The Corticohippocampal Circuit: Anatomy Flashcards
what controls executive control in the circuit?
dlPFC
what connection controls dopaminergic modulation?
connection between midbrain and dlPFC
what controls integration and storage of multiple sources and modalities of information
sensory association areas
what controls encoding and recall of declarative memories?
hippocampal formation
how does information move in this circuit?
bidirectional, generalized and flexible circuit
cortical regions
nearly 360 distinct cortical regions
Brodmann areas
identified nearly 50 on each hemisphere
how did brodmann identify areas?
- looking at post-mortem brain
- looking at the structure of cells in the cortex
columns and layers in cortical region
columns and layers within columns
(ex. single rat whisker has one to one connection with column in brain) similar to humans
1 to 1 ratio in humans
can do this with visual, audio, sense of touch, motor functioning in humans
homunculus through the years
got it wrong, between single one to one mapping is action/ body, which creates better control of body and mind
columns layer 3
intra cortical communication
primarily supports PFC connections with other regions
(critical executive control) how different layers of cortex communicate with each other
column layers 4
input
column layers 5-6
output
to all subcortical targets (hippocampus, amygdala, VS, thalamus, brainstem)
layers
gabaergic inhibitory neurons (shaping input and output of pyramidal neurons)
communication between dlPFC and sensory association areas
dorsal (“Where”) stream
primary visual cortex (goes to dorsal and ventral)
ventral (“What”) stream
unimodal –> heteromodel (info processing)
(goes from one to many modes of info processing)
PFC - heteromodal hotspots
where does dlPFC get info from?
auditory cortex, posterior parietal cortex, motor structures, medial temporal structures, inferior temporal cortex
STUDY: brain size and connectivity
early brain development experiences a massive expansion of size
- no new neurons but greater connections of existing neurons (synaptic density)
what is synaptic density?
greater connection of existening neurons
differentianes human brain from other brains
pruning
around 6 years old, thinning of connections
activity dependent pruning, to make us a highly efficient system
why PFC last to mature?
takes not of time to separate the signal from the noise
Hippocampal formation
supports declarative memories
little change with development bc critical to survival
HF anatomy
tail, body, head
“seahorse”
gray matter of HF
cornu ammonis (CA)
anatomy of tail
dentate gyrus –> cornu ammonis –> entorhinal cortex –> parahippocampal cortex
subiculum around
midbrain
DA signaling from VTA critical for input-dependent activity of dlPFC
