Neuroanatomy Flashcards
What is the cerebrum divided into?
Frontal lobe
Temporal lobe
Parietal Lobe
Occipital Lobe
What are sulci and gyri?
Sulci: valleys
Gyri: ridges
The heavy foldings of the lobar surfaces
What are the primary (major) sulci?
More invariant in appearance than secondary sulci
What is the central sulcus?
Divides frontal lobe from parietal lobe?
What divides frontal lobe from parietal lobe?
Central sulcus
Where is the precentral gyrus?
Frontal lobe
Where is the primary motor cortex?
Precentral gyrus
Where is the motor homunculus?
Primary motor cortex
Where is the postcentral gyrus?
Parietal lobe
What is the postcentral gyrus?
Primary somatosensory cortex
Where is the sensory homunculus?
Primary somatosensory cortex
What is the Sylvian fissure?
Lateral sulcus
What divides the frontal lobe from the temporal?
Lateral sulcus
What does the Sylvian fissure do?
Divides frontal lobe from temporal.
What is the fifth lobe of the cerebrum?
Insula
Where is in the insula?
Deep in Sylvian fissure
What is the insula?
Seat of the primary gustatory cortex
Where is the middle frontal gyrus?
Between the superior and inferior frontal sulci
What is in the middle frontal gyrus?
Dorsolateral prefrontal cortex
What does the dorsolateral prefrontal cortex do?
Executive functions
Where is the cingulate sulcus?
Medial side of frontal lobe
Where is the seat of motivation?
Anterior position of adjoining cingulate gyrus
Which sulci are on the inferior surface of frontal lobe?
Olfactory and orbital sulci
What does the orbitofrontal cortex do?
Seat of associative learning and decision-making
What does the superior temporal sulcus do?
Primary auditory cortex
What separates the superior and inferior parietal lobes?
Superior temporal sulcus
What does the superior temporal sulcus do?
Seat of primary auditory cortex
What part of the cortex is involved in executive functions?
Dorsolateral prefrontal cortex
Where does decision-making and associative learning occur?
Orbitofrontal cortex
What is the inferior parietal lobe made of?
Angular gyrus
Supramarginal gyrus
What is the inferior parietal lobe important for?
Visuospatial attention
Where does visuospatial attention occur?
Inferior parietal lobe
Where is the primary visual cortex?
Calcarine sulcus in medial occiptal cortex
What is the sulcus in the medial occipital cortex?
Calcarine sulcus
What happens to higher level of associative functions in the hemispheres?
Lateralize to one or other hemisphere
Where is language comprehension?
Localized to left temporal corte
What is prosody?
Tonal modulation of speech
Where is prosody located?
Right hemisphere
Where is the dominant hemisphere?
Contralateral to dominant hant
What does the dominant hemisphere do?
Mediates language and speech functions
How can dominance be tested?
Annette’s handedness scale
Edinburgh handedness inventory
How many right-handed people have a dominant right hemisphere?
10%
How many left-handed people have a right dominant hemisphere?
20%
How many left handed people have left dominant hemisphere?
64%
How many left handed people have bilateral dominance?
16%
Where is the planum temporale?
Upper surface of superior temporal gyrus
Larger on left in 65% of people
What is the planum temporale?
Triangular region, important for language processing.
What is the most asymmetrical structure in the human brain?
Planum temporale
Which asymmetry is reduced or reversed in schizophrenia?
Plaum temporale
Signs in left hemisphere lesions
Aphasia Right-left disorientation Finger agnosia Dysgraphia (aphasic) Dyscaculia (number alexia) Limb aprexia
Signs in right hemisphere lesions
Visuospatial deficits Anosognosia Neglect Dysgraphia (spatial, neglect) Dyscalculia (spatial) Constructional apraxia Dressing apraxia
Which hemisphere lesion leads to face recognition?
Bilateral
What are the subcortical structures?
Limbic system Medial Temporal structures Basal ganglia Thalamus Hypothalamus
Who first described the limbic lobe?
Broca
Who first assigned the function of emotional processing to limbic structures?
Papez, then Maclean
What is the Papez circuit of the limbic system?
Hippocampus Fornix Mamillary bodies Mammillothalamic tract Anterior thalamic nucleus Genu of internal capsule Cingulate gyrus Parahippocampal gyrus Entorhinal cortex Perforant pathway Back to hippocampus
What are the boundaries of the limbic system post-Papez?
Include amygdala, septum, basal forebrain, nucleus accumbens, orbitofrontal cortex
Functions of limbic system?
Mediation of emotional responses via amygdala
Influencing neuroendocrine responses via hypothalamus
Reward system regulation via nucleus accumbens
Function of nucleus accumbens?
Reward system
Function of hypothalamus?
Neuroendocrine response
Function of amygdala?
Mediation of emotional repsonses
Fear conditioning
Emotional regulation
What are the medial temporal structures?
Hippocampus
Amygdala
Entorhinal and parahippocampal cortex
Function of hippocampus?
Memory processes
Continuous production of new neurons in adult life
What is the basal ganglia?
Group of gray matter nuclei
What is the largest subcortical structure?
Basal ganglia
Function of basal ganglia?
Planning and programming of movement
Concerting abstract thought into voluntary action
What is in the basal ganglia?
Striatum: caudate nucleus + putamen
Pallidum: globus pallidus
What are the lentiform nucleus?
Putamen and globus pallidus
What is the striatum in basal ganglia made up of?
Caudate nucleus
Putamen
What structures are functionally related to basal ganglia but not part of structure?
Substantia nigra
Subthalamic nuclei
Where does basal ganglia receive input from?
Glutamatergic corticostriatal projection
Who described the circuits in the basal ganglia?
Alexander
What are the important circuits in the basal ganglia?
Motor Oculomotor Dorsolateral prefrontal (executive) Anterior cingulate (motivation) Lateral orbitofrontal (social intelligence)
Which circuit in the basal ganglia is for social functioning?
Lateral orbitofrontal circuit
Which circuit in the basal ganglia is for motivation?
Anterior cingulate
Which circuit in the basal ganglia is for executive?
Dorsolateral prefrontal circuit
Disorders involving basal ganglia dysfunction
OCD Tourette's Huntington's chorea Wilson's disease CO poisoning Hemiballismus Parkinsonism Fahr's disease
What basal ganglia dysfunction causes OCD?
Volumetric changes + higher blood flow to caudate nuclei.
Increased caudate metabolism reduces after effective treatment.
What is he basal ganglia dysfunction in Tourette’s?
Striatal dopaminergic dysfunction
What is the basal ganglia dysfunction in Huntington’s chorea?
Degeneration of striatum - mainly caudate nucleus - and selective loss of GABAergic neurons
What is the basal ganglia dysfunction in Wilson’s disease?
Copper deposits in lenticular nuclei
What is the basal ganglia dysfunction in CO poisoning?
Acute bilateral anoxic damage to basal ganglia
What is the basal ganglia dysfunction in hemiballismus?
Subthamalic nucleus damage - especially infarction
What is the basal ganglia dysfunction in Parkinsonism?
Depigmentation of substantia nigra - Lewy bodies seen.
Striatal overactivity associated with bradykinesia
What basal ganglia dysfunction is linked with bradykinesia in Parkinsonism?
Striatal overactivity
What basal ganglia dysfunction is linked to Fahr’s diease?
Progressive calcium deposition in basal ganglia.
What is the thalamus?
Oval mass of grey matter nuclei in subcortial region.
What does the thalamus do?
Relays all types of sensory information except olfaction onto cortex.
Filter sensory information in preparation for cortical processing.
Relays cerebellar and basal ganglia inputs to cerebral cortex.
Structure of anterior thalamus
Receives mamillothalami tract and fornix
Connects to cingulate cortex
What does anterior thalamus do?
Relays information from hypothalamus and hippocampus onto frontal cortex
What in the thalamus is associated with visual attention?
Pulvinar
Where are sleep spindles in the thalamus?
Generated in reticular nucleus
Function of hypothalamus
Regulates physiological functions - eating, drinking, sleeping, temperature regulation
Neuroendocrine role
What is the ventromedial hypothalamus?
Satiety centre
Where is the satiety centre?
Ventromedial hypothalamus
Where is the feeding centre?
Lateral hypothalamus
What type of lesion leads to obesity in animals?
Lesion in ventromedial hypothalamus hyperphagia
Where is the inferior olivary nucleus?
Brainstem
What does the inferior olivary nucleus do?
Aids in motor coordination by projecting climbing fibres to contralateral cerebellar cortex via inferior cerebellar peduncle
Signs in inferior olivary nucleus lesions
Appendicular ataxia due to motor incoordination of contralateral arm and leg
Fail finger-nose test
Role of cerebellum
Preparing motor plan
Predicting balance needed between muscle groups to carry out action
Cognitive processes
Signs of cerebellar lesions
Ataxia Coarse intentional tremors Hypotonia Past pointing Pendular knee jerk
Function of cerebellum in schizophrenia
Disrupted cortico-cerebellar circuity can lead to cognitve dysmetria - difficulty in coordinating and monitoring process of receiving, processing and expressing information.
What is the brainstem made up on?
Midbrain
Pons
Medulla