Effect of bemegride on root potentials of the frog spinal cord

The effect of the convulsant bemegride (β-ethyl-β-methylglutarimide) on spinal-root potentials was investigated in frogs. After intravenous injection in subconvulsant doses (5–12 mg/kg) bemegride caused rapid depression of the dorsal-root potentials evoked by stimulation of the neighboring dorsal or ventral root. Their amplitude fell by 55–67% 3–6 min after bemegride injection. The action of bemegride was reversible and the amplitude of the dorsal-root potentials returned to its initial level within 1 h. Ventral-root potentials showed greater fluctuations of amplitude after injection of bemegride than in the control. Bemegride is evidently an effective agent blocking depolarization of primary afferents in the frog spinal cord.     

Tono Reservoir fishery contribution to poverty reduction among fishers in northern Ghana

Fishery characteristics and livelihood status of fishers at Tono Reservoir, Ghana, were investigated between January 2015 and June 2016. Data on fisher demography, fishing gears, fishing methods, perceptions of the state of fish stocks, management practices, income and consumption of fishers were obtained through structured interviews. Censuses of fishers and fishing gears were conducted through direct observation and counts. The population of fishers was 950 and the majority (74%) of the sampled respondents fell within the ages of 24–41 years. Gillnet, cast net, trap and hook and line were the four main gears utilised. Illegal methods of fishing observed included the use of mosquito nets (nets with mesh <1.0 cm) and the use of brewer’s waste (pito mash) as bait. Brycinus nurse, Synodontis spp., Parailia spiniserrata and Chrysichthys spp. were perceived to have disappeared from the reservoir. The fishers were unaware of the existence of any fisheries regulations, hence there was no adherence to management practices. Their daily income was derived mainly from fishing. The incidence of poverty among fishers was low (8%). The Tono Reservoir has a great potential for supporting livelihood if it is properly managed.     

The Maloti minnow Pseudobarbus quathlambae (Barnard, 1938) is not extinct in South Africa

Despite concerted surveys, the Maloti minnow Pseudobarbus quathlambae (Barnard 1938) had not been recorded in South African waters for almost eighty years since the original collections were made at the type locality in the upper uMkhomazana River in 1938. The species was therefore declared extinct in South Africa, whereas extant populations were considered confined to various rivers in the Lesotho highlands. In April 2017, however, this species was rediscovered in the Mzimkhulu River system in KwaZulu-Natal. The rediscovery of a species that was considered locally extinct supports the need for extensive surveys to determine its distribution range, estimate population sizes, assess conservation status and implement effective strategies to ensure its continued existence in KwaZulu-Natal.     

Ipsilateral motor responses of the facial muscles to intracortical microstimulation in the white mouse

Motor responses (MRs) of facial muscles to intracortical microstimulation (ICMS) of lightly anaesthetized outbred white mice were observed visually and recorded by means of photodiodes. ICMS rostral to bregma, within cortical band along sagittal suture (area 6) evoked mostly ipsilateral MRs of vibrissae and upper lip, more often from the left hemisphere. MRs of the lower jaw, tongue and larynx were induced by ICMS in symmetrical zones of both hemispheres. The lowest thresholds of ICMS, 2-20 mcA, were revealed at the depth from 0.8-1.1 mm up to 1.3-1.7 mm, i. e. in layers III and V. Short-latency (from 10 to 25 ms) MRs of the vibrissae, lip and jaw were evoked by high-frequency volleys of 2 to 5 pulses. The participation of some oligosynaptic components in cortico-facial descending projections in the white mouse is supposed.     

Restructuring of the topical organization of the rat motor cortex after damage to the opposite hemisphere

Topical organization of the motor cortex was compared in outbred rats by the method of intracortical microstimulation in the norm and in different periods after unilateral partial decortication of the motor projection (MP) of the hind-leg. Stable state of the MPs of the fore- and hind-limbs was in the norm, and within their bounds there was an individual variability of MP zones of separate joints. After the operation, the reconstruction of the motor cortex organization in the opposite hemisphered appeared in later periods, in 5-7 months. Expansion was observed of the boundaries of the excitable area in caudal direction and reduction of the part of responses of the limbs distal muscles as compared to proximal ones and of the body muscles. 8-16 months after the operation, the reactions of axial muscles, including the ipsi- and bilateral ones, became more expressed.