horizontal) Section of Brain

Sagittal Section

Cenbtral Nervous System

Spinal cord and brain

protected by bone

Peripheral Nervous System

Projects out of body

somatic nervous system ineracts with external world

autonomic nervous system is automatic stuff

Sympathetic and parasympathetic branches

Sympathetic branch

PNS, autonomic

fight, flight, freeze, fawn response

sympathetic ganglia are close to the spinal cord

Parasympathetic Branch

PNS, autonomic

rest and digest

Ganglia are near the target organs

Protection of CNS

Bone surrounds tissue in CNS

Mengines surround the CNS to hold it in place

Cerebrospinal fluid fills the spaces in and around the meninges to absorb shocks and carry away waste

Blood-brain barrier provides chemical protection,

Dura Mater

tough outer coating meninges

Arachnoid Mater

web-like structure that connects dura and pia mater

Pia Mater

touch inner layer that adheres to surface of the brain

Blood brain barrier

chemical protection

astroglia hold cells of blood vessels tightly together

regulation of what molecules can exit the blood supply to enter brain

Blood Supply to Brain

multiple arteries supply blood to the brain so that damage to one blood vessel won’t interrupt blood flow to the entire brain

Arteries branch to form smaller arteries

Stroke

interruption of blood supply either because the artery becomes blocked or because the artery bursts

clot (block), hemorrhage (cut)

Anterior Cerebral Artery Location

Middle Cerebral Artery Location

Posterior Cerebral Artery Location

Neuroblast cells

Arise from stem cells dividng which gives rise to neuroblast cells which than develop into neurons

Glioblasts

Stem cells dividing into these which differentiate into glia

Sensory Neurons

Transduce information from the environment

bipolar and somatosensory neurons

afferent as they are how the body is affected

Bipolar Neuron

One dendrite and one axon

sensory neuron

Somatosensory Neuron

one projection from the soma

sensory neuron

Interneurons

Connect sensory and motor neurons within the CNS

will have very extensive branching of dendrites to gather information

Motor Neurons

Found in the brainstem and the spinal cord

project to muscles to carry out movement

efferent as they are how the body has an impact on environment

Ependymal Cell

Small, ovoid; secretes cerebrospinal fluid

Astrocyte

Star-shaped, symmetrical; nutritive and support function

Microglial Cell

Small, mesodermally derived; defensive function

Oligiodendroglial Cell

Asymmetrical; forms insulating myelin around axons in the brain and spinal cord

will wrap around multiple cells to make myelin

Schwann Cell

Asymmetrical; wraps around peripheral nerves to form insulating myelin

can make a guide to reconnect neurons in peripheral nervous system

Gray Matter

Contains cell bodies and capillaries that supply them with blood

typically outer part of the cortex but inner part of the spinal cord

White Matter:

Myelinated axons that connect with other parts of the brain

typically underneath the cortex

eg corpus callosum is only axons that go from one side of the brain to the other

Reticular Matter

Netlike appearance that is a mix of grey and white matter, alternating white and gray matter, so it’s striped

found in brainstem, then the info in processed in cortex and sent to spinal cord

Three Enlargements of the Embryonic Spinal Cord

Prosencephalon

Mesencephalon

Rhombencephalon

Prosencephalon

In mammals, this divides to form the telencephalon (cortex and stereotypical brain) and the diencephalon (thalamus and hypothalamus)

Mesencephalon

Remains and becomes the midbrain

Forms: tectum, tegmentum, cerebral aqueduct

Rhombencephalon

Divides to form the metencephalon (pons and cerebellum) and the myelencephalon (medulla oblongata)

Telencephalon

Comes from prosencephalon

Forms neocortex, basal ganglia, limbic system, olfactory bulb, lateral ventricles

endbrain

Diencephalon

Comes from the prosencephalon

between brain

forms; thalamus, hypothalamus, pineal body, third ventricle

Metencephalon

Comes from the rhombencephalon

across brain

forms cerebellum, pons, fourth ventricle

Myelencephalon

spinal brain

Forms from the rhombencephalon

Forms the medulla oblongata and the fourth ventricle

Ventricles

Brain develops as a hollow tube and the hollow parts of the tube develop into the ventricles which are filled with CSF

lateral, third, fourth

Lateral Ventricle

Contained in the telencephalon

Third Ventricle

At the midline of the brain

Fourth Ventricle

between cerebellum and brainstem

Spinal Cord

gray matter surrounded by white matter

nerve roots branch from the cord to carry motor commands to the body and conduct sensory info into the CNS

4 segments: cervical, thoracic, lumbar, sacral

Law of Bell Magnide

afferent sensory info enters the posterior route of the spinal cord, whereas efferent motor neurons exit the anterior

Dermatomes

describe the region of the body surface innervated by each nerve

Cervical, Thoracic, Lumbar, Sacral Numbers

8

12

5

5

Spinal Reflexes

Are basic behaviours that occur without cognitive input

Generated in the spinal cord based on posterior sensory input, making a direct connection to the anterior motor output pathways

More complex reflexes will integrate information across multiple spinal cord segments (eg walking)

Cranial Nerves

twelve pairs of nerves branch from the brain and brainstem to provide sensory and motor innervation to the head, similar to what the spinal nerves do for the body

some are afferent (sensory) and some are efferent (motor), and some are mixed

Need to know: Olfactory, optic, oculomotor, auditory, vestibular, vagus

Brainstem

Extends from where the spinal cord enters the skull to the forebrain

Hindbrain

Cerebellum, pons, medulla, reticular formation

Pons

connects cerebellum with the rest of the brain

Cerebellum

Important for motor control and sensory integration

medulla

regulates functions such as breathing and heart rate

Reticular Formation

spans the pons and medulla, and sends projections to the cortex to maintain alertness and arousal

Up through the spinal cord through the pons and medulla to send info to cortex

damage could lead to a coma

Midbrain Contains

Tectum and Tegmentum

Tectum

Posterior aspect of the midbrain

Superior colliculi relay visual information

Inferior colliculi relay auditory information

Tegmentum

Anterior aspect of the midbrain

Nuclei here are involved in motor control, including the substantia nigra and red nucleus

What surrounds the cerebral Aqueduct?

periaqueductal gray matter and it is important for pain and fear responses

Hypothalamus

Many nuclei influence a wide range of behaviours

Produces and releases hormones that influence the entire body

Hypothalamic-pituitary axis: hormonal release (neural to endocrine system)

Thalamus

sensory relay

Almost all info destined for the cortex passes through the thalamus

it has nuclei that do preprocessing then relay info

• relaying sensory info to cortex

• relaying info between cortical regions

• relaying from cortex to the brainstem

Epithalamus

Nuclei found posterior to the thalamus

Thalamic Projections Anterior

mammillary bodies coming in

signals to cingulate gyrus coming out

Thalamic Projections Ventral Anterior

Basal Ganglia signals coming in

Thalamic Projections Ventral Lateral

Cerebellum

Basal ganglia,

Substantia Niagara signals coming in

Thalamic Projections Ventral Lateral Posterior

Somatosensory signals coming in

Thalamic Projections Lateral and Medial Geniculate Body

Visual and auditory signals coming in respectively

Thalamic Projections Posterior

Areas 17 and 18 Superior colliculus

Thalamic Projections Dorsal Medial

Amygdala, Caudate Nucleus, and Frontal Cortex signals all go in

Basal Ganglia

Are important for motor control and motor learning (higher order)

includes putamen, caudate nucleus, and globus pallidus

Integrates sensory and motor information to produce fluid, skilled movements and is important for motor learning

diseases like Huntington disease with extra movement show hyperkinetic disorders of the basal ganglia

diseases like Parkinson disease show loss of movement which indicates hypokinetic disorders

associative learning(voluntary movement) takes place in the basal ganglia

Limbic System

Important for spatial and emotional functions

Represents an older part of the brain from evolutionary history

amygdala, hippocampus, cingulate cortex

Amygdala

small nuclei in medial temporal lobes

important in emotion and understanding emotion in others

Hippocampus

seahorse-shaped structure in medial and temporal lobes

important in personal memories and navigation

memory

Cingulate Cortex

arcs over the lateral ventricles

involved in decision making and executive functions

Neocortex

outer layers of forebrain

1.5-3mm thick and includes 6 layers of cells

divided into two hemispheres by longitudinal fissure

each of the 4 lobes has different functions

Gyri

ridges in the brain

Sulcus

clefts

precentral gyrus

central sulcus

post central gyrus

intraparietal sulcus

lateral sulcus /sylvian fissure

superior temporal gyrus, medial temporal gyrus, inferior temporal gyrus

superior and inferior temporal sulcus’s

Cingulate Sulcus

cingulate gyrus

Callosal Sulcus