Neuro2 Flashcards
How many neurons are estimated to be in the cortical gray matter?
10 Billion
What 6 layers make up the cortical gray matter?
Molecular External Granular External Pyramidal Internal Granular Internal Pyramidal Multiform
Name 5 types of important cells in the 6 layers of cortical gray matter.
Pyramidal Stellate Fusiform Horizontal cells of Cajal cells of Martinotti
What two directional categories does white matter have in relation to cortical gray matter?
Radial fibers - run toward the cortex
Tangential fibers - run parallel to the cortex
What is the smallest division of functionally-grouped activity within the cortex?
Vertical columns
Vertical columns form:
Functionally specialized areas
Functionally specialized areas of vertical columns are grouped together into anatomically distinct:
Lobes or Cortices
Lobes/cortices can be further grouped into other connected areas in:
Functional circuits
Functional circuits can be connected via what 3 pathways?
Association fibers (intra-hemisphere) Commissural fibers (contralateral hemisphere) Projection fibers (thalamocortical - fibers leave cortex and go ANYwhere other than cortex)
What do association fibers connect anatomically?
to the same hemisphere
What do commissural fibers connect anatomically?
to the opposite (contralateral) hemisphere
Where do projection fibers originate?
The Thalamus
Name 5 important functional areas of the cortex.
Primary Sensory cortices Sensory Association cortices Motor Planning cortices Primary Motor cortices Association cortices
Where is the primary somatosensory cortex?
Post-central gyrus
this is the sensory homunculus
What does a lesion on the somatosensory cortex cause?
Deficit in sensation from the opposite side of the body
hemi-anasthesia contralateral to lesion
Where is the somatosensory association complex?
Superior parietal lobe and supramarginal gyrus
this identifies the object you are feeling
Where is the primary visual cortex?
Cuneus and Lingual gyri
analyzes visual world without association
Where is the visual association cortex?
Medial and lateral occipital gyri
Angular gyrus
Where is the primary auditory cortex?
The auditory association cortex?
Superior Temporal Gyrus/Transverse Temporal gyri
Superior Temporal Gyrus
Wernike’s area is a specialized part of what?
function?
The auditory association cortex in the superior temporal gyrus.
Spoken language comprehension
What do the uncus, piriform cortex, periamygdaloid, and part of parahippocampal gyrus make up?
The Primary Olfactory Cortex
What is Agnosia?
Inability to recognize an object or to interpret sensory stimuli.
Name 3 types of Agnosia.
Tactile
Visual
Auditory
Where does executive function reside?
Frontal lobe
specifically: superior, middle frontal gyri, and medial frontal lobe
What is meant by Executive Function?
refers to all planning (motor, cognitive, emotional)
as well as regulate Affect with sensation
What can be termed a negative sign?
Loss of function (paralysis)
What can be termed a positive sign?
Abnormal function (hallucination)
What does the Limbic association cortex regulate?
Emotions, mood, affect, memory
closely tied to the sense of smell
What would a tumor or stroke cause if it was in the limbic system?
visual and auditory hallucinations
What cortex is involved in sensory integration (including interpretation), problem solving, speech, and spatial processing?
Parietotemporal Association Complex
What can a lesion of the non-dominant (usually right) Parietotemporal association complex cause?
Hemineglect Syndrome on the Left
this won’t effect speech because in most people it is localized in the left hemisphere
Where is the Primary Motor Cortex?
The precentral gyrus
Motor Homunculus
What will a lesion in the primary motor cortex cause?
Paresis (weakness/partial paralysis) in the opposite side.
Where are the Premotor Cortex and the Frontal Eye Fields?
Middle Frontal Gyrus
Where is the Supplemental Motor Cortex?
Superior Frontal Gyrus
Where is Broca’s area and what is its function?
Inferior Frontal Gyrus
speech planning
What are symptoms of Broca’s Aphasia?
Normal comprehension of language, but speech expression is limited
Define aphasia:
language disorder
Define apraxia:
disorder of sensory integration causing an inability to plan and perform complex movements
What is the inability to carry out spontaneous movement?
Akinetic apraxia
What is the inability to carry out movement on command (due to inability to remember command)?
Amnestic apraxia
What is the inability to perform complicated motor tasks called?
Motor apraxia
What is the inability to demonstrate use of objects called?
Ideational apraxia
What is the most common Apraxia?
Facial apraxia
the inability to perform facial-oral movements on command (like lick lips)
What one area is consistently an asymmetry in the brain?
Wernicke’s speech area
upper surface temporal lobe
What hemisphere is usually dominant/non-dominant?
Left usually dominant
What are some functions of the dominant hemisphere?
Language
Praxia (motor formulation)
Analytical skills (in math)
Sequential processing
What are some functions of the non-dominant hemisphere?
Prosody (emotion in voice) Spatial skills (analysis, math, orientation)
The cells of Martinotti tend to be:
Input
What is astereognosis?
tactile agnosia
inability to identify what is placed in hand without other sensory input
What is homonymous hemianopia?
Loss of 1/2 of the visual field
usually affects both eyes at midline
What is visual agnosia?
inability to determine what one is seeing
not a deficit in acuity
Are conscious location of sounds and auditory agnosia located in different areas?
Yes. Agnosia is more anterior
Where do (nearly) all the inputs to the cerebrum first synapse?
The Thalamus
VPL nucleus
Type/Input/Output/Function
Sensory relay
Ascending somatosensory pathways from body
Somatosensory cortex
Relays somatosensation of body to cortex
(the homunculus processor)
VPM
type/input/output/function
Sensory relay
Somatosensory from face/taste (V, VII, IX)
Somatosensory cortex
somatosensation from face/taste to cortex
(VPM island in VPL)
VL
type/input/output/function
Motor relay
Cerebellum and basal ganglia
Motor, Premotor, Supplemental motor cortices
motor from basal ganglia/cerebellum to cortex
VA
type/input/output/function
Motor relay
Cerebellum/basal ganglia
Widespread to frontal lobes
motor from basal ganglia/cerebellum to cortex
P
type/input/output/function
Association
Sensory pathways from Tectum (visual colliculi)
Parietotemporooccipital association cortex
Behavioral orientation to visual stimulus
Pulvinar - think visual association
LGN
type/input/output/function
Sensory relay
Retina
Primary visual cortex
visual input to cortex
little tonguelike thingy
MGN
type/input/output/function
Sensory relay
Inferior colliculus
Primary auditory cortex
Auditory information to the cortex
(teeny one on the bottom)
MD
type/input/output/function
Association
Limbic structures
Frontal cortex
Emotional/memory input to cortex
AN
type/input/output/function
Association
Limbic and Hippocampus
Cingulate gyrus
relays info from limbic system
What are the 3 main functions of the Limbic System?
Homeostasis - Hypothalamus
Memory - hippocampus
Emotions - Amygdyla
What regulates Homeostasis?
includes sex, behavior, autonomics, and endocrine
Hypothalamus
What regulates memory in the limbic system?
Hippocampus
What regulates emotions in the limbic system?
fear/anxiety center
Amygdala
What does Fornix mean?
Arch
What is an important pathway that converges cognitive activities, emotional experience, and expression?
Circuit of Papez
this is a Fornix circuit
Outline the pathway of the Circuit of Papez:
Parrahippocampal gyrus > hippocampus > fornix > mammilary bodies (part of hypothalamus) > thalamus > cingulate gyrus > parahippocampal gyrus
What does the Stria Terminalis connect?
Amygdala and Hypothalamus
What connects the Amygdala with the basal ganglia, olfactory cortex, cingulate gyrus, prefontal cortex, hypothalamus, and septal nuclei?
Ventral amygdalofugal pathway
What structure is a diffuse group of axons that carry info between amygdala, brainstem, and hypothalamus?
Medial forebrain bundle
Name 7 pathologies that arise when the limbic system is damaged:
Memory loss Olfactory dysfunction Emotional disturbances Autonomic and homeostatic dysfunctions Personality changes Changes in sexual behaviors and grooming Seizures
Where is the Pituitary housed?
Sella Turcica
What are the two divisions of the pituitary, and what structure connects it to the Hypothalamus?
Anterior/Posterior
Pituitary stalk called the Infundibulum
What is the glandular division of the pituitary?
Anterior
What is the neural tissue division of the pituitary?
Posterior
Name the 6 hormones secreted/synthesized by the Anterior Pituitary.
GH TSH ACTH FSH LH PRL
What other structure in the brain does the Anterior Pituitary have an endocrine relationship with and how is it connected?
Hypothalamus
Hypothalamic-Hypophysial portal system
Does the Posterior Pituitary make any hormones?
No! They just store hormones synthesized by neural tissue.
What are 2 hormones secreted by the Posterior Pituitary?
Vasopressin (aka - ADH)
Oxytocin
Pretty much every hormone in the Anterior Pituitary is mediated/controlled by hormones in the:
Hypothalamus
What is the most anterior region of the hypothalamus and what does it contain?
Preoptic region
contains medial and lateral preoptic nuclei
What are the 6 nuclei in the Supraoptic (anterior) region of the hypothalamus?
Periventricular nucleus Paraventricular nuc. Anterior nuc. Suprachiasmatic nuc. Supraoptic nuc. Lateral hypothalamic nuc.
What 5 nuclei make up the middle (tuberal) region of the hypothalamus?
Periventricular Arcuate (infundibular) Dorsomedial Ventromedial Lateral hypothalamic
What 3 nuclei make up the Posterior (mammilary) region of the Hypothalamus?
Posterior nuc.
Mammilary body
Lateral hypothalamic nucleus
Name 3 functions of the Hypothalamus:
Regulate circadian rhythms
Appetite/thirst
Thermoregulation
