A Framework for Investigating Thalamocortical Activity in Multistage Information Processing

Abstract

A framework for investigating information processing in cortico-thalamocortical (cortico-TC) networks is presented, that in part can be used to model and interpret individual changes in electroencephalographic spectra and event-related potentials such as those from the Brain Resource International Database. Scientific work covering neurophysiology, TC firing modes, and TC models are explored in the framework to explain how the brain might process complex information in a multistage process. It is proposed that the thalamus and the cortico-TC system have unique ionic properties and transmission delays (in humans), which are suited to the function of taking "snapshots" or samples of complex environmental stimuli, rather than continuous data streams. This leads to careful and sequential coordination of stimulus and response processes, and increases the probability of information transfer and the resulting information complexity in higher cortical regions. Given the scope of this framework, the multidimensional and standardized Brain Resource International Database provides a pertinent set of measures for both testing hypotheses generated from the model, and for fitting the model to experimental data to investigate mechanisms underlying information processing.

Brain Structure and Function Correlates of General and Social Cognition

“…Presumably, this style of more rapid propagation does benefit from faster neural processing, as reflected by the faster latency ERP components. However, as the processing load increases, as observed predominantly with the executive function factor, we suggest that ERP latencies will increase as the cortex shifts into a more optimal range of processing that leads to sufficient temporal delays that permit processing of complicated stimuli and relationships [87].…”

“…This is somewhat counterintuitive to findings that often associate cognitive abnormalities and poorer cognitive performance with delayed ERP components [63,78,98]. Like the theta/beta1 measurement, perhaps there is a more optimal latency of event-related processing in the frontal cortex that facilitates more efficient processing [87].…”

“…In contrast, an increase in the amplitude of positive-going components is associated with a decrease in general cognitive performance on such tasks. According to the ERP model of Rennie and Robinson et al [79], negative-going components are initially generated by positive thalamocortical volleys that represent broad excitatory activation of their target cortical areas [87]. By contrast, positive-going components reflect more inhibitory and focal actions such that there is a narrowing or focus of the thalamocortical activation in the neocortex.…”

“…The extent of the structural differentiation is such that at the local level, the visual cortex contains less diffuse and less combinatorial connections between neighboring neurons compared to the frontal cortex. In addition, the processing in the visual cortex can be considered relatively simple compared to the complex processing that occurs in the frontal cortex, and which is believed to be responsible for human intelligence, complex reasoning, creativity and personality [87]. The frontal cortex is built with a different neural structure, with diffuse and more intricate connectivity between neighboring cells.…”

“…Scientific evidence is emerging to suggest optimal delays in the transfer of neural impulses via thalamocortical circuitry through to the neocortex is crucial for increasing the probability of neocortical activation in response to a stimulus [45,58,94]. It is hypothesized that these spatial and temporal relationships between neural activity in corticothalamic and thalamocortical pathways are responsible for the higher intelligence and complex information processing capacity observed in humans [87].…”