Lecture 2 - Functional Neuroanatomy

caudal

towards the tail

rostral

towards the nose

ventral

towards the belly

dorsal

towards the back

ipsilateral

same side

contralateral

on the opposite side

unilateral

applies to one side of the brain

bilateral

applies to both sides of the brain

proximal

brain regions near

distal

brain regions far

medial

closer to the midline

anterior/posterior axis

front and back

ventral and dorsal axis

top and bottom of the brain, front and back of the body

sagittal plane

split brain into left and right hemisphere, the corpus callosum connects them, also brainstem, closer to the midline

coronal plane

split brain into front and back, shows the brain as if looking at the person straight on

horizontal/axial plane

splits brain into top and bottom, parallel to the floor, useful for birds eye view from below to the top

what plane would you use for basal ganglia?

coronal because its a deep brain structure

foramen magnum

hollow region, where the brainstem exits the skull and connects to the spinal cord

what slice would you use for the cerebellum?

an axial/horizontal slice because it separates the two areas in the posterior region of the brain

optic radiations

connects the thalamus to the occipital cortex

ventricles

they have a C like shape

temporal lobe

located at the anterior ventral part of the brain, responsible for hearing and language

occipital lobe

located at the posterior ventral part of the brain, responsible for vision

parietal lobe

located at the posterior dorsal part of the brain, responsible for motor movement, sensory information, orientation/grasping something

frontal lobe

located at the anterior dorsal part of the brain and responsible for executive functions, cognition, decision making and planning

rostrolateral frontal cortex

front and outer part of the frontal cortex

dorsolateral frontal cortex

top and outer part of the frontal cortex

ventromedial hypothalamus

bottom, middle part of the hypothalamus

posteromedial hypothalamus

back, middle part of the hypothalamus

anatomical divisions

divisions for physical structure, landmarks in the brain/cytoarchitecture (ex; frontal lobe, brodmann area 17)

functional divisions

divisions based on the area’s function so patterns of activity and role in cognitions (ex; primary motor cortex and broca’s area)

broca’s area

responsible for the expression of language, when damaged ppl can’t produce speech but they can understand it

telencephalon

includes the cerebral cortex and subcortical nuclei, this is also know as the forebrain which includes the outer layer of the brain, it is covered by meninges and floats in CSF, it is included in limbic system structures

diencephalon

includes the thalamus, hypothalamus, lateral geniculate and medial geniculate

mesencephalon/midbrain

includes the tectum and tegmentum

metencephalon

includes the cerebellum and pons

myelencephalon

includes the medulla, it is important for sensory information/incoming tracts and motor information/outgoing tracts

forebrain

telencephalon and diencephalon

hindbrain

metencephalon and myelencephalon

cerebral ventricles

hollow regions filled with CSF, there are two c shaped lateral ventricles, third ventricle in the midline and the fourth is between the cerebelum and brain stem connected to the third ventricle

cerebral aqueduct

connects the 4th ventricle to the 3rd one

central nervous system (CNS)

consists of the brain and spinal cord encased in bone, skull and vertebrae respectively

peripheral nervous system

everything outside of the CNS, includes somatosensory (afferent) nerves, motor (efferent) nerves and the autonomic nervous system

somatosensory (afferent) nerves

arrives, signals going into the system

motor (efferent) nerves

takes info out of the nervous system to cause action into the muscles

enteric nervous system

involved in the contraction of smooth muscles and other internal organs

microglia

involved in synaptic pruning and secretion, they are immune cells that eat up excess debris and by products of the cellular system

oligodendrocytes

provide trophic support, responsible for presynaptic regulation, provide the myelin sheath that helps with conduction of electrical information

astrocytes

involved in neurotransmitter release, extracellular environment regulation, and synapse engulfment, they modulate responses, and they are involved in regulating the blood-brain barrier

OPC (NG2) glia

responsible for bidirectional synaptic communication, synapse elimination and secretion

sensory neurons

usually unipolar or bipolar, processes are extensions from the cell body to determine the polarity

gray matter

cell bodies of the neurons in the CNS

white matter

axons carrying info from one region to another in the PNS, they are information highways consisting of axons and neurons, they connect different regions to one another

neurons

excitable cells that generate and conduct electrochemical signals

dendrites

detect neurotransmitters and generate post synaptic potentials

cell body

contains organelles for sustaining function and creating new proteins

axon hillock

location where potentials from dendrites is integrated

axon

response for action potential transmission

axon terminal

sends neurotransmitter to subsequent cell

transmission of information

the action potential drives synaptic vesicles to fuse with the membrane, then the neurotransmitter inside the vesicles spills out into the space between the presynaptic and postsynaptic neuron (dendrite), the neurotransmitter interacts with the receptor on the postsynaptic neuron, this interaction induces a PSP, and they combine with others to encourage or discourage potential firing

lock and key

the idea that certain receptors are needed for certain molecules to be recognized

amino acids

class of neurotransmitters that include glutamate (GO) and GABA(STOP)

systems neurotransmitters (modulators)

a class of neurotransmitters that includes serotonin, acetylcholine, dopamine and noradrenaline

serotonin (5HT)

involved in regulating mood, sleep and pain, implicated in depression and anxiety

acetylcholine (Ach)

supports learning, memory and attention

dopamine (DA)

involved in reward, motivation and reinforcement learning, involved in parkinson’s and addiction

noreadrenaline (NE)

enhances attention and arousal

cortex

mostly made of gray matter, the outer layer of the cells are called bark, highly wrinkled and thin in humans, made of gyri (bumps) and sulci (folds)

longitudinal fissure

divides the hemispheres

central fissure

frontal (located at the precentral gyrus before the fissure) and parietal (located at the postcentral gyrus after the fissue) lobes

lateral fissure

separates the top half (frontal and parietal) from the bottom half (temporal) of the brain

insula

this is a cortical region located between the temporal and frontal lobe deep within the lateral (sylvian) fissure, it is responsible for taste, pain and salience, it is important for emotional responses like disgust

neocortex

makes up 90 % of the cortex, made of 6 layers, it is more evolved and explains the majority of higher order behaviors, it enables us to have certain higher order cognitive abilities

allocortex

makes up 10% of the cortex, made of 3 layers

basal ganglia

a subcortical region of the brain, its a group of brain structures that play an important role in motor control, executive functions and reward learning, it plays a role in parkinson’s and huntington’s disease as well as addiction

ventral striatum

involved in habit control and learning, part of the nucleus accumbens, relevant to addiction

caudate and putamen

dorsal striatum as well as globus pallidus, important for movement

the limbic system

includes the cingulate cortex, the hippocampus, amygdala, mamillary body and the septum, it has many functions like emotion regulation, memory formation, motivation and reward, autonomic regulation and olfaction

hippocampus

located in the medial temporal love, responsible for forming new episodic memories and the rich retrieval of those memories, if disrupted it can cause anterograde amnesia, alzheimer’s disease, epilepsy and spatial disorientation

amygdala

it plays a role in emotion, arousal, reward, decision-making, memory (modulation), anxiety, fear and decision making, it plays a significant role in mood disorders

bilateral amygdala damage

in the case of patient SM, they were unable to recognize fear in facial expressions

anterograde amnesia

when you can’t form new memories after onset of the region

thalamus

all senses have to go through it except for olfaction

medial geniculate

responsible for auditory info going into the thalamus

lateral geniculate

responsible for visual info going to the thalamus

brainstem

includes the medulla, pons and midbrain, it is responsible for basic bodily functions like respiration, heart rate, thirst, hunger and sleep/wake cycle

superior colliculus

the vision related area of the midbrain

inferior colliculus

the auditory related area of the midbrain

substantia nigra

the area of the midbrain responsible for motor coordination

ventral tegmental area

the area of the midbrain responsible for reward and dopamine

reticular formation

the area of the brain responsible for arousal

periaqueductal grey area

the area of the brain responsible for nociception/pain

cerebellum

part of the metencephalon, plays a major role in cognition

commissural fibers

connects from side to side

projection fibers

connects from top to bottom

association fibers

connects within the same lobe different cortical regions

MS lesions

can be very widespread and leads to overall slower processing and cognitive dysfunction, causes deficit in processing speed

arcuate

connects the temporal and frontal lobe, involved in language (the regions in the broca’s area are in the left inferior frontal lobe)

uncinate

connects the temporal and frontal lobe but involved in memory and emotion

inferior longitudinal

connects the occipital and temporal lobes for object recognition