[Recurrent dysregulation of body temperature during antipsychotic pharmacotherapy]. / Rezidivierende Temperaturregulationsstörung unter Therapie mit Neuroleptika.

OBJECTIVE: This case report presents a rare, potentially life-threatening vegetative disturbance, which can occur during pharmacotherapy of schizophrenia. METHOD: A retrospective descriptive transversal and longitudinal section consideration of in-patient treatments of one female was performed. RESULTS: A 50-years old woman suffering from oligophrenia and disorganized psychosis (ICD-10: F71, F20.1; DSM-IV: 318, 295.10) successively evolved hypothermias up to 32.0 degrees C rectal, between them fever up to 40.0 degrees C rectal, hypothermia-accompanied bradycardias up to 32/min, recurrent subclinical hypoglycaemias up to 55 mg/dl and somnolence until coma under benperidol with levomepromazine or melperone, pipamperone with and without amisulpride, promethazine as well as zuclopenthixole. Within hours the hypothermias responded to antipsychotic drug holiday. No pathbreaking finding could be ensured on levels of internal medicine, toxicology, neurology as well as neurophysiology including a transient aetiologically uncertain partial insufficiency of the adenohypophysis. CONCLUSIONS: During long-term treatment with antipsychotics especially in higher dosage unpredictable vegetative crises may occur. Antipsychotics having pronounced 5HT2- and D2-antagonism seem to be rather associated with hypothermia. We recommend in case of hypothermia below 35,5 degrees C immediate antipsychotic or anticholinergic drug discontinuation, usage of benzodiazepines like lorazepam for a few days and a following trial with ziprasidone, aripiprazole or clozapine. These atypical neuroleptics show receptor binding profiles potentially advantageous in hypothermia.

Stimulus-Dependent Assembly Formation of Oscillatory Responses: I. Synchronization.

Current concepts in neurobiology of vision assume that local object features are represented by distributed neuronal populations in the brain. Such representations can lead to ambiguities if several distinct objects are simultaneously present in the visual field. Temporal characteristics of the neuronal activity have been proposed as a possible solution to this problem and have been found in various cortical areas. In this paper we introduce a delayed nonlinear oscillator to investigate temporal coding in neuronal networks. We show synchronization within two-dimensional layers consisting of oscillatory elements coupled by excitatory delay connections. The observed correlation length is large compared to coupling length. Following the experimental situation, we then demonstrate the response of such layers to two short stimulus bars of varying gap distance. Coherency of stimuli is reflected by the temporal correlation of the responses, which closely resembles the experimental observations.

Stimulus-Dependent Assembly Formation of Oscillatory Responses: II. Desynchronization.

Recent theoretical and experimental work suggests a temporal structure of neuronal spike activity as a potential mechanism for solving the binding problem in the brain. In particular, recordings from cat visual cortex demonstrate the possibility that stimulus coherency is coded by synchronization of oscillatory neuronal responses. Coding by synchronized oscillatory activity has to avoid bulk synchronization within entire cortical areas. Recent experimental evidence indicates that incoherent stimuli can activate coherently oscillating assemblies of cells that are not synchronized among one another. In this paper we show that appropriately designed excitatory delay connections can support the desynchronization of two-dimensional layers of delayed nonlinear oscillators. Closely following experimental observations, we then present two examples of stimulus-dependent assembly formation in oscillatory layers that employ both synchronizing and desynchronizing delay connections: First, we demonstrate the segregation of oscillatory responses to two overlapping but incoherently moving stimuli. Second, we show that the coherence of movement and location of two stimulus bar segments can be coded by the correlation of oscillatory activity.