Normally the hippocampus delivers 700 new cells daily: Spalding et al Spalding et al
1:- glutamate overactivityN.B. [ hippocampal failure in neurogenesis would lead to this - reduced neurogenesis means reduced inhibition on Ca3, to glutamate overactivity.
2 :-dentate neurogenesis
The hippocampus keeps the brain networks ready to deal withliving in theworld around them, by a steady alerting low wave distribution.
see ready at rest
roots of NG
origin hippo DG ng
ng diversity origin ? pruning and Immunity problems?
? pruning and Immunity problems?
Sekar et al :-
Schizophrenia is a heritable brain illness with unknown pathogenic mechanisms.
Schizophrenia's strongest genetic association at a population level involves variation in the major histocompatibility complex (MHC) locus,
but the genes and molecular mechanisms accounting for this have been challenging to identify.
Here we show that this association arises in part from many structurally diverse alleles of the complement component 4 (C4) genes. We found that these alleles generated widely varying levels of C4A and C4B expression in the brain, with each common C4 allele associating with schizophrenia in proportion to its tendency to generate greater expression of C4A. Human C4 protein localized to neuronal synapses, dendrites, axons, and cell bodies.
In mice, C4 mediated synapse elimination during postnatal development.
These results implicate excessive complement activity in the development of schizophrenia and may help explain the reduced numbers of synapses in the brains of individuals with schizophrenia.
the possible connection of immunity response to a cause of pruning, leading to schizophrenia
If immunity plays a part, might it lead to this new treatment ;- go to So, should a trial goes ahead
Well, it might raise questions about capacity of patient subjects to fully understand, to give informed consent.
Side effects of monoclonal anti bodies: Natalizumab
Hippocampal failure is the proximate cause of schizophrenia.
Click these academic references- those supporting and affirming hippocampus failure So, hippocampus early development will be an important start in thinking how and why things have gone wrong.
[ Schneider describes aprimary delusion ..... = abnormal salience ..... something normally considered insignificant is taken on as significant by sufferer, becomes the basis for a delusional belief.
Beta oscillations play at least two important roles in the processing of incoming task stimuli in healthy subjects, the second of which is disrupted in schizophrenia.
"First, both relevant and irrelevant task stimuli induce a rapid but transient phasic reduction in beta amplitude relative to baseline, probably due to the retuning of local excitatory-inhibitory encoding circuits from the beta to the gamma range."
[ We know that different gamma waves sort out access to which new things are perceived. But how for example how does the amygdala give emotional value priority - how to 'click' on which of the gamma assignments should go into available longterm store for usefully held context enables an intention to proceed correctly ]
"Second, in response to task-relevant stimuli, there is enhancement of a more gradual phasic increase in beta amplitude relative to baseline, postulated to represent a beta signal implicated in integrating information across widely distributed brain regions. Together, these two opposing beta effects (early suppression of local beta in favor of gamma; more gradual increase in long-range beta integrative signal) sum to produce an initial net beta amplitude reduction (beta ERD) followed by a sharp increase (beta ERS).
In schizophrenia, we conclude, the local beta encoding signal, reflected in the early beta desynchronization, is not abnormal. However, in the insula network, the integrative beta signal showed an attenuated response to task-relevant stimuli while conversely actually showed a significantly increased response to irrelevant stimuli.
Taken together with robust evidence for grey matter deficits in the bilateral insula, this suggests that in patients with schizophrenia a faulty salience network fails to signal the salience of task-relevant stimuli, resulting in disruption to the integrative processes required for efficient evaluation of stimuli and appropriate response selection.
Such disruption could lead both to failure to recognize what is relevant, and to attribution of salience to what is irrelevant"
From --- E B Liddle
Early hippocampus development
roots of adult ng
perinatal asphyxia and hippocampus damage
Perinatal hippocampus damage
hippocampus stem cells to .....
attention fixes hippocampus
two memories co-operates
stress shifts the memory stream
thalamic spindling: background
go to Striatum Studies
a Hub like this
The medial temporal lobes (MTL), and more specifically the hippocampus, are critical for forming mental representations of past experiences-autobiographical memories-and for forming other "nonexperienced" types of mental representations, such as imagined scenarios.[ ED: and futurepossibilities ] . Examining PHC connectivity patterns revealed that the PHC seed was distinctly connected to other MTL structures during the autobiographical task, to posterior parietal regions during the spatial task and to a distributed network of regions for the conceptual task. Examining hippocampal connectivity patterns revealed that the anterior hippocampus was preferentially connected to regions of default mode network during the autobiographical task and to areas implicated in semantic processing for the conceptual task whereas the posterior hippocampus was preferentially connected to medial-posterior regions of the brain during the spatial task. We interpret our findings as evidence that there are MTL-guided networks for forming distinct types of mental representations that align with functional distinctions within the hippocampus.
The perirhinal (PER) and lateral entorhinal (LEC) cortex form an anatomical link between the neocortex and the hippocampus. However, neocortical activity is transmitted through the PER and LEC to the hippocampus with a low probability, suggesting the involvement of the inhibitory network. This study explored the role of interneuron mediated inhibition, activated by electrical stimulation in the agranular insular cortex (AiP), in the deep layers of the PER and LEC. Activated synaptic input by AiP stimulation rarely evoked action potentials in the PER-LEC deep layer excitatory principal neurons, most probably because the evoked synaptic response consisted of a small excitatory and large inhibitory conductance. Furthermore, parvalbumin positive (PV) interneurons-a subset of interneurons projecting onto the axo-somatic region of principal neurons-received synaptic input earlier than principal neurons, suggesting recruitment of feedforward inhibition. This synaptic input in PV interneurons evoked varying trains of action potentials, explaining the fast rising, long lasting synaptic inhibition received by deep layer principal neurons. Altogether, the excitatory input from the AiP onto deep layer principal neurons is overruled by strong feedforward inhibition. PV interneurons, with their fast, extensive stimulus-evoked firing, are able to deliver this fast evoked inhibition in principal neurons. This indicates an essential role for PV interneurons in the gating mechanism of the PER-LEC network.
adolescence is a time of brain 'pruning'.
New August 2017 :-
Human Brains need the structure of a Story
Gazzinga. studying 'splitbrain' patients done for epilepsy suppresion concluded that the left brain does the cognitive and analytic work: the right brain organising the sensory/motor networks. fear arrives
New hippocampus academic research
Important - current academic references