Long-term follow-up of patients with obsessive-compulsive disorder treated by anterior capsulotomy: a neuropsychological study

BACKGROUND

For treatment-refractory Obsessive-Compulsive-Disorder (OCD) patients, anterior capsulotomy is a potential therapy. We investigated what kinds of cognitive deficits treatment-refractory patients have and how anterior capsulotomy modifies their clinical and cognitive profiles.

METHODS

Ten treatment-refractory OCD patients were examined in two groups (operated and non-operated) with 5 participants in each group, matched for symptom severity, gender, age and education. The operated group was treated with anterior capsulotomy; the non-operated group was treated only with pharmaco- and psychotherapy. The Yale-Brown Obsessive-Compulsive Rating Scale (Y-BOCS) was used to measure OCD symptoms, and ten neuropsychological tests were used to measure cognitive functioning.

RESULTS

In the operated group, the score of Y-BOCS score significantly decreased during the two-year follow-up period. Additionally, we found a significant increase in neuropsychological test scores on the Wechsler Intelligence Test (MAWI), California Sorting Test Part A (CST-A), Stroop Test Interference Score (STR-I), Verbal Fluency Test and Iowa Gambling Test. As a negative result, we observed intrusion errors in the Category Fluency Test. In the non-operated group significant improvement was found in Y-BOCS scores. At follow-up, we found significant differences between the operated and non-operated groups on three neuropsychological tests: Trail Making Test Part B, Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Attention Index and RBANS Language Index, with better performance in the non-operated group.

CONCLUSIONS

Both treatment methods (i.e. anterior capsulotomy and pharmaco- and psychotherapy) seem effective in reducing OCD symptoms and cognitive deficits, but, importantly, to different degrees. The clinical and neuropsychological improvements were more impressive in the operated group.

Frequency of gamma activity is modulated by motivation in the auditory cortex of cat

Repetitive acoustic stimuli elicit steady-state response (SSR) in the gamma-band both in humans and in mammals. Our aim was to investigate changes of the spontaneous gamma activity and the SSR in the auditory cortex of cats in the background of an instrumental conditioning situation. Epidural electrodes were chronically implanted above the auditory neocortex. The presentation rate of the clicks varied between 20 and 65/s. Spontaneous EEG and SSR were collected in three behavioral states: in an indifferent environment, in the instrumental cage while the cat was waiting for the light CS, and when she stepped on the pedal and was waiting for the meat reward. Using different repetition rate clicks we determined which stimulus rate elicited the largest SSR in these three situations. In quiet animal the highest SSR appeared at 28-30/s. Before and during the CS the optimal stimulus rate shifted to 32-38/s. The frequency of the spontaneous gamma activity changed in parallel way depending on the situation. We conclude that both the SSR and the spontaneous gamma activity reflect resonant activity of the same neuronal circuit of the auditory cortex, and it is modulated by the motivational state of the animal.

Separation of mismatch negativity and the N1 wave in the auditory cortex of the cat: a topographic study

OBJECTIVE

The amplitude distribution of the frequency mismatch negativity (MMN) and that of P1 and N1 components were investigated in cats to reveal their sources in the auditory areas of the neocortex.

METHODS

Pure tone stimuli were given in a passive oddball paradigm with different degrees of deviance between the standard and deviant tones. Amplitude maps of event-related potential (ERP) components were generated from the responses, recorded in awake, freely moving animals by a chronically implanted epidural electrode matrix, covering both the primary and secondary auditory fields.

RESULTS

The P1 and N1 components appeared with highest amplitude on the middle ectosylvian gyrus, while the amplitude maximum of the MMN was ventral and rostral to them on the AII area. Both the latency and the peak amplitude of the MMN depended on the degree of deviance.

CONCLUSIONS

The MMN is generated in the rostroventral part of the secondary auditory area, well separated from the sources of the P1 and N1 components.