Our lab investigates human memory and its neural basis utilizing a combination of behavioral, computational, and neurophysiological strategies. In our computational investigations, we construct mathematical and Memory Wave Audio laptop-simulation fashions to account for the dynamics of memory retrieval in a variety of episodic and spatial memory tasks. As a result of behavioral data supplies a sparse reflection of the brain’s activity supporting memory, we simultaneously file neurophysiological indicators as patients with arrays of implanted electrodes perform memory duties. In these investigations we research neural activity at multiple spatial scales, starting from particular person neurons to spatially-distributed networks of subject-potential activity supporting memory. A number of of our current initiatives additionally use electrical stimulation to manipulate memory circuits, both for understanding basic memory mechanisms and also for creating therapies to restore memory in patients with brain harm or neurological illness. Please click here for extra info and errata. To help explain the processes underlying encoding, group and retrieval of episodic recollections, now we have developed, prolonged and refined a category of models based on the concept gadgets in memory change into related to a time-varying representation of spatio-temporal context.

The temporal context mannequin (TCM; Howard and Kahana, 2002 and TCM-A Sederberg, Howard, and Kahana, 2008) sought to explain the time-scale invariance of recency and contiguity effects in free recall, and dissociations between recall of latest and remote memories. Subsequent modeling work generalized TCM beyond temporal context to account for the affect of semantic knowledge on recall dynamics (CMR, Polyn, Norman, and Kahana (2009)). MATLAB scripts to run the CMR model could be downloaded right here. Lohnas, Polyn, and Kahana (2015) provided a serious overhaul of the sooner CMR model, going past earlier modeling of individual lists to clarify the interplay between reminiscences realized across a number of experiences . Of their CMR2 model, memory accumulates throughout multiple experimental lists, and temporal context is used both to focus retrieval on a goal listing and to censor retrieved data when its match to the current context indicates that it was discovered in a non-target checklist.

The mannequin concurrently accounts for a wide range of intralist and interlist phenomena, including the sample of prior-list intrusions noticed in free recall, construct-up of and launch from proactive interference, and the power to selectively target retrieval of objects on particular prior lists (Jang & Huber, 2008; Shiffrin, 1970). Healey and Kahana (2015) used CMR2 to raised perceive why Memory Wave Audio tends to get worse as we age. By fitting CMR2 to the efficiency of particular person younger and older adults, they identified deficits in 4 critical processes: sustaining consideration across a research episode, producing retrieval cues, resolving competition, and screening for inaccurate reminiscences (intrusions). Healey and Kahana also extended CMR2 to simulate a recognition memory process utilizing the same mechanisms the free recall mannequin makes use of to reject intrusions. With out fitting any additional parameters, the mannequin accounts for age variations in recognition memory accuracy. Confirming a prediction of the model, free recall intrusion charges correlate positively with recognition false alarm charges.

MATLAB scripts to run the CMR2 mannequin will be downloaded here. Cohen and Kahana (2021, Psychological Assessment) launched CMR3 to include the crucial function of arousal and emotion in human memory. They utilized their mannequin to various phenomena including the function of emotion in organizing memories, state-dependent and mood congruent memory, the function of emotional experiences in producing persistent mood states, together with depression, and a novel account of PTSD and its therapy. A review of this line of research appeared in Kahana (2020), Computational Fashions of Memory Search, within the Annual Overview of Psychology. Python code that runs CMR2 and CMR3 may be downloaded from the lab's publication web page. We investigate the neurophysiology of episodic memory with electrocorticographic (ECoG) and single neuron recordings from neurosurgical patients who have had electrodes surgically implanted on the cortical floor of the mind or in the medial temporal lobes (together with hippocampus) as a part of the clinical technique of localizing seizure foci. One focus of this analysis is to find out the oscillatory correlates of successful episodic memory formation and retrieval. Analyses of such recordings have proven that prime-frequency activity (HFA, 70-one hundred fifty Hz) enhance whereas participants are studying words that they will efficiently, as opposed to unsuccessfully, recall.

EEG voltage traces for every item and measure when and the place power at specific frequencies modifications. Successful memory formation is associated with increases in HFA in left lateral temporal lobe, medial temporal lobe, and left prefrontal cortex. The identical analyses may be carried out on items during recall to assess when and where recollections are retrieved. Profitable memory retrieval is related to will increase in gamma band activity in the left neocortex and hippocampus as well as increases in theta band (four -eight Hz) activity in right temporal lobe. The flexibility to reinstate this contextual info throughout memory search has been thought-about a hallmark of episodic, or event-based mostly, memory. In Manning et al., 2011, we sought to determine whether contextual reinstatement could also be noticed in electrical indicators recorded from the human brain throughout episodic recall. We examined ECoG exercise from 69 neurosurgical patients as they studied and recalled lists of words in a delayed free recall paradigm (Fig. 4A), and computed similarity between the ECoG patterns recorded just prior to every recall with these recorded after the patient had studied every word.