From Stream of Conscious to Flash Memory : Required Neuronal Machinery

1. From Stream of Conscious to Flash Memory: Required Neuronal Machinery Samantha Ganz and Donald M. O’Malley Dept. Biology & Program in Behavioral Neuroscience SG supported by the Eileen Robert Matz Coop Scholarship MACHINERY: The fleetingness of experience might entail TARGETED plasticity, generated perhaps by a conjunction of neuromodulatory, oscillatory and/or attentive processes, possibly involving Basal Ganglia. This process might depend upon neocortical prediction stretching forward across time scales, operating perhaps as semantic contextual-prediction enables grammatical mismatch detection as early as 120 msec post-outlier (Dikker et al. 2010). The active trans-cortical state is the precursor to flash memory, although DMRs generally encode (in a retrievable form) but a tiny fraction of our entire SoC. FM is thus a second filter operating on energized, transcortical networks to bind the elements of each conscious epoch. DMR Analysis Scoring Criteria for Items in DMRs Frequency of Item Occurrence Fifty-three NU students were asked to record a brief epoch of their DMR as an extra credit assignment and 38 responses were received. All identifying information was stripped before analysis. Based on DMR content we established categories of memory items and quantified their frequency of occurrence. We attempted to roughly link the DMR memory components to specific regions of human neocortex and associated structures, based on ascribed functions in the neuroscience literature. FLASH MEMORY 1. Utilizes Stored Representations 2. Has a Capacity that is Proportional to Related Prior Experience 3. is Likely Stored in Neocortex 4. is Largely Non-Linguistic 5. is an Excerpt of Conscious Experience 6. Perhaps relies on CEP mechanism? Consciousness-Enabling Plasticity Working Theory • DMR content reflects trans-cortical processing and is constructed mainly from past experience • DMR content is mostly non-linguistic items but they can be both Abstract and Symbolic • The FLASH mechanism links active representations perhaps via coupled oscillators & silent synapses(Gioioso & O’Malley, 2009) • Hippocampus may help to sequence DMR content (Jensen and Lisman, 2005) • DMRs are perhaps utilized for many hours post-writing via analytical & memory consolidation processes • Analysis of patient DMR content might provide insight into neurological & psychiatric problems Training the Network Evolutionary Specifications define the precise, virgin form of neocortical, hippocampal and subcortical architectures Innate Knowledge reflects the evolutionary encoding of specific crucial memories e.g. recognition of prey items, visual cliff, etc. (Baum 2004) Acquisition of Experience: Massively entangled, context-driven representations of the world are laid down in neocortex w/ hippo. help Contextual Linkages: Experiences are stored as both single items and as pieces of extensively interconnected contextual memories Ongoing Experience utilizes stored information to construct unified snapshots or epochs of the world Flash Memory furtheruses pre-existing representations AND linkages. Semantics Comes from Experience: In parallel with FM’s storage of life experiences, the semantic system binds arbitrary symbols to experiences DMR Content Construction of Conscious Experience Consciousness is a highly synthetic construct (Baars and Franklin, 2005). Neocortical Prediction (Hawkins, 2004): Contextual Prediction enables rapid interpretation and integration of incoming signals. ThalamoCortical Arrays massively parallel WTA algorithms operate across size scales, modalities and cortical domains to resolve the world.  Invariant Representation: Autoassociative Nets (WTA operations) define / recognize objects, people, places, actions, thoughts and feelings. Hierarchical Evaluation of Inputs: Inputs are evaluated for novelty, salience and immediacy en route to potential conscious representation. Contextual Binding: The conjunction of WTA analyses with spatial and dynamic structure (and neocortical prediction) flows to unified experiences. Basal Ganglia Role? Role in SoC Decision-Making? Sequences thoughts? Consciousness-Enabling Plasticity creates quite transient yet integrated transcortical experience (which is distinct from STM/WM/LTM systems).  Flash Memory System excerpts epochs of consciousness and stores iconic replicas in our Daily Memory Record (DMR). FM is an excerpt of Transcortical Representations and as such seems transcortical (as opposed to hippocampal) in nature. FLASH PROCESS Analysis of DMR content revealed frequently recurring items such as people, objects and places. DMRs also showed a clearly chronological structure, in virtually every case. Although DMRs are conveyed using language, the content of DMRs is largely non-linguistic in nature and uses items as the “glue” of the chronology. Transcortical Representations: DMR items reflect widely distributed processes. As an example of Integrated Information, sounds represent items, locations and actions (e.g. of children, cars, dogs) which may rely on invariant representations, known functions, spatial arrangement and other neuronal coding schemes spread across cortical and subcortical structures. WTA = Winner Take All GENERAL INTRO SELECT REFERENCES Flash Memory (FM) is the effortless storage of our day’s experience into a Daily Memory Record (DMR). While the precise size of this store has not been quantified, it vastly exceeds the short-term and working memory stores typically studied (Baddeley, 1992), and is consistent with the large capacity of object-recognition memory (Brady et al., 2008). While DMRs normally fade over several days (with the residues becoming enduring episodic memory; Tulving, 1984), in some individuals these stores are extremely long-lived (Parker et al., 2006). We present here a quantitative analysis of DMR content, as recorded by NU students. These excerpts of our Stream of Consciousness (SoC) are surprisingly detailed and comprised of highly-processed and integrated experiences including internal mental activity. The often symbolic content of DMRs, and the one trial or “flash” writing process, together suggest a neuronal mechanism whereby linkages between stored experiences are flashed ON and chronologized as successive information passes thru SoC.