L10 Hippocampus pt 2 Flashcards
The hippocampus plays a role in integrating _______ and _______ input into ____________. It has connections to and from ________ areas, and is part of the ___________ system, so has connections with the ____________.
Integrates visual and spatial input into behaviour
Has cortical and subcortical connections, ie amygdala, limbic system
Using rodents as a model, the hippocampus can be divided into 3 different sections, which are?
Septal, intermediate, and temporal
In humans, the rodents septal hippocampus is equivalent to the humans ____________ hippocampus, and the temporal hippocampus is equivalent to a humans _________ hippocampus.
Rodent septal = human posterior
Rodent temporal = human anterior
How as the hippocampus divided in terms of cell function, in rodents(basic explanation), and give an example for each?
Septal for visual and spatial info processing, i.e place cells
Intermediate for behavioural outputs, i.e locomotor drive, fear related sensorimotor control
How is place cell processing organized from septal, to intermediate, to temporal hippocampus?
Place cell firing much more accurate in septal hippocampus, so hypothesized this area encodes for place cells. Firing reduces an accuracy, so more widespread and less specific, as you travel down intermediate to temporal hippocampus.
NMDA stimulation of hippocampus to the ___________ and __________regions of the hippocampus drove locomotor activity, but the ________ hippocampus did not.
NMDA to temporal, and then intermediate, drove locomotor activity, but not NMDA to septal
It is believed that the temporal and intermediate hippocampus have direct links to the ___, ___________ ________ and _____, where activity passed through these connections drive ___________________ transmission. Microdialysis studies further support this, with increased NAC and PFC ______________ following _____________ and ____________ hippocampal stimulation.
Temporal and intermediate hippocampus drive behavior with links to PFC, VTA and nucleus accumbens, where activation drives dopaminergic transmission.
Stimulation of temporal and intermediate hippocampus increases dopamine transmission in NAC and PFC.
In the watermaze task, ________ trials can be used to measure the rats time spent in the _________ zone relative to ______ zones.
Use probe trials to measure time spent in correct zone relative to time spent in all zones
In a one trial place learning lesion task, lesions to the tips, sparing the intermediate region, _______________________________ accuracy and rapid place learning. Lesions to __________ and ____________ regions respectively, caused the greater deficits.
Sparing intermediate left performance on rapid trial place learning relatively intact
Lesions to septal and temporal respectively caused biggest deficits.
Other than whole hippocampal lesions, a combined ____________-____________ hippocampal lesion caused the greatest deficits in one rapid trial place learning. It is thought however that _________ ___________ itself is intact, but cannot be translated into behaviour.
Combined hippocampal intermediate temporal lesion lead to greatest deficits other than complete lesion - place learning encoding intact, but cannot translate into behaviour
Despite lesions causing deficits in rapid place learning, what was relatively intact?
Whilst encoding of rapid place learning was effected by lesions, on day 6 performance no different from control, and slow incremental place learning was intact
The dissociation from learning and behavioural outcome was further showed in findings where lesions to the hippocampus left only the septal region spared. What evidence showed this?
A Place cell firing still occurred in the septal hippocampal area, when the rat was in a specific area in the spatial field
B Rats could still find their way through a maze, after only a couple trials
C Evoked potential recordings show that plasticity still took place at the entorihinal-temporal input regions
D Both A and C
D both A and C
Knowing the role of the hippocampus in integrating spatial learning into behaviour, how might hippocampal dysfunction/overactivity in SZ lead to symptoms?
Projections of temporal (anterior hippocampus) to frontal, attentional, striatal networks might disrupt cognitive functions - overactivity projected to dopamine transmission might disrupt this.
What are two main experimental methods to study how hippocampal overactivity in SZ relates to network alterations and behavioural impairments?
MRI and PET in humans to examine connectivity and activity
In animals, neurochemical, functional, electophysiological imaging and effects of GABA inhibition
Measures of blood flow showed increased cerebral blood flow in the anterior region of the hippocampus in _____ patients, as well as ___________ patients who went on to have ___________. Anterior hippocampal blood flow correlated with _________ symptoms in SZ.
Increased anterior hippocampal blood flow in SZ patients, and prodromal patients who went on to have psychosis.
Correlated with delusional symptoms of SZ.
Hippocampal overactivity is found in SZ patients, and correlated with deficits in what cognitive tasks?
A Visual learning
B Working memory
C Attention and vigilance
D all of the above
D all of the above
Hippocampal induced overactivity in rats using _________ receptor blockers, increased neural firing ________, and lead to deficits in the _______ _______ task as well as a __________ ___________ task.
Hippocampal induced overactivity using GABA receptor blocker
Increased neural firing spikes, and lead to deficits in attention task and visual spatial learning water maze task.
