J. Chládek

Executive functions processed in the frontal and lateral temporal cortices: intracerebral study.

OBJECTIVEnThe study was designed to investigate the neurocognitive network in the frontal and lateral temporal cortices that is activated by the complex cognitive visuomotor tasks of letter writing.nnnMETHODSnEight epilepsy surgery candidates with implanted intracerebral depth electrodes performed two tasks involving the writing of single letters. The first task consisted of copying letters. In the second task, the patients were requested to write any other letter. The cognitive load of the second task was increased mainly by larger involvement of the executive functions. The task-related ERD/ERS of the alpha, beta and gamma rhythms was studied.nnnRESULTSnThe alpha and beta ERD as the activational correlate of writing of single letters was found in the sensorimotor cortex, anterior cingulate, premotor, parietal cortices, SMA and the temporal pole. The alpha and beta ERD linked to the increased cognitive load was present moreover in the dorsolateral and ventrolateral prefrontal cortex, orbitofrontal cortex and surprisingly also the temporal neocortex. Gamma ERS was detected mostly in the left motor cortex.nnnCONCLUSIONSnParticularly the temporal neocortex was activated by the increased cognitive load.nnnSIGNIFICANCEnThe lateral temporal cortex together with frontal areas forms a cognitive network processing executive functions.

Changes in connectivity and local synchrony after cognitive stimulation – Intracerebral EEG study

Electroencephalographic studies utilize event-related power decrease/increase in order to analyze changes of neuronal activity in a single EEG channel during cognitive tasks. Other analytical approaches draw on bivariate methods which evaluate connectivity between two EEG channels. Despite the fact that spatial mapping of combined results of power and connectivity analyses may be used to study the dynamics of neuronal activation patterns, they are normally evaluated separately as different phenomena. Here we show the evaluation of dynamic changes in linear correlation after cognitive stimulation together with changes in power levels in the same channel pairs. Our results demonstrate the temporal evolution of synchronization patterns across the whole brain with a focus on the anatomical structure of the hippocampus. We observed a pattern of local and distant synchrony during cognitive processing, occurring 500 ms after stimulus onset in approximately 1% of all channel pairs. We hypothesize that evaluation of changes in connectivity, together with dynamic changes in power levels, can help identify dominant structures in the process of mental activity after a certain type of cognitive task. This can possibly lead to better understanding of synchronization processes at the neuronal and systemic level.

ID 44 – Comparison of P300 and MMN protocols in subthalamicus nucleus, internal globus pallidus and thalamus. Are these subcortical structures involved in thinking?

Introduction The aim was to compare evoked potentials (EP) from the P300 paradigm against mismatch negativity (MMN) paradigm, both recorded in the subthalamic nucleus (STN), internal globus pallidus (GPi) and thalamus (Th) and thus electrophysiologically isolate conscious cognition component in these structures. Methods We included 8 patients in Deep brain stimulation program and recorded EP (patients with Parkinson‘s disease, Generalized dystonia, Essential tremor, Epilepsy). The two four-contacts intracerebral electrodes were implanted into the left and right STN, GPi or Th bilaterally. We computed local potentials on the left and right electrode and we studied the latency of cognitive response (from 200 to 400xa0ms). Results In the comparison of infrequent stimuli related P300 and MMN a significant difference was found in 14 from 16 electrodes. Comparing frequent answers we found significant difference in 13 from 16 electrodes. Conclusion The difference between evoked potentials of MMN and P300 protocols in 200–400xa0ms latency suggests that STN, GPi and Th are involved in conscious cognitive processes at the time of stimuli application.

ARE SUBTHALAMICUS NUCLEUS, INTERNAL GLOBUS PALLIDUS AND THALAMUS INVOLVED IN THINKING?

Introduction The aim was to compare evoked potentials (EP) from the P300 paradigm against mismatch negativity (MMN) paradigm, both recorded in the subthalamic nucleus (STN), internal globus pallidus (GPi) and thalamus (Th) and thus electrophysiologically isolate conscious cognition component in these structures. Methods We included 8 patients in Deep brain stimulation program and recorded EP (patients with Parkinsons disease, Generalized dystonia, Essential tremor, Epilepsy). The two four-contacts intracerebral electrodes were implanted into the left and right STN, GPi or Th bilaterally. We computed local potentials on the left and right electrode and we studied the latency of cognitive response (from 200 to 400u2005ms). Results In the comparison of infrequent stimuli related P300 and MMN a significant difference was found in 14 from 16 electrodes. Comparing frequent answers we found significant difference in 13 from 16 electrodes. Conclusion The difference between evoked potentials of MMN and P300 protocols in 200–400u2005ms latency suggests that STN, GPi and Th are involved in conscious cognitive processes at the time of stimuli application.

55. Is nucleus subthalamicus involved in thinking? Separation of conscious and subconscious cognition component in the subthalamic nucleus using P300 and MMN protocols

Introduction P300 wave is considered a correlate of cognitive process and an oddball paradigm is used for its recording. MMN (Mismatch negativity) is considered a correlation of automatic sensory memory on a subconscious level and also a reflection of subconscious primitive sensory intelligence. When the MMN is recorded the same protocol as P300 paradigm is used, only with the difference that the proband pays no attention to the stimuli. The aim of this study was to compare evoked potentials from the P300 paradigm against MMN paradigm, both recorded in the subthalamic nucleus (STN) and thus electrophysiologically isolate conscious cognition component in this structure. Methods We included 3 patients (2 of whom were women) with Parkinson‘s disease and recorded the evoked potentials using protocols P300 and MMN during installation of DBS (Deep brain stimulation). The average age of the patients was 59 xa0±xa08xa0years, disease duration 9 xa0±xa03xa0years. The electrodes were implanted into the STN bilaterally and each wore four contacts on the left and on the right side (L1,2,3,4 and R1,2,3,4). We were interested in local potentials – in signal from the connection of contacts to each other on one intracerebral electrode (on each side 3 bipolar montages were monitored: L1-2, L2-3, L3-4, R1-2, R2-3, R3-4). We were interested in the latency of 200–400xa0ms - thus in the area of cognitive responses P300. Results When the averaged signal of infrequent stimuli between P300 and MMN paradigm was compared a significant difference between them in each left and right electrode at least in one montage was found. The same we found when comparing averaged frequent answers. There was also a statistically significant difference between the evoked potentials obtained during P300 paradigm and MMN paradigm. Conclusion and discussion The difference between evoked potentials of MMN and P300 protocols in latency of 200–400xa0ms suggests that STN is involved in conscious cognitive processes at the time of stimuli application. Thus the thinking – at a given time – is not a function of the brain cortex only. What component of the cognitive processes STN does represent cannot be exactly specified. Although oddball paradigm is very simple, during this paradigm the patient uses a variety of cognitive functions – attention, executive function, working memory, calculation and proper level of motivation is necessary too.

17. The contribution of intracranial eeg to research on the empathy for pain

In the last decade, a number of functional neuroimaging studies have identified a set of neural structures that are involved in empathy for another person’s pain. Bilateral anterior insular cortex and medial/anterior cingulate cortex seem to play a crucial role, but several other brain regions are also co-activated; this includes structures associated mostly with “Theory of Mind” or “mentalizing”, including precuneus, ventral prefrontal cortex, superior temporal cortex, and temporo-parietal junction. Electrophysiological pain-empathy responses have been analyzed to investigate the temporal dynamics of neural activity underlying this process. To the best of our knowledge, however, this has been performed with scalp recordings only; pain empathy-related brain potentials have not recorded using intracranial electrodes until now. In the present study, we investigated intracranial event-related brain potentials (ERPs) from three intractable epileptic patients who underwent preoperatively diagnostic invasive video-EEG monitoring. During the experiment, patients watched 3-second dynamic visual stimuli depicting needle injections into a left hand (Nxa0=xa042), or the same left hand touched by a cue tip (Nxa0=xa042). Intracranial EEGs were recorded using intracerebral and subdural electrodes, investigating in total more than 300 brain sites. The ERPs in each condition (needle and cue tip) were averaged separately off-line, and statistical differences in response amplitudes after painful vs. non-painful stimuli were detected. In all three subjects, significantly different event-related responses to painful vs. non-painful stimuli were observed in some investigated neural structures, including left-hemispheric temporo-parietal junction, right-sided temporo-occipital junction, and right-sided lateral occipital cortex. In these brain sites, painful needle stimuli evoked more prominent ERPs compared to cue-tip touch. The latency of these intracranial ERPs can be used for direct measurement of local activation with millisecond temporal resolution, and can be compared across different brain structures as well as with the scalp ERPs. Our pilot data demonstrate the ability of intracranial ERP recordings to contribute to our understanding of pain empathy. More generally, these data provide important insights into more complex social phenomena, and complement widely available functional neuroimaging data which are limited by their reliance on hemodynamic rather than direct neural measurements.

10. Electrophysiological correlate of auditory processing initiative on an unconscious level in the nucleus subthalamicus

Superior temporal sulcus (STS) is a brain structure, which has been related to many cognitive functions recently. It can be presumed that it is a part of many cognitive functions and that in particular situation, its relationship with other brain areas is relevant. Our work aimed to its effective connectivity during processing of potentially relevant unusual events. Twenty healthy volunteers were investigated by functional magnetic resonance during visual oddball task – they were instructed to react to different visual stimuli, randomly dislocated among frequent ones. Further processing was done by SPM5 programme. Next step was psychophysiological interaction analysis, method of effective connectivity. We have detected two areas related to target stimuli detection in STS. The anterior area had increased connectivity with mesiotemporal cortices, the posterior one with anterior cingulate cortex. We have found decreased connectivity of the anterior area with dorsolateral prefrontal cortex and the posterior area with parietal cortex – attention related structures. We can hypothesize that STS in detection of rare events is not related to attention, but to later stages of stimuli processing. This hypothesis is supported by association of STS and mesiotemporal areas.

P8.16 Neural cross-talk during discrimination of odds

Functional connectivity (FC) is crucial for cognition. Thus finding ways of increasing FC may facilitate improved cognitive performance. Our previous research demonstrates increased FC following Quadrato Motor training (QMT); a complex whole body movement technique performed in response to verbal commands; in female college students. Increased FC, specifically enlarged fronto-parietal alpha and temporal theta coherence, was accompanied by improved creativity and reaction time. However, while FC changes following motor training may be gender dependent, no research examined this issue. Therefore, the current study was aimed at examining gender dependent FC changes following motor training. 12 participants were tested (6 males) for FC changes following QMT. Electrophysiological changes were examined using a within-subject design, examining alpha and theta power and coherence. Cognitive performance was assessed using the Alternate Uses and Embedded Figures (EFT) tasks. Our main result was a distinct electrophysiological difference between females and males following QMT training; which mainly concerned significant decreased theta power and increased coherence in the female group. In addition, change in theta power was positively correlated with change in cognitive flexibility and negatively correlated with change in EFT in the female group; and positively correlated with change in EFT in the male group. Interestingly, increased cognitive flexibility following training was correlated with increased coherence in both genders. In conclusion, motor training has a differential effect on FC depending on gender and task context.

P5-24 Involvement of the subthalamic nucleus and globus pallidus internus in orientation and attention

disease (PD). In addition to motor symptoms, the patients with PD have been reported to show sensory processing deficits. Little has been reported on the effect of STN-DBS for sensory symptoms (especially temperature sensation and pain) in PD. The aim of this study is to quantitatively assess the effects of STN-DBS on temperature sensation and pain in PD by quantitative sensory testing. Methods: Participants were 17 patients with PD who underwent bilateral STN-DBS in Osaka University Hospital between 2001 and 2009 and 13 healthy controls. We assessed thermal thresholds for cold and warm and pain thresholds in the patients with PD in ‘DBS-ON’ and ‘DBS-OFF’ condition and in healthy controls by means of thermal quantitative sensory testing. Results: The cold sense and warm sense thresholds of the patients in ‘DBS-ON’ were significantly lower than those in ‘DBS-OFF’. And the cold sense and warm sense thresholds of the healthy controls ware significantly lower compared with those in ‘DBS-OFF’ of the patients with PD. On the other hand, the pain thresholds for cold and heat did not significantly differ between ‘DBS-ON’ and ‘DBS-OFF’. Conclusions: This finding suggested that temperature sensation of the patients with PD was disturbed compared with that of healthy controls, and STN-DBS could improve temperature sensation in the patients with PD. There are few reports about the effect and mechanisms of STN-DBS for temperature sensation. Therefore, we will report and discuss this result with consideration from literatures.

P5-14 Time-frequency and spectral analysis of auditory executive event-related potentials in subthalamic nucleus

In our present work we have noted clear 8-10 Hz activitynrelated to auditory ERPs. It is important to observe whethernsuch an activity can be replicated in higher number ofnpatients. We have not observed such an activity recorded fromnthe globus pallidum internum in a patient with generalisedndystonia (we do not report these results here). We alsonobserved the major activation in frequency of 20 Hz and more inndirect relation to P3-like potentials. Here, the correspondentnchanges were present in latencies of P3 potentials in standardnand modified protocols.